Protective antibodies persist for months in survivors of serious COVID-19 infections

People who survive serious COVID-19 infections have long-lasting immune responses against the virus, according to a new study led by researchers at Massachusetts General Hospital (MGH). The study, published in Science Immunology, offers hope that people infected with the virus will develop lasting protection against reinfection. The study also demonstrates that measuring antibodies can be an accurate tool for tracking the spread of the virus in the community.

The immune system produces proteins called antibodies in response to SARS-CoV-2, the virus that causes COVID-19. "But there is a big knowledge gap in terms of how long these antibody responses last," says Richelle Charles, MD, an investigator in the Division of Infectious Diseases at MGH and a senior author of the paper. To find out, she and her colleagues obtained blood samples from 343 patients with COVID-19, most of whom had severe cases. The blood samples were taken up to four months after a patient's symptoms emerged. The blood's plasma was isolated and applied to laboratory plates coated with the receptor-binding domain (RBD) of the virus's "spike" protein, which attaches to cells, leading to infection. The team studied how different types of antibodies in the plasma bound to RBD. The results were compared to blood samples obtained from more than 1,500 individuals prior to the pandemic.

The researchers found that measuring an antibody called immunoglobulin G (IgG) was highly accurate in identifying infected patients who had symptoms for at least 14 days. Since the standard PCR (nasal swab) test for SARS-CoV-2 loses sensitivity over time, augmenting it with a test for antibodies in patients who have had symptoms for at least eight days (at which time 50 percent are producing antibodies) will help identify some positive cases that might otherwise be missed, says Charles.

The researchers found that IgG levels remained elevated in these patients for four months, and were associated with the presence of protective neutralizing antibodies, which also demonstrated little decrease in activity over time. "That means that people are very likely protected for that period of time," says Charles. "We showed that key antibody responses to COVID-19 do persist."

In another finding, Charles and her colleagues showed that people infected with SARS-CoV-2 had immunoglobulin A (IgA) and immunoglobulin M (IgM) responses that were relatively short-lived, declining to low levels within about two and a half months or less, on average. "We can say now that if a patient has IgA and IgM responses, they were likely infected with the virus within the last two months," says Charles.

Knowing the duration of the immune response by IgA and IgM will help scientists obtain more accurate data about the spread of SARS-CoV-2, explains Jason Harris, MD, a pediatric infectious disease specialist at MGH and co-senior author of the study. "There are a lot of infections in the community that we do not pick up through PCR testing during acute infection, and this is especially true in areas where access to testing is limited," he says. "Knowing how long antibody responses last is essential before we can use antibody testing to track the spread of COVID-19 and identify 'hot spots' of the disease."

Anita S Iyer, Forrest K Jones, Ariana Nodoushani, Meagan Kelly, Margaret Becker, Damien Slater, Rachel Mills, Erica Teng, Investigation, Mohammad Kamruzzaman, Wilfredo F Garcia-Beltran, Michael Astudillo, Diane Yang, Tyler E. Miller, Elizabeth Oliver, Stephanie Fischinger, Caroline Atyeo, A John Iafrate, Stephen B Calderwood, Stephen A Lauer, Methodology, Supervision, Validation, Jingyou Yu, Zhenfeng Li, Jared Feldman, Blake M Hauser, Timothy M Caradonna, John A Branda, Sarah E Turbett, Regina C LaRocque, Guillaume Mellon, Dan H Barouch, Aaron G Schmidt, Andrew S Azman, Galit Alter, Edward T Ryan, Jason B Harris, Richelle C Charles.
Persistence and decay of human antibody responses to the receptor binding domain of SARS-CoV-2 spike protein in COVID-19 patients.
Science Immunology, 2020. doi: 10.1126/sciimmunol.abe0367

Most Popular Now

Lilly's neutralizing antibody bamlanivimab (LY-CoV…

The U.S. Food and Drug Administration (FDA) granted Emergency Use Authorization (EUA) for Eli Lilly and Company's (NYSE: LLY) investigational neutralizing antibody bamlan...

Scientists identify synthetic mini-antibody to com…

The ability of SARS-CoV-2 to infect cells depends on interactions between the viral spike protein and the human cell surface protein ACE2. To enable the virus to hook ont...

New drug candidate for the treatment of COVID-19

Researchers from the University of Kent, the Goethe-University in Frankfurt am Main (Germany), and the Hannover Medical School (Germany) have identified a drug with the p...

Cancer treatment could be replicated for COVID-19

Beta-blockers could potentially be used to treat COVID-19, according to a new international study by Italian and Australian scientists. University of South Australia c...

European Commission approves contract with BioNTec…

Today, the European Commission approved a fourth contract with pharmaceutical companies BioNTech and Pfizer, which provides for the initial purchase of 200 million doses ...

Swissmedic begins rolling review of Moderna's mRNA…

Moderna, Inc., (Nasdaq: MRNA) a biotechnology company pioneering messenger RNA (mRNA) therapeutics and vaccines to create a new generation of transformative medicines for...

Medicago and GSK announce start of Phase 2/3 clini…

Medicago, a biopharmaceutical company headquartered in Quebec City, and GSK have announced the start of Phase 2/3 clinical trials of its plant-derived vaccine candidate f...

Pre-existing coronavirus antibodies could help pro…

Researchers at the Francis Crick Institute and University College London have found that some antibodies, created by the immune system during infection with common cold c...

Fluvoxamine may prevent serious illness in COVID-1…

In a preliminary study of COVID-19 patients with mild-to-moderate disease who were attempting to recover in their homes, researchers at Washington University School of Me...

Remdesivir for COVID-19: FDA approved but still un…

The United States has become the epicenter of the world in the ever increasing pandemic of COVID-19. While public health prevention strategies of social distancing, crowd...

The Sputnik V COVID-19 vaccine efficacy amounted t…

The National Research Center for Epidemiology and Microbiology named after N.F. Gamaleya of the Ministry of Health of the Russian Federation (Gamaleya Center) and the Rus...

Novartis provides update on CAN-COVID trial in hos…

Novartis today announced new data from an interim analysis for the randomized, double-blind, placebo-controlled CAN-COVID trial evaluating the efficacy and safety of cana...