DAKAR (Thomson Reuters Foundation) - A new vaccine against meningococcal A, the bacteria which causes meningitis A, has been highly successful in Chad and could make the deadly infection a thing of the past in sub-Saharan Africa, according to research published in the medical journal The Lancet.
Scientists writing in the journal reported 94 percent fewer cases of meningitis A in the 2012 meningitis season in regions of Chad that had followed a vaccination programme in 2011, than in regions where mass vaccination had not been undertaken.
The newly published Chad study shows that after the vaccination of around 1.8 million people between the ages of one and 29 years with PsA-TT (also known as MenAfriVac ®), the incidence of meningitis was 2.5 per 100,000 people, compared with 43.8 per 100,000 in non-vaccinated regions.
The handful of cases that did occur in the vaccinated regions were different strains of meningitis, none of which were targeted by MenAfriVac as they are uncommon in sub-Saharan Africa.
“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,” said the author of the study, Professor Brian Greenwood from the London School of Hygiene & Tropical Medicine (LSHTM), who has studied meningococcal meningitis in Africa since the early 1970s.
“We now have impressive evidence in hand that this vaccine stops transmission of meningitis A. We have a real opportunity over the next few years to make meningitis A epidemics a thing of the past,” said Dr. Marie-Pierre Préziosi, Director of the Meningitis Vaccine Project, the organisation that developed the vaccine.
Meningitis can be caused by several species of bacteria, but meningococcal A is the predominant bacteria in the African meningitis belt, a region stretching from Senegal to Ethiopia.
The last major outbreak of meningitis, in 2009, involved 14 countries, infected 80,000 people and killed 4,000, according to the World Health Organization.
The current vaccine, used in emergencies, loses its efficacy after two or three years and does not work well in children, leaving much of the population of Sub-Saharan Africa unprotected, the co-author of the study, Dr. James Stuart at LSHTM, told Thomson Reuters Foundation.
“In response, the World Health Organization teamed up with the non-governmental organisation PATH (with funding from the Bill & Melinda Gates Foundation) to develop an affordable vaccine that works in children and lasts longer - MenAfriVac is just 50 cents a shot,” Stuart said.
“Impressively, the MenAfriVac not only protects people against the meningococcal A, but drives out the bacteria that latently lives in the throat, hence preventing the transmission of the bacteria to others in the community – a double protection,” he said.
Outbreaks of meningitis happen every 8 to 12 years in the African meningitis belt, according to the Centers for Disease Control and Prevention in the United States.
“If all goes well, MenAfriVac could be rolled out in time for the next big outbreak, but we have to keep monitoring to make sure it remains effective,” said Stuart.