# 2762
Amid growing concerns that the poultry vaccination programs in China may be masking bird flu infections, but not preventing them, the Guangxi Zhuang Autonomous Region has announced a new push to get all live poultry vaccinated.
Given that today is the 7th, and the deadline in the article is the 8th, one has to suspect that this news may be coming a bit belatedly.
Guangxi Province was the site of a Bird Flu fatality in January, but reportedly has not observed any outbreaks in poultry.
First the announcement by Xinhua News, and then some discussion.
Compulsory vaccination to prevent bird flu outbreak
www.chinaview.cn
2009-02-07 20:50:41
BEIJING, Feb. 7 -- The Guangxi Zhuang Autonomous Region has started a compulsory bird flu vaccination program which aims to cover all live poultry by Feb. 8.
The region's administrative office said Monday the government is strengthening control over its live poultry market with thorough inspections to curb the disease.
The program uses veterinarians and animal epidemic monitoring staff.
An 18 year-old bird flu patient died in Guangxi last month, the most recently reported death in the country.
China has reported eight human bird flu cases this year, including five deaths.
Xinhua News Agency correspondents reporting from Guangxi. (XHTV)
Before we begin, I'm making no claims of being an expert in vaccination of poultry against avian influenza, and I honestly don't know whether, overall, the vaccination programs help or hurt the situation.
The debate over wholesale vaccination of poultry against the H5N1 virus has been ongoing for years. Many countries forbid the practice, relying instead on the quick eradication of infected poultry by mass culling.
The argument against vaccinating has long been the fear that vaccinated flocks may still become infected, but not show symptoms. I could give many examples of warnings against the practice, but we'll settle for one.
In February of 2006, when the UAE (United Arab Emirates) was considering the introduction of bird flu vaccinations, Dr Linda Logan, USDA attache for the Middle East and North Africa, said "Vaccinations will mask and hide the symptoms. You won't see the birds dying [even though they are infected] so you may spread it to your neighbors."
If this sounds familiar, it is essentially the same warning espoused recently by Dr. Zhong Nanshan of China. Dr. C.A. Nidom of Indonesia has also been highly critical of the vaccination programs.
Chinese expert issues new bird flu warning
www.chinaview.cn
GUANGZHOU, Feb. 6 (Xinhua) -- A leading Chinese expert on respiratory diseases has warned the public to be aware that poultry can be infected with the bird flu virus but show no symptoms.
"Special attention should be paid to such animals, including those that have been vaccinated," said Zhong Nanshan.
"The existing vaccines can only reduce the amount of virus, rather than totally inactivating it," he said.
Just as with human vaccines for seasonal influenza, poultry vaccines provide less than 100% protection against the avian influenza virus. As new clades or strains of the virus appear (and no one really knows how many strains exist), they may more easily evade the vaccines currently in use.
- In December of 2008, the question of the effectiveness of the vaccines being used in Hong Kong was called into question by Dr. York Chow (see Hong Kong: Poultry Vaccine May Be Losing Effectiveness).
- Again in December, Chinese officials announced a variant of the H5N1 virus in Jiangsu Province that required a `modification of the vaccine program in the surrounding provinces of Zhejiang, Shanghai, Anhui and Shandong'.
And if we go back, again, to August of 2006, the journal Nature carried a cautionary article, warning that vaccines that were less than 95% effective could enhance the spread of the H5N1 virus.
Bird flu warning over partial protection of flocks (excerpts follow)
Talent Ngandwe
16 August 2006
In a paper published tomorrow (17 August) in Nature, they say that vaccinating poultry flocks against H5N1 will only be effective if the vaccine protects at least 95 per cent of birds.
A less effective vaccination programme would encourage the 'silent spread' of the virus between flocks, warn the researchers, led by Nicholas Savill of the University of Edinburgh in Scotland.
<snip>
They conclude that 90 per cent of birds need to be protected by a vaccine to reduce the risk of an outbreak by half, but say this could mean some outbreaks escape detection and spread to other flocks.
The researchers say that at least 95 per cent of birds need to be protected to prevent the virus spreading silently.
In practice, it is difficult to protect more than 90 per cent of a flock; protection levels achieved by a vaccine are usually much lower than this.
A compromise solution, proposed in this article and elsewhere, recommends farmers leave a small percentage of their flock unvaccinated to act as `sentinels'. The unvaccinated birds would sicken, and possibly die, if the virus attacked the flock alerting the farmer that something was wrong.
Some of these warnings from 2006 and before appear to be eerily prophetic when we look at the news of the past few weeks.
There does, indeed, appear to be a problem with `silent infections' among birds in China (and probably elsewhere).
Meanwhile, for countries like China, Vietnam, Egypt and Indonesia, vaccination of poultry has been hailed as an important tool in their fight against the bird flu virus. Even if it isn't 100% effective.
In nations where many people go hungry each day and protein is a scarce commodity, the idea of massive culling instead of vaccination is politically, economically, and socially unpalatable.
Three years ago Vietnam's aggressive vaccination program appeared to work. They went from having the worst record of bird flu outbreaks in 2004-2005 to seeing no human cases in 2006.
Gradually, though, bird flu has crept back into that nation. Whether that is due to a laxity in vaccinations, or a shift in the virus away from the vaccine, isn't clear.
With conflicting agendas and inconclusive science, this debate is likely to go on for some time.
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