World Health Organization has recommended that all immune-compromised patients should get a third dose or booster shot of a vaccine against Covid-19.

According to Subject Advisory Group of Experts (SAGE) of the UN health body, moderately and severely immunocompromised people should be offered an additional dose since they are less likely to respond adequately to vaccination following a standard primary vaccine series and are at high risk of contracting severe Covid-19.

“When implementing this recommendation, countries should initially aim at maximising two-dose coverage in that population, and thereafter, administer the third dose, starting in oldest age groups,” SAGE said. In India, booster shots have not been approved yet. However, the clamour for this step is growing. “We are doing great at vaccinating our adult population against Covid-19. Now, with approval granted to the vaccine against Covid-19 developed by Bharat Biotech for those aged 2-18 years, children may also get protection. However, we must not ignore the need for a booster or third additional dose in the elderly and the immune-compromised,” Dr N K Mehra, emeritus scientist at Indian Council of Medical Research (ICMR), said.

“The functional ability of the body to mount a quick immune response goes down when people grow older. Same is the case with immune-compromised patients, for example a cancer patient or someone who has undergone organ transplant recently. Such people need a booster dose six to seven months after the second dose to prevent serious illness if they get Covid-19,” Dr Mehra said.

A booster dose is essentially an additional dose of the vaccine you have already received. Vaccine manufacturers claim a booster dose may be needed for two reasons: first, to provide prolonged immunity, and second, to fight off the mutant variants. Countries like France, Germany and Israel, where a significant population have received two doses, have allowed a third dose. The US and the UK have also approved it.

India started immunisation against Covid-19 this January and healthcare workers were the first to get it, followed by people above 60 years and those above 45 years who had qualifying comorbidities. In April, the facility was extended to everyone above 45 years and, finally, to those above 18 years from May.

Dr Jamal Yusuf, professor of cardiology at GB Pant Hospital, said many people had completed six to seven months since full vaccination. “We must think about allowing a booster dose at some point.”