After studying antibody samples collected from 6,000 people infected with coronavirus, researchers in the United States have concluded that immunity against COVID-19 lasts for at least five months.
The research led by Indian-origin Deepta Bhattacharya, associate professor at University of Arizona, has concluded that the antibodies against SARS-CoV-2 virus last for around five months in a human body.
“We clearly see high-quality antibodies still being produced five to seven months after SARS-CoV-2 infection,” said Professor Deepta Bhattacharya.
“Many concerns have been expressed about immunity against COVID-19 not lasting. We used this study to investigate that question and found immunity is stable for at least five months,” said Bhattacharya, who led the study, published today in the journal Immunity. The research was conducted with Professor Janko Nikolich-Zugich.
This comes even as several cases of coronavirus re-infection being detected in many countries. A US resident recently contracted Covid-19 within a span of 48 days.
Explaining the findings, the experts said that when a virus first infects cells, the immune system deploys short-lived plasma cells that produce antibodies to immediately fight the virus. Those antibodies appear in blood tests within 14 days of infection.
The second stage of the immune response is the creation of long-lived plasma cells, which produce high-quality antibodies that provide lasting immunity. Bhattacharya and Nikolich-Zugich tracked antibody levels over several months in people who tested positive for SARS-CoV-2 antibodies.
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 lasting protection against SARS-CoV-2 has been one of the most difficult questions to answer,” said University of Arizona Health Sciences Senior Vice President Michael D Dake.
“This research not only has given us the ability to accurately test for antibodies against COVID-19, but also has armed us with the knowledge that lasting immunity is a reality,” Dake said.
Earlier studies extrapolated antibody production from initial infections and suggested antibody levels drop quickly after infection, providing only short-term immunity.