Stop Transmission of Polio (STOP). This image depicts a number of Indian health care practitioners setting up their booth on a country-wide National Immunization Day (NID), from which they distributed informative leaflets, as well as administered polio vaccinations. Thousands of children throughout the country receive a polio vaccine on each NID. Since its inception in the fall of 1998, the STOP Transmission of Polio (STOP) immunization initiative teams have worked in over 50 countries. In the first years of the program, most STOP team members worked primarily to bolster acute flaccid paralysis (AFP) surveillance, support "national immunization" days, and conduct polio case investigation and follow-up. In collaboration with local and national counterparts (Ministry of Health/WHO/UNICEF), STOP Team members promoted, conducted and evaluated active surveillance for acute flaccid paralysis; planned, monitored and evaluated supplemental immunization activities, e.g., national immunization days (NIDs), measles catch-up campaigns; as well as promotion, monitoring and evaluation of routine immunization programs. They also supported integrated disease surveillance and measles mortality reduction strategies. Uttar Pradesh in northern India.