Healthy Individuals May Not Require Covid Booster Dose: Experts
Manas Dasgupta
NEW DELHI, Oct 31: Healthy individuals in India may not need any booster dose of Covid-19 vaccine, several expert doctors believe. The Union Health Ministry has also indicated that currently it was not thinking about booster dose and was concentrating on vaccination coverage for all. Booster dose of COVID-19 vaccination might be an optional choice for specific individuals depending on medical conditions, it said.
The indication comes at a time when the World Health Organisation (WHO), with the support of the Strategic Advisory Group of Experts (SAGE) on Immunisation and its COVID-19 Vaccines Working Group, continues to review the emerging evidence on the need for and timing of a booster dose for the currently available COVID-19 vaccines which have received Emergency Use Listing (EUL).
A senior Health Ministry official speaking about whether the Government plans to roll out booster doses for all said: “Experts are definitely looking into research and suggestions from across the world and we are open to this evolving situation. Currently our main focus is to ensure that we extend our ongoing vaccination programme to all. Booster doses in case a recommendation comes in would be first offered to those who medically need it.”
Doctors say that following COVID-19 infection, the immune system retains a memory of the virus. If a person gets exposed to the SARS COV-2 virus again, the immune cells will recognise the viral pathogen and kill the pathogen. This is called immunological memory. This is the basis for durable protective immunity after COVID-19 infection or vaccination.
Some experts quoting studies undertaken in the past had shown that durable memory could last more than 12 months.
However, this would not protect everyone from re-infection. People could still have re-infection with SARS CoV-2 virus but the severity of illness and rates of hospitalisation was less in people with prior infection.
“Emergence of new strains pose a substantial risk of re-infection, which may go undetected in PCR tests. Hence, vaccinating these populations who had the previous infection is a strategy to enhance immune response and can develop strong resistance against the new emerging strains which are of concern. Thus the necessity of booster vaccination in case, if recommended in the coming days, will be more of use for people who are vaccinated alone than people who had SARS COV-2 infection followed by vaccination,’’ the experts said.
According to Dr Rajeev Jayadevan, vice-chairman, Research Cell, Indian Medical Association, Kerala, vaccine remains highly effective in preventing severe diseases and are critical to pandemic control but emerging data now suggest that vaccination alone was not enough to prevent infections with COVID-19 virus variants needing to sustained measures to curb the transmission to be still in place.
“Healthy individuals are able to generate a robust immune response after two exposures to the antigen; that is either by two doses of vaccine or by one bout of infection and one dose of vaccine,” says Dr. Jayadevan.
The second dose was actually the booster dose, while the first dose was called a priming dose. “Whether adding a third dose will increase the existing protection from severe disease and death is not known in the case of healthy individuals,” he said. Dr Jayadevam said in case of immune compromised individuals, giving a third dose was suggested because two doses were not always enough to generate a sufficient immune response. Further studies and careful observation were needed to see if older people would benefit from a third dose, in terms of better survival, he said.
