London, July 16 (IANS) A ‘universal’ flu vaccine that protects against many strains of virus could be available within a few years, scientists have said.
They believe that they have solved the problem of designing a ‘one fits all’ jab by using a new two-step approach to immunisation.
Early safety trials of the vaccine have already started and it could be tested on patients as early as 2013, the Telegraph, UK, reported.
Working with mice, ferrets and monkeys, the US team ‘primed’ the immune system with a ‘base’ of influenza DNA.
They added a ‘booster’ consisting of a regular seasonal flu vaccine which increased and broadened its immunity. The vaccine’s effectiveness improved each year until, theoretically, recipients would be immune to flu.
Mice and ferrets were able to fight off viruses dating from before 1999, including the deadly strain of 1934, and also strains from 2006 and 2007. The vaccine was also effective against H5N1 ‘bird flu’, reports the journal Science.
Gary Nabel, from the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, who led the study said: ‘The prime-boost approach opens a new door to vaccinations for influenza that would be similar to vaccination against diseases as hepatitis, where we vaccinate early in life and then boost immunity through occasional, additional inoculations in adulthood’
The scientists measured how well the prime-boost vaccine protected mice and ferrets against deadly levels of flu virus.
Three weeks after receiving the boost, 20 mice were exposed to high levels of 1934 flu virus and 80 percent of them survived. When mice were given the ‘prime’ or ‘boost’ elements alone, or a sham vaccine, all died.
Similar results were seen in ferrets, which are good predictors of flu vaccine effectiveness in humans.
Flu viruses are notorious for their ability to mutate and become resistant to vaccines.
John Oxford, professor and Britain’s leading flu expert at St Bart’s and Royal London hospitals, said: ‘They seem to have identified a universal or general antibody that attacks many different types of virus.’
