Ending polio immunisation: stars and gutters.

Although we are moving towards eradication, risks remain. The number of people at risk of polio paralysis has been seriously underestimated, as has the danger of escape of polioviruses from laboratories. Virulent strains, still used in the US, should be destroyed. Surveillance of acute flaccid paralysis (AFP) and tracing suspected cases is difficult and still uncertain in many countries. The crucial definition by WHO of polio paralysis as asymmetric is ambiguous and misleading: in the Indian sub-continent and elsewhere, 75% have received unnecessary injections for fever 48 h before paralysis. These injections alter the severity and pattern of paralysis: 50% of Indian cases have symmetrical paralysis by limb and 25% by muscle. Eradication of polio promises a New Deal for Health, it must succeed.