Research shows that patients with mild cases of COVID-19 11 months after infection still have antibodies and may even receive lifelong protection from the coronavirus.
A new study shows that people with mild cases of COVID-19 still have an antibody response nearly a year after clearing the infection.
According to the Daily Mail, researchers at the University of Washington School of Medicine in St. Louis said reports of the outbreak of a pandemic claiming that antibodies to coronavirus are rapidly weakening are misleading.
The results showed that the immune cells in the bone marrow still produce antibodies even after their blood levels have dropped.
The study found that patients developed neutralizing antibodies seven to 11 months later – and the team suggests that these people may even have lifelong protection.
“Last fall, there were reports of antibodies weakening rapidly after infection … and mainstream media interpreted this as short-lived immunity,” said senior study author Dr. Ali Hellebedi, associate professor in the Department of Pathology and Immunology, Medicine and Molecular Microbiology at the University of Washington. … “But this is a misinterpretation of the data. It is normal for antibodies to drop after an acute infection, but not to zero. Here we found antibody-producing cells in humans 11 months after the first symptoms. These cells will live and make antibodies for the rest of people’s lives. This is strong evidence of long-term immunity. “
When infected, short-lived immune cells are rapidly formed that secrete an early wave of protective antibodies. As the immune cells die off, the level of antibodies decreases. But a supply of these immune cells, called long-lived plasma cells, remains in reserve after infection. Most of them migrate to the bone marrow, Dr. Hellebedy explains.
The study, published in the journal Nature, studied 77 participants who had mild cases of COVID-19, only six of the total were hospitalized.
Volunteers donated blood samples every three months, including about a month after the first positive test result.
Although antibody levels did drop during the first few months after infection, the antibodies did not disappear, but simply stabilized.
The results showed that scientists were able to detect immune cells within 11 months after the patient contracted the virus.
In addition, 18 participants donated bone marrow samples seven or eight months after infection. Four months later, five participants donated a second bone marrow sample.
The samples were compared to samples provided by 11 people who have never tested positive for COVID-19.
The results of the study showed that 15 patients had long-lived plasma cells secreting antibodies against the coronavirus in their bone marrow after seven to eight months. Five of the 15 had a second bone marrow biopsy 11 months after the onset of symptoms, and all still had long-lived plasma cells secreting antibodies against the virus.
In comparison, none of the 11 people who have ever had the disease had antibody-producing immune cells in their bone marrow.
“People with mild cases of COVID-19 clear the virus from the body two to three weeks after infection, so seven or 11 months after infection there will be no virus causing an active immune response,” says Dr. Hellebedy. “These cells … just sit in the bone marrow and secrete antibodies. They have been doing this since the infection disappeared and will continue to do so indefinitely. ”
The team says that while it appears that people with moderate exposure to COVID-19 may have lifelong protection, it is possible that those with severe cases of coronavirus will have less protection.
“It could be a different path,” said Dr. Jackson Turner, professor of pathology and immunology at the University of Washington, in a statement. – Inflammation plays an important role in severe COVID-19, and too much inflammation can lead to a compromised immune response. But on the other hand, the reason people do get sick is often because they have a lot of viruses in their bodies, and having a lot of viruses can lead to a good immune response. So it’s not clear. ”
See also: “One of the main myths of coronavirus prevention debunked”
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