Saturday, May 23, 2009

From simple to stupid

Epidemic: from the Greek, epi- (upon) + -demos (the people)

Pandemic: from the Greek, pan- (all) + -demos (the people)

Pandemic (according to the WHO): from external pressure and internal weakness, highly-virulent + "justified" panic + all + the people

The definition of a pandemic used to be simple: a worldwide outbreak of disease in excess of what would normally be expected (a global epidemic).  

The WHO even came out with a definition of worldwide spread (community transmission in 2 or more WHO regions).

But now, apparently, the WHO intends to change the definition of a pandemic from simple to stupid.

Bowing to pressure from member nations, the WHO is (according to the New York Times) going to change the definition to include the severity of disease, and will probably do so in such a way that the current H1N1 outbreak will never count as a pandemic (unless it becomes more virulent, which it very well might).

Now, you may remember that we've had three pandemics in the last century, one in 1918, one in 1957 and one in 1968... or, at least, that used to be true.  If this new definition goes into effect as described, we'll have to erase those last two from the list, because they were no more severe than this new H1N1 strain appears to be right now.

Whether a given outbreak is a pandemic or not is a separate question from how severe that pandemic is.  

If the WHO thinks a severity scale would be useful, then by all means they should create one. There are some good arguments against using a severity scale (flu viruses evolve so quickly, severity varies between and within countries, etc.), but it's possible a severity scale would help countries and communities to better plan for and respond to a pandemic... but the role of a severity scale should be to better describe an existing pandemic, not to determine whether an outbreak is a pandemic.

If the WHO goes through with this, there will be two definitions of a pandemic: One used by epidemiologists and other public health professionals, and one used by the WHO --because the WHO's new idea for a definition doesn't make any rational sense.  By setting up such a situation, the WHO will be undercutting its own credibility in a time when its ability to lead is more important than ever.

Instead of caving to the pressure of politicians from the member nations who feel that declaring a pandemic would cause "unjustified panic," the WHO should be using this as a teachable moment, to educate the public about what a pandemic is, what can be done about it, and why panic is never a justified reaction regardless of severity.


Wednesday, May 20, 2009

Obesity and H1N1

The Washington Post just ran a story with the headline "Survey finds link between obesity and flu severity."  Now, I'm usually a big fan of The Post, but that turns out to be completely inaccurate.  

The study in question, entitled "Hospitalized Patients with Novel Influenza A (H1N1) Virus Infection --- California, April--May, 2009," was published online as an early release by the CDC's Morbidity and Mortality Weekly Report (MMWR), and there is nothing in that study to indicate that obesity is a risk factor for severe disease with H1N1.  Nothing at all.  

The authors don't interpret their findings that way in the paper, and the simplest of math shows that such a conclusion makes no sense on the basis of this data.

As the wonderful XKCD t-shirt my wife got for me says, "Stand back, I'm going to try SCIENCE!"

The prevalence of obesity among the 30 hospitalized cases in California was 4/30 = 13.33%
The prevalence of obesity in California (in 2001) was about 20.9%

13.33% is less than 20.9%

Now, you shouldn't take that to mean that obesity is protective against the H1N1 virus.  (The numbers are just too small for statistical stability.)  But there's absolutely no reason on the basis of this data to conclude that obesity "obesity may raise risk for flu complications," as the Post's running title for this piece reads.  Which is why the authors make no such assertion.

Does that mean the same thing as "there's absolutely no reason at all to conclude that obesity is a risk factor for severe disease with H1N1?"  No, it does not.  Thirty cases are too few to draw definitive conclusions.  And, in fact, the article goes on to say:

"We were surprised by the frequency of obesity among the severe cases that we've been tracking," said Anne Schuchat, one of the CDC epidemiologists managing the outbreak. She said scientists are "looking into" the possibility that obese people should be at the head of the line along with other high-risk groups if a swine flu vaccine becomes available.

And it is entirely possible that there's something to that, though the article gives us no direct evidence to support it.

But if any such evidence exists, it certainly isn't to be found anywhere in the MMWR paper.  And the paper's authors make no claim that it is, so don't blame them for the inaccuracy.  

Tuesday, May 19, 2009

Swine flu + Japan = Karaoke boom?

Apparently, a lot of students at Japanese high schools that have been shut down due to the H1N1 outbreak haven't been staying home; instead, they've been going out for karaoke

As someone who discovered firsthand that karaoke microphones make good fomites (someone shared a nasty cold with me once, by way of a karaoke mic), I'd like to point out that this is a Very Bad Idea.  --All the more so, since a lot of the karaoke venues in Japan include smallish private rooms, where the ratio of students to square feet (and, therefore, the opportunities for large droplet spread) can be quite high.

Is this an argument for not shutting down schools, then?
Probably not.  

Unless a very high percentage of students from these closed schools are crowding into the karaoke joints or other venues where there is a relatively high risk of transmitting the flu, school closings are still likely to be more effective than not in slowing the spread of the virus.

Friday, May 15, 2009

Another edition of "Complete Rubbish"

Adrian J. Gibbs, a retired plant virologist recently claimed that the H1N1 "swine flu" virus must have originated as the result of a laboratory accident.  

According to the New York Times, his theory (or, rather, his poorly thought out hypothesis) has now been debunked by the WHO. 

A brief excerpt from the article:

Dr. Gibbs, who had studied the gene sequences of the swine flu virus posted on public data banks, argued that it must have been grown in eggs, the medium used in vaccine laboratories. He reached that conclusion, he said, because the new virus was not closely related to known ones and because it had more of the amino acid lysine and more mutations than typical strains of swine flu.

His theory was reported by Bloomberg News on Tuesday. Even though scientists at theCenters for Disease Control and Prevention were skeptical and some prominent virologists openly derisive, news outlets have repeated and magnified the theory, adding speculation about bioterrorism that even Dr. Gibbs repudiated. He was also interviewed Thursday on the ABC News program “Good Morning America.”

Dr. Fukuda said a W.H.O. panel of experts had concluded that “the hypothesis does not really stand up to scrutiny.” The lysine residues and mutation rates were typical, he said, and many swine flus seem unrelated because not enough pigs are tested each year.

The article went on to make some astute points about the damage that misinformation like this has caused in the fight against diseases like AIDS and polio.

This is why the cultural expectation in science is that you publish, then pronounce.  Or, in cases where the early dissemination of your research could save lives, that you at least get your work through the peer review process before typing up your press release.  

Because science matters.  Getting it wrong matters. Reducing the public's trust in the people working to protect them matters

Dr. Gibbs should have known better.

Related posts:

Bogus bioweapon claims for H1N1 Swine Flu

From the comments: Is the bioengineering theory really rubbish?

Thursday, May 14, 2009

Disturbing results of a recent survey

According to a new poll by Zogby / University of Texas: 
  • Only 30% of Americans would get a vaccine against the H1N1 "swine flu" virus, if one were available.
This shows that we aren't getting the message across to the majority of Americans: This virus may appear relatively mild right now, but we can't trust it to remain so.  The first wave of infections caused by the 1918 pandemic flu virus was also mild... and then it went on to kill tens of millions of people in a world of only 1.8 billion.  We don't know that the same thing will happen with this virus, but we also don't know that it won't.  If a protective vaccine becomes available, take it.  Immediately.
  • A whopping 38% of those surveyed managed to combine ALL of the following: Not vaccinated against the flu, not practicing good hygiene, and not restricting travel or mall shopping.
Now, I'm not too concerned about that last part at the moment.  Healthy people aren't being encouraged to curtail their social interactions right now.  But unvaccinated people who practice poor personal hygiene (e.g. they don't wash their hands regularly) aren't only putting themselves at risk: they're gambling with everybody's health.  By making choices that make them more likely to become infected, they are also increasing the risk that they'll pass that infection on to someone else.

Which is why the next bullet is so striking:
  • "The same was true of 25% of health care workers polled, 28% of caregivers in nursing homes and 33% of those whose children are vulnerable due to asthma, diabetes, or HIV. Particularly concerning is that only 48% of these children were vaccinated." (emphasis added)
Now, you might be thinking: "Yes, but maybe these people would vaccinate if there were an H1N1 vaccine; this is just how they react to the 'regular' flu, after all."

To which I respond:
  1. These people all provide care to those who are at high risk of severe complications (including death) from "regular" seasonal flu.  
  2. Are you forgetting the poor hygiene issue?  Handwashing, good cough/sneeze etiquette, and the like are not just for special occasions.  They save lives every day.
These groups have a special responsibility as care providers to ensure that they are not putting their patients (or high-risk children!) in danger through their own negligence.  Some of those parents may not know any better, but none of the healthcare workers / nursing home caregivers have that excuse.

No amount of good advice from the government can take the place of personal responsibility.  Do your part: cover your mouth when you cough or sneeze (preferably with a tissue or the crook of your elbow); wash your hands regularly (try for at least five times a day, for at least 20 seconds); get a flu shot* if you're medically fit to do so (especially if you provide care to people who are at high risk of complications), and vaccinate your kids*, unless your healthcare provider tells you not to.  

*The current flu vaccine won't help against the H1N1 "swine flu" virus, so when a vaccine for that strain becomes available (hopefully by this fall), roll up your sleeve and take it.  And make sure your kids get it, too.

Sunday, May 10, 2009

Pandemic Partners - A way to help each other during a pandemic

During a pandemic, we all know a lot of people are going to get sick.  

Whether they get treated in a hospital or recover at home, a lot of those who get sick are going to need some help... and not just with their illness.  Even the seasonal flu can knock you onto your back for a week or more, and a pandemic flu virus is likely to to be worse.  So a lot of people who get sick will also need some help managing their day-to-day lives until they're back on their feet, simple things like:
  • Making sure there is food in the house
  • Contacting healthcare providers  
  • Helping provide care for children or other dependents
  • Helping provide care for pets
  • Contacting family members
  • Picking up medicine from the pharmacy

But in today's society there are many of us who could fall off the map without anyone noticing right away.  In many cases, it's all too possible for a person to be home sick for weeks before anyone thinks to check on them, and this will be even more true during a pandemic.  

Because the same social distancing measures that will help to protect us from the flu (staying away from other people as much as possible, working from home if you can, etc.) will also reduce social interaction to the point that even those who would ordinarily be missed after a very brief illness will be at risk of falling through the cracks.

To help fix this problem, people can pair up with people they trust (friends, neighbors, family members, co-workers, members of their place of worship) to keep track of one another during a pandemic and help each other as needed.

The Reveres over at Effect Measure mentioned one program to do just that, a faith-based initiative called Flu Friends.

A similarly-alliterative initiative called Pandemic Partners is also under development to help people help each other through a pandemic.  Right now, it mostly consists of a set of forms people can use to share the information their "pandemic partners" will need to be able to assist them.

Copies of the form are available as a Word Document: Pandemic Partners.doc 

The forms are a work in progress, so if you have any suggestions for improving them, let me know and I'll pass them along.

Friday, May 8, 2009

FDA Q&A on PPE (especially N95 respirators)

With a title like that, I can't help but feel as though I'm back in the Army.  It's the only organization in the world that would take a nice 3-letter word like "job" and expand it into "military occupational specialty," just to abbreviate it with the 3-letter acronym MOS...

Anyway, here is the latest and greatest from the Food and Drug Administration (FDA) on the use of FDA-regulated personal protective equipment (PPE) for preventing infection with the H1N1 flu virus.  

Some of the questions it addresses are regulatory clarification issues that are unlikely to be of much interest to the general public, but they also include some excellent basic advice on PPE, including things like "What is the difference between a face mask and an N95 respirator?" and "Is it OK to re-use or share a disposable N95 respirator?"

You can also find the original version here.

The FDA and Personal Protection Equipment for the 2009 H1N1 Flu Virus
Questions and Answers

Q:  What are facemasks and N95 respirators?

A: Facemasks and N95 respirators are devices that when properly worn may help prevent the spread of germs (viruses and bacteria) from one person to another.

Facemasks and N95 respirators do not provide complete protection from airborne germs and other contaminants.  They are one part of an infection-control strategy that should also include frequent hand washing, social distancing, and staying home when sick.

Facemasks and N95 respirators should not be shared. Facemasks and respirators may become contaminated with germs (viruses and bacteria) that can be spread between people.  

It is important to understand that if you are exposed to infectious material while wearing a facemask or N95 respirator, it should be considered contaminated. After you remove it and dispose of it properly, wash your hands thoroughly.

Q: What’s the difference between a facemask and an N95 respirator?

A: A facemask is a loose-fitting, disposable device that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment.

If worn properly, a facemask is meant to help block large-particle droplets, splashes, sprays or splatter that may contain germs (viruses and bacteria) from reaching your mouth and nose. Facemasks may also help reduce exposure of your saliva and respiratory secretions to others.

While a facemask may be effective in blocking splashes and large-particle droplets, a facemask, by design, does not filter or block very small particles in the air that may be transmitted by coughs, sneezes or certain medical procedures. Facemasks also do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the facemask and your face.

An N95 respirator is a respiratory protective device designed to achieve a very close facial fit and efficient filtration of airborne particles. In addition to blocking splashes, sprays and large droplets, the respirator is also designed to help prevent the wearer from breathing in small particles that may be in the air.

To work as expected, an N95 respirator requires a proper fit to your face.  It is designed to fit tightly over your mouth and nose, with no gaps.  And gaps will allow air to pass around and reach your nose, mouth, and lungs without being filtered. 

The ‘N95’ designation means that when subjected to careful testing, the respirator blocks at least 95 percent of small test particles. If properly fitted, the filtration capabilities of N95 respirators exceed those of face masks. However, even a properly fitted N95 respirator does not completely eliminate the risk of contracting illness through airborne viral particles.

N95 respirators are not designed for children or people with facial hair.  Because a proper fit cannot be achieved on children and people with facial hair, the N95 respirator may not provide the expected protection. Also, people with chronic respiratory, cardiac, or other medical conditions that make it harder to breathe should check with their healthcare provider before using an N95 respirator because the N95 respirator can require more effort to breathe.

FDA has cleared the following N95 respirators for use by the general public in public health medical emergencies:

    * 3M™ Particulate Respirator 8670F
    * 3M™ Particulate Respirator 8612F
    * Pasture Tm F550G Respirator
    * Pasture Tm A520G Respirator

These devices are labeled "NOT for occupational use.”

Q: Do  N95 respirators reduce the chances of contracting the 2009 H1N1 flu virus?

A: When worn properly, N95 respirators help reduce your exposure to airborne germs.  They do not provide complete protection from airborne germs and other contaminants, however. They are one part of an infection-control strategy that should also include frequent hand washing and staying home when sick.

Q: Is it OK to use one disposable N95 respirator for a long time?

A: Disposable N95 respirators are not intended to be used over long periods of time. If the respirator is damaged, torn or soiled, or if it becomes difficult to breathe while wearing it, remove it and replace it with a new one. 

It is important to understand that if you are exposed to infectious material while wearing an N95 respirator, your respirator should be considered contaminated. After you remove it and dispose of it properly, wash your hands thoroughly.

Additional references on this can be found at the following:

U.S. Centers for Disease Control and Prevention
“Recommendations for Facemask and Respirator Use in Certain Community Settings Where H1N1 Flu Virus Transmission Has Been Detected”

“The Department of Health and Human Services Guidelines for the Use of Facemasks and Respirators in Non-Occupational Settings during an Influenza Pandemic”

Q: Is it OK to re-use or share a disposable N95 respirator?

A: Disposable N95 respirators are not intended to be used more than once. They should also never be shared. Their protective capabilities cannot be assured when they are reused either by yourself or another person. Perhaps more importantly, by sharing, one may inadvertently be exposing another person to infectious material.

It is important to understand that if you are exposed to infectious material while wearing an N95 respirator, your respirator should be considered contaminated. After you remove it and dispose of it properly, wash your hands thoroughly.

Q: What other personal protective equipment does FDA regulate?

A: Personal protective equipment (PPE) is any type of face mask, glove, eye shield, or specialized clothing that acts as a barrier between infectious materials and the skin, mouth, nose, or eyes (mucous membranes). When used properly, PPE can help prevent the spread of infection from blood, body fluids, or respiratory secretions. 

The U.S. Department of Labor's Occupational Safety and Health Administration (OSHA) requires employers to provide appropriate PPE for workers who could be exposed to blood or other infectious materials (bloodborne pathogens). OSHA may also require employers to provide PPE to protect against other hazards at work. Although OSHA requires the use of specific equipment, it does not regulate the marketing of these devices nor grant claims of disease prevention. For more information, go to

The U.S. Centers for Disease Control and Prevention (CDC) gives recommendations for protecting yourself from infection, including swine flu. For more information, go to

The National Institute for Occupational Safety and Health (NIOSH) has established certification requirements for various respiratory PPE, which are found at 42 CFR part 84. NIOSH tests products for compliance with these regulations and issues a certification for products that comply. NIOSH certification evaluates the performance of respiratory protection equipment in functional terms and not in terms of claims for use in preventing disease.  Employers subject to OSHA and the Mine Safety and Health Administration (MSHA) regulation may be required to provide NIOSH-certified respiratory protection equipment to satisfy their OSHA and MSHA requirements.

Q: Where can I find additional information on personal protective equipment (PPE)?

A: For more information on Personal Protective Equipment (PPE), go to:

Q: What is the purpose of the FDA's Emergency Use Authorization for certain N95 disposable respirators?

A: The FDA issued an Emergency Use Authorization (EUA) for certain disposable respirators known as N95 respirators.  This EUA permits the deployment of these products, accompanied by fact sheets with information for use during the 2009 H1N1 flu virus emergency, from the Strategic National Stockpile for use by the general public to help reduce wearer exposure to airborne germs during this emergency. The term "general public" in this EUA is broad and includes people performing work-related duties.

Q: Does the FDA’s Emergency Use Authorization for certain disposable N95 respirators cover only products in the Strategic National Stockpile?

A: The FDA’s EUA for certain disposable N95 respirators for use by the general public during the 2009 H1N1 flu emergency is limited to only those products deployed from the Strategic National Stockpile (SNS) before or after the signing of the EUA on April 27, 2009.  The specific products covered by the EUA are identified by manufacturer and model number (see

Q: Does the FDA’s Emergency Use Authorization for certain disposable N95 respirators permit them to be re-used in health care settings?

A: The FDA’s EUA for certain disposable N95 respirators for use by the general public does not permit the re-use of N95 respirators.
Q: Does the FDA’s Emergency Use Authorization for certain disposable N95 respirators cover health care employees?

A: Yes, the term "general public" in this EUA is broad and includes people performing work-related duties, for example in occupational health care settings.  However, this EUA does not affect Occupational Safety and Health Administration (OSHA) requirements.  If respirators are used for people in occupational settings, employers must comply with the OSHA Respiratory Protection Standard, (29 CFR 1910.134), which can be found at

Q: Does the FDA’s Emergency Use Authorization for certain disposable N95 respirators lift the fit-testing requirements?

A: No, the EUA does not waive fit testing and other OSHA requirements that apply when respirators are used for people performing work-related duties.

The FDA’s EUA and accompanying fact sheet can be found on the FDA’s Web site at:  For further information on OSHA requirements, go to