New Delhi,  Vaccination and natural infection both boost herd immunity against Covid, but people who remain uninfected yet are more at risk, thus inoculating them is of utmost importance, according to an AIIMS professor.

New variants of Covid-19 have been emerging consistently for the last two years and the vaccine drive is on with the same intensity to mitigate the infection, and other severity brought in.

While vaccines are a priority for the susceptible population, natural infection is also helping boost immunity just like vaccines.

"Vaccine is the smart way of controlling diseases. However, in the current scenario, those recovered from Covid infection are best-protected people, so vaccinate such people first, who are not Covid infected," Dr Sanjay Kumar Rai, Professor, Department of Community Medicine, AIIMS, New Delhi, said at a weekly health show by the New-Delhi-based HEAL Foundation.

Recently, the US Centers for Disease Control and Prevention also observed that natural infection provides better and longer protection. Several studies also prove that one may develop lifelong immunity after a natural infection.

Rai said that "vaccination and natural infection will provide herd immunity. Natural immunity provides a better and longer duration of protection".

Further, to observe the efficacy of vaccines, Rai suggested making two comparator groups for vaccination -- one who recovered from Covid, and another who are uninfected.

"Universal vaccination is completely irrational as there is no additional benefit. It is unethical because the risk is more than the benefit. Now, there is sufficient evidence that those who have recovered from Covid are the best-protected persons on the earth," Rai noted, emphasising the need for judicious use of vaccination.

"Currently, 334 vaccines for Coronavirus are in different stages of development (140 in clinical trials and 194 in pre-clinical stages); and 33 vaccines are approved for full use," Rai said

"We must vaccinate those who haven't had Covid ever. Vaccines are effective in preventing severity and death up to 80-90 per cent in a susceptible population. More than 60 per cent of the population across the world have received 1st dose of Covid vaccines,"he noted.