The cause of death from COVID-19 is the accumulation of the coronavirus itself in the lungs, according to experts from New York University. This contradicts current versions that the patient is killed by concomitant infections or an autoimmune reaction. The researchers talk about this in more detail in an article in the journal Nature Microbiology.
The researchers took samples of lung contents from 589 ventilated patients. In 142 of them, who underwent bronchoscopy, it was also possible to obtain samples of the contents directly from the lower respiratory tract.
Scientists determined the microbial composition of the samples, and also studied the state of immune cells. Those who eventually died had an average of 10 times the number of viral particles in the lower respiratory tract than those who survived. However, the researchers did not find a noticeable difference in the composition of bacteria and fungi in the samples of the deceased and survivors. This may be due to the course of antibiotics that all critically ill patients received, but, in any case, the bacterial infection in these cases could hardly be considered the cause of death of the patients.
Also, the researchers did not identify significant autoimmune reactions. At the same time, the production of proteins, important for “memorizing” new microbes and preparing the body to counteract them, was reduced by 50% in deceased patients. Apparently, violations of the adaptive immunity allow viral particles to accumulate in the lungs, which leads to death, the authors of the work believe.
The use of antiviral drugs for seriously ill patients on mechanical ventilation is now not encouraged – there are still no specialized drugs for COVID-19, and other drugs can worsen the patient’s condition due to side effects. However, it is possible that the drugs will still have a positive effect, the researchers admit. They also hope they can find a way to strengthen adaptive immunity and help the body fight infection.