As India goes ahead with the third dose of coronavirus vaccine – dubbed “precaution dose”, the United States is rolling out second booster doses and has approved a third booster too for a select group of people.
Earlier, Israel had also started administering the second booster dose – the fourth dose of a vaccine – to people at high risk from the virus.
Not everyone, however, agrees with the rollout of booster doses, as they are not convinced of their need or their efficacy. Here is all you need to know about boosters, the current research on them, the ongoing debate on their rollouts, and their status in India.
What are booster doses and what’s the idea behind them?
Most of the coronavirus vaccines across the world have a two dose regime. Booster doses refer to the additional doses (third, fourth, or fifth) administered after completing the two-dose regime.
The basic idea behind booster doses is that a person’s immunity wanes over time and boosters serve as a kind of an update to the immune system.
Moreover, some coronavirus variants such as Delta and Omicron have been found to be able to evade vaccine-induced immunity or at least weaken it. A booster dose is therefore seen as being on the side of caution – perhaps why the Indian government named their boosters “precaution dose”.
However, not everyone is convinced of boosters’ need or efficacy.
What does research say about booster doses’ need and efficacy?
The third dose of mRNA vaccines was found to be very effective in the United States during Delta- and Omicron-drive surges, according to the US Centers of Disease Control and Prevention.
The US CDC said in a study published in January that the third dose prevented COVID-19-related emergency and urgent care encounters by 94 per cent and 82 per cent respectively and prevented COVID-19-related hospitalisations by 94 per cent and 90 per cent respectively.
Pfizer reported last month that an analysis of data from over 1.1 million adults in Israel showed coronavirus infection was two times lower and severe illness was four times lower among people who had received two booster shots of Pfizer-BioNTech vaccine compared to those who only received one booster dose.
This data from Israel came from people aged 60 and above. The focus of boosters have been at the most vulnerable groups – older adults and people with compromised immune systems.
Not everyone sees it this way. Sceptics of boosters cite limited data on it and even call the focus on boosters misplaced.
What are the arguments against booster doses?
The focus on boosters is misplaced as the world needs better coronavirus vaccines, not more doses of existing ones, according to science journalists and Bloomberg columnist Faye Flam.
She wrote in an article, “It’s become clear that our current vaccines won’t end the pandemic. But that’s no reason to give up hope; a vaccination campaign with better vaccines still might.”
The current vaccines were made with the objective of preventing COVID-19 deaths and severe disease, not necessarily infections and transmission. The next generation of vaccines might succeed with infections and transmissions.
Infectious disease expert Sabrina Assoumou said it does not make sense to go for boosters when many people across the world have not even completed the original vaccination regime.
She said, “The most important thing that we as individuals can do right now is, number one, to vaccinate the unvaccinated. There are so many people who have not started their series for whatever reason. The solution to this pandemic is to get as many people vaccinated as possible.”
India initially rolled out a targeted booster dose program
The Indian government started administering booster doses – called precaution doses – on 10 January to healthcare workers, frontline workers, and people above 60 years of age.
A section of experts had at the time said that the dubbing of boosters as “precaution doses” meant that India would roll out a targeted booster program rather than a universal one. This has been recommended by experts outside India as well, who have said that people with weakened immune systems and pre-existing conditions need boosters rather than young and healthy people – or even older healthy adults.
Baylor College of Medicine’s Dr Prathit Kulkarni told NBC News, “There is a difference between somebody who is 51 and otherwise healthy without any major medical problems and somebody who is 85 and has multiple medical problems.
"The bottom line is, it depends on individual risk profile: What is your age? What are your comorbidities?”
However, earlier this month, the Indian government approved precaution doses for all adults.