New Delhi: A booster dose of the Covishield vaccine can significantly increase the levels of antibodies against the Omicron SARS-CoV-2 variant (B.1.1.529), according to a new study.
In the preprint study, uploaded on 22 December, researchers from the University of Oxford found that the levels of neutralising antibodies were higher in people who had taken a third dose of the Oxford-AstraZeneca vaccine — known as Covishield in India — than they were in individuals who had formerly been infected with the previously circulating SARS-CoV-2 variants.
Blood serum obtained from individuals one month after receiving the third dose neutralised the Omicron variant to levels that were similar to those observed one month after the second dose against the Delta variant.
Two doses of the AstraZeneca vaccine have been associated with protection against the Delta variant in previous, real-world studies.
The study analysed blood samples taken from individuals infected with Covid-19, those who had been vaccinated with a two-dose schedule and a third dose booster, and those who had reported previous infection from other Covid-19 variants of concern.
The study, which is yet to be peer reviewed, included samples from 41 individuals who had received three doses of Covishield, which is now known as Vaxzevria in the UK.
“These results support the use of third dose boosters as part of national vaccine strategies, especially to limit the spread of variants of concern, including Omicron,” John Bell, a professor at the University of Oxford and one of the study investigators, said in a statement.
Another study has shown that although two doses of Covishield remain effective against Omicron, there is a decrease in efficacy compared to its performance against the original strain of the coronavirus.
(Edited by Rohan Manoj)