Monday, October 24, 2005

Immunising Poultry Workers

BBC TV Points West news has reported tonight on my action as a General Practitioner who has just given his chicken farmer patient a shot of Influenza A vaccine.

I would like to explain the thinking behind my actions.

This will not stop my patients from getting Avian flu, but it will reduce the chance that this year's Influenza A virus will survive for long in their bodies. If Avian H5N1 virus should ever come to their farm, it is more unlikely that it would be able to combine with the human flu virus to produce the feared pandemic virus. To an infinitesimal degree therefore, my action has reduced the chance of a H5N1 pandemic. If this action were to be reproduced millions of times again in areas of high risk, it would give us a chance that the pandemic could be averted.

The Health Protection Agency has been reported as responding that my action was premature. I dispute this. It takes 10-14 days before protective antibody levels develop after vaccination. In the exceedingly unlikely event of a migrating bird infecting my patient's flock, vaccination would be too late.

It is absolutely true that poultry in the UK are not at risk of avian flu, at present. Our poultry farmers should be vaccinated at leisure, but the priority effort of immunisation should be targeted in South Asia, where experts agree the combination is most likely to occur. The UK Medical Research Council is flying experts to South Asia to boost flu surveillance programmes. It is good to monitor: but the medics should also be setting up vaccination programmes targeted on poultry workers.

I fully realise the logistical difficulties of vaccinating each and every last Chinese and South Asian chicken farmer, but it is well worth attempting.

I have today written to twenty vaccine manufacturers in the world to alert them to this possibility, and seek feedback on the feasibility of producing enough vaccine. I believe that the WHO could succeed in this project, given a major effort and adequate resources. The cost would be negligible compared with the astronomical cost and economic disruption caused by a pandemic of virulent influenza arising from a combination of Avian flu and common, seasonal Influenza A.

We do have time to do this. At present we know of only 120 people worldwide that have caught avian flu from their birds. As this number rises, so too does the probability of a new strain combining the virulence of avian flu and the infectivity of seasonal influenza: but it may need thousands of cases to produce a serious probability of this worrying combination.

The proposal is in line with WHO policy, which is to use influenza A vaccine widely, but the WHO has not yet gone the extra step of advising that poultry farmers and bird workers should be given front-line status. I have been writing to medical authorities including Dr David Nabarro, the WHO medical officer with responsibility for policy in meeting the challenge of the pandemic.

Pandemic flu is not inevitable. Given a major effort in immunising at-risk poultry workers, the probability of emergence can be reduced to a significant degree.

No comments: