Maximising the lessons learned from trial data after emergency use listing of a novel oral polio vaccine.

During the past 6 years, outbreaks of circulating vaccine-derived type 2 poliovirus (cVDPV2) originating from the live oral polio vaccine (OPV) have complicated the global efforts towards poliovirus eradication. Responding to cVDPV2 by providing doses of monovalent type 2 OPV (OPV2) carries the risk of new cVDPV2 outbreaks. 1 Jorba J Diop OM Iber J et al. Update on vaccine-derived poliovirus outbreaks—worldwide, January 2018–June 2019. MMWR Morb Mortal Wkly Rep. 2019; 68: 1024-1028 Crossref PubMed Scopus (56) Google Scholar Thus, to ensure that children are protected against poliovirus type 2, WHO in 2020 authorised the use of a novel OPV2 (nOPV2), a more genetically stable form of monovalent OPV2 for outbreak response under an emergency use listing. Since then, nOPV2 has been provided to almost half a billion children younger than 5 years. 2 Bandyopadhyay AS Zipursky S A novel tool to eradicate an ancient scourge: the novel oral polio vaccine type 2 story. Lancet Infect Dis. 2022; (published online Sept 23)http://doi.org/10.1016/S1473-3099(22)00582-5 Summary Full Text Full Text PDF Scopus (8) Google Scholar nOPV2 is produced similarly to older types of OPV, and the safety profile is more favourable because of a lower risk of conversion to virulent forms. However, only a few previous clinical trials have been done, 2 Bandyopadhyay AS Zipursky S A novel tool to eradicate an ancient scourge: the novel oral polio vaccine type 2 story. Lancet Infect Dis. 2022; (published online Sept 23)http://doi.org/10.1016/S1473-3099(22)00582-5 Summary Full Text Full Text PDF Scopus (8) Google Scholar , 3 Sáez-Llorens X Bandyopadhyay AS Gast C et al. Safety and immunogenicity of two novel type 2 oral poliovirus vaccine candidates compared with a monovalent type 2 oral poliovirus vaccine in children and infants: two clinical trials. Lancet. 2021; 397: 27-38 Summary Full Text Full Text PDF PubMed Scopus (37) Google Scholar and before the trial by Khaelqu Zaman and colleagues, 4 Zaman K Bandyopadhyay AS Hoque M et al. Evaluation of the safety, immunogenicity and faecal shedding of novel oral polio vaccine type 2 (nOPV2) in healthy newborn infants in Bangladesh: a randomised, controlled, phase 2 clinical trial. Lancet 2022; Published online Dec 5. http://doi.org/10.1016/S0140-6736(22)02397-2 Google Scholar to our knowledge none had been done in poliovirus-vaccine-naive children, who are also targeted in the outbreak response campaigns. Evaluation of the safety, immunogenicity, and faecal shedding of novel oral polio vaccine type 2 in healthy newborn infants in Bangladesh: a randomised, controlled, phase 2 clinical trialnOPV2 was well tolerated and immunogenic in newborn infants, with two doses, at birth and 4 weeks, resulting in almost 99% of infants having protective neutralising antibodies. Full-Text PDF Open Access