Protection of infant mice against pertussis, tuberculosis and influenza by co-administration of nasal pertussis vaccine candidate BPZE1 and BCG

Protecting neonates at risk of serious pertussis disease or death represents a global emergency. BPZE1 is the most advanced, next-generation pertussis vaccine undergoing clinical evaluation in children and adults. We investigated the feasibility of co-administering BPZE1 and Bacillus Calmette-Guerin (BCG), the most widely used tuberculosis vaccine worldwide. We showed that BPZE1 can be co-administered with BCG without altering its immunogenicity and protective efficacy against <i>B. pertussis</i> in infant mice. Conversely, BCG immunogenicity and protective efficacy against <i>M. tuberculosis</i> are not affected by BPZE1. Both vaccines induce off-target protection against heterologous infections. In this study, we showed that BPZE1 and BCG alone or in combination induced high levels of protection against influenza challenge in infant mice. In contrast to BCG, the off-target properties of BPZE1 were independent of the age of vaccination. Vaccination with BPZE1 might be considered at the same time as BCG, facilitating its effective implementation in the childhood immunization schedule.