A 'booster' jab with a new strain could protect these ‘pre-vaccinated’ people within a week.Pandemic flu has been labelled the ‘gravest threat’ to the UK in a recent government report because of the speed it could sweep the world. Some fear an emerging virus could reach the UK within a week. In the time it takes a vaccine that exactly matches the new strain to be developed and administered, thousands could die.Most people will have very little immunity to avian flu, unlike seasonal flu, which most people have been exposed to at some point.A series of vaccinations given over a month would be needed to give protection, and it would take another few weeks for the body's antibodies to build up. But the Leicester researchers say a single ‘booster’ jab with a new vaccine would be enough if people were ‘pre-vaccinated’ with an old strain of avian flu and it could work within a week. The investigators studied a population of people vaccinated against the H5N3 strain of bird flu between 1999 and 2001. Years later, a ‘booster’ jab with the H5N1 strain appeared to generate protection in 80 per cent of this group, whose immune systems had been 'primed' against avian flu. Just one in five people with no prior protection showed changes in their immune system that indicated protection against the new strain. The researchers said the vaccine had not only protected against the original strain, but laid foundations for protection against other avian flu viruses.One of the researchers warned that if a bird flu pandemic arrived tomorrow, we may not have the six weeks needed to vaccinate people, before it reached the UK.
Dr John Wood, from the National Institute for Biological Standards and Control, a government funded body which helps in the production and testing of vaccines for emerging flu strains, backed the study.
He told the BBC: 'The fact that they seem to have this protection after eight years is really interesting.'
'If governments are thinking about stockpiling vaccine, you could actually be stockpiling it in people's arms.'