Coronavirus vaccination: What is a booster vaccine shot? Who will need it and other FAQs answered

Even as vaccination drives have paced across the world, it has slowly come to notice that the jabs we have- single or double doses aren’t as entirely effective against mutant strains of the SARS-COV-2 virus. The lowered efficacy has thus made a case for the availability of ‘booster’ or third COVID-19 vaccine doses, which will work to strengthen efficacy.

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There has been concerning evidence that for some people with frail immunity, preconditions or immuno-compromising conditions, current COVID-19 vaccines may not work well, or may not offer lasting antibodies, as it would do to the general population. The availability of booster shots will be particularly helpful for people with such conditions since it would amp up the levels of protection offered.

Healthcare workers and frontline staff, who face high exposure rates and dangers from the pandemic may also stand to gain from booster shots right now. Priority vaccinations for these groups have been considered by many countries as well.

There are no fixed timelines as to when and where booster shots would be needed. Studies done by Oxford researchers have suggested that the booster (third) dose would be most effective in boosting immunity when delivered weeks after the second dose, or at least 10 months after the first dose. With mRNA vaccines, the gap could be smaller.

While mix and match of COVID vaccines are also being tested out, there's no information available if people would be able to get a different booster shot than their original vaccine, or how safe such a choice would be.

While boosters may be necessary one day, WHO has maintained that there is currently no evidence they were needed yet. As for the mixing or adding of doses, there is no consensus among scientists as well, as of yet.

Even as companies have been urging the need to press booster shots into use, global health bodies have suggested that relying on booster shots, right now will only dry up resources for countries with scarce resources or where vaccines are deficient.

There are also some early reports that suggest that booster shots may also mount some side-effects that may not be welcome by everybody. Therefore, experts are asking people to wait for more concrete evidence on the same to come up, before completely advocating their use.