A world-leading, UK-based study has found that booster vaccines can raise antibody levels by as much as 32 times

Vaccination

A study published in The Lancet has found that booster vaccines ‘significantly’ strengthen the body’s immune defences against COVID-19.

The study was conducted as part of the COV-BOOST trial of third-dose booster vaccinations, a multicentre, randomised, controlled trial and the first of its kind. It had 2878 participants separated into younger and older age groups, with similarly positive results regardless of age.

Researchers investigated the body’s reaction to seven different COVID-19 vaccines as a third dose after two doses of ChAdOx1 nCov-19 (AstraZeneca) or BNT162b2 (Pfizer). They found all the boosters to be effective in increasing the body’s immune defences.

The Pfizer vaccine, currently being used for boosters in the UK, raised the antibody levels of those who had had two doses of AstraZeneca to nearly 25 times that of the equivalent control patients after a month. For those who had previously had two doses of the Pfizer vaccine instead, it was still an increase of more than eightfold.

The most significant differences occurred in those given a booster of mRNA1273 (Moderna), as a full dose of the Moderna booster came with antibodies 32-times and 11-times higher than control groups in those already vaccinated with AstraZeneca and Pfizer respectively. It is worth noting that standard UK Moderna boosters are only a half dose.

Most of the study’s vaccine boosters—excluding AstraZeneca and VLA2001 (Valneva)—also increased T-cell levels regardless of previous vaccination, another crucial component for preventing severe illness. The Moderna booster in particular more than doubled T-cell levels in those previously vaccinated with AstraZeneca vaccines.

Fatigue and pain were the most common side effects. Serious adverse events were uncommon, similar in active vaccine and control groups, and were considered no cause for concern.

‘These are remarkably effective immunological boosters, way above what is needed to prevent hospitalisation and death,’ said Professor Saul Faust, the Trial Lead and Director of the National Institute for Health Research clinical research facility at University Hospital Southampton NHS Foundation Trust, to the Guardian. Asked if the finding might be relevant to the Omicron variant, Professor Faust said: ‘Our hope as scientists is that protection against hospitalisation and death will remain intact.’

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