Less Vaccine Can Be More

摘要

The meningitis season has begun in Africa-and once again, it will be a tough battle. Health officials will use vaccines that act like fire brigades, squelching outbreaks where they erupt; but vaccine stocks are so tight, they have to be deployed sparingly, and there's always the danger of shortages.rnIn a paper this week in PloS Neglected Tropical Diseases, a team led by epidemiologist Philippe Guerin of Medecins Sans Fron-tieres (MSF) shows a way to stretch those limited supplies. The team reports that just one-fifth of the standard vaccine dose triggers an immune response almost as good as that of the full dose. That means the stockpile of some 10 million doses that will be available this season might be used to vaccinate as many as 50 million people.rnThe idea has excited meningitis experts in and around the World Health Organization (WHO). But it has also triggered controversy. The main vaccine manufacturer, Sanofi Pasteur, worries about liability problems and wants nothing to do with the strategy. Switching doses is a logistical challenge as well and can be politically risky if it is seen as lowering the level of care. Still, WHO is laying the groundwork for a move to "fractional doses" if shortages occur, says WHO meningitis expert William Perea.