Following an immunization campaign, oral poliovirus vaccine rapidly evolved, with 61% of OPV-1, 71% of OPV-2, and 96% of OPV-3 samples showing reversion at the key 5' UTR attenuating position.
Observational (n=1,652)
Cluster randomized
Yes
Does oral poliovirus vaccine (OPV) use lead to rapid emergence of virulence-associated mutations in children and their contacts?
OPV exhibits rapid genetic instability and reversion to virulence-associated mutations following vaccination campaigns, underscoring the need for intensive surveillance.
There is an increasing burden of circulating vaccine-derived polioviruses (cVDPVs) due to the continued use of oral poliovirus vaccine (OPV). However, the informativeness of routine OPV VP1 sequencing for the early identification of viruses carrying virulence-associated reversion mutations has not been directly evaluated in a controlled setting. We prospectively collected 15,331 stool samples to track OPV shedding from children receiving OPV and their contacts for ten weeks following an immunization campaign in Veracruz State, Mexico and sequenced VP1 genes from 358 samples. We found that OPV was genetically unstable and evolves at an approximately clocklike rate that varies across serotypes and by vaccination status. Overall, 61% (11/18) of OPV-1, 71% (34/48) OPV-2, and 96% (54/56) OPV-3 samples with available data had evidence of a reversion at the key 5' UTR attenuating position and 28% (13/47) of OPV-1, 12% (14/117) OPV-2, and 91% (157/173) OPV-3 of Sabin-like viruses had ≥1 known reversion mutations in the VP1 gene. Our results are consistent with previous work documenting rapid reversion to virulence of OPV and underscores the need for intensive surveillance following OPV use.
Walter et al. (Mon,) conducted a observational in Oral poliovirus vaccine (OPV) shedding and viral evolution (n=1,652). Oral poliovirus vaccine (OPV) vs. Unvaccinated contacts was evaluated on Proportion of samples with evidence of a reversion at the key 5' UTR attenuating position. Following an immunization campaign, oral poliovirus vaccine rapidly evolved, with 61% of OPV-1, 71% of OPV-2, and 96% of OPV-3 samples showing reversion at the key 5' UTR attenuating position.