THIS WEEK
Polio this week as of 30 November 2016
The Global Polio Eradication Initiative (GPEI) is initiating a call for nomination of experts, to serve on the Polio Research Committee (PRC). The deadline for submission of nominations is 31 December 2016. The PRC provides guidance to the GPEI on unanswered scientific priorities in poliovirus eradication. As the eradication of polio approaches, the PRC has shifted its focus from research on the acceleration of poliovirus eradication to areas such as the development of new poliovirus vaccines, new administration methods of inactivated poliovirus vaccines, assessment of tools for poliovirus outbreak response, and anti-polio antibody seroprevalence surveys as program evaluation tools. For more on the PRC, and process for submitting nominations, please click here.
A review of ongoing and past field studies has provided additional insights into the effectiveness of fractional dose inactivated polio vaccine (fIPV). Various studies have shown that two doses of fIPV are better than one full dose of IPV at boosting not just humoral immunity, but also mucosal immunity in OPV-primed populations (mucosal immunity is critical to interrupting virus transmission in a community). Fractional dose IPV alongside OPV has also been shown to be an effective tool in outbreak settings and can be operationally implemented even in supplementary immunization activities. Finally, new evidence suggests that fIPV does offer some level of mucosal immunity to type 2 poliovirus in children primed with bivalent OPV. Further investigations on this point are ongoing, as it would be a significant finding (given that bivalent OPV contains only types 1 and 3 vaccine strains).
This evidence gives further weight to the recommendation of the Strategic Advisory Group of Experts on immunization (SAGE), for countries to consider adopting fIPV in both their supplementary and routine immunization activities. This approach could significantly improve the global IPV supply situation which is currently constrained, by reducing the volume of IPV needed to cover a population. Countries are increasingly using fIPV, both in routine and vaccination campaigns.
New this week: Vaccinating children in South Sudan; and, Intensifying Outbreak Response in Nigeria and Lake Chad Basin.