Safety assessments

Unsolicited adverse events

Unsolicited adverse events were recorded for 28 days after vaccination.

Participants were observed for 2 hours after vaccination to assess reactogenicity and were instructed to record local and systemic reactions within 7 days (days 0-7 and days 14-21) after vaccination using a diary card. Routine telephone calls were scheduled after the first 7 days after each vaccination.

Solicited adverse events

Local: pain at injection site, swelling

Systemic: fever, fatigue/ malaise, myalgia, body aches, headaches, nausea or vomiting, anorexia, chills, generalised rash, diarrhoea.

Adverse events were graded according to severity score (mild, moderate, or severe) and whether they were related or not to the investigational vaccine.

Immunogenicity assessments

Serum samples were analysed in a masked manner at Bharat Biotech and the National Institute of Virology.

Cell-mediated responses (interferon-gamma, and T-cell responses) were assessed in a subset of participants at one site by obtaining additional blood samples from consenting participants on days 0 and 28.

Statistical Analysis

Power was calculated for several levels of absolute difference between seroconversion rates for vaccine formulations and eventually chose power to find a statistically significant difference between rates if the true absolute difference was at least 20%.

Investigators did not incorporate an adjustment for multiple comparisons as the phase I study was not pivotal for licensure.

Useful Links:

Link to the Lancet article:

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30942-7/fulltext

Link to the previous article in this series:

https://communitymedicine4all.com/2021/01/24/safety-and-immunogenicity-of-bbv152-covaxin-sars-cov-2-vaccine-part-1-vaccine-basics/