LONDON: Vaccine developed by Oxford University and AstraZeneca PLC is effective against a new highly transmissible variant of the virus that causes Covid-19, according to an analysis that offers more security than a worldwide vaccination boost will help end the pandemic.
However, the small-scale study showed that the vaccine works best against the oldest and most established versions of the virus, which has so far been linked to nearly 2.3 million deaths worldwide and more than 100 million cases.
In a study published online Friday, researchers examined blood samples from about 256 participants in an ongoing clinical trial of the vaccine that tested positive for Covid-19. The findings are preliminary and have not been formally reviewed by other scientists.
Genetic sequencing allowed them to identify which participants were infected with the new variant and who had an earlier version. A little less than a third had the new variant.
By testing the levels of antibodies and other markers of activity of the immune system against the virus, the researchers found that the vaccine elicited an effective immune response against the new variant in 75% of cases showing symptoms of infection and in approximately two-thirds of cases if those who showed no symptoms were also included.