Fourth jab ‘significantly increases protection’

FOURTH Covid-19 jabs give people protection “over and above” that afforded to people who have had three jabs, a new study suggests.

Research is continuing to assess the levels of protection people have after vaccination, and for the length of time that this protection lasts.

A team of academics led by the University of Southampton have been tracking a group of people and their levels of antibodies and T cells, both measures which indicate a person’s level of protection against a virus. The CovBoost trial also examined side-effects after a fourth jab.

Some 166 people took part in the study and offered blood samples, which means that scientists could examine the concentration of antibodies in the blood.

These were examined at various time points, including 28 days after the third jab was given; again just before their fourth boost was administered – which took place, on average, just over 200 days later; and then 14 days after they had their fourth jab.

The levels of antibodies waned in the period between third jabs and fourth boosters. But a fortnight after the booster jab antibody levels rose even higher than the levels seen after the third jab.

And there were significant boosts compared with the levels seen on the day they were given their fourth booster – participants had 12 to 16 times higher levels of antibodies in the blood a fortnight after they got their fourth shot, compared with the day it was delivered.

Boosts were also seen in the cellular level, according to the study, published in The Lancet Infectious Diseases journal.

Researchers examined data on people who had two doses of the AstraZeneca jab, followed by a Pfizer booster, who then received either a Pfizer jab or half dose of a Moderna jab for their fourth vaccine. They also looked at people who had three doses of Pfizer, followed by a fourth Pfizer shot or a half-dose Moderna jab.

No severe side-effects were recorded among participants, with some reporting pain or fatigue.

Trial lead Professor Saul Faust, director of the NIHR Southampton Clinical Research Facility, said: “These results underline the benefits of the most vulnerable people receiving current spring boosters and gives confidence for any prospective autumn booster programme in the UK, if the Joint Committee on Vaccination and Immunisation considers it needed at that time.”