Turkish scientists have found that the number of SARS-CoV-2 viruses in the body of asymptomatic patients is higher than in patients with symptoms. In their opinion, this fundamentally distinguishes the new coronavirus from other pathogens and explains why the efforts of many countries to contain the pandemic are failing. The corresponding article was published in the magazine Infection.
All previous research suggests that asymptomatic carriers can spread the infection even if they don’t have a fever or cough. But what the Turkish scientists discovered was completely unexpected.
The authors of the study assessed the level of viral load in six types of patients, varying in age and severity of the disease. So they set out to determine the relationship between the course of the disease and the viral load in COVID-19.
The researchers collected samples from the nasopharynx, throat, oral cavity and rectum, as well as saliva, blood and urine tests from 60 patients with confirmed coronavirus. A quarter of them showed no symptoms. In total, the scientists analyzed 360 samples.
All asymptomatic patients were found to have higher viral loads than those with symptoms. In addition, with an increase in the severity of the disease and the age of the patient, this indicator decreased.
“COVID-19 is a tricky jigsaw puzzle. Virological and immunological studies are urgently needed to put everything together and see the big picture,” the authors write. “Our study, unlike others, demonstrates that asymptomatic patients have more higher viral load of SARS-CoV-2 than symptomatic patients, and with increasing severity of the disease, there is a significant decrease in viral load. ”
According to scientists, the low viral load of SARS-CoV-2 correlates with factors that determine the poor prognosis of the course of the infection, such as bilateral “frosted glass” on CT of the chest, low lymphocyte count and old age.
The authors suggest that the higher viral load in asymptomatic patients may be just the tip of the iceberg of problems associated with the spread of COVID-19.