A new meningitis vaccine could end devastating epidemics in hotspots like India and Africa, work suggests.
The vaccine protects against meningitis A
The new vaccine protects against meningitis A, the deadliest form of the disease.
It was developed by the Meningitis Vaccine Project, a partnership between the World Health Organization, PATH, and Serum Institute of India Limited.
Mass vaccination campaigns would target people between the ages of 1 and 29, experts envisage.
Vaccinating this high risk group should help protect the rest of the population through herd immunity, experts say.
The new vaccine was recently tested in 600 toddlers in Mali and Gambia. It produced antibody levels nearly 20 times higher than those produced by a vaccine now in use, and with minor side effects.
A further study is planned in India this summer, to be followed by a large-scale vaccination of the 9 million people most at risk in Burkina Faso, Africa, in 2008.
If these trials are successful, authorities then plan to introduce the vaccine across the rest of West Africa at a cost of about 40 US cents per dose.
But experts predict there will be a lag of about 15 years before the majority of Africa's at-risk population can be vaccinated.
Stocks of the old vaccine will still be needed to stamp out any outbreaks that arise until then.
Experts say the new vaccine, which could offer an individual up to 10 years of immunity against meningitis A, should enable health authorities to prevent outbreaks by pre-emptively vaccinating people.
In comparison, current vaccines do not provide long-term protection so cannot be used in this way.
Dr Eric Bertherat, a WHO meningitis expert, said: "With the old vaccine, we have to wait until an epidemic occurs before starting a vaccination campaign to halt the outbreak.
"It is very frustrating." The price tag of protecting the 300 million at risk in West Africa is estimated at US$300 million.
Approximately US$30 million is spent every year on existing meningitis vaccines.
Dr Orin Levine, an associate professor of international health at Johns Hopkins Bloomberg School of Public Health, said: "In the context of global health, this is an easy win for relatively little money."
Meningitis is an infection of the meninges, the thin lining that surrounds the brain and spinal cord.
Even with antibiotic treatment, at least 10% of patients die, with up to 20% left with permanent problems, such as mental retardation, deafness and epilepsy.
While meningitis groups A, B, and C are responsible for the majority of cases worldwide, group A causes deadly, explosive epidemics every 8 to 10 years predominantly in what is known as the African "meningitis belt", an area that stretches from Senegal and The Gambia in the West to Ethiopia in the East.
The belt has an at-risk population of about 430 million. The largest epidemic wave ever recorded in history swept across the entire region in 1996¿1997, causing over 250,000 cases and 25,000 deaths.