Maryn McKenna

Journalist and Author

Bats, Booze, Bugs, Birds, Blood and Bushmeat (ICEID 4)

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Since I started electing to do blog coverage of scientific meetings, I’ve run into an unfortunate reality. On any meeting day, there are one or two presentations that either are strikingly newsworthy or fit into an ongoing topic that I’m already interested in, and that therefore I feel obliged to write about. That means I’m unable to cover dozens, sometimes hundreds, of other interesting papers and posters.

I feel bad about this, especially when authors stop what they are doing to talk to me. So here’s my admittedly insufficient remedy: a quick round-up of a few of the hundreds of intriguing presentations this past week at the biennial International Conference on Emerging Infectious Diseases. (Program here; it’s a pdf, abstracts not individually searchable.) Apologies to everyone whom I didn’t get to.

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Flu Infections and MRSA Deaths in Maryland

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Sad news out of Maryland, and a reminder of how devastating MRSA, methicillin-resistant Staphylococcus aureus, can be when it combines with flu infection. According to the Maryland Department of Health and Mental Hygiene, the Washington Post and ProMED, five members of a family have fallen ill and three have died from MRSA pneumonia that took hold in lungs inflamed by flu infection.

The dead are Ruth Blake, 81, and her children Lowell, 58, and Vanessa, 56. Another child, Elaine, also fell ill and was hospitalized, and Ruth Blake’s sister has been hospitalized also. They had all contracted one of the seasonal flu strains circulating this year: H3N2. According to the Post, Ruth Blake was vaccinated against flu this season; her children were not. The assumption is that both flu and MRSA spread from the mother to the children.

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Some Paranoia for Your Weekend: CONTAGION Trailer

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Warner Brothers has released the first trailer for CONTAGION, a Steven Soderbergh bio-thriller about an influenza strain gone virally rogue that will open Sept. 9. Quoting from the movie’s website:

“Contagion” follows the rapid progress of a lethal airborne virus that kills within days. As the fast-moving epidemic grows, the worldwide medical community races to find a cure and control the panic that spreads faster than the virus itself. At the same time, ordinary people struggle to survive in a society coming apart.

Delicious exchange from the trailer (zinger response from Laurence Fishburne):

“Is there anyway someone could weaponize the bird flu?”

“Someone doesn’t have to weaponize bird flu. The birds are doing that.”

Here’s the trailer. You are made of stern stuff if it doesn’t make you want to wash your hands. (I’ll be over here in the corner, rubbing mine together in scary-disease glee.)

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Flu: Still a problem, just not here

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What a difference a year makes: At about this time in 2009, the world was still in the midst of the H1N1 “swine flu” pandemic, though cases had already trended down from their fall peak. Here at the end of 2010, flu has made barely a ripple.

In the United States, seasonal flu has been a non-story: The Centers for Disease Control and Prevention reported last week that flu activity is low by almost every metric: from the number of states where flu is widespread, to proportion of outpatient visits for flu-like illness, to adult deaths from pneumonia and influenza, to flu-related deaths among children.*

Here’s the map of flu activity in the US: By Dec. 18, only one state, Mississippi, was experiencing what is called “widespread” flu, the highest category:

And here’s the trend line for doctor visits for “influenza-like illness” — something that felt to the patient like flu. That black line is what the CDC considers the “epidemic threshold” for a flu season; this year’s case reports, the red line, fall below it:

But if there’s one thing that’s predictable about influenza, it is that it is going to behave in a not-predictable manner. That turns out to be true this year as well — because while the US is having a very mild season, the United Kingdom is getting punched. Look at this, from the BBC’s Health Desk, charting flu cases among adults — and note how close the current peak is to the peak cases during their swine flu epidemic:
The BBC is reporting that flu cases in the UK have risen by 50 percent in a week. Last weekend, the Telegraph reported that cases of flu serious enough to need intensive care had doubled in a week. And today, the Daily Mail is saying that Arrowe Park, a hospital in Wirral near Liverpool, has banned visitors in an attempt to slow down the spread of flu to vulnerable patients from the outside world.

Right now the UK seems to be alone in the intensity of its epidemic. Google’s Flu Trends (which doesn’t seem to sample the UK) is showing high search activity for flu-related terms only in Ukraine and Norway. (“High” is 4th on a scale of 1-5.) HealthMap, which does include the UK in its searches, shows hot spots only in England, Germany, and the east coast of Australia.

All of which makes it sound as though — for the US at least — flu is just not that much of a concern. That assumption would be a mistake, as two new articles underline. In Clinical Infectious Diseases, Jeffery Taubenberger (who recovered the virus of the 1918 pandemic) and co-authors remind us that 2010 marked the 500th anniversary of the first verifiable flu pandemic, suggesting that there are many more to come. And in the latest Scientific American, notable flu reporter Helen Branswell explores how little surveillance for flu there is at crucial chokepoints, such as pig farms, where new flus are likely to emerge. (Story is behind a paywall, but here’s the free podcast.) Branswell warns:

The 2009 influenza pandemic appeared to come out of nowhere. It started as what seemed like a lethal outbreak in Mexico, then spread north of the border. By the time health officials learned that the virus responsible for the alarming explosion of cases was new and an infection threat to most of humankind, they had no way to keep it from spreading around the world. By a stroke of luck, symptoms were mild in the vast majority of cases. What if next time we are not so lucky?

That question weighs heavily on the minds of influenza scientists and public health planners as they prepare for the next big outbreak. And there will be a next time.

*Frustratingly, the CDC doesn’t assign static links to its weekly FluView reports, so if you read this post after Dec. 31, that link may take you to a different report than the one this post references. I’m using data that was on the site Dec. 30 for week 50 of 2010, ending Dec. 18.

Update: Well, that was quick. The link above now goes to the FluView for the week ending Dec. 25. The number of states with “widespread” flu has risen to five: Alabama, Georgia, Mississippi, New York and Virginia. Things are picking up.

Update 2: But they’re picking up much more in the UK, and the spillover from flu cases is affecting hospital operations overall. The Guardian reported Dec. 31:

NHS pressure group Health Emergency today claimed a number of hospitals in East Anglia were on black and red alert, saying the NHS was already struggling as a result of the flu outbreak.

Chairman Geoff Martin said the James Paget University hospital in Great Yarmouth, Norfolk, yesterday declared a black alert – the most severe status level – and that the Norfolk and Norwich University Hospital was on red alert – one step lower.

He said: “We warned that hospitals would be forced on to black alert as the flu cases fill the available beds. Now it’s happening and we do not believe that the chaos is restricted to East Anglia. The NHS is now on the brink of the worst winter crisis in over a decade as the harsh reality of cuts to beds and staffing numbers is exposed with lethal consequences.”

Image: Mine, Brussels, July 2010

From 1918 Autopsy, A First Glimpse of Sickle Cell — and a Warning

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This is just amazing.

Ninety-two years and a few months ago, a US Army private died at what is now called Fort Riley, Kansas. It was July 1918, and the 21-year-old recruit had been sick for two days with a fever and a headache, an aching chest and a hard, hacking cough that didn’t bring anything up. He was admitted to the base infirmary, where they found his temperature was a scorching 105.4 degrees and his entire right lung was not functioning properly. He was diagnosed with pneumonia.

It was 10 years before Alexander Fleming would find the mold that produced penicillin, the first antibiotic, on a contaminated culture plate in his laboratory, and 25 years before World War II service-members would benefit from the compound. The medical staff at Fort Riley had almost nothing to offer the private except a primitive immunotherapy: serum refined from the blood of earlier victims of streptococcal pneumonia. It did nothing for him. He died on July 20, nine days after being admitted.

Because he was a member of the armed forces, the base hospital followed a directive that dated back to U.S. Surgeon General William Hammond in 1862: They performed an autopsy on his body, and recorded and preserved the results. Their diagnosis had been right: His lung tissue was positive for S. pneumoniae. But the damage done to his body by the infection and his immune system’s response to it was dramatic: The middle and lower lobes of his right lung, and both kidneys and his spleen, were inflamed and necrotic and speckled with hemorrhages.

In accordance with Hammond’s Civil War order, the medical staff wrote up the autopsy findings and preserved snips of the soldier’s tissues in blocks of paraffin, and sent them all to a repository that Hammond had ordered created: the Army Medical Museum, later called the Armed Forces Institute of Pathology, in the northwest corner of Washington, D.C. And there they sat, among many thousands of other records and samples, until a member of the institute’s staff delved into its archives 80 years after the soldier’s death.

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New CDC flu numbers: This may not go well

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(Constant readers: Apologies for the slow blogging. Casa Superbug’s little medical crisis from a week ago has recurred, and things are a bit distracting. Back to normal soon, I hope.)

In public health, one of the numbers you hear most often — and especially so the past few years — is
36,000. That’s the number of deaths that the CDC estimates occur in an average year from influenza.

Or rather, estimated. Because today, in its weekly bulletin
MMWR and also in a teleconference for the press, the CDC announced that it is discarding that widely used number, in favor of newer numbers from newer studies that take into account the wide variation in illness and death from one flu season to the next.

The new estimate is:
23,607. Or, a range that goes
from 3,349 to 48,614. Or, in the language recommended by a CDC scientist and a communications specialist in the press call, ”
tens of thousands of people [who] may die each year in an average flu season.”

If that sounds difficult to communicate in a concise manner, well, the reporters on the CDC call today clearly thought so too. And while reporting study results forthrightly is transparent, and more precise numbers are almost always better, I can’t help but wonder whether this attempt at precision and transparency will not be received well. After all, we are only a few months (or a few weeks, depending whose end date you accept) away from the dribbling conclusion of a worldwide pandemic that was taken so not-seriously by the public that, in the US, 71 million doses of H1N1 vaccine went unused — and in Europe, some public representatives alleged that the entire emergency was a concoction by pharmaceutical companies.

Given that history, putting out a public message that
flu kills fewer people than we thought — but is, still, a serious disease that should be planned for and vaccinated against — sounds like a hard sell.

Here’s how today’s new numbers came about:

The mortality rate from flu has always been difficult to assess: People die of influenza directly, but they also die of underlying conditions — heart disease or chronic obstructive pulmonary disease, among others — that might not kill the person if influenza were not putting an extra strain on the system. In either case, but especially in the latter, the death may not be attributed to flu, particularly if the victim has not been tested for the presence of the flu virus.

So, to arrive at an estimate, the CDC has used a statistical model. As explained in the briefing today by Dr. David Shay of the CDC’s Influenza Division:

We have two categories that we look at… One is death certificates that have an underlying diagnosis of pneumonia or influenza. 99% of those deaths are actually coded as pneumonia. So, that’s to make an estimate of deaths in a particular season from pneumonia that are associated with flu. And typically, that’s about 8.5% of deaths over the time period that we looked at…  The broader category of respiratory and circulatory deaths we think encompasses the full picture of influenza-associated deaths, including things such as people who might die because of worsening chronic obstructive pulmonary disease or worsening congestive heart failure that results in death after an infection. And we estimate that about 2% of that broader category in any typical year is associated with influenza.

One other factor affects flu mortality: Which flu strain type is dominant in the season being measures. Flu is generally taken to cause the most severe disease, and the greatest number of deaths, in the elderly; but some strains cause more severe disease than others, and some (H1N1 “swine” flu, for instance) attack the young, who are healthier and less likely to die, more than they do the old. Again, Shay:

[I]t’s important to keep in context, which we don’t really describe in this article because of space, that there’s at least four factors that affect sort of flu mortality in any particular year, and those four would be the specific strain or influenza strains that are in circulation, sort of the length of the season or how long influenza is circulating in the united states, how many people get sick, because of course, the more people get sick, there is more likely to be more serious outcomes, and finally, who gets sick.

In the study released today, the CDC did two things: It
broadened the range of flu seasons from which it took data to feed into the statistical model, and it
took a second look at the years on which the previous model, the one that produced the 36,000-death estimate, was based.

When the range of years was broadened to 31 flu seasons (1976-77 to 2006-07), here’s what shook out:

  • For deaths from influenza and pneumonia:
    from 961 in 1986-87 to 14,715 in 2003-04, an average of 6,309
  • For deaths from respiratory and circulatory complications:
    from 3,349 in 1986-87 to 48,614 in 2003-04, an average of 23,607.

(When asked which number should be used for shorthand, Shay said: “The broader category of respiratory and circulatory deaths we think encompasses the full picture of influenza-associated deaths.”)

When the 36,000-death estimate was re-examined, Shay said:

The 36,000 number that’s often used pertains to a very specific time period from 1990 to 1999. And in that decade, where we had prominent circulation of H3N2 viruses, they were prominent in eight of the nine seasons that are contained within the data that were used to make that estimate, and those are, as you know, typically more severe seasons. We had a high mortality for that nine-year period.

According to the MMWR analysis, mortality rates in the H3N2 years were 2.7 times higher than in years when other types were dominant.

So that’s the rationale behind today’s dialed-down numbers. Here’s the potential problem with it: It just took me about 1,000 words to (somewhat talkily) explain. It requires patience and detail to impart, which in the current media environment are in very short supply. As one of the participants on the call said today:

I’m really scratching my head here wondering what I’m going to use, because we really don’t have a lot of time … to present a lot of numbers, and I think in a sense to say that the range is 3,000 or 3,300 to 49,000 raises a lot of questions, and I think we don’t have time to answer those questions in every report. And I also wonder if it’s not a bit misleading to use 3,300 as the bottom number since it’s been 20 years since it was that low, and even in the last 20 years, the mortality has never been much below 12,000.

You see the problem.

To repeat: This is an effort at transparency and accountability; those are worth applauding. But it’s also a nuanced and difficult health-communication message, launched into a zeitgeist already tuned toward conspiracy theories and a media marketplace with little time or expertise to counter them.

Pessimistically, I wonder how long it will be before this message gets transformed into something like, “See? I told you so. Flu isn’t that big a deal after all.” I hope the CDC is prepared when it does.

(Here’s today’s MMWR article, the transcript of the press briefing, and a Q&A on the new calculation. The cite is: Morbidity and Mortality Weekly Report, “Estimates of Deaths Associated with Seasonal Influenza — United States, 1976–2007.” August 27, 2010. 59(33);1057-1062)

A great blog leaves the 'sphere

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Constant readers: Well, the bug finally got me, or one of its close cousins did. I’ve been on the road almost nonstop, and after a book event at University of Wisconsin last week, was felled by a violent bout of foodborne illness that was almost certainly staph — not MRSA, but the related strain of staph that causes very rapid food poisoning. (And, umm, thorough. Ick.) So I’ve been out of commission both physically and mentally. And on a plane again tonight. Back soon in both ways, promise.

But there’s important sad news today that I want you all to know about. Revere, the peerless author of the marvelous public health blog Effect Measure, is bowing out of the blogosphere. For more than 5 years now, Revere (a collective voice of an unknown number of public health experts —for simplicity, let’s say “he”) has been a reliable, thoughtful, expert, humorous and deeply knowledgeable guide to the intricacies of public health and public health politics. He has taken a particular interest in the possibility of pandemic flu and has been the unofficial leader of the loosely knit but fiercely loyal group of bloggers and crowdsourcers who call themselves Flublogia. And though few would admit it, Revere’s posts have been consistent agenda-setters in newsrooms all across the planet; insiders knew that, if Revere said something, it would start showing up in newspapers and on wires about 12 hours later.

If you are a Revere reader and missed this news, get over there and leave a note in the quickly lengthening comment string. If you never made the blog’s acquaintance, now would not be too soon.

Once again, flu and bacterial co-infection

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With the H1N1 pandemic trending down, it may seem that the question of how much bacterial co-infection affects the outcome of flu is less important than it was. But though the pandemic is subsiding — for ever, for this season, or just until a third wave, who can say — researchers are just now getting enough good data to be able to make solid observations about what happened during the past 10 months.

Case in point: Writing in the journal Public Library of Science (PLoS) ONE, a team of researchers from Australia has pinpointed the incidence of MRSA co-infection during flu in two hospitals in Perth last summer, which was the Australian winter and the height of their flu season. Of 252 patients admitted for H1N1 infection, 3 were identified during treatment as having MRSA pneumonia. They survived, but two other patients who died were found to have MRSA pneumonia during post-mortem exams. [Read more…]

NEJM: Antibiotics for pneumonia in H1N1

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The New England Journal of Medicine has been running an open-access blog on H1N1 flu, and they’ve put up a post on when to give antibiotics to prevent secondary bacterial pneumonia, including MRSA pneumonia, in flu patients.

There’s a table of key clinical points to consider, and these important points are made:

For the child or adult admitted to a hospital intensive care unit in respiratory distress, we believe that empirical initial therapy with broad-spectrum antibiotics to include coverage for MRSA, as well as Streptococcus pneumoniae and other common respiratory pathogens, is appropriate.
For the previously healthy child or adult with influenza who requires admission to a community hospital and has features that suggest a secondary pneumonia (Table 1), we would recommend empirical treatment with a drug such as intravenous second- or third-generation cephalosporin, after an effort has been made to prove the association with influenza and to get adequate lower respiratory tract specimens for Gram’s stain and bacterial culture.
If the Gram’s stain suggests the presence of staphylococci or if there is a rapidly progressive or necrotizing pneumonia, an additional antimicrobial agent to cover MRSA is appropriate. …
We do not believe that initial coverage for MRSA is indicated in all patients who are thought to have secondary bacterial pneumonia.

So, to recap:

  • Development of apparent pneumonia in the presence of flu should be met with antibiotics that will treat drug-sensitive bacteria, along with a test to show which bacteria are causing the illness.
  • If staph is present (or the pneumonia appears very serious), then the antibiotics should be upped to one that can control MRSA.
  • But if the pneumonia is serious enough to send a patient straight to the ICU, then drugs that can quell MRSA should be started right away.

For anyone concerned about pneumonia in the aftermath of H1N1, this is worth bookmarking.

CDC warns of deaths from H1N1 flu + bacterial infections

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Over at CIDRAP, my colleague Lisa Schnirring writes tonight about the CDC’s concern over increasing numbers of deaths from bacterial pneumonia in people who have come down with H1N1 flu.

We’ve talked about this before here. Our concern of course has been MRSA, and there is good evidence that there have been fatal MRSA infections in flu victims. But the primary culprit now is not MRSA but pneumococcus (S. pneumoniae):

Anne Schuchat, MD, director of the CDC’s National Center for Immunization and Respiratory Diseases, told reporters at a press briefing that the CDC is seeing an increasing number of invasive pneumococcal disease cases around the country, but the numbers were particularly high in Denver at a time when pandemic H1N1 activity was peaking in the area.
Over the past 5 years the Denver area averaged 20 pneumococcal disease cases in October, but this year the area recorded 58, and most were in adults between the ages of 20 and 59, many of whom had underlying medical conditions.
Health officials expect to see more pneumococcal disease when seasonal flu circulates, but the infections typically strike people who are older than 65. In past pandemics secondary bacterial pneumonia infections, particularly those involving Streptococcus pneumoniae, frequently contributed to illnesses and deaths.

This is particularly troubling and sad because we have good vaccines for pneumococcus, one for adults and a different one for children. Only, people are not taking them: Uptake is only about 25% in high-risk groups and much lower in the general population, despite urgings from CDC and other health advisory boards.

Perhaps it’s not surprising that people have not heeded advice to get the pneumococcus vaccine as a protection against flu’s worst effects, given that uptake of the flu vaccine itself has been so low. But if you or someone you love is in a high-risk group, it would be a really good idea to rethink that.