A Recent Study Found Covaxin Effective Against Delta Plus Variant

By Shantanu Sodhi +2 more

The Delta variant of COVID-19 was detected back in April 2021 in India. It was particularly dominant in Maharashtra, Kerala and Madhya Pradesh. As a result, government regulations have tightened the restrictions and in many parts of these states, lockdowns have been observed in the last 2 months. 

There was widespread scepticism regarding the efficacy of the Covaxin and Covishield vaccines against this new variant. However, a recent study has revealed that Bharat Biotech’s Covaxin is indeed quite effective against the new Delta Plus variant of the coronavirus.

The premise for this study

Covaxin, which is essentially a whole-virion inactivated SARS-CoV-2 vaccine, was found to be effective against the earlier Delta variant. Even during the second wave, which was mainly caused by the Delta variant, this vaccine proved to be 65.2% effective in protecting vaccinated people from the virus. Studies had been conducted in a double-blind, randomized and multicentre phase 3 clinical trial which had shown that the mass inoculation drives using Covaxin had been highly effective in controlling the spread of the earlier Delta variant.

How effective is Covaxin against the Delta variant? 

Since Covaxin had earlier proven effective against the Delta variant, it is highly possible that it has a similar potency against the Delta Plus variant. The recent study in question was conducted by the Indian Council of Medical Research and has been recently published in the online research repository known as bioRxiv. The study stated that the natively developed Covaxin of India has been deemed effective against the Delta Plus variant. It concluded that Covaxin has shown 77.8% efficacy against symptomatic COVID-19 which is a phenomenal breakthrough discovery since this gets one step further in flattening the curve.

What does this mean to the COVID-19 infection rate in India?

Since there has been great confusion regarding the extent to which Covaxin can be effective against this new variant, this study has shed light on certain facts and helped put many vaccinated people at ease. It was earlier speculated that the Delta Plus variant, which contains a mutation of the K417N spike protein can probably escape the immune response generated by the vaccines. Virologists and doctors were anxious that this new variant could surpass the effect of antibody response, thereby rendering Covaxin ineffective. However, with this new study, vaccinations using Covaxin can continue throughout the country as it shows a modest level of efficacy against the Delta Plus variant as well.

Covaxin vs Covishield – which one is more effective?

While the efficacy of Covaxin against the original variant of COVID-19 was reported to be 81%, that of the Covishield was reported to be 90%. As a result, many preferred the latter over the former homegrown vaccine. However, with the emergence of new variants like the Delta and the Delta Plus, it is seen that the effectiveness of both Covaxin and Covishield have been reduced.

A study published in the New England Journal of Medicine suggested that AstraZeneca’s Covishield, which has similar properties to that of Covaxin, is 67% effective against the new Delta and Delta Plus variants. In comparison, India’s very own Covaxin is about 65.2% effective, meaning there is not much difference between the efficacy of both.

The effect on those already Vaccinated

COVID-19 vaccinations have been faced with mixed reactions from people along with typical rumours of being a placebo. However, such is usually the case with any medical or scientific breakthrough in its initial stages. As someone who has already been vaccinated, you must remember that these vaccines have undergone extensive human trials by now and new studies are being published frequently about their increased efficacy. Therefore, if you have already been vaccinated, you can rest assured that your vaccination has not been in vain.

Another factor to consider is the protection that vaccines offer despite not having a 100% prevention rate. As late as Jan 2022, vaccines were shown that not only do all vaccinations provide protection against severe symptomatic disease, it also protects against hospitalisation for Covid-19. In turn, several studies have shown that hospitalisation and death rates from Covid-19 are much lower in those who are vaccinated vs those who aren’t. Additional data coming in also shows that a booster shot (a third shot of the vaccination) also adds to this type of protection.


Even though these new studies have proven that Covaxin or any other COVID-19 vaccine for that matter, provide a decent amount of protection against the virus, none of them has 100% efficacy. Therefore, it is important that despite being vaccinated, we still follow all necessary COVID-19 protocols in order to prevent any future waves of this virus.

Disclaimer: The information included at this site is for educational purposes only and is not intended to be a substitute for medical treatment by a healthcare professional. Because of unique individual needs, the reader should consult their physician to determine the appropriateness of the information for the reader’s situation.

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