Developing affordable inactivated polio vaccine
This area of research focuses on the post-eradication era – preparing for stopping routine use of oral polio vaccine (OPV) by developing affordable options for inactivated polio vaccine (IPV) use.
Establishing affordable options for IPV use in any setting
Once wild poliovirus transmission has been stopped globally, the vaccine-viruses will be the only source of live polioviruses in the community and could potentially lead to the re-emergence of polio. Use of the oral polio vaccine in routine immunization programmes will therefore be phased out to eliminate the rare risks posed by vaccine-derived polioviruses. Before OPV can be stopped globally, however, affordable IPV options will be needed for any country wishing to continue polio immunization.
To meet this objective, the Global Polio Eradication Initiative is pursuing a multi-pronged research agenda:
- dose-reduction strategy using intradermal administration of fractional IPV doses
- schedule requiring fewer doses (for example, two doses given six months apart)
- adjuvant use to reduce the quantity of antigen required in the vaccine
- IPV production processes to facilitate manufacture in low-cost sites.
Investigating the mucosal immune responses stimulated by IPV compared with those stimulated by OPV is also on the research agenda.
The goal of this area of research is to enable low-income countries to produce IPV. To meet this objective, the Global Polio Eradication Initiative is working with academia, government and industry to develop an inactivated polio vaccine based on the non-infectious Sabin virus strain (sIPV). A range of manufacturers and research institutes have active programmes at various stages of development, including the Netherlands Vaccine Institute, Panacea and JPRI/Takeda.
The development and licensure of IPV produced from Sabin strains aims to reduce the number of manufacturing sites generating high volumes of high titre wild polioviruses for ”traditional” IPV production. Sabin polioviruses pose less of a threat in the event of an intentional or unintentional release from the production facility. This is a particular concern in low-income countries where the transmissibility of polioviruses is high.
Work is also under way to establish and expand Sabin-IPV seed strains from which to make the vaccines, and to assess alternative, non-infectious seed strains for IPV production.