The latest findings from a nationwide National Institute for Health and Care Research (NIHR) supported study show that fourth dose MRNA booster vaccines for Covid-19 are well-tolerated in people who received Pfizer as a third dose.
MRNA vaccines essentially teach our cells how to make a protein that will trigger an immune response inside our bodies.
These MRNA jabs were also effective at increasing both antibody and cellular immunity up to and above baseline and peak levels observed following third dose boosters.
Led by University Hospital Southampton, the Cov-boost study provided the world’s first data on the safety, immune responses and side-effects of third dose in mix and match schedules.
Professor Saul Faust, trial lead and 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.’
As part of the studies 10 UK sites – including the Portsmouth Research Hub at the John Pounds Centre – recruited 166 people who had received a third dose of Pfizer, following Pfizer or AstraZeneca initial doses in June 2021.
The patients were then randomised to receive full dose Pfizer or half dose Moderna as a fourth dose, approximately seven months after their third dose.
Dr Alexander Hicks, consultant respiratory physician at Portsmouth Hospitals University NHS Trust and local investigator for the trial said: ‘I would like to thank our participants from Portsmouth and the surrounding communities for helping with this study.
‘Once again, we can be reassured that Covid-19 vaccines are safe to use and helpfully this study shows that fourth doses continue to effectively boost our immune systems.
‘Going forwards this new evidence will be invaluable in informing decisions for any future booster programmes.’
Fourth doses of Covid-19 vaccines have already been offered as a spring booster for those most vulnerable in the UK. A wider group of people may be offered a fourth dose booster later this year.