Russia’s Sputnik V vaccine for the new coronavirus has 91.6% efficacy, according to interim analysis of data from its ongoing phase III trial in the country published Tuesday in The Lancet.
The analysis is based on close to 20,000 participants, of which 14,964 participants received two doses of the vaccine, and 4,902 received a placebo. Twenty-one days after the first dose, 16 participants in the vaccine group were confirmed to have COVID-19 as well as 62 participants in the placebo group. There were 2,144 participants aged more than 60 years old, and vaccine efficacy for this group was 91.8%.
The study was also 100% effective against moderate or severe COVID-19, based on analysis 21 days after the first dose.
Why it matters: Much of the known efficacy about the Russia vaccine were based on press releases and press briefings conducted by the Russian Direct Investment Fund and the Gamaleya Institute, raising suspicions on the validity of the efficacy claims. Researchers, including the World Health Organization, have been asking for the results to be published in a peer-reviewed journal for independent scrutiny and transparency.
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The study’s caveats: COVID-19 was detected only in participants who self-reported their symptoms and later confirmed to have COVID-19 based on a polymerase chain reaction test. So the efficacy analysis is only based on symptomatic cases of COVID-19, and further research is needed for asymptomatic cases and transmission. The study could not assess the duration of protection either.
There was little diversity in study participants. This will need further study, as well as the vaccine’s efficacy and safety in those younger than 18 years old and among pregnant women.
On safety: Three of the participants in the vaccine group who received at least one dose of the vaccine died. But none of the deaths “were deemed to be associated with vaccinations,” according to the study.
What’s next: The trial is ongoing to reach a total of 40,000 participants. But the research team also plans to investigate the effectiveness of the vaccine when given as a single dose.
