Sáez-Llorens X, Bandyopadhyay AS, Gast C, et al. - In the present study, the researchers sought to evaluate the safety and immunogenicity of the two novel oral poliovirus vaccine (OPV) candidates compared with a monovalent Sabin OPV in children and infants. Two single-center, multi-site, partly-masked, randomised trials were carried out including healthy cohorts of children (aged 1–4 years) and infants (aged 18–22 weeks) in Panama: a control phase 4 study with monovalent Sabin OPV2 before global cessation of monovalent OPV2 use, and a phase 2 study with low and high doses of two novel OPV2 candidates. Researchers administered one OPV2 vaccination to all participants; subsets were administered two doses 28 days apart. They enrolled 150 children (50 in the control study and 100 of 129 assessed for eligibility in the novel OPV2 study) and 684 infants (110 of 114 assessed for eligibility in the control study and 574 of 684 assessed for eligibility in the novel OPV2 study) and administered them at least one study vaccination. Outcomes suggest that in children and infants, both novel OPV2 candidates were safe, well-tolerated, and immunogenic. In view of the current epidemiological situation, the novel OPV2 may be a significant addition to the resources against poliovirus.