Fourth Covid jab can give higher immunity than initial booster, study finds

UK-based team finds antibodies peaked higher after fourth jab given after gap of more than six months than after third

A fourth dose of a Covid vaccine can ramp up the body's immune defences beyond the peak achieved after a third dose, research suggests.

A second booster - often a fourth dose of a Covid vaccine - is currently offered in the UK to those aged 75 or over, people living in care homes for older people, and those over the age of 12 who are immunosuppressed.