A NEW intranasal vaccine candidate, BPZE1, has demonstrated encouraging results in preventing or substantially reducing colonisation by Bordetella pertussis, the bacterium responsible for whooping cough. The findings come from a randomised, placebo-controlled, phase 2b trial conducted at University Hospital Southampton and the University of Oxford, designed to assess both safety and efficacy in healthy adults aged 18–50 years.
BPZE1 Reduces Whooping Cough Colonisation
The study enrolled 53 participants, all fully vaccinated against COVID-19, and excluded individuals recently vaccinated against or infected with pertussis. Participants were randomly assigned to receive a single intranasal dose of 109 colony-forming units (CFU) of BPZE1 or placebo, followed 60–120 days later by a controlled challenge with virulent B. pertussis. Nasal washes and blood samples were collected to monitor bacterial colonisation and immune response.
Results showed that in the modified intention-to-treat population, 58% of participants receiving BPZE1 had no detectable colonisation at days 9, 11, and 14 post-challenge, compared with 33% in the placebo group. In participants receiving an adequate challenge dose, 60% of BPZE1 recipients remained free of detectable B. pertussis versus 25% in the placebo group, a statistically significant difference.
The vaccine was well tolerated, with the majority of participants reporting only mild adverse events, such as nasal irritation or headache, and no serious adverse events or trial discontinuations. Unsolicited adverse events occurred at similar rates in both the vaccine and placebo groups.
Safe and Well Tolerated in Healthy Adults
The intranasal BPZE1 vaccine’s ability to prevent colonisation highlights its potential to reduce transmission of whooping cough, which current vaccines do not fully address. With its favourable safety profile and promising efficacy, BPZE1 is positioned as an attractive candidate for larger phase 3 trials.
For healthcare professionals, these findings signal an important advance in pertussis prevention, offering hope for a vaccine that could better protect both individuals and communities from whooping cough.
Reference
Gbesemete D et al. Efficacy, immunogenicity, and safety of the live attenuated nasal pertussis vaccine, BPZE1, in the UK: a randomised, placebo-controlled, phase 2b trial using a controlled human infection model with virulent Bordetella pertussis. Lancet Microbe. 2025; DOI:10.1016/j.lanmic.2025.101211.
