Thursday, October 20, 2005

H5N1 -- Drawing a line between concern and panic

It's nice to finally write a post about H5N1 that doesn't have to start with an explanation, thanks to recent publicity about avian flu. Unfortunately that same publicity has given rise to the usual spate of inappropriate responses, illustrating the old adage about "a little knowledge is a dangerous thing."

H5N1 Blog points to a short piece from Canada that focuses the picture in a short summary worth repeating. I don't think anyone will mind my reproducing it here.

Dizzying explosion of 'bird flu' events, coverage create confusion

Helen Branswell, Canadian Press, October 20, 2005

TORONTO (CP) - To many people trying to make sense of their newspapers or newscasts these days, it must seem like actresses Tippi Hedren (The Birds) and Sandra Bullock (Speed) conspired to write a script for a really bad horror movie.

Lethal bird viruses lurking to infiltrate the lungs of innocent people, threatening to turn a seasonal respiratory ailment into a mutant killer flu. Migratory birds winging the virus from Asia to Russia towards the heart of Europe. Ashen-faced public health authorities warning of potential fatalities ranging from the merely awful to the barely conceivable.

Pandemic influenza has a steep learning curve, ladies and gentlemen. It's time to strap on the crampons.

Setting the record straight

Experts are worried we may be watching a pandemic unfold, but there's no evidence yet that one has started. The noise and fury is about what's thought to be a serious looming threat, not an actuality.

"I think there are some people in the public who think probably with the attention that pandemic human influenza is actually here. And it isn't," notes Dr. Ross Findlater, Saskatchewan's chief medical officer of public health.

Since late 2003, a very deadly strain of avian influenza called H5N1 has been infecting and killing domestic poultry, some wild birds, zoo tigers and on rare occasions people in Southeast Asia. But it isn't spreading in a sustained fashion among people.

If it mutates to be able to do that, it would trigger a pandemic, a wave of illness that would sweep around the globe. There's no way of knowing if it ever will do that or how soon it will if it does.

About that flu shot

It seems a few people around the country are presenting themselves at flu shot clinics thinking they can get a shot to protect against "bird flu." That is not the case.

The shots offered at the clinics protect against the three main strains of human flu experts believe will circulate this winter. They won't offer any protection against a pandemic strain when it emerges.

Flu, bird flu and pandemic influenza

At the heart of the confusion is, well, more confusion. Most people aren't entirely sure what flu is for starters. Unless you've had a bad case of the flu, you won't necessarily know if the bug you have is influenza or one of the myriad pathogens that provoke respiratory hell every winter.
Human influenza causes severe cold-like illness, with fatigue, muscle aches and the potential to progress to pneumonia caused by a secondary bacterial infection.

Bird flu - more accurately called avian influenza - is a term that actually describes a large range of viruses that live in the guts of some species of wild water birds. Occasionally domestic poultry become infected with one of those viruses, which can trigger an outbreak of avian influenza among flocks.

Very occasionally a novel strain of avian flu will cross the species barrier and start transmitting easily among people. Or a bird flu virus will swap genetic material with a human or a pig flu virus, giving it the ability to transmit easily among humans. That's the start of a flu pandemic.

The death and taxes thing

Politicians occasionally talk about flu pandemics with the modifier "if" attached. That's wishful thinking.

"The first big issue is 'if', because a lot of people are still talking 'if' - and that's a fundamental misperception," says Dr. Allison McGeer, one of Canada's leading infectious disease experts.
They can't tell you when or how often, but the experts are united - flu pandemics will continue to occur.

The myth of quarantine

George W. Bush recently talked about using the National Guard to cordon off affected parts of the U.S. when a pandemic strikes. Nice notion, but it can't work.

Flu is too infectious a disease to be contained through quarantine. And people can pass on the virus before they know they're sick, so how would you know who to quarantine if you tried?

"Quarantine will not work. Closing the borders will not work. Closing schools will not work. Nothing will stop the transmission of the pandemic," says McGeer, head of infection control at Toronto's Mount Sinai Hospital.

Lowering expectations

People may be tempted to think modern medicine can curb pandemic influenza. Heck, it stopped SARS.

In actuality, experts say medicine still doesn't have much to offer when an individual goes into acute respiratory distress syndrome - which can be triggered by pandemic influenza. When hundreds or thousands in a community need medical care, the sheer volume of illness will swamp medical systems, planners believe.

Infectious disease expert Dr. William Schaffner says there has to be some realism attached to discussions about how much any government can do to prepare for pandemic flu. Schaffner, from Vanderbilt University School of Medicine in Nashville, likens it to preparing for a hurricane.
"We can't prevent the hurricane. But what we're trying to do is gear ourselves up so that our response to the hurricane is as good as we can reasonably hope it can be," he says.
"There is out there an expectation of perfection on the part of some people in the government and many citizens. They expect us to be 'completely prepared.' That's not a relevant concept when you're dealing with hurricanes. It's not a relevant concept when it comes to potential pandemic influenza."

Back to that vaccine

Canada and some other countries have plans in place to make pandemic vaccine. But because we don't know in advance what strain of flu will cause the next pandemic, it can't be prepared in advance.

Making vaccine isn't a quick process.

"If you could get full production of a licensed vaccine up within six months of the start of a pandemic, we'll be doing very, very, very, very well," says Dr. Perry Kendall, chief medical officer of health for British Columbia.

"So if we're talking about a pandemic that comes in a number of waves, each of which lasts about 15 or 16 weeks, separated by some months, then we won't have vaccine for the first wave.

"But we might be able to get vaccine ready for the second wave and give it to the most vulnerable people - health care workers, essential service workers, police, firemen, etc. ... before then giving it to the broader population."


Elsa said...

Which means the vaccine will be in any case be far too late when it comes to a pandemic influenza.
It takes years to make the vaccine and in Europe they now already know that there will not be enough, even if the vaccine is ready.

I wrote in my own blog that there are so many things happening around us and I wonder whether we have to be concerned or not.

By the way is the hurricane Wilma effecting you or is it too far away?

Hoots said...

The challenge will be how best to confront the disease when and if it comes, not how to protect everyone. If it is as bad as the experts think, there will be high mortality rates for those who contract the virus, but not everyone will get it. We need to figure out why some do not and try to emulate whatever they do that results in protection...hand-washing, avoiding crowds, not contacting too many public surfaces, using protective equipment, frequent bathing, frequent clothes washing...whatever. Also, the population that gets a virus and recovers represents a valuable human resource that can be identified and utilized strategically. Survivors who are willing and able will become very sought-after people.

And no, I am safely inland (150 miles or so) from hurricane threats. All we get where I live is rain and winds, either from the Atlantic or the Gulf of Mexico.

Thanks for visiting!

Elsa said...

You are so right. We can do so many things to try to avoid. I heard people in Holland saying: when it happens we trust the government to help us. I think that's far beyond reality, don't you think so?

We have to trust ourselves and take all precautions necessary.

Thanks for your clear vision on this.