Experts urged citizens not to deviate from the norm and mandatorily take the second
dose of Covid-19 vaccine because it adds to the durability of protection, against the concern
that some beneficiaries were not turning up for it after taking the first shot.

“The second dose ensures that it boosts not only the virus-specific antibodies but also the T
cells (T-lymphocytes) — the memory cells which are a part of the broader immune response
against the virus. It (second dose) also adds to the durability of protection,” said senior
scientist Raman Gangakhedkar, former head of the epidemiology and communicable
diseases division of the Indian Council of Medical Research (ICMR).

Gangakhedkar said, “It is important to adhere to the evidence generated by the manufacturer
through the vaccine trials and take two doses. Single dose and the duration for which it will
protect currently lacks in data.”

The latest state health department report has revealed that 70 lakh people haven’t taken their
second jabs despite completing the interval between the doses. Officials stated that most
were delaying or skipping the second dose despite being eligible as the festivals had set in
and the second wave appeared to be abating.

Not just for Covid vaccines, multiple doses are required for most vaccine strategies to induce
efficient protection.

“After a first priming dose, immunity is stimulated. But over time, it contracts. At this time, a
second dose improves the breadth of immune response and ensures the durability of the
same,” said infectious diseases expert Sanjay Pujari, a member of the national Covid task
force.

In Covid-19, studies have consistently shown lower vaccine efficacy after the first dose as
compared to the efficacy after the second dose for all vaccine platforms. “Hence, it is critical
to complete the vaccine schedules at the right time to ensure optimal protection,” Pujari said.