OIE Statement On Live Markets And H7N9

Credit Dr. Ian MacKay Virology Down Under 

 

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H7N9 is genetically a `bird flu’, but one of the ongoing mysteries in the H7N9 outbreak in China is how – with more than 125 people infected - only 46 positive virus samples have been detected out of nearly 70,000 tests conducted on poultry and their environment.

 

Thus far, the virus has not been detected on farms or commercial poultry operations, only in a handful of samples taken from live bird markets.

 

Today, the OIE – which has been in meetings with China’s Ministry of Agriculture – released  a press release on the H7N9 outbreak and the role they suspect that live-market birds may play in its spread.

 

Utilizing phrases  like `the team made the hypothesis’, `The experts believe’ and `live bird markets may play a key role’ – it is pretty obvious that major gaps remain in our understanding of how this virus is spreading and infecting humans.

 

The available data remains sparse and incomplete, and a lot of it – frankly – still doesn’t fit together particularly well. All of which helps explain the lack of certainty.

 

This from the OIE newsroom.

 

OIE expert mission finds live bird markets play a key role in poultry and human infections with influenza A(H7N9)

Paris, 30 April 2013 – The Ministry of Agriculture of the People’s Republic of China asked the Director General of the World Organisation for Animal Health (OIE) to send OIE experts to assess the situation with influenza A(H7N9) in animals and provide advice.

 

The mission took place in the spirit of the Tripartite framework between the OIE, the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) of the United Nations. The WHO was leading a mission the week before in collaboration with the Chinese Ministry of Health, while FAO is represented in the country by its local officer, a veterinary doctor who provided support.

 

The OIE appreciated the availability and transparency of the Chinese authorities in sharing important information, acknowledged the rapid and considerable response made by the Veterinary services to investigate the animal source of human infections, and recognised their efforts to keep the international community informed about the disease situation, including official notifications to the OIE World Animal Health Information System (WAHIS).

 

According to the information and data collected, the mission confirms that many of the human cases of H7N9 appear to have a link with live bird markets. To date no human cases or animal infections of H7N9 have been detected on poultry farms. During the mission the team made the hypothesis that people could be infected through exposure to infected birds in markets or to a contaminated environment such as live poultry markets where virus is present.

 

The experts believe that live bird markets may play a key role in human and animal infections with H7N9 and that, even if the overall level of infection is relatively low (having not been detected yet in poultry farms), live bird markets provide an environment for amplification and maintenance of the H7N9 virus. Collaboration between human health and animal health sectors is useful to better understand transmission to humans.

 

The mission also confirms that currently infection with H7N9 does not cause visible disease in poultry therefore Veterinary Services must be especially involved in preventing its further spread in poultry, particularly through the supervision of the implementation of biosecurity measures on farms.

 

“Compared with H5N1, at this moment in time H7N9 is not pathogenic to poultry so there are no visible signs of infection, which makes surveillance, prevention and control of the virus in poultry a great challenge”, Dr Keith Hamilton, member of the OIE team, explained.

 

Because H7N9 infection is unlikely to show visible signs of disease in poultry, the use of reliable and accurate laboratory tests, complying with OIE Standards and guidance from OFFLU, will underpin surveillance and control of the H7N9 virus in poultry. OFFLU is the FAO/OIE global network of scientific expertise on animal influenza.

 

An extensive surveillance programme in animals is essential to establish the full extent and distribution of the H7N9 virus in the whole country. Effective surveillance will require cooperation between poultry owners and distributors and government Veterinary Services. Veterinary Services including laboratories will need appropriate resources for that purpose.

 

OIE Reference laboratories for avian influenza, including Harbin Veterinary Research Institute, other laboratories in China, as well as scientists of OFFLU  are conducting research on H7N9 to better understand the characteristics of this virus and to ensure that more appropriate diagnostic testing protocols are publicly available.

 

Recommendations

 

In case of outbreaks, destruction of infected poultry by Veterinary Services as well as poultry that have been in contact with infected birds is recommended. Culling of at risk-animals must be done following requirements for acceptable killing methods as described in the OIE Code.

 

There is no evidence to suggest that the consumption of poultry or eggs fit for human consumption could transmit the AI virus to humans. It is safe to eat properly prepared and cooked meat and eggs. Specific precautions when plucking poultry are recommended.

 

More assessment is needed to swiftly know whether poultry vaccination could be considered as an efficient control option for H7N9. It will be also important to verify whether the H7N9 virus is transmissible from humans to animals because if established, it could be a potential channel for the global spread of the virus.

 

Trade

 

Preventing the national and international spread of the H7N9 virus must be a priority.

 

The strict application by local and national veterinary authorities of Member Countries of OIE science-based standards published in the OIE Terrestrial Animal Health Code (volume 2; chapter 10.4) can prevent spread of the virus from infected poultry. These standards apply to international trade in live poultry, poultry meat, eggs and even feathers.

 

The application of these international standards also prevents imposition of unjustified trade barriers by importing countries. Controlling illegal trade must also be a priority.

 

 

For more from the OIE on this H7N9 virus, you may wish to visit their FAQ.

 

Questions and Answers on influenza A(H7N9)

Hong Kong: SCEZD Risk Assessment On H7N9

Fever Checks At Hong Kong School – Credit HK Govt.

 

 

# 7208

 

 

Two related stories out of Hong Kong this morning.

 

First, the risk assessment from Hong Kong’s SCEZD (Scientific Committee On Emerging And Zoonotic Diseases) on the emerging H7N9 virus, and then some basic hygiene advice from Dr Leung Ting-hung to the public on preventing the spread of the virus.

 

Although considerably more restrained than the risk assessment recently published in the Chinese Science Bulletin: Early H7N9 Risk Analysis, the SCEZD concedes that additional human infections, and expansion of the this outbreak are both likely, and that while, ` . . .  risk of human-to-human transmission appears to be low, the actual risk is currently unknown . . . ‘

 

One should not be deceived by their seemingly low-keyed approach, as Hong Kong’s CHP has a lot of experience dealing proactively with emerging infectious disease outbreaks. Their bitter experience with SARS in 2003 (see SARS And Remembrance) pretty much ensures that they take this H7N9 threat very seriously.

 

 

30 April 2013

Scientific Committee on Emerging and Zoonotic Diseases meets on risk assessment and local response to human infection of avian influenza A(H7N9) virus 

The Scientific Committee on Emerging and Zoonotic Diseases (SCEZD) of the Centre for Health Protection (CHP) of the Department of Health today (April 30) convened a meeting to assess the risk and local response in view of the recent human cases of avian influenza A(H7N9) in the Mainland.

 

The SCEZD reached a consensus view that the emergence of human infections with the novel avian influenza virus reported in the Mainland since March 31 is of concern as further human sporadic infections and expansion of geographic spread in the Mainland and other countries/areas is anticipated.

 

At the meeting, the members of the SCEZD agreed that the current epidemic strain of the avian influenza A(H7N9) virus is a novel reassortant avian influenza virus which does not cause illnesses in birds, but has gained some abilities to cross species barriers, causing sporadic poultry-to-human transmission which may result in severe disease in infected people. Genetic and epidemiological findings showed that patients are likely to be infected through exposure to infected poultry or its contaminated environment such as wet markets. However, the exact source and mode of spread still require further investigations.

 

While family clusters of infection suggest that limited human-to-human transmission may have occurred in close contacts, exposure to a common source can also be one of the explanations. Hence, the members are of the view that there is no evidence of sustained human-to-human transmission at present but the main concern is whether the virus will further adapt to enable efficient human-to-human transmission, which may result in a pandemic.

 

Turning to the local response, the SCEZD concurred with the view that the enhanced preventive and control measures for human infection with avian influenza should be continued. Surveillance for human avian influenza A(H7N9) infection is crucial. Although the risk of human-to-human transmission appears to be low, the actual risk is currently unknown and control measures, such as appropriate infection control precautions, isolation of suspected cases and quarantine of close contacts of confirmed cases, should be enforced.

 

As for treatment of patients infected with the avian influenza A(H7N9) virus, the members considered that the avian influenza A(H7N9) virus is expected to be sensitive to the neuraminidase inhibitors, oseltamivir (Tamiflu) and zanamivir (Relenza). Confirmed or highly suspected cases should receive antiviral treatment with a neuraminidase inhibitor as early as possible.

 

The SCEZD also recommends to continue intensive surveillance for avian influenza A(H7N9) virus infection in both humans and poultry/birds; maintain a high level of alert, preparedness and response for avian influenza A(H7N9) virus infection; strengthen publicity and public education on the prevention of the disease; and maintain close liaison with international and Mainland health authorities and local academics to monitor the latest developments. In addition, the SCEZD agrees that further studies should be carried out to fill the knowledge gaps and close monitoring of the progress of development of an H7N9 vaccine is required.

Ends/Tuesday, April 30, 2013

 

 

In a related press release, Hong Kong’s Health chief, Dr Leung Ting-hung, upon leaving this meeting called for strict personal and environmental hygiene in the coming months to prevent the spread of the virus.

 

Health chief urges strict hygiene

April 30, 2013

Centre for Health Protection Controller Dr Leung Ting-hung has called for strict personal and environmental hygiene, as the next six months will be critical in the development of the avian influenza A(H7N9) virus.

 

He made the appeal after today's Scientific Committee on Emerging & Zoonotic Diseases meeting, with its Chairman Prof Yuen Kwok-yung.

 

They said while the public should not be overly worried about the situation, the possibility of H7N9 being imported to Hong Kong from the Mainland cannot be ruled out, so people should maintain good personal hygiene by washing hands frequently especially before touching their eyes, nose and month, and to avoid contact with live poultry.

 

Dr Leung said the coming months will be critical in the virus' development, and it cannot be predicted whether and when it will be transmitted among humans, therefore good personal and environmental hygiene must be kept at the highest standard at all times.

 

He said measures are already in place against any possible H7N9 case spreading in Hong Kong, including stringent monitoring of suspected cases and strengthening exchange of information with international and Mainland health organisations and authorities.

 

A working group will formulate medical strategy and make suggestions to frontline doctors on how to treat such cases.

 

More manpower has been deployed to boundary checkpoints to monitor the body temperature of travellers.

 

Prof Yuen said so far the genetic and epidemiological data indicates low efficiency in human to human transmission of the virus. However, as H7N9 does not kill poultry, it has been difficult to monitor, adding public vigilance must be maintained.

Australia Reports Flu Vaccine Shortages

Mash up of U.S. Flu seasons from Multiple FluView Reports

 

# 7207

 

Having watched the United States come off perhaps the worst flu season in a decade – one that particularly impacted the elderly - and with early flu cases already showing up across Australia, and it is no surprise that the demand for the seasonal flu jab has skyrocketed down under.

 

Australia’s NCIRS (National Centre for Immunisation Research & Surveillance) urges broad based vaccination each year (see below), but the uptake of the vaccine rarely exceeds 20% of the population.

Since vaccines take months to prepare, quantities must be ordered well in advance. This year, based on previous vaccine uptakes, Australia ordered about 4 million doses.

 

While flu season generally doesn’t get started in earnest in the Southern Hemisphere until June, early flu cases are making headlines, and the demand for flu vaccines has outstripped the supply.

 

This report from Ninemsn.

 

Australia suffers flu vaccine shortage

Alys Francis, ninemsn

April 30, 2013

Australia is suffering a nationwide shortage of flu vaccine due to unprecedented demand from people seeking immunisation, the federal health department has warned. A department spokesperson told the Daily Telegraph the shortage could last until June if the high demand continued.

 

"Demand for seasonal influenza vaccine usually drops off in April but this has not occurred this year and it is difficult to know if the demand will continue through to the end of April and May," the spokesperson said.

 

They said the department had purchased extra vaccines for the National Immunisation Program, which provides free vaccines to those most vulnerable from flu, including pregnant women, and elderly and indigenous people.

 

bioCSL, Australia’s vaccine supplier, announced today they will resume production, and hope to have more vaccine available in 4 to 6 weeks.

 

bioCSL Goes Back into Influenza Vaccine Production for Australia

Melbourne, Australia — 30/04/2013

bioCSL announced today that it has recently restarted production of influenza vaccine for the Australian market in response to higher than expected demand this season.

 

Additional doses are expected to be ready for delivery by the end of May and will be prioritised for age-appropriate at-risk groups under the National Immunisation Program.

 

bioCSL General Manager, Dr John Anderson said the demand for influenza vaccine had increased significantly in the first two weeks of April in both the public and private markets.

 

“All our customers are reporting a much earlier and much higher uptake of influenza vaccine this year, compared to the last few years.”

 

bioCSL is the only manufacturer of influenza vaccine in the Southern Hemisphere and is a major supplier of seasonal and pandemic influenza vaccines to the Australian market. The company also supplies influenza vaccine to overseas markets including the US, UK and New Zealand.

 

 

For many people, getting the flu vaccine each year is an impulse decision - based on their perception of the risk during any given flu season - rather than a routine, yearly preventative step.

 

Which makes trying to figure out what the public’s demand for the vaccine will be – six months in advance – pretty much a crap shoot.

Chinese Science Bulletin: Early H7N9 Risk Analysis

 

Heat map – Credit Laidback Al  FluTrackers

 

 

# 7206

 

From the open access journal Chinese Science Bulletin, we’ve an early epidemiology and risk analysis of the emerging H7N9 virus in China that paints a particularly worrisome picture of where these authors believe this outbreak might be headed.

 

 

Epidemiological and risk analysis of the H7N9 subtype influenza outbreak in China at its early stage

ZHUANG QingYe, WANG SuChun, WU MeiLi, LIU Shuo, JIANG WenMing, HOU GuangYu, LI JinPing, WANG KaiCheng, YU JianMin, CHEN JiMing & CHEN JiWang

1 China National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center, Qingdao 266032, China;
2 China National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center, Qingdao 266032, China;
3 The Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, IL 60612, USA

Received April 11, 2013; accepted April 23, 2013

Dozens of human cases infected with H7N9 subtype avian influenza virus (AIV) have been confirmed in China since March, 2013. Distribution data of sexes, ages, professions and regions of the cases were analyzed in this report.

 

The results showed that the elderly cases, especially the male elderly, were significantly more than expected, which is different from human cases of H5N1 avian influenza and human cases of the pandemic H1N1 influenza.

 

The outbreak was rated as a Grade III (severe) outbreak, and it would evolve into a Grade IV (very severe) outbreak soon, using a method reported previously. The H7N9 AIV will probably circulate in humans, birds and pigs for years. Moreover, with the driving force of natural selection, the virus will probably evolve into highly pathogenic AIV in birds, and into a deadly pandemic influenza virus in humans.

 

Therefore, the H7N9 outbreak has been assumed severe, and it is likely to become very or extremely severe in the future, highlighting the emergent need of forceful scientific measures to eliminate any infected animal flocks. We also described two possible mild scenarios of the future evolution of the outbreak.

 

(Continue . . .)

 

While conceding that this virus could `disappear naturally, or maintain its low pathogenicity in birds and limited transmission ability in humans for a long period’, the authors articulate eight reasons why they believe this outbreak poses – in their words – an `enormous risk’.

 

Rather than mangle their work by selectively excerpting pieces, I’ll invite you to follow the link to read this analysis in its entirety. 

 

I suspect that this paper will induce a fair amount of heartburn among Chinese officials who are trying to reassure the public over this outbreak.  

 

As to whether these researchers have got this analysis right?

 

I believe they make some very good points, but that’s really above my pay grade. Besides, I make it a practice not to try to predict what flu viruses are apt to do.

 

I simply accept that novel flu viruses are unpredictable, and fully capable of wreaking havoc on a global scale, and so they ought not be underestimated.

 

Which is precisely why the CDC, along with other public health agencies, are taking prudent steps towards increasing their pandemic preparedness (see H7N9 Preparedness: What The CDC Is Doing).

Not because they are necessarily convinced that this virus will spark the next pandemic.

 

But because they know it could.

WHO H7N9 Update – April 29th

 

 

# 7506

 

The World Health Organization has published their latest GAR (Global Alert & Response) update on the H7N9 outbreak in China, which adds 17 new laboratory confirmed cases since their last update on April 25th.

 

 

Human infection with avian influenza A(H7N9) virus – update

29 April 2013 - 29 April 2013 - As of 29 April 2013 (16:30CET), the National Health and Family Planning Commission, China notified WHO of an additional 17 laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus.

The patients include:

• A 38-year-old man from Zhejiang province who became ill on 18 April 2013;
• an 80-year-old man from Fujian province who became ill on 17 April 2013;
• an 80-year-old man from Jiangxi province who became ill on 21 April 2013;
• a 31-year-old woman from Jiangxi province who became ill on 23 April 2013;
• a four-year-old boy from Shandong province who became ill on 27 April 2013;
• a 54-year-old man from Jiangxi province who became ill on 15 April 2013;
• a 64- year-old woman from Hunan province who became ill on 14 April 2013;
• a 38-year-old man from Zhejiang province who became illness on 17 April 2013;
• a 49-year-old man from Jiangsu province who became ill on 17 April 2013;
• a 36-year-old man from Jiangsu province who became ill on 19 April 2013;
• a 60-year-old man from Jiangsu province who became ill on 8 March 2013;
• a 65-year-old man from Fujian province who became ill on 18 April 2013;
• a 69-year-old man from Jiangxi province who became ill on 17 April 2013;
• a 76- year- old woman from Jiangxi province who became ill on 19 April 2013;
• a 60-year- old woman from Zhejiang province who became ill on 17 April 2013;
• a 50-year-old woman from Zhejiang province who became ill on 18 April 2013; and
• a 56-year-old man from Henan province who became ill 17 April 2013.

Additionally, two patients earlier reported from Jiangsu province died.

 

To date, a total of 126 laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus including 24 deaths have been reported to WHO. Contacts of the confirmed cases are being closely monitored.

 

The authorities in the affected locations continue to implement prevention and control measures.

 

Investigations into the possible sources of infection and reservoirs of the virus are ongoing. Until the source of infection has been identified and controlled, it is expected that there will be further cases of human infection with the virus.

 

So far, there is no evidence of sustained human-to-human transmission.

 

WHO does not advise special screening at points of entry with regard to this event, nor does it recommend that any travel or trade restrictions be applied.

H7N9: CFR Considerations

Credit Ian Mackay VDU

 

 

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Over the weekend we saw a few hyperbolic headlines suggesting the H7N9 virus may be the `Deadliest’ bird flu ever, but the reality is, we haven’t enough data to begin to arrive at a reasonable estimate of its CFR (case fatality ratio).  

As of today, out of 126 cases, the Flu Wiki lists 24 deaths, while 22 have been treated and discharged from the hospital.

 

Another 79 cases remain hospitalized, some reportedly still in serious condition after several weeks of treatment. 

 

 

At this time we don’t know how many of those currently hospitalized will recover, and – just as importantly - how many additional `mild’ cases might be out there that have not been diagnosed and counted.

 

Dr. Ian MacKay’s  Virology Down Under  H7N9 website provides excellent commentary and graphs, including this one which deals with the `apparent CFR’ of the virus.

 

I use the word `apparent’ because we are dealing with incomplete data.

 

Right now, it sits at roughly 20%.

 

Dr. Mackay describes the `denominator problem’ (the total number of infected), this way:

 

Obviously, if the denominator is small (like it is now with so few cases and testing regents only just becoming widely available), then we see high proportions (percentages) of severe disease (x severe cases over a small number of total cases is a high proportion).

 

If there are mild cases of avian influenza A(H7N9) virus infection out there (as we have seen today, 15.04.13) and they are in large numbers, that denominator could be much larger and the severe disease cases will be "diluted" down to a smaller proportion (x severe cases over a large number of mild and severe total cases is a low proportion).

 

 

So, the big question is, are the 125 cases we’ve seen to date a fair representation of true spread of this virus, or are only `sickest of the sick’ showing up at the hospital?

 

If, as Hong Kong scientists predicted last week (see H7N9: Trying To Define The Size Of The Iceberg), there are actually twice as many cases out there than have been identified, then the `apparent’ CFR would be cut in half.

 

Of course, there could be uncounted deaths due to H7N9, attributed to other causes, as well.  And they would serve to drive the CFR higher (if we knew about them, that is).

 

Figuring out the mortality rate from influenza remains a complex and controversial task. One that has sparked heated academic debate, which I’ve written about in the past:

 

• The H5N1 virus (see The Great CFR Divide)
• The 2009 H1N1 pandemic virus (see Lancet: Estimating Global 2009 Pandemic Mortality)
• Seasonal flu in the United States (see MMWR: Estimates Of Yearly Seasonal Influenza Deaths)

There are still debates – 95 years after the fact – over just how many people were killed during the 1918 Spanish flu.  Estimates range from about 40 million, up to 100 million.

 

Similarly, the 1957 pandemic is said to have killed between 2 million and 4 million globally, and to have caused about 70,000 deaths in the United States.

 

But nobody really knows.

 

For now, it is safe to say that the H7N9 virus appears to produce severe, and all-too-often fatal illness in a significant portion of the people it infects.

 

But whether we are seeing 80%, 50%, or only 10% of the cases out there is unknown.

 

While we bandy numbers like 20% and 60% CFR (for H5N1) around, it is worth remembering that the  worst pandemic on record – the 1918 Spanish Flu – had a highly variable fatality rate as it spread around the globe (see Study: Impact Of 1918 Pandemic In Mexico).

 

Its global CFR has been estimated at about 2.5%, but in 2006 in a Lancet journal (doi:10.1016/S0140- 6736(06) 69895-4) article cited as much as a 30-fold difference in mortality rates around the world:

 

Estimation of potential global pandemic influenza mortality on the basis of vital registry data from the 1918—20 pandemic: a quantitative analysis

Christopher JL Murray , Alan D Lopez , Brian Chin , Dennis Feehan , Kenneth H Hill

Excess mortality ranged from 0·2% in Denmark to 4·4% in India. Since there was some under-registration of mortality in India, total pandemic mortality could have been even higher.

 

Illustrating nicely just how variable the impact an emerging influenza virus can have, depending on things like geography, genetics, nutrition, healthcare standards, climate, locally circulating clades, and no doubt other factors that have yet to be identified.

 

While I expect we’ll get a better handle on the attack rate and CFR of this virus in the coming weeks, no one should get too comfortable with these numbers.

 

Influenza viruses have an amazing capacity to mutate and change (for better or worse), meaning the virus we see today may act little like the virus that we see next week, next month, or next year.

 

Stay tuned.

H7N9: Hong Kong’s Revised Reporting Criteria

Taiwan Intl Airport – Credit China News Agency

 

# 7204

 

 

Yesterday, in H7N9: Fujian Province Reports Second Case, I posed the question : `exactly what criteria is being used (in China) to decide whether to test patients for the H7N9 virus?’

 

While the answer to that question remains elusive on the Mainland, I have run across revised criteria -issued late last week to doctors and hospitals - in Hong Kong.

 

As of today, Hong Kong’s Centre for Health Protection  has received notification of 18 cases that fulfill their reporting criteria for suspected H7N9 infection, but as of yet, none have tested positive for the virus.

 

Reporting criteria for Human Influenza A (H7N9) infection

 
(Last updated on 25 April 2013)

An individual fulfilling both the Clinical Criteria AND Epidemiological Criteria should be reported to CHP for further investigation.

Clinical Criteria

Patient with

• influenza-like-illness (fever >38 oC with cough or sore throat); OR
• person with severe pneumonia; OR
• person died of unexplained acute respiratory illness.

Epidemiological Criteria

One or more of the following exposures in the 10 days prior to symptom onset:

• contact with a human case of influenza A (H7N9); OR
• contact with poultry or wild birds or their remains or to environments contaminated by their faeces in countries/areas with documented avian influenza A (H7N9) infection in birds and/or humans in the recent 6 months (see List of affected areas); OR
• consumption of raw or undercooked poultry products in countries/areas with documented avian influenza A(H7N9) infection in poultry and/or humans in the recent 6 months (see List of affected areas), OR
• close contact with a confirmed influenza A(H7N9) infected animal other than poultry or wild birds; OR
• worked in a laboratory that is processing samples from persons or animals that are suspected from avian influenza infection

The list of affected areas is regularly uploaded to the Centre for Health Protection (CHP) website
(http://www.chp.gov.hk/files/pdf/global_statistics_avian_influenza_e.pdf

 

While an argument could be made for broader testing – with no evidence of H2H spread, and no cases reported in humans or poultry in Hong Kong – the requirement for a plausible route of exposure is not unreasonable.

 

Exactly what criteria is being used in Mainland China - in provinces where the virus has already been detected - isn’t clear. 

 

This latest letter to doctors also extends the incubation period of the virus to 10 days.

 

In view of the latest best available evidence, the longest incubation period of human infection with avian influenza A(H7N9) virus has been revised from 7 days to 10 days and the epidemiological criteria of the reporting criteria has been revised accordingly (see attached). Please also note that Taiwan has not been included as an affected area as the case recorded was classified as an imported infection

 

This week, Hong Kong – along with Mainland China and many other nations – celebrates Labor Day (May 1st).  Each year, millions of visitors from the mainland pour into Hong Kong during this `golden week’ to shop, and to visit.

 

While an economically important period for businesses in Hong Kong, this year, concerns over the possible importation of the H7N9 virus run high.

 

For more on this, the Wall Street Journal has details on Hong Kong’s plans to thwart the viruses’ arrival.

 

 

Hong Kong Steps Up Flu Fight

• Updated April 28, 2013, 3:38 p.m. ET

Hong Kong immigration and hospital officials are stepping up efforts to fend off the spread of H7N9 bird flu, which surfaced outside China for the first time last week, as floods of mainland Chinese tourists descend on Hong Kong for the Labor Day holiday.

 

The government is deploying greater manpower at the border at the mainland Chinese city of Shenzhen, one of the busiest border crossings in the world, to screen travelers for elevated body temperatures, and tour operators are being urged to monitor the condition of individual tourists.

 

(Continue . . .)

Shandong Province: 2nd Family Member Tests H7N9 Positive

 

Shandong Province – Credit Wikipedia

# 7203

 

The case reports continue to trickle out of China today, with word of a fifth case from Shandong Province; a 4 year-old who is the child of the first case, reported on Tuesday (see H7N9: Shandong Case Confirmed).

 

While epidemiologically linked, officials state that there is no evidence of H2H (human-to-human) transmission.

 

This report (h/t Diane Morin on FluTrackers)  from Xinhua News.

 

In Shandong, experts confirmed an H7N9 bird flu case in the city of Zaozhuang on Sunday. The patient, a four-year-old boy surnamed Zhang, developed a fever on Saturday.

 

The boy is the son of Shandong's first confirmed H7N9 patient. But initial investigation found no evidence of human-to-human infection, according to a statement from the provincial public health department.

 

The statement said the boy is in stable condition.

 

As we’ve seen in the past, when it comes to proving human-to-human transmission of a virus, the bar is usually set pretty high.

 

If there are other, equally plausible explanations – such as a common environmental exposure – then H2H transmission cannot automatically be assumed.

 

But even if H2H did occur, we’ve seen other instances of that before with this virus (and with H5N1) – where no additional cases were detected  - and so one shouldn’t read too much into it. 

 

Here is the World Health Organization’s messaging on family clusters, from a little more than a week ago.

 

 

 

Next, the syntax challenged announcement from the Shandong department of Health, then a few more excerpts from the Xinhua report.

 

 

Shandong Province new case of human infection of H7N9 avian influenza cases

[2013-04-28]

April 28 , Shandong new case of human infection of H7N9 avian influenza confirmed cases. Children Zhang, male, 4 years old, live in Zaozhuang City Central, the father of Shandong Province, the first case of human infection with the H7N9 avian influenza confirmed cases.

 

April 27 Fever symptoms in children, 28 provincial-level expert group according to the results of laboratory tests and clinical manifestations and epidemiological investigation, the overall judgment that the human infection in children with confirmed cases of the H7N9 avian influenza.

 

Currently, children with the disease is still stable, Zaozhuang City, a hospital for treatment. According to the initial findings and conclusion of the study at home and abroad, has not yet found evidence of infection. Up to now, Shandong Province reported a total of human infection with the H7N9 avian influenza confirmed cases of two cases.

 

 

From Xinhua News:

 

More H7N9 cases reported in China

Xinhua English

BEIJING, April 28 (Xinhua) -- Five more H7N9 bird flu cases were confirmed Sunday in four Chinese provinces, according to local health authorities.

 

The latest confirmed cases came from east China's Zhejiang, Jiangxi and Shandong provinces, as well as southeast China's Fujian Province.

 

<SNIP>

 

Xu Jianguo, a researcher with the Chinese Center for Disease Control and Prevention, said on Sunday that the chance of a major H7N9 outbreak is slim, although the situation must not be taken lightly and monitoring should be intensified.

 

"The biggest technical obstacle for prevention is that we don't know where the virus-carrying birds are or where they will go," Xu said, adding that the epidemic is not likely to disappear soon.

 

Xu said human infections are not related to seasonal changes.

 

He called for focusing on effective efforts to control sources of infection

H7N9: Fujian Province Reports Second Case

 

Fujian Province – Credit Wikipedia

 

 

# 7202

 

 

Fujian Province, which recorded its first H7N9 case two days ago (see H7N9: Fujian Province Reports First Case) reports a second infection today on their Provincial Health Department website.

 

 

Fujian new case of human infection of H7N9 avian influenza confirmed cases

 

Fujian Provincial Health Bureau Bulletin, April 28, Fujian new case of human infection of H7N9 avian influenza confirmed cases as of April 28 at 18 pm. Up to now, the province has found two cases of human infection with the H7N9 avian influenza confirmed cases with no deaths. Not found an epidemiological association between the two cases.

 

Newly discovered patients are as follows:

 

Patients travel a male, aged 80, Fuzhou,, Yang Fuqing City, the town of farmers. At 9:40 on April 27 patients chief complaint of "repeated coughing for 10 days, two days of fever, wheezing, shortness of breath long time" treatment in Fuqing City Hospital.

 

At 14:40 on the 28th, Fujian Center for Disease Control reports the results of laboratory tests for the H7N9 avian influenza virus nucleic acid positive. In accordance with the relevant requirements, in the afternoon of the 28th, the Fujian Provincial Health Bureau organized the provincial-level expert group to discuss the cases, the experts based on the clinical performance of laboratory testing and epidemiological data, the diagnosis of the cases of human infection of H7N9 avian influenza confirmed cases . At present, the case is in critical condition, being active treatment.

 

After investigation, the close contacts of the cases of a total of 33 people, abnormalities were found so far. (Provincial Health Department Information Office)

 

One of the unknowns in China’s surveillance is exactly what criteria is being used to decide whether to test patients for the H7N9 virus.  We’ve seen some media reports of people being refused testing, because they didn’t fit the `case definition’.

It is always a balancing act. 

 

If you try to test everyone with flu-like symptoms, you risk inundating your testing facilities.

 

If you test based on severity, or patient contact history, then you risk missing mild (or atypical) cases.

 

Another unknown is exactly how samples are being collected (throat swab or sputum), and how rigorous the testing really is. In Indonesia, we often saw repeated negative H5N1 test results before a patient was finally proved infected.

 

Yesterday, Taiwan announced new, more stringent testing recommendations after their first patient tested negative twice before finally producing a positive result.

 

Also new, is the announcement that the incubation period for this virus may be as great as 10 days, roughly three times longer than typically seen with seasonal flu.

 

This from the Taipei Times.

 

CDC updates testing directives for H7N9 avian flu

UPDATED:Based on international research, the incubation time of the H7N9 avian influenza has been increased to 10 days from the previous seven days, a physician said

 

By Alison Hsiao  /  Staff reporter

The Centers for Disease Control (CDC) yesterday updated H7N9 avian influenza virus testing directives for hospitals following the first confirmed H7N9 infection in Taiwan, whose throat swab samples tested negative twice for the virus before the infection was finally confirmed via sputum specimen testing.

 

<SNIP>

 

CDC physician Philip Yi-chun Lo  said the center now advises hospitals to obtain sputum samples from suspected cases that have coughed up phlegm, recently had pneumonia or exhibited other symptoms.

 

Lo said that based on the latest international research on H7N9 avian influenza, the virus’ estimated incubation period has been increased to 10 days from seven days.

 

“This change will affect the time needed to conduct self-health management for those who have come into close contact with an infected patient. They now have to be followed closely by health authorities until Tuesday, three days longer than the previously stated,” Lo said, adding that the three contacts who exhibited upper respiratory symptoms are recovering and all the other contacts have not exhibited any symptoms.

(Continue . . .)

China’s Premier On H7N9

 

 

Credit Wikipedia

 

# 7201

 

 

Li Keqiang, China’s second highest ranking official (after President Xi Jinping), ascended to office on March 15th, 2013 after spending more than 4 years as Executive Vice-Premier under then-Premier Wen Jiabao.

 

Li, who became governor of Henan Province in 1998, inherited an HIV blood bank scandal that resulted in the deaths of as many as 100,000 people.

 

While most of the infections occurred before he took office, Li was roundly criticized for his passive handling (and attempts of covering up) the fallout from the crisis.

 

Remarkably, Li has managed to rise to the rank of Premier despite a longstanding reputation for `bad luck’.

 

As governor of Henan Province he saw a series of disasters on his watch, including the shopping mall fire in Luoyang which killed more than 300 on Christmas day in 2000.

 

Five years later, when he was party secretary of Liaoning province, a mine explosion claimed 214 lives.

 

For more, CNN has a detailed history of his career.

 

In what may feel like a case of déjà vu for Li, just two weeks after assuming his new office news of another public health crisis – the H7N9 virus - emerged from China.

 

This time, in contrast to his more passive handling of earlier crises, Li appears willing to get visibly out in front of this outbreak.

 

Yesterday Li visited China’s CDC, and warned that while countermeasures appear to be working, that officials must be prepared for any possible development.

 

 

Chinese premier stresses vigilance against H7N9

 

English.news.cn | 2013-04-28 15:30:25 

BEIJING, April 28 (Xinhua) -- Premier Li Keqiang on Sunday urged authorities to be vigilant against the H7N9 avian flu virus and prepare themselves for any new developments.

 

"Countermeasures have been effective so far, but the situation is still developing as new cases turn up," he said while visiting the Chinese Center for Disease Control and Prevention (CDC).

 

"We cannot afford to take it easy or relax, as we are facing a new virus," he said. "We should be prepared for any possible development."

 

Li urged health departments to find the source of the infections and step up research on the virus.

 

More efforts should be made to diagnose and treat infected people as early as possible, he said.

 

Li pledged to spare no efforts in treating infected patients and reducing casualties.

 

"We will make sure no patients have to deal with delayed treatment because of costs," he said.

 

Li said the government will continue to cooperate with international organizations, release information openly and improve public awareness of the virus.

(Continue . . . )

 

 

Unlike most of China’s leadership, Li reportedly speaks fluent English.

H7N9: Jiangxi, Zhejiang Reports New Cases

 

# 7200

 

It’s now been a (very long) month since we first learned of the emerging avian H7N9 virus which killed two men from Shanghai in early March. Since then – while the case count has skyrocketed past 120 and our knowledge of this virus has increased - our understanding of how it spreads remains incomplete.

 

Over the past couple of days, the number of new cases has dropped, which some are attributing to live-market control efforts. At the same time the number of provinces reporting the virus continues to increase.

 

As everything we learn must be filtered through a state sponsored media, or gleaned from often kludgy machine translations of provincial health department postings, it is impossible to know how much of the `big picture’ we are actually seeing.

 

Confusing matters, Beijing announced on the 24th that China To Update H7N9 `Case Information’ On Weekly Basis, yet we continue to see sporadic cases reported by individual provinces.

 

That said, we have reports of three new cases so far this morning - two in Jiangxi province, and one in Zhejiang – bringing China’s official count to 124 cases (+1 asymptomatic case in Beijing).

First stop, this report from Xinhua News, which unfortunately lacks crucial details, such as onset dates.

 

Jiangxi new cases of human infection of H7N9 avian influenza confirmed cases

April 28, 2013 12:48:40
Source: Xinhua

Xinhua Nanchang, April 28 (Reporter Hao Liang)

Jiangxi Provincial Health Department Bulletin, 28, Jiangxi Province, two cases of new confirmed cases of human influenza H7N9 avian influenza.

 

Patient Xiong, male, 80 years old, Nanchang, Jiangxi, farmers, home raising chickens poultry. Now Nanchang a hospital for treatment. Patients are in stable condition, close contacts have been implemented under medical observation, yet found an exception.

 

Xu patients, female, 31 years old, Nanchang County, individual vegetable vendors, stalls next to chicken and poultry sales pitch. Now Nanchang a hospital for treatment. Patients are seriously ill, 11 close contacts have been implemented under medical observation, yet found abnormal.

 

<SNIP>

 

Up to now, Jiangxi Province, a total of five cases of confirmed cases of human infection with the H7N9 avian influenza are in the hospital receiving treatment, all close contacts of the patient's medical observation are not yet found an exception.

 

From the Zhejiang Provincial Health Department, which has reported the most cases to date (n=46), we get this report on a single new case.

 

Zhejiang new case of human infection of H7N9 avian influenza cases

Date :2013-04-28
Sources: Health Department
 

Zhejiang Provincial Health Department Bulletin, April 28 as of April 28 at 15:00, Zhejiang new case of human infection with H7N9 avian influenza.

 

Patient Xu, male, 38 years old, farmers, and now lives in Hangzhou, onset on April 18, Hangzhou, a hospital for treatment.

 

Detected by the provincial CDC, the patient specimens of human infection of H7N9 avian influenza virus nucleic acid positive. My Office experts on the patient's clinical manifestations, epidemiological data and laboratory test results are discussed, and diagnosis of human infection of H7N9 avian influenza confirmed cases. Currently, the patient is seriously ill, the hospital is under active treatment.

 

Present, the province a total of 46 cases of human infection with the H7N9 avian influenza confirmed cases, 6 cases died of his wounds, 9 patients recovered and discharged from hospital, the existing 31 patients in hospitalization, my Office will fully organize the rescue work.

 

Our last stop is a recap by Xinhua news, that provides running counts for each province.

A total of 124 diagnosed with the H7N9 avian influenza which 23 people died

2013-04-28 17:23 Source: China National Radio

 

Network Beijing on April 28, Zhejiang Provincial Health Department informed today (28), as of 15:00 today, Zhejiang new case of human infection with H7N9 avian influenza. Patients Xu, male, 38 years old, onset on April 18. Currently, the patient is seriously ill, the hospital is under active treatment.

So far, Zhejiang Province, a total of 46 cases of human infection with the H7N9 avian influenza confirmed cases, 6 deaths, nine cases of rehabilitation.

 

According to the Jiangxi Provincial Health Department reported today, Jiangxi new cases of human influenza H7N9 confirmed cases of avian influenza.

 

As of April 28 at 17, a total of confirmed H7N9 avian influenza 124, in which 23 people died, the cases were distributed in Beijing (1) Shanghai (33 cases, 12 patients died), Jiangsu (27 patients, 4 patients died ), Zhejiang (46 cases, 6 died), Anhui (4 cases, 1 death), Henan (4 cases), Shandong (1), the Jiangxi (4), Hunan (2 cases), Fujian (n = 1 ), Taiwan (1). The case is still in the dissemination of state, have not yet found evidence of human-to-human transmission.

 

 

Since this is the weekend, and it is still early evening in China as I write this post, it is possible we’ll see additional cases reported by some of the other provinces later in the day.

H7N9: Malik Peiris Video Interview

 

 

# 7199

 

Malik Peiris is the Chair Professor of Microbiology at The University of Hong Kong, a Virologist at the Queen Mary Hospital and the Scientific Director of the HKU-Pasteur Research Centre at Hong Kong.

 

And if that weren’t enough, Peiris was also one of the genuine heroes of the SARS outbreak in 2003. He and his team were the first to identify the causative agent  (coronavirus) behind that epidemic.

 

 

Today we’ve a 7 minute video interview with Professor Peiris, courtesy of the Wall Street Journal (follows a brief commercial).

 

 

Could H7N9 Become the World’s Next Flu Pandemic?

The World Health Organization warns that birds seem not be the only means of H7N9 transmission. Professor Malik Peiris, a key investigator of the virus, tells us what we need to know about prevention.

MOA: Very Few Birds Test Positive For H7N9

 

Photo Credit – FAO

# 7199

 

A remarkable statistic in China’s H7N9 bird flu outbreak is that more than twice as many people (n=120) have tested positive for the virus as have birds. 

 

The Ministry of Agriculture found, that out of more than 68,000 samples tested, only 46 were positive for the H7N9 virus.

 

Or about 1 in every 1478 samples tested.

 

Which would seem to leave 3 possibilities:

 

1. The virus is not widespread in poultry
2. The tests being used are not sensitive enough to detect the virus
3. China’s surveillance program is looking for bird flu in all the wrong places.

When coupled with a lack of overt symptoms in birds, H7N9 lives up to its billing as being a `stealth virus’, which will make its detection and eradication extremely difficult. 

 

 

Ministry of Agriculture: poultry farms around the present and H7N9

April 27, 2013 08:54:50
Source: Beijing News

Up to now, a total of confirmed H7N9 avian influenza 120 people, of which 23 people died, the cases were distributed in Beijing, Shanghai, Jiangsu, Zhejiang, Anhui, Henan, Shandong, Jiangxi, Fujian, Taiwan and other places. Cases in the dissemination of state, also found no evidence of human-to-human transmission.

 

According to Xinhua News Agency reporter on the 26th learned from the Ministry of Agriculture, Up to now around not isolated from poultry farms to the H7N9 avian influenza virus, also found no pigs infected with the virus, the H7N9 avian influenza virus has been found that 46 positive samples from live poultry operations market, pigeons and pigeon farmers.

 

As of 26 provinces and the National Avian Influenza Reference Laboratory were detected in 68060 etiology samples, found that 46 H7N9 avian influenza virus, the positive rate of 0.07%. Among them, 44 were from Shanghai, Anhui, Zhejiang, Jiangsu and Henan provinces (municipalities) 14 live poultry business market (points) poultry and environmental samples; 2 positive samples from Nanjing, Jiangsu Province wild pigeon samples from MSC County, Nantong City, Jiangsu Province, Pigeon farmers. The remaining samples were negative.

 

In addition, the information published on the 26th by the Information Office of the Ministry of Agriculture, Zhejiang Province, animal disease prevention and control center detected 6 chicken suspected positive samples for review by the National Avian Influenza Reference Laboratory confirmed, 3 were positive for H7N9 avian influenza, samples from Zhejiang Province, Lin'an, Hangzhou operating point, the highly homologous isolates April 4, the H7N9 avian influenza virus strains isolated from pigeons.

 

 

For more on the challenges facing China’s poultry industry with this virus, you may wish to revisit:

 

FAO On Biosecurity Challenges Of H7N9

Food Insecurity, Economics, And The Control Of H7N9

H7N9: Hunan Province Reports First Case

 

Hunan Province – Credit Wikipedia

 

# 7198

 

Today, Hunan Province (not to be confused with Henan Province, which already has four cases) is added to the growing list of places in China where human infections with the H7N9 virus have been confirmed.

 

This makes the third new province to report human cases over the past three days (along with Jiangxi and Fujian).

 

This from Xinhua News.

 

First H7N9 human infection reported in China's Hunan

English.news.cn   2013-04-27 20:01:53
 

CHANGSHA, April 27 (Xinhua) -- Health authorities in central China's Hunan Province on Saturday confirmed its first human infection case of H7N9 bird flu.

 

A 64-year-old woman surnamed Guan, a resident in Shaoyang City, started suffering from a fever on April 14, and laboratory tests confirmed her H7N9 infection on Saturday, Hunan Provincial Health Department said in a statement

 

The statement said Guan had been exposed to poultry four days before she developed the fever. No abnormal symptoms had been found among the 41 people who were in close contact with the patient, it added.

 

An official with the department said Guan had been critically ill but that her condition was improving.

 

Although many infections have been linked to exposure to live-market birds, the exact form of `poultry exposure’ for this case isn’t revealed.

 

In 1997, Hong Kong was able to eradicate the H5N1 virus through a rapid and bold culling of all poultry across Hong Kong’s relatively small 1104 sq km territory.

 

As the geographic range of this virus increases (Hunan Province alone is nearly 200 times larger than Hong Kong), the prospects of China being able to cull its way out of this zoonotic outbreak grow bleaker.

PHAC Guidance On Handling H7N9 Cases

N-95 Respirator         Surgical Facemask

 

 

# 7197

 

Yesterday the Public Health Agency Of Canada  published a set of Interim Guidance - Avian Influenza A(H7N9) Virus documents dealing with infection prevention and control in acute care settings.

 

Compared to the guidance released last week by the United States (see CDC Interim H7N9 Infection Control Guidelines), the Canadian version is far less stringent.

 

The CDC Interim H7N9 Infection Control Guidelines, call for fitted N95 respirators, gowns, gloves, and eye protection as a minimum level of PPEs (personal protective equipment) for all HCWs who may have contact with potential or confirmed H7N9 patients.

  

Additionally, confirmed or suspected patients are to be placed in an Airborne Infection Isolation Room (AIIR) whenever possible.

 

 

Below you’ll find excerpts that illustrate some of the differences:

 

Infection Prevention and Control Guidance for Acute Care Settings

Notes

Footnote a

Acute care - A facility/setting where a variety of inpatient services is provided, which may include surgery and intensive care.  For the purpose of this document, acute care also includes ambulatory care settings such as hospital emergency departments, and free-standing ambulatory (day) surgery or other day procedures (e.g., endoscopy) centres.

Footnote b

IPC measures included in this interim guidance are considered the minimum recommendations; a point-of-care risk assessment approach (Appendix A) should be used by the HCW prior to every patient interaction, to determine what level of respiratory, and other personal protection, supports the use of additional measures where indicated.

Footnote c

Patient's room, cubicle or designated bedspace.

Footnote d

Surgical or procedure masks.

Footnote e

Historically, H7 influenza A viruses have shown a marked ocular tropism and have been associated with conjunctivitis in humans, with occasional cases leading to more severe illness. The importance of use of eye protection/face shields/visors should be reinforced as part of IPC precautions for this virus.

Footnote f

Whenever possible AGMPs should be performed in an airborne infection isolation room.

PATIENT PLACEMENT AND ACCOMMODATION

Patients suspected or confirmed to have H7N9 infection should be cared for in single rooms, if possible, with designated private toilets and patient sinks.   If cohorting is necessary, only patients who are confirmed to have H7N9 infection should be cohorted together.  Infection prevention and control signage should be placed at the room entrance indicating contact and droplet precautions required upon entry to the room.  Airborne infection isolation rooms should be used for aerosol-generating medical procedures whenever possible.

 

<SNIP>

 

PERSONAL PROTECTIVE EQUIPMENT
Personal protective equipment (PPE) for contact and droplet precautions should be provided outside the room of the patient suspected or confirmed to have H7N9 infection.  HCWs, families and visitors should use the following PPE:

 

Gloves

Gloves should be worn upon entering the patient’s room (for care of the patient and for contact with the patient’s environment).  Gloves should be removed and discarded into a no-touch waste receptacle.

Hand hygiene should be performed after removing gloves, upon exiting the patient’s room.

 

Gowns

 

A long-sleeved gown should be worn upon entering the patient’s room.  The gown should be removed and discarded into a no-touch receptacle.

Hand hygiene should be performed after removing gowns, upon exiting the patient’s room.

 

Facial protection

Facial protection (masks and eye protection, or face shields, or mask with visor attachment) should be worn when within two metres of a patient suspected or confirmed with H7N9 infection. Facial protection should be removed after gloves and gown before leaving the patient’s room and discarded in a hands-free waste and linen receptacle within the room.

Hand hygiene should be performed after removing gloves and gown, before removing facial protection, and after leaving the room.

In a shared room/cohort setting of patients with confirmed H7N9 infection, facial protection may be worn for the care of successive patients.

 

Respiratory Protection

Wearing a respirator is recommended when performing aerosol generating medical procedures on a patient suspected or confirmed with H7N9 infection (refer to Section 12).

HCWs should use a point-of-care risk assessment approach (

Appendix A) before each patient interaction to evaluate the likelihood of exposure.

 

<SNIP>

 

AEROSOL GENERATING MEDICAL PROCEDURES (AGMPs)

 

AGMPs should be performed on patients suspected or confirmed to have H7N9 infection only if medically necessary.  The number of HCWs present during an AGMP should be limited to only those essential for patient care and support.  A respirator and face/eye protection is recommended for all HCWs present in a room where an AGMP is being performed on a patient suspected or confirmed to have H7N9 infection.

 

AGMPs should be performed in airborne infection isolation rooms, whenever feasible.  If not feasible, AGMPs should be carried out using a process and in an environment that minimizes the exposure risk for HCWs, ensuring that non-infected patients/visitors and others in the healthcare setting are not unnecessarily exposed to the H7N9 virus.

 

 

The most striking differences between the CDC and the PHAC recommendations are the minimum standards for respiratory protective gear for HCWs in contact with H7N9 cases (U.S. = N95, Canada =Surgical/procedure Mask) and the preferred placement of patients (US= AIIR, Canada = Private room).

 

The Canadian recommendations do call for  N95 respirators for HCWs performing AGMPs.

 

Admittedly, we have finite supplies of N95 respirators and shortages are likely during a severe pandemic, and the availability of AIIR facilities would dwindle quickly during an epidemic of any size.

 

So in practical terms, the tougher U.S. guidelines would likely need some adjustments once a certain threshold of cases are reached.

 

As far as relative merits of surgical masks versus N95 respirators are concerned, we’ve covered this contentious debate often, including:

 

Influenza Transmission, PPEs & `Super Emitters’

Study: Aerosolized Influenza And PPEs

Study: Longevity Of Viruses On PPEs

Why Size Matters

IOM: PPEs For HCWs 2010 Update