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
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 2 novel OPV2 candidates, conducted in Panama, found the candidates were safe, well tolerated, and immunogenic in children and infants.
Source:
The Lancet
SPS commentary:
Also in The Lancet are the results of a phase 2 clinical trial comparing the safety and efficacy of two novel OPV2 strains with monovalent OPV2 in adults.
The novel type 2 oral poliovirus vaccines (OPVs) were developed in response to the continued emergence and spread of circulating vaccine-derived type 2 polioviruses and vaccine-associated paralytic poliomyelitis from OPVs). These new vaccines were designed to have similar immunogenicity, improved genetic stability, and less potential to reacquire neurovirulence.
According to an editorial, by early 2020, the point passed at which the best case scenario was possible of stopping all type 2 poliovirus transmission using vaccine supplies produced before OPV2 cessation. It notes this situation puts the world into a new and much more challenging phase that will require careful deliberation of long-term poliovirus vaccine options and management of some insufficient poliovirus vaccine supplies. Furthermore, the disruption in immunisation caused by the COVID-19 pandemic further exacerbates the situation. It suggests these studies represent promising next steps towards the future of global poliovirus control and eradication using better performing OPV strains.