In-depth | From Covishield to ZyCoV-D, where is India's COVID-19 vaccination programme heading?

A weakened variant of a common cold virus (known as an adenovirus) from chimps is used to create the vaccine. The current gap between two doses of the vaccine has been set at 12-16 weeks for all adults.

Another existing vaccine with India being the Covaxin which is an inactivated vaccine, meaning it is made up of coronaviruses that have been killed, making it safe to inject into the body.

Made by Bengaluru-based Bharat Biotech, a 24-year-old vaccine company, the two dosages are separated by 4 weeks.

Then comes Sputnik

Sputnik, the Russian vaccine created in the Gamaleya Institute in Moscow, employs a harmless cold-type virus as a carrier to deliver a small portion of the coronavirus to the body.

Interestingly, the Sputnik vaccine, unlike other similar vaccinations, employs two slightly different forms of the vaccine for the first and second doses, which are given 21 days apart.

Sputnik V vaccine. HAZEM BADER / AFP

Recently it was reported that Mumbai-based drug manufacturer Wockhardt is planning to emerge as a major contract manufacturer of COVID-19 vaccines and is targeting to commercially make available Russia's single-dose vaccine Sputnik Light in India by the end of this year.

The company has already started manufacturing trial batches (for regulatory purposes) following technology transfer in April from the Russian Direct Investment Fund (RDIF), the report added.

After Sputnik, enters Moderna

Moderna's COVID-19 vaccine was granted emergency use authorisation by India's drug regulator in June this year. Moderna’s method of protection relies on messenger RNA (mRNA) to programme cells to generate immunity to the COVID-19 disease.

The vaccine had an efficacy rate of 94.1 percent in preliminary clinical trials and the real-world effectiveness of this jab has been measured at over 90 percent. The vaccine makers have also said that it provides protection against the newer variants of the novel coronavirus.

Moderna vaccine. Credit Jacob King / POOL / AFP

The Drugs Controller General of India (DCGI) had granted permission to Mumbai-based pharmaceutical company Cipla to import Moderna’s Covid-19 vaccine for restricted emergency use in the country.

However, there is no clarity so far when the shots would be available in India.

NITI Aayog member (Health) VK Paul had recently said the government is working actively with Moderna to see how its vaccine can be imported and made available in the country.

Could Johnson and Johnson be a viable option soon?

US pharma giant Johnson and Johnson single dose COVID-19 vaccine Janssen became the fifth vaccine to get Emergency Use Approval (EUA) by the government of India.

The single-shot vaccine, developed by J&J subsidiary Janssen Pharmaceuticals, has been shown to be 85 percent effective in preventing severe disease in phase 3 human clinical trials.

J&J's vaccine. Patrick T. FALLON / AFP picture.

Janssen’s AdVac vectors are based on a specific type of adenovirus, which is genetically modified so that it cannot replicate in humans and cause disease.

However, the exact road map for making the vaccine available in Indian markets is still under discussion. "While we look forward to meeting our delivery commitments it is premature for us to speculate on the timing of our vaccine deliveries,” Johnson & Johnson India spokesperson was quoted as saying earlier this month.

What's different about the ZyCoV-D vaccine?

The latest addition to India’s basket of vaccines is the ZyCoV-D vaccine which is also the world's first DNA vaccine against the contagion.

ZyCoV-D uses plasmids - or small rings of DNA that contain genetic information - to deliver the jab between two layers of the skin. Hence just like other vaccines, a DNA vaccine, once administered, teaches the body's immune system to fight the real virus.

Administered with a disposable needle-free injector, which uses a narrow stream of the fluid to penetrate the skin and deliver the jab to the proper tissue, ZyCov-D is also India's first needle-free COVID-19 jab.

ZyCoV-D, which received Emergency Use Authorisation (EUA) from the DCGI, was found to have a primary efficacy of 66.6 percent for symptomatic RT-PCR positive cases, according to interim results from its phase 3 clinical trials.

The key third phase of clinical trials were conducted at the peak of the deadly second wave of the virus. This according to the vaccine maker reaffirms the jab's efficacy against the mutant strains, especially the highly infectious Delta variant.

A three-dose vaccine, its second and third shots will be administered on the 28th and 56th days respectively.

The company said it plans to manufacture 100 million to 120 million doses of ZyCoV-D annually and has started to stockpile the vaccine. The firm plans to make up to 120 million doses of India's second home-grown vaccine every year. It is expected to be made available in September.

Meanwhile, Zydus is yet to take a call on the pricing of its vaccine and it could be another two weeks before that decision is made, Zydus Group managing director, Dr Sharvil Patel said on August 21. For the government, the question of procurement is intricately linked to pricing.

If the new vaccines will help prevent the speculated third wave depends highly on the intensity of it, says Dr Srivastava.
“The role of the vaccine can't be overemphasised. The people who are vaccinated are likely to have a much lesser impact of the infection even if they get it a second, maybe even a third time in some cases. However, that doesn’t negate the role of a vaccine. Taking the vaccine is our best bet to prevent the virus and minimize its effect."

To meet its goal of vaccinating the entire population before the end of this year, India will have to administer an average of 92 lakh doses per day, claims a survey conducted by LocalCircles.

While manufacturers of currently in-use vaccines like Covishield and Covaxin have announced major increases in production at multiple locations, the scope for closing the gap in supply of vaccines cannot be fully limited to the existing ones.

Availability of new vaccines will also give us the option of combining them, notes Dr Srivastava.

A recent study by the Indian Council of Medical Research (ICMR) has found that mixing of vaccine doses gives better results than two doses of the same vaccine.

“Even in the case of a flu vaccine, what a patient is given is itself called the Quadri flu which is a combination of several strains. It’s likely that coronavirus disease will also be heading in that direction where different vaccine routes, whether it is messenger RNA, or it is adenovirus mounted or a combination of both is probably going to become the norm.”

However, the medical expert observed that while the idea of mixing vaccine doses sounds like a great one in theory, it’s too early to make any claims.

“We will need to have more evidence with patients who have taken mixed vaccines and what their immune systems are going to be over the next six to months’ time. It is too early to say,” he concludes.

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