The fourth booster jab gives protection that is "over and above" what people who have had three jabs receive, a study suggests. Research is ongoing to find out how long protection lasts, and what levels of protection people have following the Covid vaccine.
The CovBoost trial keeps track of the side-effects following a fourth jab. Blood samples were taken from 166 people for scientists to examine antibodies at various time points - including 28 days after the third jab, before the fourth jab was given - on average, 200 days later, and then a fortnight after the fourth jab.
The levels of antibodies - necessary for protection - decreased between the jabs, according to the University of Southampton, but after the fourth was given, they rose higher than after the third jab. There were large boosts compared with levels seen on the day they had the fourth jab, with people having 12 to 16 times higher levels of antibodies a fortnight after their jab compared to the day they had it.
