Study: Efficacy Of Hand Hygiene Alone Against Influenza Infection

Photo Credit – CDC

 

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As was well illustrated during the opening months of the 2009 H1N1 pandemic – until a vaccine can be developed, produced, and distributed – public health interventions to reduce the spread of a virus are fairly limited, and consist primarily of NPIs – or Non-Pharmaceutical Interventions.

Credit CDC Non-Pharmaceutical Interventions

The goal, in those early months before a vaccine becomes available, is to reduce the spread of the virus as much as possible.  In this way, the burden on health care facilities, and toll of absenteeism and on the lives of those effected can be reduced.

 

Source - Community Strategy for Pandemic Influenza Mitigation

 

NPI’s have been described as being like slices of Swiss cheese, with each containing large holes through which the virus can pass, but when stacked on top of each other, can provide an effective barrier.

 

While it is known that these measures can help reduce influenza transmission, there are many open questions regarding their relative merits, cost effectiveness, and optimum combination.  

 

Among the researchers trying to nail down these merits, is Dr. Allison Aiello whose work at the University of Michigan we’ve examined previously. Back in 2010, in Michigan NPI Study: A Closer Look and Study: Effectiveness of NPIs Against ILI's, we looked at a multi-year research project that compared the effectiveness of handwashing and facemasks (alone, and in combination) at reducing the spread of seasonal influenza in a college dorm setting.

Their results?

 

Neither face mask use and hand hygiene nor face mask use alone was associated with a significant reduction in the rate of ILI, although combined, they produced a 35% to 51% reduction of infection over the control group.

 

Although this study did not directly study the effectiveness of hand washing alone, the implication here is that alcohol sanitizers and hand washing alone may not be as protective as has been hoped in the past. 

 

Flash forward four years and Dr. Aiello (now Professor of Epidemiology at UNC)  is back with a study (along with Dr. Benjamin Cowling  and V. W. Y. Wong of the University of Hong Kong) that looked at earlier studies in order to evaluate the effectiveness of hand hygiene alone in preventing influenza infection.

 

Hand hygiene and risk of influenza virus infections in the community: a systematic review and meta-analysis

V. W. Y. WONG^a1, B. J. COWLING^{a2 c1} and A. E. AIELLO^a3 

SUMMARY

Community-based prevention strategies for seasonal and pandemic influenza are essential to minimize their potential threat to public health. Our aim was to evaluate the efficacy of hand hygiene interventions in reducing influenza transmission in the community and to investigate the possible modifying effects of latitude, temperature and humidity on hand hygiene efficacy. We identified 979 articles in the initial search and 10 randomized controlled trials met our inclusion criteria.

The combination of hand hygiene with facemasks was found to have statistically significant efficacy against laboratory-confirmed influenza while hand hygiene alone did not. Our meta-regression model did not identify statistically significant effects of latitude, temperature or humidity on the efficacy of hand hygiene.

Our findings highlight the potential importance of interventions that protect against multiple modes of influenza transmission, and the modest efficacy of hand hygiene suggests that additional measures besides hand hygiene may also be important to control influenza.

 

Before proceeding, I would note that the  advice from the CDC, HHS, WHO and just about every other public health agency around to globe to `wash your hands often’ is undoubtedly sage counsel, and can protect you against a wide range of illnesses and disease.

 

I am, and will continue to be, an inveterate hand washer and you are unlikely to find me out and about without a bottle of alcohol hand-sanitizer within reach.

 

But as far as influenza (and other common ILIs) are concerned, there isn’t a lot of evidence that handwashing alone offers much of a protection against infection.  Something I wrote about at some length back in 2009 (see Sanitized For Your Protection and The Flaw In The Ointment). 

While it is true that some influenza infections undoubtedly come via fomites (contaminated surfaces which we touch and then transfer to our mouths, eyes, or nose) - and that hand-washing might prevent some of those - most researchers would grant that most influenza is probably transmitted through large droplet or aerosol routes. 

Which would explain why studies have shown that combining handwashing with respiratory protection does appear to provide a significant degree of protection against influenza-like illnesses.

 

The problem with facemasks and other forms of PPEs (Personal Protective Equipment)– particularly during a severe pandemic – is one of supply. 

 

Our Strategic National Stockpile contains more than 100 million  N95 and surgical masks (see Caught With Our Masks Down), but the demand for PPEs during a serious pandemic would far exceed the supply. 

 

At one time the HHS estimated the nation would need 30 billion masks (27 billion surgical, 5 Billion N95) to deal with a major pandemic (see Time Magazine A New Pandemic Fear: A Shortage of Surgical Masks).

 

Making it difficult for the CDC, WHO, and other public agencies to broadly recommend their use, knowing they would quickly be in short supply.

 

Still, the CDC has in the past suggested that individuals and businesses may wish to stockpile a small quantity of facemasks (see Minnesota Health Department May 2007: Volume 2, Number 5 (PDF: 127KB/4 pages) as part of their general pandemic preparedness.

 

CDC officials could not emphasize enough that masks alone will not be sufficient to eliminate the risk of infection during a pandemic. Facemasks (e.g., surgical masks) and respirators (e.g., N95 masks) should be used in combination with other preventive measures, such as hand hygiene and social distancing, to help reduce the risk for influenza infection during a pandemic. 

Respirators (e.g., N95 masks) are still only being recommended for individuals who have unavoidable close contact with infected persons. Whenever possible, rather than relying on the use of facemasks (e.g., surgical masks) and respirators (e.g., N95 masks), close contact and crowded conditions should be avoided during an influenza pandemic. Facemasks (e.g., surgical masks) should be considered for use by individuals who enter crowded settings, both to protect their nose and mouth from other people’s coughs and to reduce the wearers’ likelihood of coughing on others. The time spent in crowded settings should be as short as possible.

Last July, in The Great Mask Debate Revisited I wrote about the pros and cons regarding facemasks, and the various studies comparing the protective qualities of surgical masks vs. N95 masks.  

 

Neither type should be regarded as perfect protection against infection, and with regards to the more expensive N95s, it takes more than just having a box in your closet (see Survival Of The Fit-tested) to protect you.

 

The bottom line, is that you hope to avail yourself of the (admittedly, limited) protection afforded by facemasks during a pandemic, your best bet is to buy any supplies well before a pandemic erupts.

 

As far as the `wash your hands’  meme is concerned, while perhaps oversold for preventing influenza infection, hand washing is simple, cost effective, and has proven benefits as part of basic disease prevention and hygiene.

 

Which makes it an important component in any public health strategy, regardless of whether we find ourselves in the midst of an influenza epidemic.

The Great Mask Debate Revisited

Photo Credit PHIL (Public Health Image Library)

 

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Fears over the MERS coronavirus (and avian flu), and the recent call by the Saudi government for pilgrims to wear face masks during Ramadan and the Hajj, will no doubt reawaken the debate over the appropriateness, effectiveness and logistics of mask wearing in public to prevent infection during a pandemic. 

 

As you’ll see, while it may seem like a no-brainer, there’s conflicting evidence of their effectiveness, the supply of face-masks is finite, and governments and public health agencies around the world are not all on the same page with their advice.

 

Our primary defense against any pandemic (until a vaccine can be developed and deployed) are called NPIs (non-pharmaceutical interventions).

NPI’s can be as simple as hand hygiene, covering your coughs, and avoiding crowds, or can involve the use of personal protective barriers like N95 or surgical masks, latex or vinyl gloves, and eye protection.

 

School closures, public education, staying home when sick, and engineered barriers to avoid exposure are also examples of NPIs.

 

There are two basic types of masks available to the public; surgical or medical masks and N95 respirators. Given the higher costs, and their likely limited supply during a pandemic or epidemic, N95 masks are less likely to be used by the general public.

 

 

Surgical Facemask N-95 Respirator 

 

The simple surgical mask has the advantage of being cheap (a box of 50 is usually under $4), easy to don, and easier to breath through than the N95 respirator. Its role has traditionally been to protect others from the coughs or sneezes of someone who may be infected.

 

A 2008 NIOSH Science blog called Influenza Pandemic and the Protection of Healthcare Workers with Personal Protective Equipment describes their effectiveness thusly:

 

Medical masks are not designed or certified to protect the wearer from exposure to airborne hazards. They may offer some limited, as yet largely undefined, protection as a barrier to splashes and large droplets.

 

However, because of the loose-fitting design of medical masks and their lack of protective engineering, medical masks are not considered personal protective equipment.

 

This of course assumes a healthcare setting, where HCWs are in close, prolonged contact with probable or confirmed infected patients, and a higher standard of protection is required.

 

• The evidence for the protective qualities of surgical masks is mixed, but in 2010 we looked at a study (see (see Efficacy of Facemasks Vs. Respirators), that suggests that inexpensive facemasks may be more effective than previously thought in protecting against the H1N1 virus.

 

• And in 2009 (see JAMA: Surgical Masks vs N95 Respirators) we looked a report that HCWs using surgical masks experienced `noninferior rates of laboratory-confirmed influenza’. The implication here, according to the authors, is that surgical masks provide similar protection to N95 respirators in a routine health care setting.

 

Other studies have been less sanguine about the effectiveness of surgical masks to prevent infection in the wearer (see PPEs & Transocular Influenza Transmission), although they do appear to provide some degree of protection.  

 

Use of the N95 mask, which the CDC recommends for HCWs who may be exposed to the MERS coronavirus or H7N9 (along with gloves, gown, & eye protection – see CDC: Interim Infection Control Guidelines For MERS-CoV) would be somewhat problematic for the general public.

 

• They are uncomfortable to wear for long periods of time. 
• They saturate with exhaled moisture relatively quickly, and must be changed out every couple of hours. 
• The must be fit tested for each wearer (see Survival Of The Fit-tested)
• They are 10 times more expensive than surgical masks.
• They are considered a `last line of defense’ by the CDC and are really only effective when combined with gloves, hand hygiene, and eye protection.   
• They must be removed and disposed of properly, to avoid contamination
• And lastly, our national supply of N-95s is likely inadequate to supply even our Health Care Workers during a prolonged severe pandemic wave.

 

The bottom line is that surgical masks (and N95 respirators) may be somewhat protective for the wearer, but they will be in short supply during a severe pandemic, and are certainly not guaranteed to protect the wearer.

 

Which is why the World Health Organization has been reluctant to recommend the wearing of masks by the general public (see WHO: MERS, Masks, And The Media and More From WHO on MERS & Masks).

 

Credit @WHO June 13th, 2013

 

In Advice on the use of masks in the community setting in Influenza A (H1N1) outbreaks Interim guidance  - while not recommending the public use of masks - WHO doesn’t come out strongly against them, either. And should the threat from MERS change, WHO could very well adjust their recommendations down the line.

 

The HHS issued guidance in 2007, as part of their H5N1 and pandemic flu preparedness push, on the use of facemasks by the public during a pandemic.

 

 

Interim Public Health Guidance for the Use of Facemasks and Respirators in Non-Occupational Community Settings during an Influenza Pandemic

May 2007

This document describes interim guidance for the use of facemasks and respirators in certain public settings during an influenza pandemic. Very little information is available about the effectiveness of facemasks and respirators in controlling the spread of pandemic influenza in community settings. In the absence of scientific data, this document offers interim recommendations that are based on public health judgment and on the historical use of facemasks and respirators in other settings. In brief, these interim recommendations advise the following:

• Whenever possible, rather than relying on the use of facemasks or respirators, close contact and crowded conditions should be avoided during an influenza pandemic.
• Facemasks should be considered for use by individuals who enter crowded settings, both to protect their nose and mouth from other people's coughs and to reduce the wearers' likelihood of coughing on others.  The time spent in crowded settings should be as short as possible.
• Respirators should be considered for use by individuals for whom close contact with an infectious person is unavoidable. This can include selected individuals who must take care of a sick person (e.g., family member with a respiratory infection) at home.

Facemasks and respirators should be used in combination with other preventive measures, such as hand hygiene and social distancing, to help reduce the risk for influenza infection during a pandemic. This interim guidance will be updated as new information becomes available.

(Continue . . . )

In 2008 (see The HHS Revised Mask Recommendations) new draft guidance for mask use by the public was released with even stronger recommendations, but that document appears to be no longer online. Although it wasn’t formally adopted, the interim advice offered by the HHS in 2008 still seems prudent to me:

 

Pandemic outbreaks in communities may last 6 to 12 weeks.[3]  Persons who cannot avoid commuting on public transit may choose to purchase 100 facemasks for use when going to and from work.  An additional supply of facemasks also could be purchased for other times when exposure in a crowded setting is unavoidable or for use by an ill person in the home when they come in close contact with others.[4]

The problem, of course, is supply.

 

Our Strategic National Stockpile contains more than 100 million  N95 and surgical masks (see Caught With Our Masks Down), but the demand for PPEs during a serious pandemic would far exceed the supply. 

 

At one time the HHS estimated the nation would need 30 billion masks (27 billion surgical, 5 Billion N95) to deal with a major pandemic (see Time Magazine A New Pandemic Fear: A Shortage of Surgical Masks).

 

Which means that if you intend to avail yourself of the (admittedly limited) protection of face masks during a pandemic, your best bet is to buy any supplies well before a pandemic erupts.

 

Another alternative (offered without recommendation) was published in the CDC’s Journal of Emerging Infectious Diseases back in 2006 (see The Man In The Ironed Mask); A homemade reusable mask made out of Tee-shirt material.

 

Emerging Infectious Diseases Volume 12, Number 6, June 2006

Simple Respiratory Mask

Virginia M. Dato, David Hostler & Michael E. Hahn

Figure. Prototype mask. A) Side view, B) Face side. This mask consisted of 1 outer layer (≈37 cm × 72 cm) rolled and cut as in panel B with 8 inner layers (<18 cm²) placed inside (against the face). The nose slit was first placed over the bridge of the nose, and the roll was tied below the back of the neck. The area around the nose was adjusted to eliminate any leakage. If the seal was not tight, it was adjusted by adding extra material under the roll between the cheek and nose or by pushing the rolled fabric above or below the cheekbone. Tie b was tied over the head. A cloth extension was added if tie b was too short. Finally, tie c was tied behind the head. The mask was then fit tested.

 

Another study, which appeared in PLoS One  in 2008 (see What Everyone Will Be Wearing During The Next Pandemic Flu Season), found that homemade masks – while not as effective as N95s – could offer some degree of protection against viral infection.

 

Professional and Home-Made Face Masks Reduce Exposure to Respiratory Infections among the General Population

Marianne van der Sande, Peter Teunis, Rob Sabel

 

Although I would certainly prefer the protection of an N95 mask (and eye protection), I’ve always believed that in an potentially infectious environment, any mask beats having no mask at all.

 

But as always, your mileage may vary.

WHO: H7N9 Candidate Vaccine Viruses

 

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The road to creating, producing, and deploying an emergency pandemic vaccine can be long and fraught with many unexpected twists and turns. Under the best of circumstances it takes several months before the first commercial batches can roll off the production line.

 

So it pays to start the development process as early as possible, even before you know for certain a vaccine will be needed.

 

We’ve seen the precautionary selection of CVVs (Candidate Vaccine Viruses) before, with the H5N1, H3N2v and H9N2 viruses (see H3N2v Vaccine Trials & Bangladesh To Share H9N2 Bird Flu Virus).

 

While no nation, health organization, or pharmaceutical company has decided to proceed with the mass production of an H7N9 vaccine, the preliminary – and prudent – steps of identifying, growing, and testing  potential vaccine candidate strains is underway.

 

Yesterday, the World Health Organization released a document (02 May 2013 Candidate vaccine viruses of A(H7N9) pdf, 103kb) outlining the process.

 

A few excerpts, then I’ll return with a little more.

 

Vaccine response to the avian influenza A(H7N9)outbreak - step 1: development and distribution of candidate vaccine viruses

2 May 2013

Influenza vaccination is the most important intervention in reducing the impact of influenza, and a key component of the WHO response and preparedness efforts for influenza of pandemic potential, including avian influenza A(H5N1), A(H9N2) and A(H7N9).

 

Development of candidate vaccine viruses

The first step in the long cycle of vaccine development and production is vaccine virus selection and the development of high-growth reassortants (candidate vaccine viruses (CVVs)). This is a well-established process and has been in place since the 1970s. It was further strengthened during the response to A(H5N1) and pandemic A(H1N1) 2009, mainly through the WHO Global Influenza Surveillance and Response System (GISRS) which currently comprises 150 laboratories in 111 countries.

 

Since the detection of avian influenza A(H7N9) virus in China, GISRS has been on alert. Through the excellent work undertaken by the WHO Collaborating Centre (WHO CC) in Beijing, viruses have been isolated and shipped to other WHO CCs and Essential Regulatory Laboratories (ERLs) of GISRS for joint virus characterization, development of diagnostic tests, risk assessment and candidate vaccine virus development for pandemic preparedness purposes.

 

Using the two available technologies, classical reassortment and reverse genetics, the WHO CCs and ERLs are developing high-growth reassortants that are suitable for vaccine development and production. The status of development of CVVs will be updated routinely by WHO for influenza vaccine manufacturers, national/regional regulatory agencies and other interested parties.

 

(Continue . . .)

 

 

While emergency vaccines certainly have value – particularly for the second or third wave of a pandemic - it would be highly unlikely that one could be produced, and deployed in sufficient quantity, to have much effect on the initial wave of any pandemic.

 

Last month, in Branswell On The Challenges Of Producing An H7N9 Vaccine, we looked at some of the problems inherent in developing an emergency avian flu vaccine.

 

And a month ago, in H7N9 Vaccine Realities, we looked at the gap between predicted vaccine supplies during the 2009 pandemic, and actual vaccine deliveries.

 

At the time I wrote:

 

In a world of 7 billion, the reality is that our ability to manufacture and (just as importantly) distribute a pandemic vaccine in  a short amount of time remains severely limited.

 

<snip>

 

It is likely that relatively few people could expect to see any novel pandemic vaccine in less than six months from the time production started.

 

And most of the world would probably still be waiting after a year.

 

The truth is, our first line of defense in any pandemic is not a shot or a pill, it is a range of steps collectively called NPIs, or Non Pharmaceutical Interventions.

 

The CDC’s  Nonpharmaceutical Interventions (NPIs) webpage defines NPIs as:

 

Nonpharmaceutical interventions (NPIs) are actions, apart from getting vaccinated and taking medicine, that people and communities can take to help slow the spread of illnesses like influenza (flu). NPIs are also known as community mitigation strategies.

 

NPIs are geared to the virulence and spread of the virus, and may range from simple advice to `wash your hands and cover your coughs’ to mandatory school and business closings.

 

 

 

Should the H7N9 virus, novel coronavirus, or any other novel virus threaten, we’ll be talking a lot about NPIs, and their efficacy, impact, and practicality in the blog.

 

Admittedly, H7N9 remains a distant threat and may never spark a pandemic.

 

But H7N9 isn’t the only pathogenic contender capable of sparking the next global health crisis.

 

H5N1 circulates in Asia and the Middle East, several varieties of swine variant H1 and H3 viruses have jumped to humans in recent years, and the novel coronavirus emerging on the Arabian peninsula has many scientists visibly concerned.

 

 

All of which makes now a very good time for governments, agencies, businesses and organizations to dust off, update, and test their pandemic preparedness plans.

 

Because history has taught us that pandemics happen.

 

We just don’t know when, and from where, the next one will come.

Study: The Effects Of School Closures During A Pandemic

 

 

 

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Although not without its critics, extended school closures have been promoted as one of a list of NPIs (non pharmaceutical interventions) that might be used to slow the spread of illness during a severe influenza pandemic.

 

 

The chart above, taken from the PNAS journal article entitled Public Health Interventions and Pandemic Intensity During the 1918 Influenza Pandemic, shows the excess mortality in two American cities. The tall spike represents Philadelphia, while the lower curve represents St. Louis.

 

Many researchers believe the startling difference in attack rates, and mortality, in these two cities can be explained by the way each city dealt with the outbreak.

 

In St. Louis, the Health Department closed public venues such as schools, theatres and churches very early in the outbreak, while Philadelphia did not.

 

During the spring of 2009, when novel H1N1 first began to spread, schools closures were recommended by the CDC, and by other public health entities around the world.

 

By early May it became apparent that the severity of this particular influenza virus was less than originally feared, and many public health agencies moderated their recommendations (see CDC No Longer Recommending School Closures For A/H1N1).

 

Some school districts, in the U.S., and elsewhere around the world, continued to close schools on a case-by-case basis well into the fall of 2009.

 

School closings are controversial and they do not come without some social and economic costs (see The Debate Over School Closures).

 

Critics point out that working parents rely on schools to watch their kids for much of the year during the day, and many low income families benefit from the school lunch program.

 

And of course, when schools are closed during a pandemic, some kids may congregate elsewhere and spread the virus anyway.

 

While decisions on whether to close schools during a pandemic might well be trumped by parental concerns, it is important for policymakers to get some idea of the benefits that proactive school closings would generate. 

 

To that end we’ve seen a number of studies that came out of the most recent pandemic, and while the results have not all been in alignment, many have indicated substantial benefit from school closures.

 

In a report that appeared last year in the journal Eurosurveillance (see Eurosurveillance: New Research On Pandemic Influenza), we saw several studies that attempted to quantify the benefits of school closures:

 

• Three studies out of Japan found a beneficial effect during the 2009 pandemic by using antiviral drugs and/or school closure (of varying length and timing) to interrupt its transmission.

• Conversely, a fourth study suggested that early school closures could have adversely affected herd immunity in the school environment, with lower cumulative infection rates in schools that delayed closure.

 

Last May (see NIH: School Closings Effective In 2009 Pandemic) we saw a report indicating that school closings in Mexico reduced disease transmission by as much as 37%.

 

This from the NIH.

 

Tuesday, May 24, 2011
5 p.m. EDT

Mexican flu pandemic study supports social distancing

Fogarty research published in PLoS Medicine

Eighteen-day periods of mandatory school closures and other social distancing measures were associated with a 29 to 37 percent reduction in influenza transmission rates in Mexico during the 2009 pandemic. The research was carried out by scientists at the Fogarty International Center at the National Institutes of Health and published in PLoS Medicine.

 

(Continue . . .)

 

I’ve posted on a number of other studies of the effects of school closures over the past few years, including:

 

Study: Pandemic Mitigation by Early School Closure

Study: Student Behavior During Pandemic School Closings

School Closures Revisited

 

All of which serves as prelude and introduction for a new study, just out in the Annals of Internal Medicine, that looks at the effects of school closures in Canada during the 2009 pandemic.

 

Effects of School Closure on Incidence of Pandemic Influenza in Alberta, Canada

David J.D. Earn, PhD; Daihai He, PhD; Mark B. Loeb, MD, MSc; Kevin Fonseca, PhD; Bonita E. Lee, MD, MSc; and Jonathan Dushoff, PhD

Abstract (excerpts)

Background: Control of pandemic influenza by social-distancing measures, such as school closures, is a controversial aspect of pandemic planning. However, investigations of the extent to which these measures actually affect the progression of a pandemic have been limited.

 

<SNIP>

 

Results: The ending and restarting of school terms had a major effect in attenuating the first wave and starting the second wave of pandemic influenza cases. Mathematical models suggested that school closure reduced transmission among school-age children by more than 50% and that this was a key factor in interrupting transmission. The models also indicated that seasonal changes in weather had a significant effect on the temporal pattern of the epidemic.

 

<SNIP>

 

Conclusion: Analysis of data from unrestricted virologic testing during an influenza pandemic provides compelling evidence that closing schools can have dramatic effects on transmission of pandemic influenza. School closure seems to be an effective strategy for slowing the spread of pandemic influenza in countries with social contact networks similar to those in Canada.

 

While the entire article is behind a pay wall, for more on this we can go to the press release from McMaster University.

 

School closures slow spread of pH1N1

Should be considered as a control measure during pandemic outbreaks

Hamilton, ON (Feb. 6, 2012) - Closing elementary and secondary schools can help slow the spread of infectious disease and should be considered as a control measure during pandemic outbreaks, according to a McMaster University led study.

 

Using high-quality data about the incidence of influenza infections in Alberta during the 2009 H1N1 flu pandemic, the researchers show that when schools closed for the summer, the transmission of infection from person to person was sharply reduced.

 

"Our study demonstrates that school-age children were important drivers of pH1N1 transmission in 2009," says David Earn, lead author of the study published in Annals of Internal Medicine. Earn is professor in the Department of Mathematics and Statistics and member of McMaster's Michael G. DeGroote Institute for Infectious Disease Research (IIDR).

 

Alberta was the only Canadian province to continue extensive virologic testing throughout the first wave and continuously to the middle of the second wave of the 2009 pandemic, allowing researchers to identify the causes of changes in incidence as the pandemic progressed.

"The data that we obtained were so good that our plots immediately revealed a huge drop in incidence when schools were closed for the summer," says Earn. "Using state-of-the-art modeling, we then demonstrated that transmission was reduced by at least 50 per cent."

(Continue . . . )

 

 

Although the severity of any novel pandemic virus will no doubt figure into the equation (as will the social and economic costs of shuttering schools), today’s study adds considerable weight to the notion that school closures could be an effective intervention during the next influenza pandemic.

Our First Line Of Defense

 

Photo Credit PHIL (Public Health Image Library)

 

 

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One of the concepts well illustrated during the initial outbreak of the H1N1 `swine flu virus’ in 2009 was that – until a vaccine could be developed, produced, and deployed – our only real defenses against any emerging infectious disease are NPIs; non pharmaceutical interventions.

 

Which is why flu hygiene (covering coughs/sneezes, disposing of tissues, washing hands often, and staying home when sick) was heavily promoted to the public during the pandemic.

 

Healthcare settings, where large numbers of vulnerable people are gathered in close proximity, are also the place that those infected with a new virus are likely to show up first.

 

Making the use of NPIs all the more important, to protect not only the staff, but other patients as well.

 

This morning we’ve a couple of studies that look at attitudes towards, and actually implementation of, NPIs and basic infection control procedures by both medical students and healthcare providers.

 

The most basic of NPIs is handwashing, and despite it having been more than 160 years since Ignaz Semmelweis published his work on the importance of hand hygiene, compliance rates in healthcare settings remain disturbingly low.

 

This is a subject we’ve visited many times before, including:

 

Giving Germs A Helping Hand 

Hand Hygiene Among Doctors Exposed

A Movement With Five Moments

Despite increased awareness and concern over HAIs (Hospital Acquired Infections), global handwashing campaigns, and the proliferation of hand sanitizing dispensers there remain serious gaps in this most basic infection control practice.

 

In the American Journal of Infection Control we’ve a study that surveyed beliefs of 1st year medical students over when it was appropriate to wash you hands when interacting with a patient.

Beliefs about hand hygiene: A survey in medical students in their first clinical year

Karolin Graf, MD, Iris F. Chaberny, MD, Ralf-Peter Vonberg, MD

Medical students were asked regarding knowledge and beliefs on hand hygiene before entering the clinical phase of education. By this, we noticed a lack of knowledge concerning the correct indications for hand disinfection. Regardless of previous experience in hospitals, the medical students expected that the compliance towards hand hygiene would be worse in more experienced physicians and senior consultants—who are often considered to be role models for medical students.

 

While this study is behind a pay wall, we do get additional details from a press release from Elsevier Health Services.

 

Elsevier Health Sciences

2 out of 3 medical students do not know when to wash their hands

Washington, DC, December 1, 2011 -- Only 21 percent of surveyed medical students could identify five true and two false indications of when and when not to wash their hands in the clinical setting, according to a study published in the December issue of the American Journal of Infection Control, the official publication of APIC - the Association for Professionals in Infection Control and Epidemiology.

 

Three researchers from the Institute for Medical Microbiology and Hospital Epidemiology at Hannover Medical School in Hannover, Germany collected surveys from 85 medical students in their third year of study during a lecture class that all students must pass before bedside training and contact with patients commences. Students were given seven scenarios, of which five ("before contact to a patient," "before preparation of intravenous fluids," "after removal of gloves," "after contact to the patient's bed," and "after contact to vomit") were correct hand hygiene (HH) indications. Only 33 percent of the students correctly identified all five true indications, and only 21 percent correctly identified all true and false indications.

(Continue . . . )

 

 

The next stop is a study that appears in the SHEA journal Infection Control and Hospital Epidemiology that shows that the inadequate use of masks by healthcare workers during the opening days of the 2009 pandemic put them at greater risk of contracting the virus.

 

 

Transmission of 2009 Pandemic Influenza A (H1N1) Virus among Healthcare Personnel-Southern California, 2009.

Jaeger JL, Patel M, Dharan N, Hancock K, Meites E, Mattson C, Gladden M, Sugerman D, Doshi S, Blau D, Harriman K, Whaley M, Sun H, Ginsberg M, Kao AS, Kriner P, Lindstrom S, Jain S, Katz J, Finelli L, Olsen SJ, Kallen AJ.

Source

Epidemic Intelligence Service, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia.

We’ve a press release from SHEA with the details.

 

Study finds inadequate mask use among health care workers early in 2009 H1N1 outbreak

Inadequate use of masks or respirators put health care workers at risk of 2009 H1N1 infection during the earliest stages of the 2009 pandemic in the U.S., according to a study published in the December issue of Infection Control and Hospital Epidemiology, the journal of the Society of Healthcare Epidemiology of America.

 

The study, led by the Centers for Disease Control and Prevention (CDC), tracked 63 Southern California health care workers who had contact with six of the first eight laboratory-confirmed 2009 H1N1 cases in the U.S. Because these contacts happened before the 2009 H1N1 outbreak had been widely reported, the cases shed light on how well health care workers protect themselves before a direct epidemiological threat becomes evident.

 

The investigation found that 9 of the health care workers tracked became infected with the 2009 H1N1 virus, likely from contact with infected patients. Twenty of the 63 health care workers reported that they had worn a mask or respirator at least once when in contact with patients, and no one from that group became infected with 2009 H1N1. Meanwhile, 43 workers reported never using a mask around patients, and all 9 infections occurred in workers from this group.

 

Overall, mask and respirator use was disappointingly low, the researchers report. Only 19 percent reported using a mask during every patient encounter. Use was especially low among outpatient workers, who also made up the majority of those who became infected with 2009 H1N1.

 

"The findings highlight the challenge of getting health care personnel to routinely wear Personal Protective Equipment," Jenifer Jaeger, MD, MPH, Associate Pediatrician, Massachusetts General Hospital, said. "The study also suggests that greater attention to infection control and preparedness, particularly among outpatient workers, is needed."

 

 

The irony here is that once the threat of a new viral threat became apparent, there were difficulties in providing enough PPEs (Personal Protective Equipment) - including masks and respirators - to healthcare workers in some parts of the country.

 

In June of 2009  the CDC’s MMWR (Morbidity and Mortality Weekly Report) (Volume 58, No. 23) reported hospitals weren’t doing enough to identify potential influenza cases, to isolate them, and to protect their staff (see HCPs At Risk).

 

A month later the California Nurses Association/ National Nurses Organizing Committee (CNA/NNOC) filed a complaint against one hospital, which I reported on in California Nurses Association Statement On Lack Of PPE and Report: Nurses File Complaint Over Lack Of PPE.

 

In August 2009 I reported on Nurses Protest Lack Of PPE’s in San Francisco.  And in October, I wrote CNA/NNOC Plan Protest Over Inadequate H1N1 Protection.

 

And to this, we must also add the ongoing debate over what constitutes adequate PPE protection.

 

Ideally, the well-protected HCW (Health Care Worker) working in an infectious environment would be wearing an N95 respirator, gloves, gown and eye protection.

 

 

But during the opening months of the 2009 pandemic, it became obvious that our world faced a shortage of N95 respirators, and so strategies were adopted to maximize their use.

 

In some cases nurses were issued only one N95 mask to be used for an entire 8 hour shift, and told to don it only when in direct contact with a potentially infected patient.

 

In other venues, HCWs were issued surgical masks in lieu of N95s, despite the recommendation at the time from the CDC that N95 masks were the preferred level of protection.

 

Over the past two years we’ve seen dueling studies that alternately show surgical masks to be a reasonable protective barrier against respiratory viruses  . . . or pretty much useless.

 

Take your pick.

 

Which is why last January the IOM (Institute of Medicine) released, through the National Academies Press, an extensive, 200+ page update on the use of PPEs  that essentially calls for better science on which to base our decisions regarding the right kind of protection for HCWs.

 

We were very lucky that the 2009 pandemic virus wasn’t any more transmissible, or virulent, than it turned out to be. 

 

While instilling good infection control practices is imperative in normal times, the less talked about side to this story is that during a serious global pandemic threat sometime in the future, providing adequate PPEs to healthcare workers may prove to be a major challenge.

Study: Flu Hygiene Reduces Respiratory Infections In School Setting

 

 

# 5980

 

 

We’ve another study that – despite returning somewhat mixed results – once again suggests the importance of maintaining good `flu hygiene’ during cold & flu season.

 

During the 2007-2008 flu season 10 Pittsburg elementary schools (grades K- 5) took part in a study where half of the schools served as controls, and half (5) were selected as `intervention’ schools.

 

Children in the intervention schools watched a special video on flu prevention, and were introduced to the `WHACK the Flu’ concepts.

 

WHACK stood for:

 

(W)ash or sanitize your hands often;

(H)ome is where you stay when you are sick;

(A)void touching your eyes, nose, and mouth;

(C)over your coughs and sneezes; and

(K)eep your distance from sick people.

 

This message was reinforced continually over the study period, and hand sanitizer dispensers were installed in each classroom and in major common areas of the intervention schools.

 

The goal was to encourage a minimum of 4 uses a day; upon arrival, before and after lunch, and prior to departure. Students were also encouraged to wash their hands and/or use the hand sanitizer as needed during the day.

 

Teachers were surveyed during the year regarding compliance rates among the students. Parents of students who were absent for more than one day received a phone call, and those who reported their child to have an ILI (influenza-like-Illness) received a home health visit where nasal swabs were obtained and tested for both influenza A & B.

 

The bottom line: at the intervention schools total student absences were reduced by 26% and lab confirmed influenza A infections were reduced by 52%.

 

Curiously, rates of influenza B were not reduced in this study, although the reasons why are less than clear.  In their discussion, the authors suggest several possible reasons, including:

 

The observation of no effect on influenza B could be attributed to differences in the basic biology and epidemiology of influenza B compared with A or to the fact that influenza B infections occurred late in the season, after compliance with the intervention possibly had waned.

 

A quick Google search returned a pdf of the full study online at this link.

 

Below you’ll find some excerpts from the abstract which may be read at the following link:

 

Pediatr Infect Dis J. 2011 Nov;30(11):921-6.

Reduction in the incidence of influenza A but not influenza B associated with use of hand sanitizer and cough hygiene in schools: a randomized controlled trial.

Stebbins S, Cummings DA, Stark JH, Vukotich C, Mitruka K, Thompson W, Rinaldo C, Roth L, Wagner M, Wisniewski SR, Dato V, Eng H, Burke DS.

(EXCERPT)

RESULTS:

A total of 3360 children participated in this study. Using reverse-transcriptase polymerase chain reaction, 54 cases of influenza A and 50 cases of influenza B were detected. We found no significant effect of the intervention on the primary study outcome of all laboratory-confirmed influenza cases (incidence rate ratio [IRR]: 0.81; 95% confidence interval [CI]: 0.54, 1.23). However, we did find statistically significant differences in protocol-specified ancillary outcomes.

Children in intervention schools had significantly fewer laboratory-confirmed influenza A infections than children in control schools, with an adjusted IRR of 0.48 (95% CI: 0.26, 0.87). Total absent episodes were also significantly lower among the intervention group than among the control group; adjusted IRR 0.74 (95% CI: 0.56, 0.97).

CONCLUSIONS:

NPIs (respiratory hygiene education and the regular use of hand sanitizer) did not reduce total laboratory-confirmed influenza. However, the interventions did reduce school total absence episodes by 26% and laboratory-confirmed influenza A infections by 52%. Our results suggest that NPIs can be an important adjunct to influenza vaccination programs to reduce the number of influenza A infections among children.

In the full paper, the authors conclude:

 

This study demonstrated that a set of NPIs can be implemented successfully on a large scale within urban schools to reduce absenteeism and the incidence of influenza A.

 

Furthermore, the results provide support for currently recommended respiratory hygiene behaviors during seasonal and pandemic influenza outbreaks and should be included as part of an overall prevention strategy to reduce the burden of influenza among school-aged children.

 

 

While useful interventions during any flu season, these techniques are even more important during an outbreak of a novel virus – such as we saw in 2009.  

 

Since vaccines typically take months to develop and even longer to deploy, simple, easy to implement NPIs (Non-pharmaceutical Interventions) such as these – while not a panacea - will undoubtedly form an important part of our initial response to any influenza epidemic.

JHU: Drills Expose Gaps In Infection Protection

 

 

 

# 4557

 

 

During the weeks that immediately followed the emergence of the novel H1N1 virus, not much was known about its virulence.  Schools where cases emerged were closed as a precaution, and many hospitals attempted to identify and quarantine suspect cases.

 

One of the big topics a year ago was the protection of those on the frontlines; healthcare and emergency workers.   They were considered to be the most likely to be exposed, and were in a unique position to pass the virus on to others.

 

In this article from the Johns Hopkins Gazette, we learn of lapses in infection protection protocol during 11 drills conducted at the Johns Hopkins Children’s Center last May.  The scenario involved a pediatric patient – suspected of having H1N1 – going into cardiac arrest.

 

Of the 84 HCWs who participated in these drills, 33% failed to don eye protection, 15% didn’t stop to put on a gown, and 19% did not wear a specialized respirator (presumably N95) mask.

 

The results of these mock drills were presented to the Pediatric Academic Societies meeting last week.

 

They highlight the importance of having PPEs (Personal Protective Equipment) in easy reach on hospital floors, and having a designated `gatekeeper’ whose job it is to ensure that all HCWs are compliant with infection protection protocol before entering a patient’s room.

 

This from the JHU Gazette.

 

 

H1N1 drills expose gaps in hospital infection protection

May 10, 2010
By Katerina Pesheva
Johns Hopkins Medicine

 

Resuscitation drills conducted during the first weeks of the H1N1 outbreak in May 2009 have exposed critical gaps in basic protection among hospital first-responders, according to a Johns Hopkins Children’s Center study.

 

Failing to use personal protection such as gowns, glasses, respirator masks and gloves during infection outbreaks makes hospital staff vulnerable to infection and increases the risk for transmission to patients, the researchers say.

 

The findings, presented May 4 at the Pediatric Academic Societies meeting, emphasize the need for repeat mock drills, the researchers say, and suggest that personal-protection exercises should be included in monthly mock crisis sessions held at the Johns Hopkins Children’s Center.

 

“Having another contagious outbreak is a matter of when, not if, and the time to master protection techniques is now, before it hits us,” said study lead investigator Christopher Watson, a pediatric critical-care fellow.

 

(Continue . . . )

NPI’s and Influenza

 

 

# 4539

 

 

NPIs are Non-Pharmaceutical Interventions – ways to reduce the spread of a disease - and have been a frequent topic in this blog over the years.   

 

NPI’s can be as simple as hand hygiene, covering your coughs, and avoiding crowds, or can involve the use of personal protective barriers like N95 or surgical masks, latex or vinyl gloves, and eye protection.

 

School closures, public education, staying home when sick, and engineered barriers to avoid exposure are also examples of NPIs.

 

And the evidence to date is these steps, if widely implemented, can make a real difference in the spread of an epidemic like Influenza.

Pharmaceutical solutions, most notably vaccines, take months to develop and deploy.  The next pandemic flu to erupt may not be nearly as mild as the 2009 strain, and may hit far more suddenly. 

 

The goal, in those early months before a vaccine becomes available, is to reduce the spread of the virus as much as possible.  In this way, the burden on health care facilities, and toll of absenteeism and on the lives of those effected can be reduced.

 

 

 

NPI’s have been described as being like slices of Swiss cheese, with each containing large holes through which the virus can pass, but when stacked on top of each other, can provide an effective barrier.

 

While it is known that these measures can help reduce influenza transmission, there are many open questions regarding their relative merits, cost effectiveness, and optimum combination.  

 

Unknown too, is exactly how influenza is transmitted.   

Large droplet spread, via coughing and sneezing, is assumed to be the primary mode of transmission, but the exact role of fomites (contaminated inanimate objects we may touch), and the role of fine aerosolized particles are only beginning to be understood.

 

Allison E. Aiello of the University of Michigan is one of the researchers that has been looking for answers to these questions, and I’ve featured her team’s work a number of times.

 

Michigan NPI Study: A Closer Look

Study: Effectiveness of NPIs Against ILI's

Study: NPI's Can Help Prevent Spread Of Flu-Like Illnesses

 

Aiello’s team has recently published their findings in the May issue of the American Journal of Infection Control.   The abstract is available, but it requires a subscription to access the main article.

 

Luckily we’ve a pretty good summary available from MedPage Today. First the abstract, then the link to the MedPage article.

 

Research findings from nonpharmaceutical intervention studies for pandemic influenza and current gaps in the research

Allison E. Aiello, et al.

AJIC: American Journal of Infection Control - May 2010 (Vol. 38, Issue 4, Pages 251-258, DOI: 10.1016/j.ajic.2009.12.007)

In June 2006, the Centers for Disease Control and Prevention released a request for applications to identify, improve, and evaluate the effectiveness of nonpharmaceutical interventions (NPIs)—strategies other than vaccines and antiviral medications—to mitigate the spread of pandemic influenza within communities and across international borders (RFA-CI06-010).

These studies have provided major contributions to seasonal and pandemic influenza knowledge. Nonetheless, key concerns were identified related to the acceptability and protective efficacy of NPIs. Large-scale intervention studies conducted over multiple influenza epidemics, as well as smaller studies in controlled laboratory settings, are needed to address the gaps in the research on transmission and mitigation of influenza in the community setting. The current novel influenza A (H1N1) pandemic underscores the importance of influenza research.

 

 

 

Non-Drug Approach Can Slow Spread of Pandemic Flu

By Michael Smith, North American Correspondent, MedPage Today

Published: April 30, 2010

Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
 

Nonpharmaceutical interventions, such as handwashing campaigns, can have a significant impact on the spread of the pandemic H1N1 flu, researchers said.

 

But an analysis of 11 CDC-supported studies reveals key gaps in the research, according to Allison Aiello, PhD, of the University of Michigan Ann Arbor, and colleagues.

 

The researchers, writing in the May issue of the American Journal of Infection Control, called for large intervention studies, conducted over multiple flu seasons, to assess the impacts of such things as handwashing, cough etiquette, and mask wearing.

 

Research is also needed into the psychosocial and cultural barriers that make some groups reluctant to accept such measures, Aiello and colleagues said, as well as lab studies to pin down how the flu is transmitted.

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