Epidemics of meningitis A occur every seven to 14 years in Africa's "meningitis belt", a band of 26 countries stretching from Senegal to Ethiopia, and are particularly devastating to children and young adults.

The World Health Organisation (WHO) ruling, that vaccine MenAfriVac is safe to use for up to four days at up to 40 degrees Celsius, will save money spent on expensive "cold chain" systems in the final miles of delivery, said Orin Levine, director of vaccine delivery at the Bill & Melinda Gates Foundation, which helped fund the vaccine's development.

Meningitis Vaccine Project (MVP) and WHO experts said in 2011 that introducing MenAfriVac in seven highly endemic African countries could save up to $300 million over a decade and prevent a million cases of disease.

The ruling comes after a review by the Drugs Controller General of India (DCGI) supported by analysis from Health Canada and confirmed by the WHO Vaccines Pre-qualification Programme.

Bacterial meningitis, called meningococcal meningitis, is a serious infection of the thin lining surrounding the brain and spinal cord. It can cause severe brain damage and is fatal in 50 percent of cases if untreated.

Studies presented along with the WHO ruling at an American Society of Tropical Medicine and Hygiene conference in Atlanta showed that the vaccine, which costs just 50 cents a dose and is made by the Indian generic drugmaker Serum Institute, is already having a big impact, eliminating meningitis A in the first countries where it was introduced.

Researchers writing in the journal Clinical Infectious Diseases said that in Burkina Faso, where the vaccine was introduced in 2010, swabs taken from the throats of thousands of residents before and after its introduction showed infections with the bacteria causing meningitis A had been eliminated in both vaccinated and unvaccinated people.

Marie-Pierre Prezioso, an MVP director who led the study, said the findings showed that a phenomenon known as 'herd immunity' was being achieved.

"From early evidence ... we can say the signs are very promising," she said in a statement. "We have herd immunity ... and we can also show that after introduction in Burkina Faso, we saw the lowest level of epidemic meningitis in 15 years."

(Editing by Louise Ireland)

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