In the late hours of 25 December, Prime Minister Narendra Modi came bearing 'gifts' for children and the elderly alike.

Addressing the nation in an impromptu speech Prime Minister Modi announced that children over the age of 15 would be eligible for COVID-19 vaccines starting 3 January, and a third 'precautionary dose' of the COVID-19 vaccine would be made available to healthcare workers, frontline workers and those over the age of 60 with comorbidities, from 10 January onwards.

But unfortunately, the toys needed some assembling, and alas, the instruction manual was nowhere to be found.

Neither the kids nor the adults could tell how to put the pieces together, what parts went where, and where to find the missing pieces.

The address ended leaving the people with many question marks.

Questions like why is 15 the cut-off age for the vaccine when Covaxin's COVID vaccine was cleared by the DCGI for 12 to 18 year olds just hours before? Not to mention, the other COVID vaccine which was approved for use in children—Zydus Cadila—has also been cleared for children over 12.

Which vaccine will be administered as the third dose given that none of the COVID vaccines in India have been cleared by the health authorities (Drugs Controller General of India) against substantial clinical evidence?

Why is, what is called by the rest of the world as a 'booster dose' being referred to as a 'precautionary dose'?

Will it be a booster of the same primary dose or will a mixed dose regimen be suggested?

Let's talk about the booster, nay 'precautionary doses'.

"Available data does support boosters for the elderly, clinically vulnerable, immunocompromised individuals and healthcare workers." says Dr Swapneil Parikh, Internal Medicine specialist, and the author of the book, The Coronavirus: What You Need to Know about the Global Pandemic.

"Boosters should be rolled out in select populations to reduce their risk of hospitalization and in health workers to reduce staff shortages," he adds.

This is a sentiment that many health experts echo.

Although the move to boost the protection of high risk people is welcomed by the medical fraternity, the phrasing and the lack of details regarding the implementation of the announcement have left many confused.

"I feel that the government should really explain why this is so, instead of giving room to speculation," says Public Health Expert and National Task Force Member Dr Subhash Salunkhe.

"It needs to be explained why they have chosen this name.This could save a lot of confusion – to people and the scientific community."

While we wait for clarity on the choice of words, and more importantly, what it entails, we are left to speculate. FIT spoke to some scientists and experts in the field who present various explanations.

Booster doses have been rolled out in several countries, especially ones with high primary vaccine coverage as an added protection against vaccine efficacy waning over time.

While in some countries like the UK, it has been approved for high-risk categories of people, in others like the US and South Africa, it has been approved for all adults. In the UK, the boosters being given are Pfizer's single dose and Moderna's half dose.

These decision have, moreover, been backed by data that vouch for the need for and the efficacy of the mRNA vaccines as boosters.

In India, Serum Institute of India applied for approval to roll out booster shots of its COVID vaccine, Covishield earlier this month, but the decision was stalled by the NTAGI (National Technical Advisory Group on Immunization) citing a lack of data.

Perhaps it is this lack of data when it comes to the most widely administered COVID vaccines in India, Covishield and Covaxin, that is making the authorities wary of calling it boosters, and instead, choose to term it 'precautionary shots'.

Speaking to FIT, Dr Rakesh Mishra, former director of the Center for Cellular and Molecular Biology says,

"Booster shot is something that is more specific, and more studied on. Therefore, it is more accurate to call it precautionary dose," he adds.

Epidemiologist Dr Chandrakant Lahariya, on the other hand, tells FIT, "There is an informal understanding that there is not enough clarity to administer booster shot. If and when there is evidence to give booster shot, the vaccine should be of a another platform – one that is different from the first two shots.

"In India, there is no booster shot available, and the government is more likely to use the same vaccine for the additional shot. Therefore, it does not fit the criteria of a booster shot. Maybe, the government has called it precautionary for the same reason."

So it's likely that the government is being 'precautionary' with their phrasing of the third dose at the moment.

Perhaps, given the impending threat of the highly transmissible Omicron variant, we are in a position to act first and ask questions later.

According to Dr Salunkhe, the need of the hour is to start rolling out a third dose to those who need it despite the lack of clinical data as at the moment, the benefits outweigh the risk.

"For those who have taken Covaxin or Covishield, they can take a third dose of the same. I do not know how effective it will be – no studies have been done. But it cannot do any harm to people. So instead of giving room for speculation, the government should start using it and protecting people. The extent of the benefit will be clear only after further studies. But we do not have the time to wait," he says.

Whether the reason behind calling them 'precautionary doses' is scientific, pragmatic or mere semantics, we can only hope that the next surprise gift has more clear instructions on who exactly qualifies for these precautionary doses, and which vaccines they'll be given.