The Covid-19 vaccine from Pfizer Inc and BioNTech SE was able to neutralise a new variant of the coronavirus spreading rapidly in Brazil, according to a laboratory study published in the New England Journal of Medicine on Monday.

Blood taken from people who had been given the vaccine neutralised an engineered version of the virus that contained the same mutations carried on the spike portion of the highly contagious P.1 variant first identified in Brazil, the study conducted by scientists from the companies and the University of Texas Medical Branch found.

The scientists said the neutralising ability was roughly equivalent the vaccine's effect on a previous less contagious version of the virus from last year.

The spike, used by the virus to enter human cells, is the primary target of many Covid-19 vaccines.

In previously published studies, Pfizer had found that its vaccine neutralised other more contagious variants first identified in the United Kingdom and SA, although the variant found in SA may reduce protective antibodies elicited by the vaccine.

Pfizer has said it believes its current vaccine is highly likely to still protect against the variant first found in SA.

However, the drugmaker is planning to test a third booster dose of their vaccine as well as a version retooled specifically to combat the variant in order to better understand the immune response.