Research: Low Vaccination Rates Among 2013-2014 ICU Flu Admissions

Yearly Flu Hospitalizations by Age Cohort – CDC FluView

Showing 2009-10 & 2013-14 Hitting ages 18-64 unusually hard

 

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Despite reduced VE (Vaccine Effectiveness) estimates in recent years, and a production schedule that requires predicting – 6 months in advance – what flu strains will dominate in the upcoming flu season, we continue to see evidence that most years the seasonal flu shot manages to convey a fairly decent level of protection against influenza.

 

Despite the mantra of the CDC, and other public health organizations, urging people to get the yearly jab, only just over 1/3rd of adults (aged 18-64) got the flu shot last year (see TFAH Report Finds Low Uptake Of Flu Shots Among Young Adults). 

 

This year, we are seeing the pH1N1 strain dominate for the first time since 2010, and as it did in 2009, it appears to be targeting younger adults harder than usual. As a result, we’ve seen reports of an uptick in ICU hospitalizations, and deaths, among younger adults across the nation this winter.

Which brings us to a research letter, published yesterday in the American Journal of Respiratory and Critical Care Medicine, that finds – between November 2013 and January 8th, 2014 – a `high number of otherwise healthy individuals with critical illness requiring care in the ICU. Most patients who required ICU level care were not previously vaccinated.’

 

High ICU admission rate for 2013-2014 Influenza is associated with a low rate of vaccination

Jelena Catania, Loretta G Que, Joseph A Govert, John W Hollingsworth, and Cameron R Wolfe

 

While most of this letter is behind a pay wall, we have a press release from Duke University, with some of the details. First an excerpt, after which I’ll return with more.

 

Duke University Medical Center

Young, unvaccinated adults account for severest flu cases

DURHAM, N.C. – A snapshot of patients who required care at Duke University Hospital during this year's flu season shows that those who had not been vaccinated had severe cases and needed the most intensive treatment.

In an analysis of the first 55 patients treated for flu at the academic medical center from November 2013 through Jan. 8, 2014, Duke Medicine researchers found that only two of the 22 patients who required intensive care had been vaccinated prior to getting sick.

The findings were published online in Monday, Feb. 10, 2014, in the American Journal of Respiratory and Critical Care Medicine.

"Our observations are important because they reinforce a growing body of evidence that the influenza vaccine provides protection from severe illness requiring hospitalizations," said lead author Cameron Wolfe, M.D., assistant professor of medicine at Duke. "The public health implications are important, because not only could a potentially deadly infection be avoided with a $30 shot, but costly hospitalizations could also be reduced."

Wolfe said this year's flu season was marked by hospitalizations of previously healthy young people, with a median age of 28.5 years. Among those who were hospitalized at Duke, 48 of the 55 were infected with the H1N1 virus that caused the 2009 pandemic. That outbreak also hit young adults particularly hard.

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This research also found a high rate of failure of the rapid flu test (something we’ve discussed before in MMWR: Evaluating RIDTs and No Doesn’t Always Mean No) which has led to delays in starting antiviral treatment for some patients.

The authors conclude:

Together, our observations during this influenza season support a high prevalence of the H1N1 virus affecting young adults and requiring ICU care, high false negative rates of rapid flu tests, and delay in starting antiviral treatment," Wolfe said. "Added to the finding of very low vaccination rates among both hospitalized and ICU admissions, our observations support previous findings that vaccination reduces the severity of disease and vaccinations should be encouraged as recommended by the U.S. Centers for Disease Control and Prevention."

 

While the effectiveness of the seasonal flu shot has often been oversold, I certainly get one every year, and urge others to do the same.  

 

Not because it is guaranteed protection, but because – like wearing a seatbelt in a vehicle – it improves your odds of a good outcome.

 

And despite disappointing VE numbers (see CIDRAP: A Comprehensive Flu Vaccine Effectiveness Meta-Analysis) - particularly among the elderly ( see PLoS One: Limited Effectiveness Of Flu Vaccines In The Elderly & BMC Infectious Diseases: Waning Flu Vaccine Protection In the Elderly) - we continue to see evidence of benefit from the shot, even if full protection isn’t conveyed to the recipient.

 

In  2011,  NFID - the National Foundation for Infectious Diseases - convened a group of experts to address the issues of influenza and the elderly. From that panel a 5-page brief has emerged, called: Understanding the Challenges and Opportunities in Protecting Older Adults from Influenza.

Although the elderly generally see less protection from the flu vaccine, older individuals may still mount a robust immune response. In populations 65 and older, the brief points out that:

• Hospitalization rates for influenza and pneumonia are lower in community-dwelling adults who received the seasonal influenza vaccine.
• Immunization is associated with reduced hospitalization of older patients for cardiac, respiratory, and cerebrovascular diseases.

While the goal of vaccinating the younger population is to prevent infection, the authors point out that:

• . . . the goal in older adults is to prevent severe illness, including exacerbation of underlying conditions, hospitalization, and mortality.

 

Similarly, over the past couple of years, we’ve seen studies suggesting the flu vaccine may reduce the risk of heart attack and stroke (see JAMA: Flu Vaccine and Cardiovascular Outcomes & Study: Flu Vaccine May Reduce Heart Attack).  Not a slam dunk, but intriguing nonetheless.

 

There is obviously a great need for better, and faster to market, flu vaccines.  A topic that was well addressed back in 2012 by CIDRAP: The Need For `Game Changing’ Flu Vaccines.

 

But until they can be developed - the flu shots we have –  when coupled with good `flu hygiene’ (washing hands, covering coughs, staying home when ill)  remain the best preventative actions you can take against the flu.

 

And this year’s flu season shows that being young, and healthy, is no reason to avoid getting the shot.

Australian Doc: ICU’s Were On `Verge of Collapse’ During Pandemic

 

 

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Despite years of planning and preparing for a much worse pandemic (which may yet come), hospitals – particularly ICUs – in many regions around the world found themselves severely tested during the peak of the 2009 pandemic.

 

The vast majority of people who contracted this virus recovered without incident, but for something less than 1% of those infected, swine flu proved far more serious.  

 

Today, a detailed overview of how ICU’s in Australia coped with the influx of patients last year – and hopefully, some lessons learned – from ABC (Australia) News.

 

 

 

 

Swine flu put hospitals 'on edge' last year › News in Science (ABC Science)

Thursday, 27 May 2010 Helen Carter
ABC

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Australia's intensive care system was on the verge of collapse for the first time ever during last year's swine flu epidemic, according to one intensive care physician.

 

Associate Professor Steve Webb from the Royal Perth Hospital hopes lessons learnt in 2009, together with vaccination, and the fact many now have some immunity to swine flu, will help prevent a repeat scenario this year.

 

Webb will tell the Australasian Society for Infectious Diseases annual scientific conference in Darwin this week that early diagnosis and treatment with antivirals is vital, as is expanding the ICU system, to cope with admissions.

 

Webb and colleagues recently investigated influenza H1N1 (swine flu) admissions to all 187 intensive care units (ICUs) in Australia and New Zealand in 2009.

 

"ICUs were on the point of collapse which was unprecedented. The ICU system in every region in Australia came close to collapse and we've learnt a great deal from that and will be better prepared to manage ICU surge capacity this year," says Webb.

 

"One Sydney doctor said that in one week during last year's flu season, his intensive care unit saw more people with severe acute respiratory distress than in any other week of his 30 year career in intensive care...There was a massive wave of very sick people."

 

(Continue . . . )

 

 

The sobering lesson here, of course, is that we remain woefully unprepared to deal with a truly severe pandemic. 

 

A repeat of 1918 could be 100 times worse than what we saw in 2009.   While that may never happen, history suggests that we shouldn’t take that for granted.

 

Obviously, no health care system can prepared adequately for a `worst-case’ pandemic.   

 

But when a `mild-to-moderate’ pandemic tests our health care capacity the way H1N1 did, it demonstrates just how vulnerable we are to even a moderately severe public health crisis.

UK: Percentage Of Hospitalized Patients In ICU Rising

 

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From the BMJ (British Medical Journal) this morning, a news report indicating that the percentage of those hospitalized for Swine flu in the UK requiring ICU beds is going up. 

 

Last July only about 7% of those hospitalized required critical care, whereas now that number is about 21%.

 

While ICU units are obviously under increasing patient loads, this change in admittance ratio needn’t signify a change in the virus.   Doctors may simply be less inclined to hospitalize less-severely ill patients today than they were four months ago.

In absolute terms, however, the number of new ICU admissions for this virus in the UK is at a new weekly high. 

 

 

 

Number of swine flu patients going into intensive care is rising

Published 2 November 2009, doi:10.1136/bmj.b4528
Cite this as: BMJ 2009;339:b4528

Nayanah Siva

1 London

The proportion of patients in hospital with swine flu who have been admitted to intensive care continues to rise in England, said the chief medical officer, Liam Donaldson, last week.

 

In the week to 28 October 157 of 751 hospitalised patients with the illness (21%) had to go into intensive care, up from 63 of 840 patients (7.5%) in the last week of July, when the epidemic reached a peak before the school holidays began.

 

"There is an eerie similarity to what happened in Australia," said Professor Donaldson at a press briefing on 29 October. At one point during Australia’s winter months of June to August 25% of hospitalised patients were in critical care.

 

Children under the age of 5 years had the highest rate of hospitalisation in the week to 28 October, Professor Donaldson said, and younger patients admitted to critical care were much less likely than older patients to have underlying health conditions.

 

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The View From The ICU

 

 

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While the H1N1 virus has proved to be a moderate illness for the vast majority of those infected, for a small percentage of mostly younger patients, infection has proved life-threatening. 

 

Betsy McKay of the Wall Street Journal has report today on the severity of illness being seen in ICUs around the world, and how that raises concerns on what we may see this fall and winter in the northern hemisphere.

 

 

• OCTOBER 12, 2009, 10:45 A.M. ET

Swine Flu Is Severe for Some, Studies Show

by BETSY MCKAY

Swine flu may be mild for most people, but some become so gravely ill that they require sophisticated techniques, equipment, and aggressive treatment in intensive-care units to survive, according to three new studies.

 

"This is the most severely ill that we've ever seen people," said Anand Kumar, lead author of one of the studies and ICU attending physician for the Winnipeg Regional Health Authority in Canada.

 

"There's almost two diseases. Patients are either mildly ill or critically ill and require aggressive ICU care. There isn't that much of a middle ground."

 

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JAMA  (The Journal of The American Medical Association) has a series of 4 articles published today on the impact of H1N1 on ICUs from around Canada, Mexico, and Australia & New Zealand.

These are freely available without subscription.

 

Critically Ill Patients With 2009 Influenza A(H1N1) Infection in Canada Published October 12, 2009.

 

Critically Ill Patients With 2009 Influenza A(H1N1) in Mexico Published October 12, 2009.

 

Extracorporeal Membrane Oxygenation for 2009 Influenza A(H1N1) Acute Respiratory Distress Syndrome Published October 12, 2009.

 

Preparing for the Sickest Patients With 2009 Influenza A(H1N1) Published October 12, 2009.

 

The first two studies outline the experiences of ICUs in Canada and Mexico. 

 

The 3rd study, on ECMO use in Australia & New Zealand, indicates that the average length of time severely ill patients required this heart-lung bypass was a remarkable 10 days.  Despite this intervention, patients placed on ECMO saw a 21% mortality rate.

 

For more information on ECMO, you may wish to revisit my blog The ECMO Option.

 

The last article is basically a summation of some of the information from the first 3 studies.  

 

All four are worth your time to review.

The ECMO Option

 

 

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ECMO or Extracorporeal Membrane Oxygenation is a specialized heart-lung bypass machine used to take over the body’s heart and lung function – for days or weeks if necessary – while the body heals from injury or illness.

 

ECMO is a highly specialized, and technically demanding life support option which is not available a most hospitals around the globe.  It is most commonly used in neonatal intensive care units for newborns in respiratory distress, although it is also used for pediatric and adult patients with severe heart or respiratory deficits.

 

One of the disturbing hallmarks of the novel H1N1 `swine’ flu virus is that it produces – in a very small percentage of victims – severe lung damage resulting in ARDS (Acute Respiratory Distress Syndrome).  

 

Over the summer, a number of these flu patients have been placed on ECMO machines, to give their damaged lungs time to heal, as demonstrated in the CBS Evening News Video below (hat tip mcphilbrick on FluTrackers).

 

 

 

 

Normally, patients with ARDS are placed on mechanical ventilation in ICUs, and treated with a variety of pharmacological agents to reduce infection (antibiotics) and lung inflammation (corticosteroids, Nitric Oxide, etc.).  

 

Despite these measures, ARDS is generally fatal in 50% of patients.

 

With H1N1 viral pneumonia, mechanical ventilation often does not result in adequate oxygenation, as the lungs are too congested to allow oxygen exchange in the alveoli.

 

(Image adapted from Wikipedia)

 

With ECMO, the burden of pumping and oxygenating the blood is taken from the heart and lungs, and they are given time to heal. 

 

A more detailed explanation is available in this emedicine article on ECMO (above image from that article).

 

In a Lancet Study, published earlier this week, UK researchers determined that ARF (Adult Respiratory Failure) patients that received ECMO support as opposed to conventional ventilation have a greater survivability without disability.

 

Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial

 

 

ECMO resources are extremely limited of course, and are not available in many regions of the world.  

 

Even in places where it is available, triage decisions regarding which severely affected H1N1 patients will get this sort of life support – and for how long – will become tougher as we progress into this flu season.

 

The number of staffed ECMO support beds available in the US appears to number in the low-to-mid hundreds. 

 

While ECMO can improve a patient’s odds of surviving, it is by no means a sure thing. Complications, including infection at the site of cannulation, are not uncommon.

 

This is a last ditch, heroic measure, reserved for those who cannot survive without it.   But for those with severe H1N1 induced ARDS, it may be their last, best option.

Study: Half Of ICU H1N1 Patients Without Underlying Conditions

 

 

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A hat tip to Crof over at Crofsblog for finding this report in the Barcelona Reporter about a study, published on Friday in the journal Critical Care, that examines the risk factors of 32 ICU patients admitted for pandemic influenza.

 

First the news story, then the abstract to the paper.

 

Study involving 21 Spanish hospitals states 50% of swine flu, ICU patients had no health problems

About half of people admitted to ICU in hospitals for severe complications of influenza A had no risk factor or disease, according to a study conducted in 21 Spanish hospitals.

Study involving 21 Spanish hospitals states 50% of swine flu, ICU patients had no previous health problems

 

The study, presented on the website of the medical journal ‘Critical Care’ is the largest ever conducted in Europe on influenza cases requiring intensive care. Their findings contradict one of the messages on influenza A released by the Ministry of Health and the Department of Health, which have repeatedly reported that patients with influenza A cases had previous health problems.

 

The findings contain important messages for both the general population and for health authorities and medical intensivists. For the general population, an appeal to healthy people without risk factors to avoid falling prey to overconfidence in regard to influenza A. Although the vast majority of those affected will overcome the flu without complications, a small percentage will have pneumonia and should be hospitalized.

(Continue . . . )

 

Over the summer many countries have repeated the mantra that those who are experiencing severe illness nearly all have underlying medical conditions.   Apparently they feel this is a reassuring message.

 

Over and over, of course, we’ve seen reports to the contrary.  

 

While underlying conditions might put you at greater risk, previously healthy individuals are seeing bad outcomes with this virus as well. Once again, this study raises questions about obesity being an underlying factor – a theory that has fallen in and out of favor several times over the past few months.

 

The good news is, those who are seriously impacted by this virus remain a very small percentage of the total infected.

 

This (slightly reparagraphed) abstract is from the journal Critical Care.   A provisional PDF file of the study is available to download, as well.

 

 

Intensive care adult patients with severe respiratory failure caused by Influenza A (H1N1)v in Spain

Jordi Rello , Alejandro Rodriguez , Pedro Ibanez , Lorenzo Socias , Javier Cebrian , Asuncion Marques, Jose Guerrero, Sergio Ruiz-Santana , Enrique Marquez , Frutos del Nogal-Saez , Francisco Alvarez-Lerma , Sergio Martinez , Miquel Ferrer , Manuel Avellanas , Rosa Granada , Enrique Maravi-Poma , Patricia Albert , Rafael Sierra , Loreto Vidaur , Patricia Ortiz , Isidro Prieto del Portillo , Beatriz Galvan , Cristobal Leon-Gil  and The H1N1 SEMICYUC working group

Critical Care 2009, 13:R148doi:10.1186/cc8044

Published:
11 September 2009

Abstract (provisional)

Introduction

Patients with influenza A (H1N1)v infection have developed rapidly progressive lower respiratory tract disease resulting in respiratory failure. We describe the clinical and epidemiologic characteristics of the first 32 persons reported to be admitted to the intensive care unit (ICU) due to influenza A (H1N1)v infection in Spain.

<SNIP>

Results

Illness onset of the 32 patients occurred between June 23 and July 31, 2009. The median age was 36 years (IQR = 31 - 52).

 

Ten (31.2%) were obese, 2 (6.3%) pregnant and 16 (50%) had pre-existing medical complications.

 

Twenty-nine (90.6%) had primary viral pneumonitis, 2 (6.3%) exacerbation of structural respiratory disease and 1 (3.1%) secondary bacterial pneumonia.

 

Twenty-four patients (75.0%) developed multiorgan dysfunction, 7 (21.9%) received renal replacement techniques and 24 (75.0%) required mechanical ventilation. Six patients died within 28 days, with two additional late deaths. Oseltamivir administration delay ranged from 2 to 8 days after illness onset, 31.2% received high-dose (300mg/day), and treatment duration ranged from 5 to 10 days (mean 8.0 + 3.3).

 

Conclusions

Over a 5-week period, influenza A (H1N1)v infection led to ICU admission in 32 adult patients, with frequently observed severe hypoxemia and a relatively high case-fatality rate. Clinicians should be aware of pulmonary complications of influenza A (H1N1)v infection, particularly in pregnant and young obese but previously healthy persons.