Background: Despite the fact that wild poliovirus (WPV) circulation has not been detected for the past six years, cases of poliomyelitis caused by pathogenic circulating vaccine-derived polioviruses (cVDPVs) have been identified in the Democratic Republic of Congo (DRC). Most cVDPVs implicated in polio outbreaks are recombinants between mutated strains of the oral poliovaccine (OPV) and other human enteroviruses (HEV) of species C (HEV-C).The aim of this study was to determine the disease trend and the genetic makeup of cVDPVs strains isolated in DRC from 2008 to 2016.
Methods: A retrospective descriptive study was conducted among children, 0-15 years with acute flaccid paralysis (AFP), evaluating the disease trend and understanding the genetic diversity of cVDPVs strains collected from 2008 to 2016 by the National Reference Polio Laboratory (NRPL) located within the Institut National de Recherche Biomédicale (INRB) in Kinshasa.
Results: During the study period, a total number of 71 cVDPV cases have been reported with a variation in terms of number of cases per year. Clinically, most of infected children had two or three doses of polio vaccine, fever and sudden onset of paralysis. Molecular analysis of cVDPVs revealed that all strains collected were VDPV type 2, with various genetic recombination with other HEV-C, especially coxsakievirus A 11 (CV A11), CV-A13, CVA17 and CV-A20.
Conclusion: The study showed that the cases of cVDPVs declined significantly from 17 cases in 2012 to 2 cases being detected in 2016. Although WPV and cVDPVs have virtually disappeared, it is recommended that high quality AFP surveillance be maintained for the timely detection and appropriate response to OPV seems to be frequent, it is crucial to investigate the role of other non-polio enteroviruses among AFP patients. Potential cVDPVs reemergence. Since recombination of coxsakievirus and OPV seems to be frequent, it is crucial to investigate the role of other non-polio enteroviruses among AFP patients.
Hugo Kavunga, Edgar Simulundu, Steve Ahuka, Aaron Mweene, Jean Jacques Muyembe