‘Booster Pe Booster’: How Many More Vaccine Doses Before COVID-19 Leaves Us?

COVID-19 cases are on a rise again driven by a surge in the XBB.1.16 variant.

COVID-19 cases are on a rise (yet again) driven by a surge in the XBB.1.16 variant and its sublineage XBB.1.16+NS3_V13L.

This time around, the infection is spreading at a relatively high speed as well, even to those who've taken the vaccine and been infected already.

Does this mean we'll need another booster dose to keep the virus away? And if yes, how many more booster doses will we possibly need till this virus leaves us?

FIT reached out to experts for answers.

Is Another Booster Dose Needed To Counter Infection?

"We have no idea how many boosters (we will need) and when to give them. Studies from mRNA vaccines seem to indicate that boosters give some protection from infection and disease for a short period of time – about 3 months."

Dr Gagandeep Kang, Renowned Virologist

Renowned virologist Dr Gagandeep Kang told FIT that very few countries have so far generated data about vaccines and those that have done so, have released data about mRNA vaccines and booster doses.

What does this mean? Will we need a booster dose every time there's a new variant? Or every year when cases increase? No, says Dr Kang.

The latter, a flu vaccine-like situation, could be something that high-income countries consider, but she adds that booster doses are not likely to become an yearly thing at least in India.

Dr Umang Agrawal, Infectious Disease Consultant at Mumbai’s PD Hinduja Hospital & MRC, explains:

"Generally if it's a new variant, we need to see how different it is from the variant against which the vaccine was made. For instance, the influenza bug's antigenicity changes every year, so you need to take a vaccine for it every year. However, with COVID-19, that's not the case."

Who Should Take Booster Doses?

While the World Health Organization has recommended that older individuals and senior citizens take the booster doses, Dr Kang says that this is a decision that countries will have to make individually based on risk factors. 

Speaking about India, she told FIT, "If you are young and healthy you probably do not need it. Recent surveys show that 90 percent of the Indian adult population has taken the vaccines and has antibodies."

But, in a Twitter thread, Dr Kang said:

With all new variants/sublineages, age continues to be most important risk factor, followed by immune compromise.other co-morbidities. As with all infectious agents, particularly viruses, some unpredictability as some people with no risk factors can develop severe disease. 5/19

— G Kang (@GKangInd) April 23, 2023

Dr Agrawal agrees. He says that while the preference should be given to older people and those with comorbidities, ideally, everyone should take the booster dose.

He adds,

"Those who haven't taken the third dose should consider getting it as soon as possible. It's a preventable disease and you can save yourself from severe health complications."

What Do We Know About Taking Fourth Or Fifth Doses?

Whether it's the COVID-19 vaccine or any other vaccine for that matter, there's "very little evidence of benefit" to show that a fourth or fifth booster dose would actually help, says Dr Kang.

And currently the situation is such that even if a medicine is available or is being used to treat patients, there's no surety of how well it would work or for how long, she adds.

However, Dr Agrawal disagrees. He says that studies have time and time again shown that the immunisation provided by any vaccine lasts 6-9 months. If you take a fourth booster dose, the vaccine won't really harm you or cause health complications, but will reboost your immunity for another few months and have a protective effect.