COVID-19 vaccine: Study finds AstraZeneca booster jab safe, effective
Seven COVID-19 vaccines are safe and stimulate a strong immune response when used as a booster jab to those who have already vaccinated, a study published in The Lancet said. The study titled COV-BOOST examined the safety, immune response, and side-effects of the vaccines based on its trial in the United Kingdom. The seven vaccines included AstraZeneca, Pfizer, Novavax, Janssen, Moderna, Valneva, and Curevac.
Why does it matter?
The findings of the Lancet study come as India's Serum Institute is seeking the drug regulator's nod to allow Covishield (AstraZeneca/Oxford formulation) as a booster jab. The study is likely to help SII to get approval from the Drugs Controller General of India (DCGI). Booster doses have gained importance as protection from vaccines is known to wane over time, particularly after six months.
Who conducted the study?
The study was funded by the UK Vaccine Taskforce and the National Institute for Health Research. The researchers involved in the study belong to institutions such as the University Hospital Southampton NHS Foundation Trust, University of Southampton, Imperial College London, and NIHR Oxford Biomedical Research Centre. Researchers from the University of Oxford and the Oxford Vaccine Group were also part of the study.
Study involved 2,878 participants
The randomized Phase II trial of the study involved a total of 2,878 healthy participants. The participants were reportedly recruited between June 1-30, 2021, in the UK from different communities. All participants were 30 years or older, with half of them above the age of 70. The vaccines were used as booster jabs 10-11 weeks after the participants completed their two-dose vaccination.
What did the study focus on?
The study focused on the adverse effects after seven days of booster jab and the level of antibodies after 28 days. The other outcome studied was the T-cell immune response. T-cells are key in controlling disease severity.
Findings indicate positive trend with boosters
While all the seven vaccines boosted spike protein immunogenicity after two doses of AstraZeneca, the booster jab of Valneva was not found to be effective after two doses of Pfizer. In the case of AstraZeneca, the antibody levels rose 1.8 times to 32.3 times depending on the booster used. The antibody levels rose 1.3 times to 11.5 times in the case of Pfizer.
What were the side-effects?
The common side-effects included fatigue, headache, and injection site pain. Of the 2,878 participants, 912 experienced a total of 1,036 "adverse events," 24 of which were severe. "The side-effect data show all seven vaccines are safe to use as third doses..." said Professor Saul Faust, trial lead of the study. He said the levels of inflammatory side-effects were "acceptable."
Results encouraging: Trial lead
Professor Faust further said the study is "encouraging" and gives the "confidence and flexibility" in developing booster programs both in the UK and globally. However, he acknowledged the impact of factors such as supply chain and logistics.
'Interpret booster jab data with caution'
The study's authors warned that the data on booster doses should be interpreted. The data only evaluates immune response, not protection against COVID-19, they said. It also fails to establish a relationship between antibody levels on Day 28 and long-term protection. Notably, intervals between the doses also varied among participants. Further, the participants were all aged over 30 years and were mostly white.
