Posts Tagged ‘h5n1’

Kent Brockman: Hordes of panicky people seem to be evacuating the town for some unknown reason. Professor, without knowing precisely what the danger is, would you say it’s time for our viewers to crack each other’s heads open and feast on the goo inside?
Professor: Mmm, yes I would, Kent.
(from The Simpsons)

According to the CDC, as of June 11th, 2009, the United States has lost 45 people to H1N1 (swine flu).  This is out of 17,855 confirmed or probable cases.  This is a higher number than the WHO numbers, and an even higher figure is being reported on Wikipedia.

We also heard from the province’s chief provincial public health office, Dr. Joel Kettner, that our chances of catching H1N1 in Manitoba is at least 50%.

We are hearing conflicting reports about the severity of H1N1, with some people calling it overblown and others saying that we should be worried.  So what is the truth?

The answer, from what I can determine, is that no one actually knows just yet.

This form of H1N1 has been in Manitoba for months, and it’s true that many people have already been exposed and have had only minor symptoms.  But there are a few Manitobans who are fighting for their lives, and four Canadians have died.  This means that this flu is causing serious illness in a small percentage of cases, which makes it appear very similar to regular seasonal influenza.

Influenza viruses return each year because they are always evolving; this prevents antibodies from consistently recognizing the flu when it comes back the next year for a return visit.  This doesn’t mean that our antibodies always fail to stop the flu; one hypothesis of why the Spanish Influenza outbreak of 1918 killed more adults aged 20-40 than senior citizens is that seniors had been exposed to an earlier Russian flu outbreak in 1889.

Because influenza viruses mutate, and because this H1N1 strain is considered highly unstable, it means that we may see a second wave of flu in the fall.  The 1918 epidemic started off similar to a seasonal flu, but in August of 1918 it became deadlier and started to kill healthy adults instead of infants, elderly, and people with compromised immune systems.  There are definite concerns that the current pandemic is running a similar course to the epidemic of 1918, which killed somewhere between 50 and 100 million people worldwide.  So what are the chances that this will happen again?

There are several possibilities for this H1N1 strain:

  1. It could continue more or less as it has until it disappears.  There does not seem to be a full understanding of why influenza epidemics disappear after time, but it may be due to the fact that the best transmitters of the disease develop resistance, and stop spreading the disease to anyone who has yet to be infected.  This would be why almost half of Manitobans may end up not being infected.
  2. It could become even less harmful as time goes by.  A virus doesn’t want to kill its host if it doesn’t have to, so it’s possible that the virus will adapt to a point where it won’t be as deadly.  This is one theory on why the epidemic of 1918 stopped so suddenly.
  3. It could become more deadly by mutating.  Influenza viruses can exchange genetic material with each other, so it’s possible that H1N1 could mix with another flu strain; it’s not impossible that the H1N1 could mix with H5N1 (avian flu), which has a much higher mortality rate.  Even if this does happen, which is considered very unlikely, the genetic mix may not result in a more dangerous virus.  This type of mutation might have caused the second wave of the 1918 epidemic, but no one is sure due to a lack of samples of other influenza viruses from the time (only the Spanish flu virus was purposely preserved from that time, as opposed to any regular seasonal varieties).

I’m not a bookie, so I won’t come up with any odds on the outcome.  I don’t believe that a more deadly mutation is likely, but I wouldn’t dismiss the possibility.

The danger in this situation is that citizens, governments, and health care professionals may become complacent, thinking of this as a regular flu, and not preparing for the possibility of the virus becoming more deadly.  There are antiviral drugs and a possible vaccine that should be ready by fall, and governments need to be aware of what combination of drugs, vaccinations, and quarantines will be best to deal with the second wave.  For instance, Tamiflu will probably not work for all H1N1 cases, so it’s important to have other options like Relenza available for resistant cases or for use in an antiviral cocktail similar to those used against HIV.  Also, because of the 1976 swine flu vaccination having been worse than the actual epidemic or because of general distrust of government, many people will resist the vaccination; governments need to research the risks and rewards of vaccination to decide if it should be part of the solution.

In situations like this, where many lives could be at stake and where the situation changes rapidly, there are going to be some mistakes made.  The media might not always report things accurately, governments may not be as forthcoming as they should be on the current situation, and health care providers may misdiagnose.  But the biggest concern is that decision makers in our governments and health care systems won’t be worried or prepared enough.  That is the one mistake that could cost millions of lives.

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