Thursday, August 23, 2007

Still Not Ready For Prime Time?

 

# 1081

 

 

The fact that a pandemic hasn't erupted would seem to be prima facie evidence that the H5N1 virus hasn't acquired the required genetic changes in order to make it a `human influenza'.  

 

 

Researchers at St. Jude's' Hospital, one of the premier influenza research facilities in the world, in examining the differences between avian and human influenzas, now tell us that the H5N1 virus may be further away from becoming a pandemic than previously thought.

 

First the article, then some discussion.

 

 

 

 

Fears of bird flu pandemic subside

By Amy Fagan
August 22, 2007

 

Researchers have discovered numerous changes a flu virus likely would have to make in order to spread as a human pandemic, but so far it seems the avian-flu virus has made just a few of those changes.

 

 

"It's reassuring," said David Finkelstein, who led a team of researchers from St. Jude Children's Research Hospital in Memphis, Tenn. Their findings were recently published in the Journal of Virology.

 

 

The scientists identified 32 "markers," or clear differences between influenza viruses found in birds and in those that infect humans.

 

 

Scientists hope that by learning these markers they will be able to monitor whether the bird flu, referred to as H5N1, is becoming more of a "human" virus and thus a global threat, Mr. Finkelstein said.

 

 

"While we can't directly estimate how long it would take an avian virus such as H5N1 to acquire these traits, we can use these markers to roughly measure the distance between an avian influenza and a pandemic," said Clayton Naeve, St. Jude Hartwell Center's director and senior author of the paper.

 

 

The good news is that so far, bird-flu viruses in humans have only occasionally shown any of these markers. Current bird-flu viruses "are no more adapted to humans today than they were in the past," the researchers say.

 

 

Despite the misleading headline, fears of a pandemic have not subsided. 

 

Is this research reassuring?   Well, a little. 

 

St. Jude's is about as prestigious as you can get when it comes to avian flu research.  Dr. Robert Webster, the dean of virologists, hangs his hat there.   When they come out with a scientific study, I tend to pay attention. 

 

But to what they say, not to what the newspapers interpret.

 

While this research is important, and it may indicate we  have more time that we thought before the next pandemic, a strong caveat was issued by one of the researchers, David Finkelstein, which appears near the end of this article.

 

Mr. Finkelstein cautioned, however, that the team's research was a statistical analysis and must be verified in a lab. And he stressed that researchers don't know definitively how many steps or how fast it would take for a virus to become a pandemic.

 

The truth is, we don't know enough about how viruses mutate and evolve to estimate how long it might be before the H5N1 virus can pick up the `right' genetic changes to make it a pandemic strain.  

 

Should the H5N1 virus combine, and reassort, with a more human adapted flu virus, it could literally happen overnight.

 

We also know that the H5N1 virus isn't the only player out there.  It's just the one that has garnered the most publicity.   The H7 viruses, like the one responsible for the outbreak in the UK earlier this year, are also considered to have pandemic potential. 

 

So, while I'm slightly encouraged by these findings, there is nothing here that makes me believe the `all-clear' has been sounded, and that we can let down our guard. 

 

A pity.  As I'd much rather be sailing.