When Does a Patient Suffering From COVID-19 Stop Being Contagious?
There is still a lot of unknown information but some things are for certain
Research conducted on the first group of people infected with coronavirus in Germany allowed determining when the discharge of patients with COVID-19 no longer poses a risk to the population, which allows the release of space in hospitals in the situation of the crisis of free beds, reports EFE agency, according to Agerpres.
In a joint statement, the Charité clinics in Berlin and Schwabing in Munich, together with the Institute of Microbiology of the German army, revealed that a patient is no longer contagious when samples taken from the nasopharyngeal area and fluids expelled by cough have less than 100,000 copies of the virus genome.
The results of the study carried out on the group of infected people in the outbreak of the German auto-parts company Webasto show that in most cases the viral load in the pharynx was significantly reduced compared to the first week of the disease, and in the lungs a little later.
Eight days after the patients had the first symptoms, the experts had not yet been able to isolate the infectious particles of the virus, although copies of the virus genome were detected in the pharynx and lungs.
This finding allows us to draw two conclusions, according to Roman Wolfel, the director of the Institute of Microbiology of the German army and one of the main authors of the study.
First, “the high viral load in the pharynx as soon as the first symptoms appear indicate that patients with COVID-19 are contagious from an early age, possibly even before they realize that they are sick.”
At the same time, the infectious potential of patients with COVID-19 appears to depend on the viral load in the pharynx or lung. This is an important factor in deciding when a patient can be discharged as soon as possible in the event of a crisis of free beds, ”explains Roman Wolfel.
According to these data, the authors of the study the results of which are published in the journal Nature estimated that patients infected with COVID-19 can be quarantined and placed in quarantine at home if ten days after the disease they present in fluids expelled by coughing less than 100,000 copies of the virus genome.
German researchers have also determined that the SARS-CoV-2 virus is likely to multiply in the gastrointestinal tract, although they have not detected the presence of the virus in the feces of patients. Moreover, they did not detect the virus in the patients’ blood or urine.
To identify antibodies against SARS-CoV-2, patients’ blood sera were analyzed. Thus, half of the people in the examined group analyzed for 28 days from the onset of the first symptoms developed by the seventh-day antibodies against the virus. Two weeks later, all patients produced antibodies. Also, as antibodies were produced, the viral load slowly decreased.
On the other hand, this research also revealed that “the new coronavirus can multiply in the pharynx without necessarily reaching the lungs, which is why it is so easily transmissible,” explains Christian Drosten, director of the Institute of Virology of Charité clinic and co-author of the study.
This group of researchers intends that, starting from this first group of patients, but also based on others infected, to analyze the long-term development of immunity against SARS-CoV-2, data that could contribute to the creation of a vaccine.