Two stages of infection in patients with severe acute respiratory syndrome “Covid-19”

A new study led by researchers at Massachusetts General Hospital (MGH) provides information that could help improve treatment strategies for patients with COVID-19.

To analyze SARS-CoV-2 at the tissue level and find out what the virus does once it enters a person’s airways and how infection in lung cells affects the immune responses of patients, the researchers examined materials that were dissected from 24 patients with “Covid-19”.

Study co-author David Ting, associate clinical director of innovation at Mass General Cancer Center and assistant professor of medicine at Harvard Medical School, said:

“We use a method called RNA in situ hybridization to visualize the actual SARS-CoV-2 virus in human lung samples. This test is now a clinical test used at Massachusetts General Hospital to understand which tissues might be infected with the virus.” .

The analyzes revealed two stages of infection in patients with severe acute respiratory syndrome “Covid-19”.

The early stage is determined by high levels of the virus in the lungs, which stimulate patients’ cells to express genes linked to the IFN pathway, an important part of the immune response.

In the later stage, the virus is no longer present, but the damage to the lungs is so severe that recovery is impossible.

Ting explained: “The interferon response to SARS-CoV-2 indicates that people’s immune systems can attack SARS-CoV-2, but the response is variable between patients and even in different parts of the lung of the same patient. which makes single-drug adoption a suitable treatment approach. Everyone is difficult. “

He noted that treatments that target virus replication, such as remdesivir, can only be effective in the initial stage of infection.

The research team also found that there is very little sudden replication of the virus in the lungs, indicating that the virus often multiplies in the nasal passages and then falls into the lungs, where it can cause pneumonia and other complications.

It will be important to perform additional autopsy analyzes to understand the extent and timing of SARS-CoV-2 infection in the lungs and other tissues, which could improve treatment strategies for “Covid-19” patients.