Bird Flu Alarm

Understanding Avian Influenza

Vaccines against Bird Flu - do they work?

Vaccines against Bird Flu - do they work?

Vaccines are very effective so long as the virus causing a particular illness is stable, and we have enough time to scale up production - both of these things are true of polio for example. Immunity will then last a very long time.

However, new vaccines take time to develop, once scientists have identified a new strain of virus. it takes many months to scale up enough to treat the most vulnerable in the wealthiest nations, and years to generate enough for most people in the world, which is why governments have started stockpiling drugs that have some effect on flu illness - if taken early enough. The drugs are nothing like as powerful as antibiotics in bacterial infections, but they are all we have, and viruses can rapidly become resistant - as we are already seeing in treating early cases of bird flu in South East Asia. There are also problems in producing antiviral drugs fast enough. Some governments will not get the amount of drugs they have ordered until well into the middle of 2006.

Once a mutation is identified, a vaccine can be prepared, but as I say, making it in large enough doses to prevent a pandemic is likely to take many months, and may not arrive in time. And even if it did, the fact is that 3 billion people live in areas with low health budgets and poorly developed health care systems.

It would be impossible to vaccinate the whole world in time, because a Bird Flu pandemic could sweep around the entire globe in a few weeks or months.

However it may be that a new mutation could be similar enough to old flu viruses for existing vaccines to have some effect. We just do not know.