JOHANNESBURG  For over a century, epidemics of bacterial meningitis have swept across Africa, arriving with the dry harmattan winds to kill with terrifying speed. But on Monday, a drive starts to inoculate tens of millions of West Africans with a new vaccine in what scientists hope will be the beginning of the end of ravaging meningitis epidemics.

The aim is for these immunization campaigns to spread from Senegal in the west to Ethiopia in the east, bringing the disease under control and saving an estimated 150,000 lives by 2015 in a belt of 25 nations that girds the continent.

Hundreds of millions of dollars are still needed to accomplish that goal, public health officials say. But the meningitis vaccine itself is a milestone in developing inexpensive vaccines against neglected diseases that afflict poor countries, experts say.

More than a million cases of meningitis have been reported in Africa over the past two decades, and the vaccine works against the group A meningitis strain that causes more than 8 out of 10 cases on the continent. Moreover, it costs less than 50 cents a dose. In the United States, Novartis and Sanofi Pasteur market a single dose of meningitis vaccines against multiple strains of the disease for $80 to $100.