Vaccines are effective in decreasing hospitalization and deaths from COVID-19 infection but the emergence of viral variants of concern may diminish their efficacy. A study publishing in PLOS Pathogens by Emma Thomson, Brian Willett, and colleagues at the MRC-University of Glasgow Centre for Virus Research, United Kingdom and colleagues suggests that COVID-19 Delta variant may be more successful at evading the protective response of vaccines.
Mutations change the shape of the COVID-19 spike protein, preventing antibody recognition and enabling the virus to escape vaccine-induced immunity; however, the extent to which vaccine recipients are immune from the Delta variant is unknown. To quantify the capacity of different variants (Alpha, Beta and Delta) to evade protective immune response in vaccines, researchers analyzed serum samples collected from healthy people who had received either the Pfizer or Astra Zeneca vaccine. 156 people had received two doses and 50 people had received one dose. They exposed SARS-CoV-2 proteins in a virus model system to sera from vaccinated people and observed the antibody response, measuring how effectively antibodies prevented each variant from infecting cells (virus neutralization).
Release date: 02 December 2021