Vaccine to protect children in West African 'meningitis belt'
20 June 2007
A vaccine to protect people living in West Africa from a lethal and highly infectious form of meningitis has shown promising results in a phase 2 clinical trial. The vaccine is designed to protect children from a strain of meningitis known as serogroup A Neisseria meningitidis.
A child waits to receive a vaccine in The Gambia.
Every 8 to 10 years, the group A infection sweeps through 21 sub-Saharan nations collectively named the ‘meningitis belt’ that stretches from Senegal and The Gambia in the west, to Ethiopia in the east. Between 1996 and 1997 more than 25,000 people died from meningitis A infection in this region.
The population of 430 million people has been relatively spared in recent years, but the 47,925 cases reported from 1 January to 6 May 2007 bring the fear that a new epidemic wave may have begun.
The trial results have been announced by the Meningitis Vaccine Project (MVP), a partnership between the World Health Organisation and PATH, a nonprofit Seattle-based organisation that aims to help communities break long-standing cycles of poor health.
Along with the Centre for Vaccine Development (CVD) in Mali, scientists working at the MRC laboratories in The Gambia helped to run the new group A vaccine trial. A total of 600 toddlers aged between 12 to 23 months participated in the trial. The results show that it is not only safe but generates up to 20 times more protective antibody against meningitis A infection than the vaccine currently in use.
The high level of antibodies produced by children in response to the vaccine suggests that they will be protected from infection for several years. Blocking infection by meningitis bacteria in this way helps to generate the herd immunity that protects unvaccinated people in the children’s communities from meningitis.
The key to the new vaccine’s efficacy is its structure. It is a conjugate vaccine meaning that sugars from the meningitis bacterium are joined together with a protein designed to stimulate the immune system. When injected into the body, the combination of a bit of bacteria and a bit of protein prompts immune cells to produce antibodies that will protect against meningitis A infection.
Dr. Brown Okoko, principal investigator at the MRC site in Basse, said:
“The clinical teams at MRC and the Centre for Vaccine Development in Mali identify with the vision, mission, and mandate of the Meningitis Vaccine Project. We are all highly motivated and very proud to be able to contribute to the development of a vaccine that is critically needed in Africa.”
MVP is collaborating with the vaccine production company Serum Institute of India Limited to make the new vaccine, it is expected that it will be sold at a price of 40 US cents a dose.
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