[Absence of poliovirus circulation in Colombian departments with vaccination coverage below 80%]

This study aims to explore a possible silent circulation of wild and vaccine-derived polioviruses in departments of Colombia with polio vaccination coverage of below 80%. The study collected 52 samples of wastewater concentrated as a result of precipitation with polyethylene glycol and sodium chloride. The viral detection was carried out through isolation and the identification through neutralization of the cytopathic effect, as well as through a conventional polymerase chain reaction following reverse transcription. The isolated polioviruses were characterized by the VP1 gene sequence. In two of the 52 samples, there was a presence of the Sabin type 2 poliovirus with more than 99% sequence similarity with the Sabin type 2 strain polio. Circulation of the nonpolio enterovirus was detected in 17.3% of the samples. The serotypes identified corresponded to coxsackievirus B1, echovirus 30, and echovirus 11. No evidence of the spread of either vaccine-derived poliovirus or wild poliovirus was detected in the departments of Colombia with polio coverage lower than 80%.