However, the study also hinted that a small number of people might reach a 'ceiling' in terms of the amount of protection that they could get from a fourth jab.
Boosts were also seen in the cellular level, according to the study, which has been published in The Lancet Infectious Diseases journal.
They also looked at people who had three doses of Pfizer, followed by a fourth Pfizer shot or a half-dose Moderna jab. However the authors said the study also provided a"hint" that a small number of people might reach a"ceiling" in terms of the amount of protection they could get from a fourth jab. Health and Social Care Secretary Sajid Javid added:"This is further evidence underlining the importance of people coming forward for their booster as soon as they are eligible.thanks to the protection provided by our phenomenal vaccine programme and a booster dose will top up your immunity to continue to keep you and your loved ones safe.