Whether to boost or not is the question. In the face of rising contamination numbers triggered by the highly contagious Delta variant of COVID-19 and hints that immunity produced by Coronavirus vaccines might fade over time, some nations are considering whether to give further doses to people who have been fully vaccinated.

As on 12th August 2021, there have been confirmed 204,644,849 cases of Coronavirus globally.

Israel and Germany have announced plans for booster-shot programmes and a thriving list of countries consisting Russia, China and the United Arab Emirates have already started administering extra doses.

But scientists suggest that the case for Coronavirus vaccine boosters at this stage is weak. They might not be required for most of the people and could reroute much-needed doses away from others.

India has administered 17.85 crore people so far with the first dose of vaccine and over 5.54 crore Indians have received both the vaccine doses, this amounts to less than 4 per cent of 140 crore population. Still a considerable size of population is yet to receive even the first dose of vaccine.

US has given 16.9 crore of first doses and has 46.6 per cent of fully vaccinated population.

On 4th August, the World Health Organization called for an embargo on boosters until at least the end of the month September. 

Right time for COVID boosters

The data on whether and when boosters might be required are coming in. But it is expected that key gaps will be there for some time. Resultant, people might begin to get boosters that have no real advantage. For now, not enough is known about groups that might really need extra doses, such as senior citizens and those with weaker immune systems. And, as the Delta variant surges across many countries, health service authorities might not have the luxury of waiting around for decisive answers. 

Do boosters actually work?

Vaccination cause an initial rise in the number of immune cells churning out antibodies and other molecules, which then gradually falls. This leaves behind a little pool of long-running ‘memory’ B and T cells that vigil the body for future contaminations by that pathogen.

A booster does various things to these cells. It makes antibody-producing B cells to multiply, raising the measure of antibodies against the pathogen once more. With time, their numbers will reduce again, but the pool of memory B cells left behind will be greater than before, giving rise to a stronger and faster response to subsequent exposures. Boosters also advance a procedure called affinity maturation, in which ‘engaged’ B cells — those that have been triggered by the vaccine — travel to the lymph nodes. Here, they obtain mutations, letting the antibodies they produce cohere with pathogens more strongly, potentially amplifying their potency.

Can COVID vaccines stop transmission?

A few trials to have tested extra doses support this. Third doses of vaccines developed by Pfizer–BioNTech, Moderna, Oxford–AstraZeneca and Sinovac gave rise to a spike in levels of infection-blocking ‘neutralizing’ antibodies, when positioned few months after the second dose. An ongoing trial in UK will test several combinations of boosters, including utilizing a different vaccine from the actual inoculations. Initial studies of these ‘mix and match’ plan of action propose that they could entail more powerful immune responses, identified by high levels of both T cells and antibodies, that kill infected cells and assist other antiviral responses.

These trials also indicate that usual vaccine-related side effects like fever and headache, aren’t much different from those seen with earlier immunizations.