Who lengthens Covid?Research may provide clues

New studies suggest that blood tests may one day help determine a person’s risk to long Covids.

A study published in the journal on Tuesday Nature CommunicationsPeople who continue to develop long Covids have found that levels of certain antibodies in the blood are low shortly after being infected with the coronavirus.

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When confirmed in larger studies, the findings help develop tests to predict who may continue to suffer from symptoms for weeks, months, or even years after infection. May be useful.

Dr. Onur Boyman, a researcher at the Department of Immunology at the University of Zurich Hospital and author of the new study, said: ..

Since the beginning of the pandemic, Long Covid has plagued doctors and researchers around the world, with no standard definition, diagnosis, or cure, and a poorly understood condition.

The exact number of long Covid patients is unknown, One-third of Covid patients Overall, symptoms may appear for at least a month.

According to outside experts, early insights that could make a patient a so-called long-haul carrier are welcomed.

Charles Downs, a Longcovid researcher and associate professor of nursing and health at the University of Miami, called the study “very promising.”

“There is no single test or imaging test that can be used for diagnosis,” Longcovid said. “This helps move us in that direction.”

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Boyman’s research began in early 2020 during the first wave of the pandemic. His team followed the patient for six months after the acute phase of the infection, and for a year as the long Covid phenomenon became apparent.

Compare more than 500 Covid patients — some of them Long Covid Others who have resolved their symptoms — he said, some important differences have emerged.

The most obvious was how the patient’s immune system, which continued to develop long Covids, first responded to the virus.

Such patients in Boyman’s study showed a significant decrease in levels. of Two immunoglobulins, IgM and IgG3, are antibodies that the immune system produces to fight infection. In a healthy immune system, These levels Immunoglobulins tend to rise in the face of infection.

Combined with other factors such as middle-aged and asthma history, these antibody levels were 75% effective in predicting long Covids, Boyman said.

Researchers knew which patients were suffering from long Covids, so more research is needed to determine if the criteria are as accurate as the onset of the disease.

“These individuals may have disadvantages from the beginning, and because of the asthma background, they can react slightly differently to the virus, which can lead to a false immune response. There is sex. ”

Downs of the University of Miami said in his experience that many long Covid patients tend to have a history of underlying allergy-related disorders such as chronic runny nose associated with asthma or seasonal allergies. ..

If confirmed in a larger study, the study is ” Postcovid-19 Clinic Dr. Kartik Sehgal, a longtime Covid researcher and medical oncologist at the Dana-Farber Cancer Institute in Boston, wrote by email.

There are some caveats to the new research. Patients in this study were infected between April 2020 and August 2021 before the Omicron variant had settled.

Therefore, the survey results are Omicron infection.

In addition, this study did not consider the vaccination status of participants. Many long-term Covid patients became ill in early 2020, before the vaccine became available.

Claire Steves, senior clinical instructor at King’s College London, said in a statement, “These markers are vaccinated in people who have been vaccinated or previously infected in much of the world. It’s still important to see if it’s predictable. ”

But “there are still many cases, so more people are at risk of developing long-term symptoms,” said Steves, who was not involved in the new study. “There is an urgent need to expand research on how to prevent this.”

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