Recent Poliovirus Outbreaks and Vaccination: a Perspective

Abstract

Poliomyelitis is an enteroviral disease, caused by “Poliovirus” a non-enveloped RNA virus, belonging to the Picornaviridae family. Three serotypes of Poliovirus (PV1, PV2, and PV3) with minimal heterotypic immunity are known [1]. It is transmitted through the feco-oral route and primarily affects children less than 5 years old. Up to three-fourths of poliovirus infections are asymptomatic; however, around 24% experience constitutional symptoms such as low-grade fever and sore throat [2]. Around 1% of cases face CNS spread causing transient or permanent acute flaccid paralysis (AFP), termed Poliomyelitis [3,4]. Polio has been a cause of debilitating outbreaks and high morbidity, and mortality, but owing to global eradication programs, vaccination campaigns, and improved health education, infection is either eliminated or on the verge of being eliminated from the world. The widespread vaccination have decreased the incidence of poliomyelitis by 99% over the past four decades [4]. The wild poliovirus types 2 and 3 were declared eradicated in 2015 and 2019, respectively. However, the transmission of wild poliovirus type 1 (WPV1) has been detected only in Afghanistan and Pakistan [5]. Vaccine-derived poliovirus cases are reported periodically from other parts of the world, especially in Asia and Africa.