India okays Moderna vaccine for emergency use: How does it work and how effective is it?

The vaccine made by the US-based Moderna is the fourth COVID-19 shot to have obtained an emergency use nod in India. The mRNA platform on which it is built has given some of the vaccines with the highest efficacy rates in trials. Although the Centre had introduced specific criteria to ease the arrival of foreign-made vaccines to India, regulatory, legal and infrastructural issues had
so far prevented their actual launch in the country. The approval to Moderna thus assumes significance at a time when the country is planning to massively expand vaccine coverage amid fears of a third wave of COVID-19.

What is an mRNA vaccine?

Vaccines such as the ones made by Pfizer-BioNTech and Moderna in the US and India-based Zydus Cadila's ZyCoV-D are classified as nucleic acid vaccines. But while the Zydus Cadila vaccine is a DNA vaccine, the Moderna and Pfizer vaccines are built on the mRNA platform. They belong, however, to the same class of vaccines because what they essentially do is to use the target pathogen or, in this case, the virus's genetic material to train the immune system to combat it.

For creating such vaccines, scientists extract genetic material embedded in the virus and insert it inside the human body. In the case of the COVID-19 mRNA vaccines, this genetic material prompts human cells to specifically create the spike protein that studs the surface of the novel coronavirus and helps it to infect people. As the human cells produce this spike protein, the immune system recognises it as a threat and begins to produce antibodies against it, thus helping the body build up resistance against the virus.

While such vaccines induce a good immune response and are considered safe because they use no live components of the virus that can trigger an infection, the platform on which they are built is relatively new and, prior to the emergency nod to such vaccines during the COVID-19 pandemic, no nucleic acid vaccines had been launched for use in humans although DNA vaccines for animals are
available.

What is the efficacy rate Of The Moderna vaccine? Does it protect against variants?

The Moderna jab was the second vaccine to get an emergency nod in the US after the Pfizer vaccine, another mRNA shot. Both are two-dose vaccines. Preliminary clinical trial data had shown that the Moderna vaccine has an impressive 94.1 percent efficacy against the novel coronavirus. According to experts, the body takes about two weeks after the second dose to develop full immunity against the virus.

Outside of clinical trials, the real-world effectiveness of this jab has been measured at over 90 percent and it has also been seen to provide protection against the newer variants of the novel coronavirus.

Moderna said on 29 June that its vaccine is able to combat the Delta variant, or B.1.617.2, that was first detected in India and is now the most prevalent variant in the country. The vaccine-maker said that the mRNA jab was more effective in producing antibodies against the Delta variant than against the Beta variant, or B.1.351, which was first identified in South Africa.

Only a modest 3.2 to 2.1-fold reduction in its antibody impact was seen against the Delta and Kappa, or B.1.617.1, lineages of the variant, the company said.

"These new data are encouraging and reinforce our belief that the Moderna vaccine should remain protective against newly detected variants," said Moderna CEO Stephane Bancel.

Will this vaccine be produced in India? What about the legal and logistical hurdles?

According to GAVI The Vaccine Alliance, a public-private global health partnership working to increase access to immunisation for poorer countries, "it is relatively quick and easy to design" a nucleic acid vaccine once the virus's genome has been sequenced. The Moderna vaccine had entered clinical trials within two months of the SARS-CoV-2 genome being sequenced.

Reports suggest that the first doses of the vaccine will be imported into the country by Moderna's local partner, Cipla, and will come in the form of donations. There is no confirmation yet on when the commercial launch of the vaccine will happen.

Moderna, like Pfizer, had flagged issues of indemnity and bridging trials in India as the key factors that were keeping it away from the country even after the Centre cleared the decks for their speedy launch in April this year. Announcing the decision to grant the emergency nod to the Moderna vaccine, NITI Aayog member Dr VK Paul said that the issue of indemnity, which implies a waiver from legal liability in India, "is being addressed and (the Centre has) taken it up for examination".

Logistics is an important aspect for the launch of mRNA vaccines in India as these vaccines are known to require ultra-cold storage facilities. However, Paul said that sealed vials of the vaccine can be stored for up to 30 days at temperatures of 2-8 degrees Celsius, which fits in with India’s cold storage infrastructure as part of the country's Universal Immunisation Programme. However, storing it for longer periods requires the vaccine to be frozen at over -20 degrees Celsius.

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