Safety and immunogenicity of a hybrid-type vaccine booster in BBIBP-CorV recipients in a randomized phase 2 trial

SARS-CoV-2 variants with immune escape capability highlight the need for the development of cross-neutralising vaccines and regimens. Here, the authors assess the immunogenicity and safety of NVSI-06-08, that integrates antigens from multiple SARS-CoV-2 strains into a single immunogen, as a heterologous booster in adults previously vaccinated with the inactivated vaccine. NVSI-06-08 is a potential broad-spectrum recombinant COVID-19 vaccine that integrates the antigens from multiple SARS-CoV-2 strains into a single immunogen. Here, we evaluate the safety and immunogenicity of NVSI-06-08 as a heterologous booster dose in BBIBP-CorV recipients in a randomized, double-blind, controlled, phase 2 trial conducted in the United Arab Emirates (NCT05069129). Three groups of healthy adults over 18 years of age (600 participants per group) who have administered two doses of BBIBP-CorV 4-6-month, 7-9-month and >9-month earlier, respectively, are randomized 1:1 to receive either a homologous booster of BBIBP-CorV or a heterologous booster of NVSI-06-08. The incidence of adverse reactions is low, and the overall safety profile is quite similar between two booster regimens. Both Neutralizing and IgG antibodies elicited by NVSI-06-08 booster are significantly higher than those by BBIBP-CorV booster against not only SARS-CoV-2 prototype strain but also multiple variants of concerns (VOCs). Especially, the neutralizing antibody GMT against Omicron variant induced by heterologous NVSI-06-08 booster reaches 367.67, which is substantially greater than that boosted by BBIBP-CorV (GMT: 45.03). In summary, NVSI-06-08 is safe and immunogenic as a booster dose following two doses of BBIBP-CorV, which is immunogenically superior to the homologous boost with another dose of BBIBP-CorV.

Automated summary

The study evaluates the effectiveness of NVSI-06-08 as a COVID-19 vaccine and finds that it performs better as a heterologous booster in enhancing immunity. NVSI-06-08 shows good neutralization antibody response against different SARS-CoV-2 variants and has a similar safety profile compared to homologous booster.