Immunity to coronavirus lingers for months, study finds

Immunity to Covid-19 infection lingers for at least five months, researchers reported — and probably longer than that.



a man and a woman looking at her cell phone: PERTH, AUSTRALIA - APRIL 20: Registered nurse Heather Hoppe receives a flu vaccination in the trial clinic at Sir Charles Gairdner hospital on April 20, 2020 in Perth, Australia. Healthcare workers in Western Australia are participating in a new trial to test whether an existing tuberculosis vaccine can help reduce their chances of contracting COVID-19. 2000 frontline staff from Fiona Stanley, Sir Charles Gairdner and Perth Children's Hospital are taking part in the research trial, which will see half of participants receiving the existing Bacillus Calmette-Guérin (BCG) vaccine in addition to their flu vaccine, while the other half receive the regular flu shot. The BCG vaccine was originally developed to work against tuberculosis, but it is hoped it might help reduce the chance of contracting coronavirus as well as lessen the severity of symptoms and boost immunity in the long term. The BRACE trial is being led by by the Murdoch Children's Research Institute. (Photo by Paul Kane/Getty Images)


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PERTH, AUSTRALIA – APRIL 20: Registered nurse Heather Hoppe receives a flu vaccination in the trial clinic at Sir Charles Gairdner hospital on April 20, 2020 in Perth, Australia. Healthcare workers in Western Australia are participating in a new trial to test whether an existing tuberculosis vaccine can help reduce their chances of contracting COVID-19. 2000 frontline staff from Fiona Stanley, Sir Charles Gairdner and Perth Children’s Hospital are taking part in the research trial, which will see half of participants receiving the existing Bacillus Calmette-Guérin (BCG) vaccine in addition to their flu vaccine, while the other half receive the regular flu shot. The BCG vaccine was originally developed to work against tuberculosis, but it is hoped it might help reduce the chance of contracting coronavirus as well as lessen the severity of symptoms and boost immunity in the long term. The BRACE trial is being led by by the Murdoch Children’s Research Institute. (Photo by Paul Kane/Getty Images)

While the report may seem confusing and contradictory to a similar report out of Britain this week, it really isn’t. People’s bodies produce an army of immune compounds in response to an infection and some are overwhelming at first, dying off quickly, while others build more slowly.

The new report out Wednesday shows 90% of people who recover from Covid-19 infections keep a stable antibody response.

“While some reports have come out saying antibodies to this virus go away quickly, we have found just the opposite — that more than 90% of people who were mildly or moderately ill produce an antibody response strong enough to neutralize the virus, and the response is maintained for many months,” Florian Krammer, a professor of vaccinology at the Icahn School of Medicine at Mount Sinai, who led the study team, said in a statement.

“This is essential for effective vaccine development.”

The team looked at the antibody responses of more than 30,000 people who tested positive for Covid-19 at Mount Sinai’s Health System between March and October. They characterized their antibody responses as low, moderate or high. More than 90% had moderate to high levels, or titers, of antibodies to the spike protein of the virus — the structure it uses to grapple the cells it infects.

They then closely studied 121 patients who recovered and donated their plasma — once three months after they first developed symptoms, and again five months later.

They did see a drop-off in some antibodies. But others persisted, they reported in the journal Science.

“The serum antibody titer we measured in individuals initially were likely produced by plasmablasts, cells that act as first responders to an invading virus and come together to produce initial bouts of antibodies whose strength soon wanes,” said Dr. Ania Wajnberg, director of Clinical Antibody Testing at the Mount Sinai Hospital.

“The sustained antibody levels that we subsequently observed

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