NEW YORK, March 29 — The Covid-19 vaccines developed by Pfizer Inc with BioNTech SE and Moderna Inc are highly effective and reduced the risk of infection by 90 per cent by two weeks after the second shot among healthcare personnel and first responders, according to a the US study released today.

The findings from a study by the US Centres for Disease Control and Prevention of the real-world use of these messenger RNA (mRNA) vaccines confirm what was seen in large controlled clinical trials conducted before they received emergency use authorisations from the US Food and Drug Administration. — Reuters