COVID-19 vaccination and BA.1 breakthrough infection induce neutralising antibodies which are less efficient against BA.4 and BA.5 Omicron variants, Israel, March to June 2022
Limor Kliker, Neta S. Zuckerman, Nofar Atari, Noam Barda, Mayan Gilboa, Ital Nemet, Bayan Abd Elkader, Ilana S. Fratty, Hanaa Jaber, Ella Mendelson, Sharon Alroy‐Preis, Yitshak Kreiss, Gili Regev‐Yochay, Michal Mandelboim
Abstract
This work evaluated neutralising antibody titres against wild type (WT) SARS-CoV-2 and four Omicron variants (BA.1, BA.2, BA.4 and BA.5) in healthcare workers who had breakthrough BA.1 infection. Omicron breakthrough infection in individuals vaccinated three or four times before infection resulted in increased neutralising antibodies against the WT virus. The fourth vaccine dose did not further improve the neutralising efficiency over the third dose against all Omicron variants, especially BA.4 and BA.5. An Omicron-specific vaccine may be indicated.