Defining the optimal intranasal administration strategy for inactivated poliovirus vaccine
Mucosal immunity plays a pivotal role in protection against infection and the transmission of pathogens from person to person. Ideally, novel vaccines should be easy and safe to administer, provide mucosal immunity, be safe to manufacture, and be affordable for low-income countries. Alternative delivery strategies, such as the intranasal route, may fulfill at least some of these preferred vaccine characteristics. Moreover, vaccination via mucosal routes has the potential to evoke strong mucosal immunity at the entry site. In the current study, the potential of the intranasal route was investigated for an inactivated polio vaccine based on Sabin strains (sIPV). Different vaccination regimes for intranasal administration of sIPV were evaluated by measuring both systemic and mucosal immune responses in mice. Heterologous prime-boost schedules using a combination of parenteral and mucosal administration showed to elicit virus neutralizing antibody titers in serum and polio-specific IgA titers at different mucosal sites in mice that were vaccinated with sIPV. Moreover, the inclusion of an adjuvant was able to further enhance immune responses. Intranasal administration of adjuvanted sIPV combined with a regular intramuscular sIPV vaccination can significantly improve mucosal immune responses while maintaining systemic immune responses, which can lead to better protection against polio infection and possibly prevent virus transmission. An intranasally delivered inactivated polio vaccine might be of value for use in routine vaccination or outbreak control, and therefore, a helpful tool towards polio-eradication.