Third booster dose of COVID-19 vaccines should be considered for vulnerable groups, say experts

While the studies are going on to study the need of the booster doses in healthy volunteers post six months of the vaccination, the individual studies are also being done to study the effectiveness of third dose in certain vulnerable groups.

Dr Sathyajit Mohapatra who led the trials of Covaxin vaccine at SRM Medical College and Research Centre said that a study is being done on the need for a booster dose of the vaccines. "The efficacy of both the vaccines in use in the State will last for about nine months to a maximum of one year. A booster dose is being administered in healthy volunteers after six months of complete vaccination. There will be a need of booster dose of the vaccine to help increase the immune response in the individuals," said Dr Sathyajit Mohapatra.

Senior virologist Jacob John says that several group of vulnerable individuals will require a third dose to enhance the antibody mechanism as they would have not developed adequate antibodies against COVID-19 after two doses. "Elderly people, especially men and obese are likely to get infected as the vaccines also work against viral antigens and a booster dose of inactivated virus vaccine will help in increasing the effectiveness of the vaccine," said Dr Jacob John.

The same is also brought up by a study in the medical journal Lancet that revealed a low antibody response in completely vaccinated healthcare workers, especially the ones with obesity, comorbidities, men and elderly.

However, with the limited academic data evidence and unavailability of the vaccines, the experts say that the efficacy of the vaccine beyond the said time period might reduce. "The individuals who have frequent and high dose exposure to the virus, such as healthcare workers and frontline workers, should be given the third booster dose of the vaccine should be considered after the efficacy period of the vaccine post complete vaccination. The third dose vaccination might not be required for general public and more research data is required for the same to consider booster dose for them," said public health expert Dr K Kolandaisamy.