New Delhi: The immunity received after the Covid-19 vaccine lasts for 9 months or more. This information has been given by Dr. Balram Bhargava, Director, Indian Council of Medical Research (ICMR). He has described vaccination against Coronavirus as the most important. On Thursday, the government said that a precautionary (third) dose of the vaccine would be given to healthcare, frontline workers, and citizens above 60 years of age with other illnesses. This dosage is to avoid serious illness, hospitalization, and death.
Dr. Bhargava said that the SARS-CoV-2 virus infects a person in the natural environment and elicits antibody-mediated, cell-mediated immunity and immunological memory. He said that hybrid immunity, which develops as a result of vaccination and natural infection, produces a stronger response and stronger antibody titer after the second dose. However, measuring antibodies alone does not tell about overall protection, he said. Bhargava said in a press conference, ‘The stability of immunity after infection is maintained for about nine months.’
He said, ‘If you got the infection and you have also been vaccinated, then your immune response will be higher than those who only got the infection or those who only got vaccinated. That’s why the important thing is that vaccination is very important.’ Citing global evidence, Bhargava said that the immunological memory of SARS-CoV-2 naturally persists for more than eight months after infection.
Bhargava said, ‘It is published in ‘Science’ in the US, and antibodies and cellular responses have been found more than nine months after infection in China. Then several studies investigated in the US have shown that antibody responses persist for more than 13 months after infection and in a systematic review of 10 studies from Israel, England, Denmark, the US, Austria, and Italy in more than 90 percent of cases. There has been a reduction in re-infections for 10 months.
He said, ‘… we want to say that taking a slightly conservative estimate of nine months and beyond, this is the evidence. There are three studies from India, two from ICMR and one from Mumbai, on 284 patients, 755 patients, and 244 patients that persist for eight months, seven months, and six months (respectively) and all of these took place in 2020, 2021 There are published figures of infection.
Talking about the vaccines being used in India, Bhargava said that there is a complete ‘virion kill’ vaccine which is Covaccine and the other is a viral vector-based subunit vaccine Covishield. Bhargava said that the precautionary dose is not the dose to prevent infection. He said that this is primarily to reduce the severity of the infection, reduce the chances of hospitalization and reduce deaths.
