Covaxin vs Covishield: The corona vaccines in India

“Tough Times, Tougher Decisions”

People knew harsh times were coming after the country was placed in lockdown on March 25, 2020, which was only partially removed by June 2020. As of today, almost 3 lakh people have died, while 2.4 crore people have fortuitously recovered from a total of 2.7 crores who were infected. While the economy is yet improving, more than 20 crore doses of covid vaccination have been successfully distributed. This article is merely a scientific comparison of the two corona vaccines in India, namely, Covaxin and Covishield.

Covaxin is an intramuscularly administered, dead/inactivated viral vaccine developed by Bharat Biotech using Whole-Virion Inactivate Vero Cell-derived technology. Although these inactivated viruses are unable to infect a person, they can nevertheless elicit an antibody-mediated immune response. Its efficiency is reported to be roughly 81 per cent, according to the interim 3^rd phase trial finding. Covaxin’s dosage interval remains the same, i.e. 4-6 weeks. After the application of the second dose, the vaccine’s effectiveness is said to be about 78-100%.

Covishield, on the other hand, is made using the viral vector platform technology. Similar to covaxin, administration of covishield too is via intramuscular aid. A harmless and weakened chimpanzee adenovirus, ChAdOx1, was modified to carry Covid-19 spike protein. When the vaccine is injected into a person, it enters the cells, rendering them to produce the spike protein. This triggers a cell-mediated immune response, which results in production of antibodies and T-cells, thus attacking the cells producing spike proteins. The Covishield dosage gap was recently revised to 12-16 weeks instead of 4-8 weeks after the National Expert Group on Vaccine Administration for Covid-19 (NEGVAC) reported that increasing the time between doses would improve efficacy. Its efficiency after the second dose can range from 70 to 90%.

Recently added to the Cowin platform, Sputnik V is a two-dose Covid-19 vaccine created by the Gamaleya Research Institute of Epidemiology and Microbiology in Moscow. It employs two separate human adenoviruses and uses the same technology as Covishield. The prime or the first dose is rAd26 and the second or booster dose consists of rAd5. According to a study published in The Lancet, Sputnik V has a 91% efficacy. Meanwhile, the new version, Sputnik Light is Sputnik V’s prime dose rAd26 and has been approved as a standalone vaccine. Moderna being in the same race is another robust single dose covid-19 vaccine which in association with Cipla would arrive by next year in India.

Recently a US pharma giant Pfizer has already said that it is ready to offer five crore doses to India between July and October this year. This will add to the list of corona vaccines in India. The vaccine is capable of confering 87.9% efficacy against B.1.617.2 variant, the most reported in India and is also effective on children aged 12yrs. Waiting to get approval, Pfizer was the first two-dose, mRNA based vaccine (manufactured by Pfizer and BioNTech collaboration) to get FDA Emergency Use Authorization (FDA EUA).

Either of the two corona vaccines in India can be used, thus rendering them completely safe for administration. We strongly recommend that everyone should get vaccinated as soon as possible. Proposing a delay in vaccination not only poses danger to oneself, but also to the community in which they reside. Getting vaccinated is the first step towards restoring society to its original state. Being a responsible and socially aware citizen, it is important to continue following covid appropriate behaviour even after receiving the shot.