Evaluating the (comparative) safety profile of the novel oral polio vaccine type 2 using individual case safety reports in VigiBase.

AIM: Novel oral polio vaccine type 2 (nOPV2) was used under the WHO emergency use listing for circulating vaccine-derived polio virus (cVDPV) outbreaks from 2021 to 2023. We assessed nOPV2 adverse events following immunization (AEFIs) and compared its safety profile to other vaccines using VigiBase.

METHODS

We descriptively analysed AEFIs to nOPV2 and other vaccines reported to VigiBase from January 1, 2010 to December 31, 2023. Proportional Reporting ratios (PRRs) at Medical Dictionary for Regulatory Activities (MedDRA) higher level group term (HLGT) compared signals of disproportionate reporting (SDR) between nOPV2 and two comparators.

RESULTS

In total, 409 001 AEFIs were included (nOPV2 specific AEFIs: n = 18 911 [4.6%]), of which 54.0% males (n = 10 209) and 22.6% serious (n = 4283). Most events had resolved (n = 9418, 49.8%) or were resolving (n = 6239, 33.0%) at reporting. Body temperature conditions, gastrointestinal and respiratory tract-related events were most reported to nOPV2. Five 'novel', mostly non-serious SDRs were identified - oral soft tissue conditions (PRR: 2.47, 95% CI: 1.71-3.59), haemoglobinopathies (PRR: 31.53, 95% CI: 3.38-312.72), malabsorption conditions (PRR: 4.65, 95% CI: 1.79-12.09), neoplasm-related morbidities (PRR: 3.61, 95% CI: 1.44-9.11) and skin and subcutaneous tissue infections and infestations NEC (PRR: 3.55, 95% CI: 2.61-4.82). Among the serious events, nervous system-related events were reported more.

CONCLUSION

nOPV2 appears to retain a positive safety profile in real-world use. We support its continued use for cVDPV outbreak response and advocate continued monitoring as coverage increases and reporting is no longer mandated.