Efficacy of COVID vaccines satisfactory, finds ICMR study as over 115 crore inoculated in India so far
The study, submitted to The Lancet for publication, showed effectiveness was the highest with a gap of 6-8 weeks between two shots of Covishield and Covaxin.
NEW DELHI: The first nationwide measurement of the real-world effectiveness of Covid-19 vaccines Covishield and Covaxin have shown 80% and 69% efficacy against severe disease, respectively. Although lower than the protection reported in clinical trials, the figures are still considered to be good.
The findings are a result of an analysis by ICMR in 11 hospitals across 10 cities between May and July, which studied severely ill and hospitalised Covid-19 patients. In all, 1,143 cases of severe infection and 2,541 negative cases were studied.
The study, submitted to The Lancet for publication, showed effectiveness was the highest with a gap of 6-8 weeks between two shots of Covishield and Covaxin. Importantly, efficacy estimates were similar against Delta strain and sub-lineages.
In Phase 3 trials, Covishield had shown nearly 100% protection from severe illness and it was nearly 93% for Covaxin — India’s first indigenously developed Covid vaccine. Tarun Bhatnagar, scientist with the National Institute of Epidemiology, ICMR, and principal investigator for the study, explained that real-world effectiveness estimates will always be lower than trial-based efficacy estimates.
“This is the largest study on real-world effectiveness (of vaccines) and findings indicate that two doses of Covaxin and Covishield have good effectiveness against the Delta strain which is the dominant circulating strain in India,” Bhatnagar said.
He pointed out that as a majority had taken Covishield, the numbers for Covaxin are smaller in the study and hence the lower precision of the effectiveness estimates for Covaxin.
Bhatnagar stressed that considering that effectiveness against severe infection is not close to 100%, masking and social distancing cannot be totally done away with, more so among those not vaccinated, and those who may be more vulnerable to get severe infection such as the elderly, immune-compromised and people with comorbidities
In the pre-print of the study, scientists said these findings highlight significant real-world protection with two vaccine doses against severe Covid-19 and specifically against the Delta variant in India.
“Substantial effectiveness of only one dose, more so for Covishield, supports the policy decision from a public health perspective to initially maximise coverage with single dose in the country,” they said. In India, most studies are limited to healthcare and frontline workers with small sample size, and none are population-representative.
Meanwhile, the total number of COVID-19 vaccine doses administered in the country crossed 115 crore on Thursday, the Union Health Ministry said.
According to officials, around 82 per cent of the eligible population in India has received the first dose of the vaccine while more than 41 per cent has been fully inoculated.
In a tweet, Union Health Minister Mansukh Mandaviya said, "The country is getting protected through vaccination every day.
As India's vaccination coverage crosses the 115 crore mark, PM Narendra Modi ji's words ring true -- once Indians decide to do something, nothing is impossible! Har Ghar Dastak strengthening the world's largest vaccination drive!" On Thursday, more than 65 lakh (65,45,982) vaccine doses have been administered till 7 pm.
The daily vaccination tally is expected to increase with the compilation of the final reports for the day by late night, the ministry said.
The ministry had on Wednesday declared that the number of individuals fully vaccinated against COVID-19 surpassed the partially vaccinated population.
The government has recently launched a month-long 'Har Ghar Dastak' campaign for house-to-house COVID-19 vaccination of those who are yet to take a dose and those whose second dose is overdue.
Mandaviya had recently said that over 12 crore beneficiaries are due for their second dose of COVID-19 vaccine and urged the state health ministers to ensure that all adult population is covered with the first dose during the ongoing 'Har Ghar Dastak' campaign, while those who are due for the second dose are also motivated to take the jab.
(With PTI Inputs)