Days after a Banaras Hindu University (BHU) study reported long-term adverse events of “special interest” in a group of over 900 people a year after they were vaccinated with Bharat Biotech’s Covaxin, the Indian Council of Medical Research (ICMR) has called it a “poorly designed study” with critical flaws.
The director-general of the apex medical research body has also written to the authors of the paper and the editor of the journal in which it was published, stating that it “incorrectly and misleadingly” acknowledges ICMR though the body did not offer any financial or technical support for the paper. “ICMR cannot be associated with this poorly designed study,” say the letters.
Why did ICMR denounce the paper?
According to ICMR, the study has four critical flaws. One, it does not have a control group of unvaccinated individuals to prove that the side-effects are indeed associated with vaccination. Two, it does not mention how frequently these adverse events were reported by the sample population to establish that they were associated with vaccination. Three, the study tool was not consistent with the definition of “adverse events of special interest” that is globally accepted. Four, the responses of the participants were recorded one year after immunisation without verification of any clinical records or physician examination, increasing the chances of biased reporting.
According to the methodology mentioned in the paper, the researchers contacted over 1,000 adolescent and adult recipients of the vaccine telephonically 14 days after immunisation to check whether they had experienced any side effects. The researchers again contacted the recipients one year later — when 926 of the 1,024 initial participants answered — to check whether any of the symptoms persisted or whether they had developed any other side effects of “special interest.”
What did the research claim?
The study claimed that over a one-year follow-up, over 40 per cent of the participants reported upper respiratory tract infections that were not confirmed to be Covid-19. It said 10.5 per cent adolescents developed new skin or under-skin disorders and 4.7 per cent developed nervous system disorders. Among adults, the study said, 5.8 per cent reported musculoskeletal disorders and 5.5 per cent nervous system disorders. About 4.6 per cent of girls and women reported menstrual abnormalities. And 0.3 per cent of the participants experienced strokes and 0.1 per cent had Guillain Barre syndrome — a rare disorder where the immune system starts attacking the nerves.
The methodology used for the current study cannot determine whether the symptoms were caused by the vaccine, the infection, or several other reasons that also cause these symptoms.
It is important to note that having provided the virus isolate for Covaxin, ICMR receives royalty from the vaccine.
What are adverse events of special interest?
These are conditions that vaccine manufacturers pre-identify or identify during the roll-out to be tracked for longer durations. International organisations such as Brighton Collaboration and the Coalition for Epidemic Preparedness Innovations (CEPI) have come together to define and track these events for newly-developed Covid-19 vaccines.
What did the Covaxin trial show?
The phase III trial of Covaxin, with over 24,000 participants, found that 12 per cent participants reported common side effects and 0.5 per cent severe side effects, which was similar to the group that was administered placebo vaccine (without any therapeutic efficacy). The phase 3 trial in 2021 that followed recipients for a median 146 days found only one serious adverse event possibly linked to the vaccine — a case of immune thrombocytopenic purpura (an autoimmune condition that results in low platelet count) 39 days after the second dose. Most reported adverse events such as fever, fatigue and body aches.