London: Coming soon: A "universal" jab
that would protect against every type of flu, say scientists.
An international team is working on such a vaccine
that will fight off all major strains of influenza -- from the
routine winter flu to virulent new strains of bird flu -- and
it claims that the jab could be available within a few years.
In fact, the scientists believe they have solved the
problem of designing a "one fits all" jab using a new two-step
approach to immunisation.
According to them, early safety trials of flu vaccine
have already started and it could be tested on human patients
as early as 2013, the British media reported.
Though the jab for humans is at an early stage
of development, the scientists have tested it successfully on
mice, ferrets and monkeys whose immune systems were "primed"
with a "base" of influenza DNA.
In monkeys, they added a "booster" consisting of
regular seasonal flu vaccine which increased and broadened its
immunity. The vaccine`s effectiveness improved each year
until, recipients would be immune to flu.
The "priming" or base vaccine came from a 1999 virus
but antibodies were generated that neutralised viruses of
different sub-types and from different years, the scientists
wrote in the `Science` journal.
"We are excited by these results. 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.
"We may be able to begin efficacy trials of a broadly
protective flu vaccine in three to five years," Dr Gary Nabel,
the study leader from the US National Institute of Allergy and
Infectious Diseases in Bethesda, said.
The scientists also 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 per cent
survived. When mice were given only 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.
Experts have more or less welcomed the research.
Prof John Oxford, Britain`s leading flu expert and
a virologist at St Bart`s and Royal London hospitals, said:
"This a new and interesting approach and they are a very
respected group. I would take this very seriously. They seem
to have identified a universal or general antibody that
attacks many different types of virus.
"This is something that we have been after for a long
time but the next stage is crucial. Many new vaccines fall at
the human trial stage."
Prof Hugh Pennington of Aberdeen University said:
"It is an exciting and attractive approach. We really do
desperately need something along these lines. It is a nice
idea but the proof will be in the pudding and seeing whether
it works in humans."
PTI
