A case of vaccine-derived Polio was confirmed in New York, according to the CDC.

Analyst Comment: Vaccine-derived Polio occurs when a person vaccinated with the liquid Polio vaccine infects someone who is unvaccinated against Polio. This occurs because the liquid vaccine contains a live Polio virus that can replicate and be transmitted. In the US, most were vaccinated with the Polio shot which contains a dead Polio virus. Those vaccinated against polio are not at risk of catching “wild Polio” or vaccine-derived Polio. The side-effects of vaccine-derived Polio are mild, however, if it continues to spread it could mutate and regain the ability to paralyze an infected host.