Immunity lasts at least a year after infection, gets stronger after jab

The key findings

NEW DELHI: Antibodies and immune memory among people who contract Covid-19 remains stable up from six months to a year, and they get even better protection when vaccinated, according to a study published on Monday, which also found the body’s defences to have evolved over time to offer protection from mutations.

The findings, from researchers led by a team from Rockefeller University and Weill Cornell Medicine in New York, were published in Nature as an accelerated article on Monday, and offer among the first concrete clues that immunity to the Sarscov-2 may be long-lasting.

The researchers followed up with 63 people who were infected with Covid-19 1.3 months, 6 months and 12 months after they got infected. Of these, 26 (41%) received one dose of either the Pfizer-bion

Tech or the Moderna vaccine.

“In the absence of vaccination, antibody reactivity to the receptor binding domain (RBD) of Sars-cov-2, neutralising activity and the number of Rbd-specific memory B cells remain relatively stable from 6 to 12 months,” said the paper.

It added that in the case of those who got the vaccine, all components “of the humoral response” – or the antibodies that bind to and neutralise the virus – increased and even neutralised variants of concern (VOC) in a manner that was similar or better than how people fought off the original virus that first emerged from Wuhan in 2020. The study‘s findings could provide important clues about the future of the pandemic and, partly, answer one of the crucial questions that have been asked since the pandemic began: How long will immunity last? The answer seems to be 12 months.

Experts who reviewed the study and spoke to HT said the findings were promising.