Immunity to coronavirus could be lost within months of contracting the killer bug, which may return each year like common colds, a UK study claims.
King's College London scientists found levels of antibodies - the body's main line of defence - were at their highest around three weeks after symptoms arose but quickly decline.
That suggests any potential vaccine may follow the same pattern and require annual boosting immunisations, while the idea of 'herd immunity' could be unlikely to work.
Sixty per cent of the close to 90 patients and healthcare workers at Guy's and St Thomas' NHS foundation trust - which treated Boris Johnson - involved in the research had a "potent" antibody response at the peak of their battle.