Despite pandemic challenges, so far this calendar year, only two cases of wild poliovirus have been reported — one in Afghanistan and one in Pakistan — compared to 116 last year (as of 28 September 2021). There has also been a significant reduction of wild poliovirus detected in the environment and a decline in cases of circulating vaccine-derived poliovirus (cVDPV), which occur when the live, weakened virus used in the oral polio vaccine circulates in under-immunized communities.