Covaxin phase 3 data shows 77.8 pc efficacy against Covid-19: Lancet

Noted peer reviewed journal for general medicine The Lancet on Friday said interim data related to Covaxin, the Covid vaccine developed and manufactured by Hyderabad-based Dr Reddy’s Laboratories in collaboration with Indian Council for Medical Research (ICMR), indicated that the vaccine was safe and two doses offer 77.8 percent protection against symptomatic Covid positive cases and 65.2 percent protection from the Delta variant.

The Lancet, which published the phase three clinical trials data of Covaxin a few hours ago, said ‘BBV152 (Covaxin) was highly efficacious against laboratory-confirmed symptomatic Covid-19 disease in adults. Vaccination was well tolerated with no safety concerns raised in this interim analysis”.

The study, funded by Bharat Biotech and ICMR, was conducted between November 16, 2020, and Jan 7, 2021, on a total of 25,798 participants who were randomly assigned to receive Covaxin or placebo. As part of the study, which was also carried out at the Nizam’s Institute of Medical Sciences (NIMS) and ESI Hospital, Sanathnagar, a total of 12,221 participants were administered with BBV152 while another 12,198 participants formed the placebo wing.

“The study showed an overall estimated vaccine efficacy of 77·8 percent. The study shows that the BBV152 (Covaxin) vaccine is generally effective against Covid-19, preventing symptomatic disease and decreasing severity and the need for hospitalization,” The Lancet researchers said.

“Efficacy against any severity of Covid-19 with onset of 14 days after the second



vaccination was 77·8 percent and efficacy against severe Covid-19 was 93·4 percent. Efficacy against asymptomatic Covid-19 was 63·6 percent. 

Our preliminary analysis found an efficacy of 65·2 percent against the delta variant, but further investigations are necessary to confirm clinical efficacy against this variant and others. Safety monitoring and reactogenicity assessments of BBV152 did not raise concerns about the vaccine,” they said.

The phase 3 clinical trials also made it clear that Covaxin was effective against severe Covid-19, especially among individuals who have co-morbid conditions like diabetes, blood pressure and other pre-existing diseases related to heart, kidneys etc.

“Cases of severe disease, which require hospitalisation and have threatened to overwhelm healthcare facilities, could be markedly decreased in fully vaccinated populations. Additionally, although the study was not powered to definitively assess efficacy in subgroups categorised by age or the presence of pre-existing comorbid conditions, efficacy against symptomatic Covid-19 was high in these groups (more than 66 percent). 

The number of older participants was lower than anticipated, representing less than 11 percent of the study cohort. Nonetheless, 1858 older participants were included in the efficacy analysis, and the resulting efficacy rate had a lower confidence bound greater than zero; this result can thus be considered meaningful according to FDA guidance,” the researchers said.