Form of words:
New Delhi: A new study by the Indian Council of Medical Research (ICMR) states that the effectiveness of two COVID vaccines – Covishield and Covaxin – is highest when the interval between two doses is between six and eight weeks.
NS Study, yet to be peer-reviewed and posted on the pre-print portal on November 11, also stated that two doses of the vaccines are effective against Delta and other variants.
While Phase III clinical trials have evaluated the efficacy of COVID vaccines, it is important to evaluate its effectiveness in the real world, especially from a health care perspective.
Researchers from the ICMR-National Institute of Epidemiology (ICMR-NIE) reviewed the evidence for the effectiveness of the two vaccines being used in India as of 31 October 2021.
The team reviewed data from the National Library of Medicine article database and MedRxiv, a pre-print publication portal, using the terms effectiveness, BBV152, Covaxin, AZD1222, Covisheeld, India, and Covid-19. BBV152 and AZD1222 are the official names of the two vaccines.
Researchers found that the overall effectiveness of two doses of Covishield was 80 percent, compared to 69 percent for Covaxin against severe COVID-19.
“Our findings indicate a substantial reduction in the risk of severe COVID-19, and in particular the delta strain,” the researchers wrote.
According to the team, the study results suggest that the vaccination strategy is effective in the country, especially since most parts of India have a high level of prevalence.
“Continuous expansion of two-dose vaccination coverage and stringent application of control measures are essential to contain the increase in cases in the country in the near future,” he said.
Talking about the aim of the study, the researchers said that they have found very few studies in India that describe the effectiveness of Covaxin or CoviShield vaccines against Covid in different geographies, with different sampling and recruitment strategies- The accompanying study design has been used.
Most of the studies are limited to healthcare workers and policemen in small sub-national areas, with a small sample size, he said, adding that this is because these frontline workers were among the first to be vaccinated in India.
The team notes that, according to these studies, vaccine effectiveness ranges from 77 percent to 92 percent, with wide confidence intervals. In addition, none of the studies provided a vaccine effectiveness estimate specifically against the delta variant.
“This multicentre hospital-based study in 11 cities represents a national level of vaccine effectiveness, including large expanses of India and a period of dominance of the delta strain of SARS-CoV-2 in the country,” the team wrote in the study.
Read also: ‘Die in 2 years, be a monkey’: Why this Nagaland district has India’s lowest vaccine coverage
overall effectiveness
The team found that the vaccine’s effectiveness was highest for the 6-8 week interval between two doses of any vaccine. This difference was significantly greater when the difference was less than six weeks.
When calculated separately, the vaccine’s effectiveness was highest for the 6-8 week interval for CovShield — 92 percent. When the difference between the two doses was less than six weeks, the effectiveness dropped to 76 percent. In India, this vaccine is being given at an interval of 12-16 weeks.
For Covaxin, the vaccine’s effectiveness was 91 percent when the two doses were administered at 6-8 week intervals. If the dose difference was less than six weeks, efficacy dropped to 65 percent. The current interval in India is 4-6 weeks.
The researchers said there was not enough data to evaluate the efficacy of the two doses taken after an interval of more than 12 weeks.
(Edited by Neha Mahajan)
Read also: ‘Covidshield gap, sky won’t fall’ as vaccines pile up, members of the Covid task force say
subscribe our channel youtube And Wire
Why is the news media in crisis and how can you fix it?
India needs independent, unbiased, non-hyphenated and questionable journalism even more as it is facing many crises.
But the news media itself is in trouble. There have been brutal layoffs and pay-cuts. The best of journalism is shrinking, crude prime-time spectacle.
ThePrint has the best young journalists, columnists and editors to work for it. Smart and thinking people like you will have to pay a price to maintain this quality of journalism. Whether you live in India or abroad, you can Here,