Humoral and cellular response induced by a second booster of an inactivated SARS-CoV-2 vaccine in adults

Authors:
Preprint
Publisher website
Google Scholar
Abstract
Summary: The SARS-CoV-2 Omicron variant has challenged the control of the COVID-19 pandemic even in highly vaccinated countries. While a second booster of mRNA vaccines improved the immunity against SARS-CoV-2, the humoral and cellular responses induced by a second booster of an inactivated SARS-CoV-2 vaccine have not been studied. In the context of a phase 3 clinical study, we report that a second booster of CoronaVac ® increased the neutralizing response against the ancestral virus yet showed poor neutralization against the Omicron variant. Additionally, isolated PBMCs displayed equivalent activation of specific CD4 + T cells and IFN-γ production when stimulated with a mega-pool of peptides derived from the spike protein of the ancestral virus or the Omicron variant. In conclusion, a second booster dose of CoronaVac ® does not improve the neutralizing response against the Omicron variant compared with the first booster dose, yet it helps maintaining a robust spike-specific CD4 + T cell response.

This publication has 34 references indexed in Scilit: