BHU’s Covaxin safety study riddled with major limitations
The HinduAn observational study carried out by researchers from the Banaras Hindu University, Varanasi to assess the safety of Covaxin, particularly the long-term adverse events of special interest one year after vaccination, in adolescents and adults has been criticised by ICMR for the poor study design. Given the limitations of the study one can “certainly say that the study can’t be used to draw the conclusions it does,” Dr. Menon says in an email. Thus their conclusion that “nearly one-thirds of participants receiving the BBV152 vaccine reported adverse effects of special interest” is misleading, and most likely erroneous,” says Dr. Rajeev Jayadevan, co-chairman of the National IMA COVID task Force. Dismissing Dr. Patwardhan’s argument that a control group may not be necessary in a longitudinal observational study, Dr. Menon says: “If the question, as here, is the possibility of adverse effects following vaccination, it is a question about causality. If, in a normal non-COVID year, an equally substantial fraction of people were afflicted by upper respiratory tract infections, that would certainly be relevant to asking if the vaccine was responsible for the AESIs picked up by this survey.” Objecting to Dr. Patwardhan’s claim made in a tweet that the “goal is often to observe natural progressions and associations rather than to establish direct causal relationships with the use of a control group”, Dr. Menon points out that the paper clearly states that “serious adverse events may occur in 1% of BBV152 recipients”, which is a statement of specific causality.