New research suggests that Pfizer's Covid-19 vaccine can protect against a mutation found in two highly contagious variants of the coronavirus that erupted in Britain and South Africa.

Both variants share a common mutation called N501Y, a slight alteration on one spot of the spike protein that coats the virus. That change is believed to be the reason they can spread so easily.

Most of the vaccines being rolled out around the world train the body to recognise that spike protein and fight it. Pfizer teamed with researchers from the University of Texas Medical Branch in Galveston for laboratory tests to see if the mutation affected its vaccine's ability to do so.

They used blood samples from 20 people who received the vaccine, made by Pfizer and its German partner BioNTech, during a large study of the shots. Antibodies from those vaccine recipients successfully fended off the virus in lab dishes, according to the study posted on an online site for researchers.

The study is preliminary and has not yet been reviewed by experts, a key step for medical research, AP reported.