Bird Flu: What Me, Worry?

JC's decision to post a link to Bush v. Bird Flu yesterday gave me the idea of doing something with all the avian flu material that's been cluttering up my desk.

In announcing all the money he's devoting to this new "national security" threat, Bush says we are "likely to face another pandemic." Well, no one knows really for sure if/when/where a pandemic will erupt. So let's look at some of what is known:

"Inside the Race To Find Vaccine For Avian Flu," The Wall Street Journal, Oct. 28, 2005

So far, H5N1 has killed some 60 people over the past two years, a small fraction of the nearly quarter- to half-million people who die each year from regular flu. But because humans do not have a natural immunity to this virus, the search for a vaccine has become a pressing priority.

GlaxoSmithKline, Roche, and Sanofi Aventis are just a few of the companies searching for a vaccine that would offer broad immunity and protect against any human-to-human strain that may emerge. The National Institute of Allergy and Infectious Diseases, a unit of the National Institutes of Health, is working closely with companies to try to develop a vaccine. According to John Treanor, a virology expert at the University of Rochester (NY), a mismatched vaccine is better than no vaccine but "it's going to be difficult to be confident of making an exact match."

This story reports that just one avian-flu vaccine has withstood clinical testing. Over the summer, researchers from Sanofi Aventis, NIH, and St Jude Children's Research Hospital created a vaccine designed to protect against the human-to-human spread of H5N1. The US government has placed an order valued at $100 million.

The drawback to this vaccine is that it requires two doses to spark a robust immune reaction, which isn't useful if a pandemic breaks out. In a pandemic, authorities would implement an emergency "ring vaccination," rushing vaccine to people around the site of an outbreak. Anything that requires more than one dose isn't practical in those circumstances. Chiron has also developed a vaccine that has not been tested, yet the US placed a $62.5 million order.

Although companies and governments are pulling out all the stops to develop an effective vaccine, no one can say for sure how long it will take.

There has been a surge in demand for Tamiflu, in the meantime, to the point where people are asking their doctors for prescriptions they can fill now, in order to stockpile in the event of a pandemic. Roche has suspended shipments to private-sector recipients in the US to ensure that enough is available for use during the regular flu season.

In the meantime, Glaxo and Sanofi are attempting to form an adjuvant, which would make a flu vaccine effective against a broader range of virus strains. It could also potentially help circumvent the scarcity in manufacturing capacity by increasing the power of a vaccine and stretch it into more doses.

Stratfor: Strategic Intelligence Report

This is a newsletter I subscribe to and a recent one looked at the avian flu. Here are some excerpts from that newsletter--

An uncomfortable but undeniable fact is that there are a great many people and institutions in this world that have a vested interest in feeding the bird flu scare. Much like the "Y2K" bug that commanded public attention in 1999, bird flu is all you hear about. Comparisons to the 1918 Spanish influenza have produced death toll projections in excess of 360 million, evoking images of chaos in the streets.

One does not qualify for funding -- whether for academic research, medical development or contingency studies -- by postulating about best-case scenarios. The strategy is to show up front how bad things could get, and to scare your targeted benefactors into having you study the problem and manufacture solutions....

A bird flu pandemic among the human population is broadly in the same category as a meteor strike. Of course it will happen sooner or later -- and when it does, watch out! But there is no -- absolutely no -- particular reason to fear a global flu pandemic this flu season.

This does not mean the laws of nature have changed since 1918; it simply means there is no way to predict when an animal virus will break into the human population in any particular year -- or even if it will at all. Yes, H5N1 does show a propensity to mutate; and, yes, sooner or later another domesticated animal disease will cross over into the human population (most common human diseases have such origins). But there is no scientifically plausible reason to expect such a crossover to be imminent....

A virus can mutate in any host, and pound for pound, the mutations that are of most interest to humanity are obviously those that occur within a human host. That means that each person who catches H5N1 due to a close encounter of the bird kind in effect becomes a sort of laboratory that could foster a mutation and that could have characteristics that would allow H5N1 to be communicable to other humans. Without such a specific mutation, bird flu is a problem for turkeys, but not for the non-turkey farmers among us.

A more likely vector, therefore, would be for H5N1 to leap into a species of animal that bears similarities to human immunology yet lives in quarters close enough to encourage viral spread -- and lacks the capacity to complete detailed questionnaires about family health history.

According to Stratfor, the most likely candidate is the pig. On many farms, birds and pigs regularly intermingle, allowing for cross-infection, and similar pig-human biology means that pigs are more likely to be the mutation incubator--a much faster route to a human pandemic.

What about 1918?

One factor that has been driving fears of a 21st century pandemic are references to the 1918 Speanish Flu epidemic. It killed 675,000 Americans when the population was 100 million. Fifty million to 100 million people perished worldwide. Could it happen again?

The short answer is, probably not. Stratfor identifies 4 differences between 1918 and any new development:

1) The flu virus itself

No one knows how lethal H5N1 would be once it adapts to a human host. If you don't know that, you can't calculate a mortality rate. "At this point, the mortality rate among infected humans is running right at about 50 percent, but that hardly means that is what it would look like if the virus became human-to-human communicable. Remember, the virus needs to mutate before it is a threat to humanity -- there is no reason to expect it to mutate just once. Also, in general, the more communicable a disease becomes the lower its mortality rate tends to be. A virus -- like all life forms -- has a vested interest in not wiping out its host population."

2) 1918 was not a typical year

World War I was still being fought and it was fought in the trenches--not the most sanitary of places to be. And if the soldiers weren't fighting, they were living in the barracks so they already weren't in the best of health and were also susceptible to whatever airborne diseases affected the rest of their unit. Thus, the soldiers were not only susceptible to catching the flu, they were also susceptible to dying of it: Over half of U.S. war dead in World War I -- some 65,000 men -- were the result not of combat but of the flu pandemic. So it should come as no surprise that in 1918, the movement of military personnel was the primary means of infecting civilians worldwide. Suffice to say that in 2005, we've come a long way from trench warfare and the total percentage of US population fighting in Iraq and Afghanistan is far lower than the proportion that fought in WWI (0.0005% v. 2%).

3) Health and nutrition levels have improved since 1918

I think it's safe to say that in general, American health today is better than it was in 1918 despite concerns about obesity and other health-related issues. And the healthier you are when you get sick, the better chances you have of getting better.

Having said that, however, there is still a problem in this country with access to medical care. The poor tend to live in closer quarters and work in jobs that bring them in contact with large numbers of people. According to a 1931 study of the 1918 flu pandemic by the U.S. Public Health Service, the poor were about 20 to 30 percent more likely to contract the flu, and overall mortality rates of the "well-to-do" were less than half that of the "poor" and "very poor."

4) Antibiotics

Antibiotics are not a silver bullet and they can't protect against viruses. However, they can treat bacterial or fungal illnesses. The 1918 pandemic was similar to the standard flu virus in that the people didn't die of the flu, they died from the secondary illnesses--bacterial or fungal--that triggered pneumonia and could be treated with antibiotics. But penecillin wasn't discovered until 1929--11 years after the 1918 pandemic.

Personally, my philosophy is not to panic but to be concerned. The greater concern should focus on the consequences of obsessing over whether a pandemic will even occur. A new World Bank report says that an avian flu pandemic would lead to enormous global economic costs:

Tourism, transport and retail sectors would all suffer if a pandemic broke out, while East Asia's poultry industry is already struggling, the bank said.

The warning came as regional leaders met for talks dominated by bird flu.

The World Bank predicted that East Asian economic growth would slow during 2006, but would suffer much more if a pandemic erupted....

Individual efforts to avoid infection, as well as official quarantines and travel restrictions, would have an immediate impact on the economy, the report added.

The short term effect of the pneumonia-like disease SARS in 2003 was, the report says, equivalent to about 2% of incomes in East Asia. SARS killed about 800 people.

So the pandemic doesn't have to happen for the world's economy to take a hit, according to the BBC, "because business is a confidence game that relies entirely on the emotional responses of investors and consumers."

Alternate link for comments