Pandemic potential of H5N1 bird ‘flu

Making vaccines against bird ‘flu is difficult and many problems need to be overcome before production begins of a vaccine for the disease, according to an article in the February 2006 issue of Microbiology Today, the quarterly magazine of the Society for General Microbiology.

There are worldwide anxieties about the spread of influenza and mutation of the H5N1 virus to acquire the ability to transmit easily from person to person. “Since many experts believe we are on the verge of an influenza pandemic, it is important to understand what are the options for protecting the population against bird ‘flu using vaccines”, says Dr Wendy Barclay, from the University of Reading.

“Making vaccines against bird ‘flu is not as easy as making the sort of ‘flu vaccines we use every year to protect the elderly against epidemic human ‘flu”, explains Dr Barclay. H5N1 can be deadly, so it is very dangerous to work with and must be carefully contained.

However, scientists are working hard, and pilot vaccines for H5N1 bird ‘flu have been made. But there have also been difficulties in getting the vaccines to work well in people. “Even the vaccine strains that have been made so far, and are currently in clinical trials, work less well than normal ‘flu vaccines”, says Dr Barclay. “Because these vaccines don’t work very well we may have to increase doses, which means there will be less vaccine to go round”.

A further problem is likely to be in production of the vaccines. Currently, this relies on large numbers of chicken eggs, which may become limited if bird ‘flu continues to spread.

“In the next few years, H5N1, or another avian influenza virus, could emerge as the next human pandemic virus or it may be that it doesn’t happen. Some people have argued that we should not invest in production of H5N1 vaccines yet since we don’t know exactly which strain of the virus will be the source of the next pandemic”, explains Dr Barclay. “Whether or not a bird ‘flu vaccine is available when the pandemic strikes will hugely affect the public health response and could make a very large difference to mortality rates”.

Infectious diseases are one of the most terrible enemies mankind has faced during its whole existence. This issue of Microbiology Today looks at the vital role that vaccines have played in our on-going battle with microbes.

Other features in the February 2006 issue of Microbiology Today include:

· The future of vaccines (page 8)
· A single-dose, live oral typhoid vaccines: an achievable goal? (page 12)
· Challenging times for malaria vaccines (page 20)
· Advancing DNA vaccines technology (page 24)
· Comment: You only get what you pay for (page 48)

These are just some of the articles that appear, together with all the regular features and reports of Society activities.