COVID virus and vaccines … a review

The world, for almost the last 20 months, is going through a turmoil named COVID. It has not spared any country, whether rich, developing or poor. The human race has experienced the unthinkable uncertainties, suffering and agony of losing the nearest and dearest ones with severe economic depression all around. Vaccines have come as a succour – hope to life. Though it is the only major weapon to fight COVID at the moment, it’s not free of doubt, controversies and unexplained fears. The problem with the COVID virus is its fast mutation and severity with high viral load and transmissibility. From the onset of COVID, it has already passed through multiple mutations and the latest Delta variant has been found to be quite severe as for viral load and high transmissibility.

With no specific drugs and various unspecified treatment protocols, the only solution to fight the epidemic is vaccines. Vaccines build the defence system to fight against specific pathogens by creating targetted antibodies against antigens as antibody-antigen reaction.

Different vaccines and their roles
Vaccines are expected to offer prolonged immunity and protection. Its efficacy is related to immunogenicity, tolerability, time coverage and overall safety. Immunities are of two types – humeral and cell-mediated. By now, we are having a number of vaccines -Covishield, Covaxin, Sputnik, Pfizer vaccine, J&J vaccine, Chinese vaccine, etc. to fight COVID-19. So far, the major vaccine that is being used is of AstraZeneca-Oxford (Covishield), manufactured in India by the Serum Institute. Covaxin of Bharat Biotech is a complete Indian product that has also been used in good quantity.

The vaccines are safe, well-tried and tested and help in bringing herd immunity amongst people.

The actual situation
When we try to analyse the present situation in our country – post-COVID and initiation of vaccination, the following status emerges.
◆India administered more than 180 million doses in August which is more than total of all G7 countries (the UK, France, Germany, Canada, the US, Italy and Japan). The country has plans to vaccinate all adults by 21st December.
◆Although the vaccines are well tried and tested, some people still develop few unwanted side effects, known as ‘vaccine breakthrough cases.’ Usual side effects like fever, body pain and headache are common for a day or two.
◆ There was resistance from some percentage of population based on certain wrong conceptions and myth. Nevertheless, with constant information and education, this percentage has reduced.
◆There is a probability of the development of vaccine-resistant strain because of the very fast mutation of the coronavirus.
◆ Strength and length of immune response varies from person to person in relation to available antibodies.
◆ Seroprevalance is around 10 per cent.
◆ Plasma therapy had been introduced and tried, even the plasma banks have been established – but the overall result is not at all encouraging. It increases the O2 requirement, respiratory failure, creates either low or non-functioning antibodies, and variable antibody levels are also affected.

Major areas of problem and confusion
The second wave, which started sometime around March-April 2021 shattered the total emergency medical system, as India was not prepared for that deadly situation. However, after unprecedented human tragedy where lakhs suffered and died, and perhaps few are still suffering with associated health problems, one positive thing that happened is the availability of repeatedly tested and trialled vaccines to counteract COVID. Though vaccines are all effective, tried and tested on their own ways, but there are limitations.

Those who are affected with the virus, positively develop antibodies which protect them from future infection. Scientists have observed that people’s antibodies’ level rapidly decreases, making them prone to repeat infection. Recently, another positive study confirmed long-lasting immunity with activation of anti-bodies producing cells in the bone marrow after seven/eight months following infection. This obviously raises hope of longer immunogenecity of vaccines after two scheduled doses. Activation of memory T cells also plays an important role. Nevertheless, rapid mutation and identification of Delta variant causes further doubts on the efficacy of present vaccines. There were suggestions of the third booster doses to counteract and ensure further safety. A small percentage has been fully vaccinated, but even that population still develops repeated infection. Known as ‘vaccine breakthrough case,” it does not conform to the need of the third booster dose. Israel was the first country to start administering the booster dose to people aged above 60 years, and later on to all adults. Later, the UK started with the booster in people aged above 50 years and suffering with co-morbidities.

According to the World Health Organization (WHO), till date, evidence of booster and its benefit remaining limited and in conclusive; it recently recommended the same for immunocompromised people though. The last 20 months taught all of us a good lesson on how important life is and self-education and awareness are the utmost crucial things to be followed for a long and healthy life.