While a study conducted by researchers at Banaras Hindu University (BHU) showed that nearly one-third of the individuals who received Bharat Biotech’s Covid-19 vaccine Covaxin reported adverse events of special interest (AESI) after a one-year follow-up, the Hyderabad-based company pointed out lapses in the research.
Nearly 50 per cent of 926 study participants complained of infections during the follow-up period, predominated by viral upper respiratory tract infections. Serious AESI, which included stroke and Guillain-Barre syndrome, were reported in one per cent of individuals, the study, which looked at the long-term safety of the BBV152 vaccine in adolescents and adults, claimed.
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Bharat Biotech said, “For such a study in safety to be effective, informative and to avoid investigator bias, several data points are also required. For example, the AESI safety profile of the subjects prior to participation in the study; comparison of the safety profile of non-vaccinated subjects during the course of the study; comparison of the safety profile of subjects who received other vaccines during the course of the study; all study participants should be followed during the course of the study, instead of only a subset.” The vaccine maker further claimed that several studies have been executed on the safety of Covaxin and published in peer-reviewed journals, demonstrating an excellent safety track record.
However, this new study from BHU published in the journal Springer Nature says that “Close to one third of the individuals developed AESIs. New-onset skin and subcutaneous disorders, general disorders, and nervous system disorders were the three most common disorders observed in adolescents after receiving the vaccine.” The study was conducted from January 2022 to August 2023 involving 635 adolescents and 291 adults, who received the BBV152 vaccine. The participants were interviewed telephonically about long-term adverse events of special interest after one year of vaccination.
Nearly 363 million doses of Covaxin have been administered in India so far, second only to AstraZeneca-Serum Institute of India’s Covishield.
It comes in the wake of UK pharmaceutical giant AstraZeneca admitting its Covid-19 vaccine can cause rare side-effects of blood clotting and lowering of platelet count in UK court.
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Krishna Ella, Executive Chairman of Bharat Biotech, had told Business Standard last September, “My first priority is always safety when developing a vaccine because we are giving vaccines to healthy people, and you can have the best platform technology in the world, but that doesn’t matter if there are safety concerns. In contrast, antibiotics are given to infected people, but vaccines are not only given to healthy people, mostly to children.”
Ella had said, “During the pandemic, everyone was talking about efficacy, and now that the pandemic is over, everyone is talking about safety. Viruses do cause problems for people, but we don’t expect the vaccine to cause problems. Covaxin is perhaps the safest vaccine in the entire world; it stays in the muscle but does not enter the body. That’s a critical aspect that makes this a safe vaccine.”
The BHU study claimed that new-onset skin and subcutaneous disorders (10.5 per cent), general disorders (10.2 per cent), and nervous system disorders (4.7 per cent) were the common AESIs in adolescents. General disorders (8.9 per cent), musculoskeletal disorders (5.8 per cent), and nervous system disorders (5.5 per cent) were the common AESIs in adults. Menstrual abnormalities were noticed in 4.6 per cent of female participants. Ocular abnormalities and hypothyroidism were observed in 2.7 per cent and 0.6 per cent of participants. Four deaths (three female individuals, one male individual) were reported in adults, the study added. All four had diabetes, while hypertension in three, and a history of pre-vaccination COVID-19 was present in two of them. The fourth death happened in a woman with multiple episodes of unconsciousness post-vaccination, the etiology of which remained unidentified until death.
In the absence of a definite causality association, no conclusions can be drawn from these events, the researchers said.
(With inputs from PTI)