New meningitis vaccine dramatically reduces Chad epidemic

A mass vaccination campaign with a new meningitis serogroup A vaccine in sub-Saharan Africa significantly reduced the number of cases of serogroup meningitis, according to a study recently published in The Lancet.

The vaccine, known as PsA-TT or MenAfriVac, was used in a mass vaccination campaign in Chad in 2011. Researchers from the Centre de Support en Santé Internationale in Chad and the London School of Hygiene & Tropical Medicine in the U.K. evaluated the effectiveness of the campaign by measuring meningitis incidence during the 2012 meningitis season and the number of individuals carrying the meningitis-causing bacteria in their throats.

In areas where mass vaccination had not taken place, there were 43.6 cases of meningitis per 100,000 individuals. The number dropped to just 2.5 cases per 100,000 people in the three regions of Chad where the vaccine was administered. There were no cases of serogroup A meningococcal meningitis in the three vaccinated regions. Carriage of the meningitis-causing bacteria also dropped significantly.

"This is one of the most dramatic outcomes from a public health intervention that I have seen during a long career of research in Africa," Sir Brian Greenwood, the study's author, said. "There are now real prospects that the devastating effects of this infection in Africa can be prevented.''

While meningitis can be caused by several groups of meningococcal bacteria, serogroup A is the predominant one in a region of sub-Saharan Africa known as the African meningitis belt. In 2009, one outbreak of meningitis in 14 countries caused more than 88,000 suspected cases and more than 5,000 deaths.

"The study emphasizes the importance, effectiveness and benefit of this vaccine on the population of Chad, where the epidemic of meningitis A has stepped back over the past two years," Doumagoum Moto Daugla, the first author of the study, said. "We can now focus our resources on integrating the vaccine into the routine immunization program as well as strengthening surveillance for early detection of this and other diseases."

The MenAfriVac vaccine was developed by the Meningitis Vaccine Project, a partnership between the Program for Appropriate Technology in Health and the World Health Organization. The project received funding from the Bill & Melinda Gates Foundation.