Covid-19 vaccine booster shots and how important it is for new variants

WHO has not yet recommended booster shots

As the threat of coronavirus still looms large with new mutations Delta, Delta Plus, Lambda, vaccine manufacturers have joined the brace to seek approval from drug controller authorities for booster doses that can increase the efficacy of the vaccine against mutant variants. While some manufacturers believe that their vaccines are effective enough to tackle the variants, others like Pfizer, Oxford AstraZeneca, Moderna, Johnson & Johnson have applied to regulators to be able to give out booster doses to the vulnerable section of the population.

However, according to the Centers for Disease Control, Americans don’t need a booster shot yet and even National Institute of Allergy and Infectious Diseases director Anthony Fauci to has said there isn’t enough data to support booster dose of Covid-19 vaccine.

What is Covid-19 booster shot?

Booster doses strengthen one’s immune response against pathogens by increasing the number of antibodies produced. The shot i.e or altered genetic blueprint of the germ triggers one’s immune system to attack the foreign organism like it would if you actually got the disease.

Sometimes scientists tweak the composition of the booster dose to tackle a new variant of the virus. With this, the memory cells get the signal to re-engage with the virus attacks. So either the booster dose amplifies the signal to produce more antibodies or recognise new features of the virus and produces antibodies depending on it is the original one or tweaked one.

Who needs a booster shot of Covid vaccine

The booster shots are given only to the fully vaccinated population but even with them, priority will be given firstly to elderly and immunocompromised people whose bodies cannot prepare themselves with a robust defense mechanism.

Pfizer and BioNTech have started designing a version of their vaccine to combat the highly -contagious Delta variant after they found a dip in their efficacy in Israel where the population received vaccination in January and February. According to Pfizer CEO Albert Bourla,, a booster dose of Pfizer elicit 5-10 fold higher antibody response.

Health experts also believe that the variants can easily break the immune response created by Covid vaccines not formulated with messenger RNA technology like Oxford’s AstraZeneca to 60 percent and preventing 90 percent from hospitalization. As for Pfizer and Moderna, effectiveness fell to 90 percent.

Can one take a different vaccine booster dose?

According to preliminary studies the person need not take booster dose of the same vaccine that was used to immunize him in the first case. A Lancet study shows that subjects who took a cocktail of Pfizer and AstraZeneca vaccines created the strongest T-cell (the cells responsible for killing the viruses) response — more than double that from two Pfizer doses.

A study published in Nature said, mixing an mRNA vaccine and an adenovirus-based one could provide “the best of two worlds”.

Health authorities view of booster shot

The World Health Organisation (WHO) has not yet recommended booster shots and has also asked to practice caution in administering the third dose. According to Chief scientist Soumya Swaminathan, such a recommendation is unnecessary and immature without enough data to support booster shots and considering the slow pace of vaccine coverage. US Centers for Disease Control and Food and Drug Administration is also on the same page with WHO and in a statement said that people who are fully vaccinated don’t need a booster shot at this time.

Middle Eastern countries, however, have already started vaccination with a booster dose for the fully vaccinated population. Thailand, too, plans to use vaccines from AstraZeneca and Pfizer as boosters for healthcare workers who earlier received Sinovac shots followed by Indonesia that is heavily hit by Covid-19 cases now. Even China is evaluating the benefit of booster shots.