COVID vaccines comparisons

Dr. Deepti Dwivedi

India has rendered more than 500 million doses of three approved vaccines – Covishield, Covaxin, and Russia’s Sputnik V. The Indian government is working with Johnson & Johnson to provide its latest vaccine for free. However, until supplies last under a new policy requiring manufacturers to conduct local clinical trials if the WHO or regulators have already approved the vaccine in other countries, including Australia, Canada, the EU (countries), Japan, and the United States.

WHAT DO WE KNOW ABOUT THESE VACCINES, AND HOW DO THEY FUNCTION?

Covaxin: Bharat Biotech created this vaccine using a sample of the covid-19 virus isolated by the national institute for virology. Covaxin is an inactivated vaccine. After vaccinating people, reactions in their immune system produce antibodies against SARS-COV2, also known as covid 19. In addition to that, immunogenicity is boosted when they add adjuvants called vaccine potentiators. There are two doses administered two weeks apart and can be stored at between 2C to 8C degrees. The vaccine is 81% effective, data from its phase 3 trial shows.

Covishield: The Oxford-AstraZeneca vaccine is being manufactured locally by the Serum Institute of India. The vaccine is injected into a patient and prompts the immune system to develop antibodies. The jab can be safely stored at temperatures of 2C to 8C degrees and administered in two doses 4-12 weeks apart. After their recent success with the Oxford-AstraZeneca vaccine, international clinical trials showed that when people were given a half dose and then a full dose, efficacy hit 90%. But there wasn’t sufficient data to approve of this idea. However, unpublished data from these clinical trials suggest leaving longer gaps between doses increases the overall effectiveness of the jab – in subgroups, those who received it this way found 70% efficacy after just one injection.

Sputnik: The vaccine, developed by Moscow’s Gamaleya Institute and which initially garnered some controversy after being rolled out prior to the final trial data being released, has now demonstrated its benefits. The vaccine is a cold-type virus engineered to be harmless. It uses a small fragment of the coronavirus as a carrier so that your body will produce antibodies explicitly tailored for it after you’ve been vaccinated and then exposed to the actual disease. The vaccine can be stored at temperatures between 2C and 8C degrees. Unlike the other jabs, Sputnik uses two different vaccine versions for the first and second doses given 21 days apart. The spike protein, which is distinct to the coronavirus, is targeted by both these versions. However, they each use a different viral vector to carry the spike to the body as the delivery mechanism. The idea behind this is that the two different formulas boost the immune system more than using the same version twice and give long-lasting protection. The vaccine’s efficacy rate in India stands at 91%.

THE KEY FACTORS OF COMPARISON

VACCINETYPE OF VACCINESTORAGEGAP B/W DOSESEFFECTIVITY
Covaxin, Bharat BiotechInactivated Virus2 to 8 °C2 Doses, 3-4 weeks81%
AstraZeneca Covishield, Serum Institute of IndiaViral Vector2 to 8 °C2 Doses, 4 – 12 Weeks70% – 90%
Sputnik, Gamaleya InstituteViral Vector2 to 8 °C2 Doses, 21 days91%

All three vaccines available in India have a few differences. We can compare the key factors when it comes to determining which vaccine is preferable. All vaccines work effectively against the virus when it comes to reducing the risk of being infected. It is a social obligation for citizens to get themselves vaccinated and prevent the spread of the virus. Being vaccinated is futile when it comes to protecting ourselves and others from being infected.