COVID vaccine booster dose not for all

Doctors in India advocating against COVID vaccination booster doses for all have said healthy individuals may not need them. The Union Health Ministry has also indicated that vaccination coverage for all is their current focus with optional COVID vaccination booster dose to specific individuals needing it for medical conditions.

The indication comes at a time when the World Health Organisation (WHO) with 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.”

Immune memory
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 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.

Dr. Hari Kishan Gonuguntla, consultant interventional pulmonologist at Yashoda Hospitals in Hyderabad, said most studies have shown that durable memory can last more than 12 months.

However, this will not protect everyone from re-infection. People can still have re-infection with SARS CoV-2 virus. However, the severity of illness and rates of hospitalistion is 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,” he added.

Tackling variants
Dr. Rajeev Jayadevan, vice-chairman, Research Cell, Indian Medical Association (IMA), Kerala, said vaccines remain highly effective at preventing severe diseases and are critical to pandemic control. However, he added that emerging data now suggests that vaccination alone isn’t enough to prevent infections with COVID virus variants needing sustained measures to curb the transmission to continue.

“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,” said Dr. Jayadevan.

According to him, the second dose is actually the booster dose, while the first dose is 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.

He added that in case of immune compromised individuals, giving a third dose is agreed upon because two doses are not always enough to generate a sufficient immune response. Further studies and careful observation are needed to see if older people will benefit from a third dose, in terms of better survival. The Hindu