By Pooja Toshniwal PahariaOct 7 2022Reviewed by Danielle Ellis, B.Sc. In a recent study published in PLoS Pathogens, researchers explored severe acute respiratory syndrome coronavirus 2 -targeted immune responses among COVAC1 participants who received a novel self-amplifying ribonucleic acid vaccine followed by the messenger RNA BNT162b2 vaccine BNT162b2 vaccine, with or without prior coronavirus disease 2019 history.
Thirty-five individuals who received saRNA in the COVAC1 trial and 40 individuals who received only BNT162b2 homologous vaccinations were enrolled for the analysis. The saRNA vaccinees also received mRNA BNT162b2 or ChAdOx nCoV-19 adenoviral vector vaccinations. Results Related StoriesFifty percent of the participants in both groups showed COVID-19 recovery with greater humoral Ab-mediated and cellular T lymphocyte-mediated immune responses among those with prior COVID-19 history and individuals who were administered heterologous vaccinations.
Neutralization against VOCs was best maintained among previously-infected heterologous vaccinees. However, the findings were significant only for Omicron BA.4/5. Cross-neutralization against Delta and Omicron VOCs was lower among homologous vaccinees than heterologous vaccinees, although significant only for BA.4/5 .