Covid-19 weakens the immune system in the long term – DW – 07/15/2024

Infection with the Covid-19 virus weakens the immune system in the long term, causing a “significant reduction in the number of immune cells in the blood,” according to a new study by Austrian scientists.

The findings of a study conducted by a team from the Medical University of Vienna (UniMed) and published this Monday in the specialist journal Allergy, They indicate long-term dysfunction of the bone marrow, the central site of immune cell production.

These results suggest that the immune system of patients who have recovered from Covid-19 infection may no longer respond optimally, UniMed said in a statement.

The consequences of the SARS-CoV-2 virus infection confirmed in the study were observed even in cases of mild disease and will form the basis for new studies of persistent COVID (“long COVID”).

Covid-19 and the decline in immune cells

“Our findings provide a possible explanation that some of the long-term consequences of Covid-19 may be related to damage to the cellular immune system” caused by the virus, the note said. Professor Winfried Pickl, head of the research group.

More specifically, the cause may be “an apparent slowdown in the maturation and/or emigration of immune cells from the bone marrow,” he adds.

“Even after a mild course of the disease, we found a significant decrease in immune cells in the blood,” the immunologist emphasizes.

In a study launched in 2020, relevant immunity parameters were examined in 133 people who had recovered from Covid-19 and 98 people who had not recovered from the infection.

In recovered patients, the number and composition of various immune cells, as well as growth factors in the blood, which play a key role in regulating cell growth, were analyzed ten weeks and ten months after infection.

Since there was no vaccine against Covid-19 at the time the study began, all participants were unvaccinated.

“It is not surprising that ten weeks after infection, recovered patients showed clear signs of immune activation in both T and B cells (white blood cells), unlike healthy subjects,” he notes.

It was the patients’ samples taken ten months after the disease that surprised the scientists, as they showed “a significant reduction in the number of immune cells.”

the(EFE, UniMed)