Any study on the safety of anti-Covid vaccine, Covaxin, and its Adverse Events of Special Interest (AESI) for individuals who received it should examine a wide range of data to avoid investigator bias and ensure effective findings, Bharat Biotech said on Thursday. 

Hyderabad-based vaccine-maker was responding to findings of a study on AESI of Covaxin by a team of researchers from the Banaras Hindu University (BHU). 

The study ‘found’ Adverse Events of Special Interest (AESI) in nearly one-third of the individuals who received Covaxin, the first indigenous Covid vaccine made by Bharat Biotech.

As per the study, about 50 percent of 926 participants in the study 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, published in the journal Springer Nature said.

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Referring to the data cited by the BHU study, Bharat Biotech said data pertaining to AESI safety profile of the subjects prior to participation in the study and comparison of safety profile of non-vaccinated subjects during the course of the study were vital for establishing the findings. 

A comparison of safety profile of subjects who received other vaccines during the course of the study was also needed, it said, adding: ​``All study participants should be followed during the course of the study, instead of only a subset. 

“Several studies have been executed on the safety of Covaxin and published in peer reviewed journals, demonstrating an excellent safety track record,” it added

The findings of BHU study on Covaxin assumes significance in the wake of recent admission of the UK- based AstraZeneca that its Covid vaccine, Covishield, can cause rare side-effects of blood clotting and lowering of platelet count.

Both Covishield and Covaxin were main vaccines administered in India public vaccination programmes during the pandemic. Pune - based Serum Institute manufactured Covishield in India.