Is there protection against reinfection after COVID-19?
If people survive a severe infection with COVID-19, they appear to have lasting immune responses to the virus afterwards. This gives hope that people infected with the virus will develop long-term protection against reinfection.
Is there protection against re-infection after getting sick with COVID-19? (Image: Monet / Stock.Adobe.com)
Surviving severe COVID-19 infection could protect those affected from long-term reinfection, according to a new study by researchers at Massachusetts General Hospital (MGH). The study was published in the English-language journal “Science Immunology”.
The spread of the virus is traceable
The researchers not only discovered a possible protective effect against re-infection with COVID-19, but also found that measuring antibodies can be an accurate tool to monitor the spread of the virus in society.
Knowledge gaps related to antibody reactions
It is known that in response to the SARS-CoV-2 virus that causes COVID-19, the immune system produces special proteins called antibodies. But so far, there is a great lack of knowledge regarding the duration of these antibody reactions, the researchers report.
Blood samples were evaluated
The research group therefore took blood samples from 343 people with COVID-19, most of whom had severe cases of the disease. Blood samples were taken up to four months after the onset of symptoms. Blood plasma was isolated and applied to laboratory plates which were coated with the receptor binding domain (RBD) of the virus spike protein, which attaches to cells and leads to infection.
The team looked at how different types of antibodies in plasma bind to RBD. The results were then compared to blood samples taken from more than 1,500 people before the pandemic.
The research group found that the measurement of an antibody called immunoglobulin G (IgG) was very accurate in identifying infected people who had been showing symptoms for at least 14 days.
Slight decrease in antibody activity
The team also found that IgG levels remained elevated for four months and were associated with the presence of protective neutralizing antibodies, which also showed a slight decrease in activity over time.
“This means that people are very likely to be protected during this time,” says study author Dr. Richelle Charles of Massachusetts General Hospital in a press release.
In another finding, the team showed that people infected with SARS-CoV-2 had immunoglobulin A (IgA) and immunoglobulin M (IgM) responses that were relatively short and averaged two months and a half. or less decreased to low values.
Better monitor the spread of COVID-19
“We can now say that if a patient has IgA and IgM reactions, he / she has probably been infected with the virus within the past two months,” concludes Dr. Charles. The results on the duration of the immune response by IgA and IgM will also provide more precise data on the spread of SARS-CoV-2, continues the author of the study.
It’s important to know how long antibody reactions take before it is possible to use antibody tests to track the spread of COVID-19 and identify so-called disease hot spots, the researchers add. .
Benefits of the new test
Since the standard PCR test (nasal swab) for SARS-CoV-2 loses sensitivity over time, adding a test for antibodies in people with symptoms of at least eight days ( at this point, 50% are producing antibodies) might help identify some positive cases that might otherwise be overlooked, experts explain. (as)
Author and source information
This text complies with the requirements of specialized medical literature, medical directives and ongoing studies and has been verified by healthcare professionals.
Anita S. Iyera, Forrest K. Jonesc, Ariana Nodoushania, Meagan Kellya, Margaret Beckera et al .: Persistence and disintegration of human antibody responses to the SARS-CoV-2 spike protein receptor binding domain in patients COVID-19, in Science Immunology (published October 5, 2020), Science Immunology, Massachusetts General Hospital: Protective antibodies persist for months in patients who survive severe COVID-19 infections (published October 8, 2020), Massachusetts General Hospital
This article is provided for informational purposes only and should not be used for self-diagnosis or self-treatment. It cannot replace a visit to the doctor.