Sunday, November 28

Covid: the Indian vaccine Covaxin sees its effectiveness reduced against the Delta variant

(Belga) Covaxin, an anti-Covid vaccine developed in India and widely used on site, has been shown to be less effective during its deployment in real life than during its clinical trials, shows a study published on Tuesday, explaining this finding by the rise of the Delta variant.

The study nevertheless testifies to the effectiveness of Covaxin against coronavirus infection “in a context of a strong surge in cases, faced with the probable domination of the Delta variant”, conclude the authors of this work published in Lancet Infectious Diseases. Produced by the Bharat Biotech group, Covaxin is the first anti-Covid vaccine developed in India. Even if it has only just been approved by the World Health Organization (WHO), Covaxin, a two-dose vaccine with inactivated virus, has been used on site since the beginning of the year, the authorities not having awaited the main results of clinical trials. The latter, finally given in early November, had shown good efficacy: among the vaccinated, there were about three quarters of cases less than in people who received a placebo. The study published Tuesday looks at what happened when the vaccine was actually campaigned in real life, so later than in clinical trials. Its data dates back to the spring of 2021, at the height of an epidemic wave in India. The authors retrospectively examined the situation of around 2,000 caregivers at a New Delhi hospital. Half had been diagnosed positive for Covid-19, the other not, asymptomatic cases being also excluded from the study. The conclusions show less efficacy than in clinical trials: these data suggest that the vaccine prevented symptomatic infection in half of the people who received it, and not three quarters. The authors largely explain this decline by the rise of the Delta variant. This is more contagious and therefore, a priori, puts the vaccination to the test. “Our results underline that we must quickly deploy (this vaccine) while continuing to implement and comply with non-pharmacological measures”, that is to say barrier gestures such as wearing a mask, they believe. The study also does not measure the effectiveness of the vaccine against only serious forms, a crucial issue for the dangerousness of the epidemic and the burden it places on the health system. (Belga)

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