MSNBC Bad vaccines may trigger China bird flu

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Expert: Bad vaccines may trigger China bird flu

China likely using inferior poultry vaccine - could explain recent outbreaks

Reuters

Updated: 10:48 a.m. ET Dec. 29, 2005

 

 

HONG KONG - China is most likely using

substandard poultry vaccine or not enough good

vaccine, which would explain recent outbreaks of

the deadly H5N1 bird flu virus in poultry, a

prominent virologist said on Thursday.

 

Thirty-one counties in China have reported

outbreaks of the H5N1 in poultry this year,

although only one county remains under isolation

and there have been no new outbreaks for three

weeks, according to Chinese state media.

 

But the fear among experts is that the virus

could mutate from a disease that largely affects

birds to one that can pass easily between people,

leading to a human pandemic.

 

Dr Robert Webster, of St Jude's Children's

Hospital in Memphis, Tennessee, said the problem

of substandard vaccines was not exclusive to

China.

 

" If you use a good vaccine you can prevent the

transmission within poultry and to humans. But if

they have been using vaccines now (in China) for

several years, why is there so much bird flu? "

Webster told Reuters in Hong Kong.

 

" There is bad vaccine that stops the disease in

the bird but the bird goes on pooping out virus

and maintaining it and changing it. And I think

this is what is going on in China.

 

" It has to be. Either there is not enough vaccine

being used or there is substandard vaccine being

used. Probably both. "

 

Webster praised China's ambitious plan to

vaccinate all its chickens, but also called for

agricultural vaccines to be standardized.

 

" It's not just China. We can't blame China for

substandard vaccines. I think there are

substandard vaccines for influenza in poultry all

over the world, " he added.

 

Human cases in Asia

Since late 2003, there have been 141 confirmed

human cases of the deadly H5N1 strain of bird

flu, all of them in Asia, including six in China.

Two people have died from bird flu in China, out

of 73 known fatalities in Asia.

 

Webster warned against underestimating the virus,

which he said has exhibited some of the worrying

characteristics of the Spanish flu virus of

1918-1919, which killed an estimated 50 million

people.

 

" If you go back to 1918, it showed that there are

about 10 critical amino acids in that virus that

seemed to be necessary (for the virus) to be

pathogenic, " Webster said.

 

" Many of those changes have been seen in the

H5N1, but not all together. Individually, these

have been out there.

 

" If you get all of these 10 all in together in

one (H5N1) virus, to get 10 amino acids all lined

up in the right order, yes the chances are very,

very small that it could happen, but it could

happen you see, " he said.

 

Webster said it was not surprising that some

strains of the H5N1 have been found to be

resistant to Tamiflu, Roche AG's drug that is

believed to be capable of reducing the symptoms

and chances of complications caused by the virus.

 

" That's the nature of the beast, there is nothing

special about this one. Flu viruses change every

time they multiply, they make mistakes, these

mutations occur naturally, " he said.

 

It was now crucial to find the cure -- the right

doses, duration of treatments and combining

Tamiflu with a few other anti-viral drugs, such

as amantadine and rimantadine.

 

" It is important to realize that the H5N1 cases

in China recently are also sensitive to the

old-fashioned drugs amantadine and rimantadine.

So we need to be thinking more about combinations

of these drugs, combinations of amantadine,

rimantadine and Tamiflu, " Webster said.

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Reuters content is expressly prohibited without

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© 2005 MSNBC.com

 

URL: http://www.msnbc.msn.com/id/10639567/

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