Immunity against Covid can persist for months after contracting the SARS-CoV-2 virus (representative)
Washington:
Immunity against COVID-19 can persist for at least five months after being infected with the SARS-CoV-2 virus, according to a study led by an Indian-born researcher in the US.
Researchers at the University of Arizona studied the antibody production of a sample of nearly 6,000 people infected with the new coronavirus.
“We clearly see that high-quality antibodies are still being produced five to seven months after SARS-CoV-2 infection,” said Deepta Bhattacharya, associate professor at the University of Arizona.
“Many concerns have been expressed that immunity against COVID-19 is not durable. We used this study to investigate that question and found that immunity is stable for at least five months,” who led the study, published today in the journal Immunity, along with Professor Janko. Nikolich-Zugich from UArizona.
When a virus infects cells for the first time, the immune system displays short-lived plasma cells that produce antibodies to immediately fight the virus, the researchers explained.
Those antibodies show up in blood tests within 14 days of infection, they said.
The second stage of the immune response is the creation of long-lasting plasma cells, which produce high-quality antibodies that provide long-lasting immunity, according to the researchers.
Deepta Bhattacharya and Janko Nikolich-Zugich tracked antibody levels for several months in people who tested positive for antibodies to SARS-CoV-2.
They found that SARS-CoV-2 antibodies are present in blood tests at viable levels for at least five to seven months, although they believe immunity lasts much longer.
“Whether antibodies provide long-lasting protection against SARS-CoV-2 has been one of the hardest questions to answer,” said UArizona Senior Vice President of Health Sciences Michael D Dake.
“This research has not only given us the ability to perform accurate antibody tests against COVID-19, but it has also armed us with the knowledge that long-lasting immunity is a reality,” Dake said.
Previous studies extrapolated antibody production from initial infections and suggested that antibody levels drop rapidly after infection, providing short-term immunity.
Mr. Bhattacharya believes that these findings focused on short-lived plasma cells and did not take into account long-lived plasma cells and the high-affinity antibodies they produce.
“The last time points we tracked in infected individuals were past seven months, so it is the longest period of time that we can confirm that immunity lasts,” Bhattacharya said.
He said that people who were infected with the first SARS coronavirus, which is the virus most similar to SARS-CoV-2, still have immunity 17 years after infection.
“If SARS-CoV-2 looks like the first, we expect the antibodies to last at least two years, and it would be unlikely that something much shorter would happen,” added the scientist.
(Except for the headline, this story has not been edited by NDTV staff and is posted from a syndicated feed.)
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