A Pandemic Is Worrisome but 'Unlikely'

[Guest guest]

On the Front: A Pandemic Is Worrisome but 'Unlikely'

By ELISABETH ROSENTHAL

OXFORD, England — The Hospital for Tropical Diseases in Ho Chi Minh

City, where Dr. Farrar works, has treated about two dozen

people with avian influenza in the last three years.

With that tiny number, Dr. Farrar and his Vietnamese colleagues

probably have more clinical experience than any other doctors with

the A(H5N1) virus — the dreaded germ that international health

officials fear may ignite the next flu pandemic.

Yet, Dr. Farrar notes, this trickle of humans infected with bird flu —

186 in all since 2003 — has provoked a flood of scientific meetings

on pandemics, accelerating in recent months.

" The ratio of meetings to patients is probably 10 to 1: Hawaii

tomorrow. Geneva and Singapore next week, " said Dr. Farrar, in jeans

and carrying a red backpack, on a break from a conference where he

was — naturally — speaking on the topic.

" The interest is phenomenal, " he said, clicking at his popular

PowerPoint presentation.

Still, Dr. Farrar is not sure that this intensity is entirely

rational:

Having observed A(H5N1) for many years in Asia, he thinks it is

unlikely that the virus is poised to jump species, becoming readily

transmissible to humans or among them. Nor does he believe the mantra

that a horrific influenza pandemic is inevitable or long overdue. He

points out that the only prior pandemic with a devastating death toll

was in 1918, and he says that may have been " a unique biological

event. "

" For years, they have been telling us it's going to happen — and it

hasn't, " said Dr. Farrar, director of the Oxford University Clinical

Research Unit at the hospital in Vietnam. " Billions of chickens in

Asia have been infected and millions of people lived with them — we

in Asia are intimate with our poultry — and less than 200 people have

gotten infected.

" That tells you that the constraints on the virus are considerable, "

he continued. " It must be hard for this virus to jump. "

Still, a part of Dr. Farrar is terrified of A(H5N1) — " a very nasty

virus, " he calls it — which he has watched kill healthy young people,

devouring their lungs.

In the last year, the virus has extended its range in birds from

Eastern China to Western Africa. Over time, it has expanded the

variety of species it can infect, including ferrets and cats.

" That is alarming, " he acknowledges in the understated British way.

Like all responsible scientists, Dr. Farrar believes the world should

prepare. But schooled in places where people die of real and present

diseases like malaria and tuberculosis, he finds the " doomsday "

predictions sketched out by some international officials unhelpful,

more fantasy than fact.

And even if these officials' dire forecasts were to come true, he

says, many of their elaborate pandemic preparedness plans are

unworkable in developing countries, which do not have the resources

or medical facilities to comply.

" I think you have to say we really don't know the odds of pandemic,

and people are not comfortable with that, " Dr. Farrar said. " It could

fizzle out and kill 98 people — one more than the number dead today.

Or it could be something like 200 million, " closer to an estimate

once made by Dr. Nabarro, chief avian flu coordinator for the

United Nations.

" It's terrifying if it happens, but it is very, very unlikely, I

think — and it is difficult to balance those facts. "

At the Tropical Disease Hospital in Vietnam, doctors have been doing

just that, bracing for a pandemic that may never come, since long

before it became fashionable in the West.

Before Vietnam began vaccinating poultry in mid-2005, the disease was

rampant among birds there. Of the world's 186 confirmed human cases,

93 are from Vietnam. There have been no new cases this year.

But in the Tropical Diseases Hospital, doctors and nurses still don

full bio-protective gear when they evaluate suspected cases,

because " you don't know if the next one will mark the start of human

to human transmission, " Dr. Farrar said.

With each new patient, they assiduously try to follow international

scientific recommendations. But their on-the-ground experience

reveals holes in the neat strategies coming from United Nations

experts in Geneva and Rome.

The World Health Organization suggests that it might be possible to

contain a pandemic by quickly diagnosing index cases, identifying

contacts, prescribing all antiviral drugs, and quarantining, for

example.

In response, Dr. Farrar shows a picture of the home of a patient: a

hut on stilts by the Mekong River. When that patient fell ill, he

took a boat to the local health station, and was transferred to the

district hospital, Dr. Farrar says. Later, an ambulance took him to

Ho Chi Minh City, where genetic analysis showed that he had avian

influenza, instead of typical pneumonia. If bird flu ever gained the

ability to spread easily among humans, that patient would have

infected thousands before diagnosis.

" You've got to act quickly, but the process now takes many days, " Dr.

Farrar said, suggesting that more money for clinics, labs and experts

should be flowing to developing nations.

" Then you're supposed to go back to the village and saturate it with

oseltamivir? " he asks, using the generic name for the antiviral drug

Tamiflu. " What do the villagers do when they hear the man has bird

flu? They don't sit still; they get on buses and flee and stay with

relatives in other villages, " potentially spreading it there.

For doctors in Vietnam, human cases of avian influenza have been a

frightening reality for more than three years, and Dr. Farrar vividly

remembers the initial terror of the devoted hospital staff, unsure if

they could catch bird flu from patients.

" Look at this lung — there's nothing there, " he said pulling up the X-

ray of a patient who is back at the university, but whose left chest

shows a vast empty cavern. Studies from the hospital have taught the

world much about A(H5N1): humans took longer to clear this virus than

normal influenza, for example, and Tamiflu can quickly breed

resistant strains.

But, to Dr. Farrar's chagrin, the treatment options have not really

improved.

Flu vaccines are still manufactured by an " ancient strategy " that

involves injecting eggs with virus, he complained, even as other

vaccines rely on more sophisticated methods. As a result, flu

vaccines — including experimental versions aimed at A(H5N1) — are

cumbersome to produce, and target just one strain.

" What we need is a vaccine that is effective across strains because

the virus can be different each year, " he said. " My mom in the U.K.

can get a shot every year, but that is not realistic in rural Asia. "

More remarkable still, he said, Tamiflu is still the only drug useful

against avian influenza, " and we all know that one drug is not

adequate to treat any viral disease, " he said, noting that multiple

drugs are used in AIDS.

Patients at Dr. Farrar's Hospital are given Tamiflu, and it appears

to help some. " It's all that we have, " he said. " So if I was sick,

I'd certainly want to get it. "

But, he rues the lack of international research and coordination to

tackle a disease that has been in Asia for nearly 10 years. For

example, he said, although Vietnam has greatly reduced the number of

bird flu outbreaks by vaccinating poultry, no one knows if the

vaccine puts pressure on A(H5N1) to mutate to develop resistance to

the shot, which could cause a rebound of disease in the coming years.

Personally, Dr. Farrar remains optimistic, believing a pandemic will

not come. If A(H5N1) changed so that it readily infected people, it

would probably become less deadly, he said.

But if disaster happens, he says: " People will look back and

say: 'This was a nasty virus that you knew could sometimes infect

other species. Why didn't you do something? All you had was a single

effective drug and no vaccine?' "

http://www.nytimes.com/2006/03/28/health/28skep.html