Intranasal vaccine against Bordetella pertussis invokes seronegative IgA response

1. Nasal secretory IgA seroconversion was achieved in more patients who received BPZE1 than those who received Tdap.

2. Both vaccines were well-tolerated with no treatment-related fatalities.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Pertussis is a contagious respiratory disease caused by Bordetella pertussis in children. Current vaccines against pertussis include whole-cell vaccines and acellular pertussis vaccines (aPVs). BPZE1 is a live attenuated pertussis vaccine made by the removal of three major B pertussis vaccines which aims to prevent infection and subsequent transmission of B. pertussis. However, long-term studies to evaluate the efficacy have been sparse to date. This randomized controlled trial aimed to assess the safety and efficacy of BPZE1 versus the standard Tdap vaccine for the prevention of B pertussis. The primary endpoint was the proportion of patients achieving IgA seroconversion against one or more B pertussis antigens on days 29 and 113. According to the study results, the greatest IgA serum responses were seen among the BPZE1-BPZE1 and BPZE1-placebo groups and the increases in serum antibodies were sustained up to the end of the study. This study was well done although it only selected patients from limited research centers in USA, affecting its generalizability.

Click to read the study in The Lancet

Relevant Reading: Safety and immunogenicity of the live attenuated intranasal pertussis vaccine BPZE1: a phase 1b, double-blind, randomised, placebo-controlled dose-escalation study

In-depth [randomized-controlled trial]: Between Jun 17, 2019, and Oct 3, 2019, 458 patients were assessed for eligibility across 3 research centers in the USA. Included were patients between 18-50 years old. In the case of women with childbearing potential, they could not be pregnant or lactating and had to use appropriate contraception throughout the study. Altogether, 280 patients (92 in BPZE1-BPZE1, 92 in BPZE1-placebo, 46 in Tdap-BPZE1, and 50 in Tdap-placebo groups) were included. The primary endpoint of seroconversion of nasal secretory IgA was achieved in 94% of BPZE1-BPZE1, 95% of BPZE1-placebo, 90% of Tdap-BPZE1, and 93% of Tdap-placebo group. The BPZE1 intranasal vaccine induced a B pertussis-specific secretory IgA response to four antigens (whole-cell extract, pertactin, filamentous hemagglutinin, and pertussis toxin) whereas Tdap produced a response to filamentous hemagglutinin only.
Both vaccines were well-tolerated and reported no serious adverse events or deaths. Findings from this study suggest that BPZE1 has the potential to avert B pertussis through functional serum responses.

Image: PD

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