 In the third country where polio remains endemic, Nigeria, there were no cases, though as few as 7% of infants were fully vaccinated in some districts.An April 2017 spill at a vaccine production facility in the Netherlands only resulted in one asymptomatic WPV2 infection, despite release into the sewer system.Laos was declared free of cVDPV1 in March, but three distinct cVDPV2 outbreaks occurred in the Democratic Republic of the Congo, one of them of recent origin, the other two having circulated undetected for more than a year.