Rediff.com  » News » Immunity against COVID-19 may last for several months: Study

Immunity against COVID-19 may last for several months: Study

Source: PTI  -  Edited By: Hemant Waje
October 14, 2020 14:32 IST
Get Rediff News in your Inbox:

Immunity against COVID-19 may persist for at least five months after being infected with the SARS-CoV-2 virus, according to a study led by an Indian-origin researcher in the United States.

IMAGE: Staff members of the Inox Cinemas demonstrate their standard operating procedure as they prepare to re-open cinema halls as a part of unlock 5.0 in Mumbai. Photograph: Mitesh Bhuvad/PTI Photo

The researchers from the University of Arizona studied the production of antibodies from a sample of nearly 6,000 people infected with the novel coronavirus.

"We clearly see high-quality antibodies 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 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," who led the study, published today in the journal Immunity, alongside Professor Janko Nikolich-Zugich from UArizona.

When a virus first infects cells, the immune system deploys short-lived plasma cells that produce antibodies to immediately fight the virus, the researchers explained.

Those antibodies appear in blood tests within 14 days of infection, they said.

The second stage of the immune response is the creation of long-lived plasma cells, which produce high-quality antibodies that provide lasting immunity, according to the researchers.

 

Bhattacharya and Nikolich-Zugich tracked antibody levels over several months in people who tested positive for SARS-CoV-2 antibodies.

They found 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 UArizona 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.

Bhattacharya believes those conclusions focused on short-lived plasma cells and failed to take into account long-lived plasma cells and the high-affinity antibodies they produce.

"The latest time-points we tracked in infected individuals were past seven months, so that is the longest period of time we can confirm immunity lasts," Bhattacharya said.

He said people who were infected with the first SARS coronavirus, which is the most similar virus to SARS-CoV-2, are still seeing immunity 17 years after infection.

"If SARS-CoV-2 is anything like the first one, we expect antibodies to last at least two years, and it would be unlikely for anything much shorter," the scientist added.

Get Rediff News in your Inbox:
Source: PTI  -  Edited By: Hemant Waje© Copyright 2020 PTI. All rights reserved. Republication or redistribution of PTI content, including by framing or similar means, is expressly prohibited without the prior written consent.
SHARE THIS STORY 
The War Against Coronavirus

The War Against Coronavirus