Vaccines may work better in people who have already had Covid – and could more effectively protect against the South African and Brazilian variants.

Those previously infected with coronavirus produced almost seven times the amount of antibodies after a single Pfizer jab compared to people who have not had the virus.

Their antibody levels against the South African and Brazilian variants were also 15 times higher, a study shows. And they had seven times more T-cells – the vital immune cells which react to the virus.