India’s Covaxin COVID-19 vaccine 77.8% effective, Lancet study finds
A new study in The Lancet is offering the first peer-reviewed and published data on the efficacy of Covaxin, a COVID-19 vaccine developed in India. The vaccine was found to be 77.8 percent effective at preventing symptomatic COVID-19 in a large Phase 3 clinical trial.
At the very beginning of 2021 India’s drug regulator, the Central Drugs and Standards Committee (CDSCO), unexpectedly issued an emergency use approval for COVID-19 vaccine Covaxin. At the time, the authorization was incredibly controversial as the vaccine was still deep in Phase 3 trials, with Phase 2 trial data yet to be formally published. One researcher went so far as calling the premature approval of Covaxin “unconscionable.”
Now, almost a year after its Phase 3 human trials kicked off, the first peer-reviewed data from that trial has been published in The Lancet. The top-line finding is the vaccine is 77.8 percent effective at preventing symptomatic COVID-19.
The Phase 3 trial enrolled more than 25,000 subjects, randomly allocated either two doses of the vaccine (administered four weeks apart) or two doses of placebo. Against asymptomatic COVID-19 the study reports an efficacy of 63.6 percent, and perhaps most importantly, the vaccine was 93.4 percent effective at preventing severe COVID-19.
No serious adverse events were detected in the trial. The vaccine was found to have a very good safety profile with only occasional mild side effects reported, such as headache or pain at injection site.
The trial spanned the period of time that saw the emergence of the Delta variant in India but the study notes it wasn't sufficiently powered to comprehensively evaluate effectiveness against that variant. A preliminary analysis of the data, however, indicates Covaxin is 65 percent effective at preventing symptomatic infection from the Delta variant.
Since Covaxin’s emergency use authorization at the beginning of 2021, more than 100 million people in India have received the vaccine. It has also already been approved for emergency use in a number of countries including Iran, Zimbabwe, Mexico and the Philippines.
Early in November the World Health Organization (WHO) finally issued an emergency use approval for Covaxin, paving the way for greater international acceptance of the vaccine and laying the foundation for those vaccinated to travel internationally. The WHO approval also allows Covaxin to be distributed to low-income countries as part of the international Covax vaccine distribution plan.
Covaxin is the most traditional COVID-19 vaccine to receive widespread global acceptance, using a century-old vaccine technology. The vaccine is known as an inactivated whole virus vaccine, similar to that of polio and flu vaccines.
Inactivated vaccines use samples of actual virus that are chemically deactivated, or killed, so they are not able to replicate. These inactivated viral particles are then combined with chemicals called adjuvants that are designed to stimulate an immune response.
This kind of vaccine technology has a long history of safe use and, unlike mRNA vaccines, doesn't require extreme cold temperatures for storage. Covaxin can be safely kept and transported in conventional refrigerators, between 2-8 °C (36-46 °F). Other inactivated COVID-19 vaccines currently in use around the world include China’s CoronaVac and SinoPharm vaccines, and Russia’s CoviVac.
The new study was published in The Lancet.
Source: The Lancet