PART 5.2

PART 5.2

The polio eradication program relied on strong surveillance efforts to inform vaccination efforts. Surveillance teams worldwide constantly searched for cases in which people had limbs that could not be moved and just hung limply, or cases of “flaccid paralysis.”When they found these cases, they would target vaccination to those regions. This was a very effective strategy when polio was widespread, because almost every case of flaccid paralysis was caused by polio. As vaccination coverage increased, cases of paralytic polio plummeted. As cases of flaccid paralysis began to disappear, polio was declared eliminated from many countries and regions. But in many areas polio persisted. It was just harder to find. First, there were other causes of paralysis among children. As polio became much less frequent, the other causes of flaccid paralysis became more frequent than polio, so flaccid paralysis was no longer a good indicator of how widespread polio was in a particular area. And second, periodically, polio outbreaks still continued to occur and these would then seed the virus to different parts of the world and threaten eradication. As cases of paralysis decreased, it became tougher to find the few cases that continued to occur. For every case missed, workers were missing several hundred cases of silent or asymptomatic infection in the community and these silent cases continued to spread the virus.

FEATURING

Dr. Manish Patel, Influenza Prevention & Control Team Leader, CDC