World.- A study of nine patients with mild symptoms published this week in Nature analyzes replication of coronavirus in the upper respiratory tract. The results show that very high concentrations are reached quickly in the throat. Researchers believe this may explain the loss of smell and taste by some infected. They also consider their data to “justify” protective strategies such as masks.
The role of those infected with mild symptoms in the development of the COVID-19 pandemic has worried researchers from the outset. However, there is little data on this type of patient.
A study published this week in the journal Nature reveals new information about how SARS-CoV-2 coronavirus works when it is not installed in the lungs, as in the most severe cases, but in the upper respiratory tract, including the nose and throat.
The study detected SARS-CoV-2 in nasopharynge, throat and sputum samples from nine patients with mild symptoms, and did so in “extremely high” concentrations
The study detected SARS-CoV-2 in nasopharynge, throat and sputum samples from nine patients with mild symptoms. And he did so in “extremely high” concentrations, in the words of the doctor at Schwabing Hospital in Munich, Germany, and co-author of the study, Clemens Wendtner. Instead, he didn’t find it in stool, urine and blood isolates.
Peak coronavirus concentrations were reached before day five and live viruses were isolated. In comparison, levels in SARS patients are more than 1,000 times lower and take up to 10 days to reach their maximum.
All this proves, according to the authors, that there is an active multiplication in the upper respiratory tract of these mild COVID-19 patients. It also fuels the theory that those infected with mild symptoms played a key role in the spread of the pandemic.
This high viral load in the upper respiratory tract, “up to 109 per milliliter,” explains “partially,” according to SINC Wendtner, why some patients suffer loss of smell (hyposmia) and sense of taste (hypogeusia).
It is a conclusion shared by researchers who have not participated in the study such as Rosalind Smyth, university college, London, UK. “High replication [del coronavirus] in the upper respiratory tract may also explain loss of taste and smell” in some people, “even in those with few symptoms.”
It is not clear, however, why the coronavirus shows this predilection for the throats
It is not clear, however, why coronavirus shows this predilection for the throats. “It will be to investigate whether ACE2 or other receptors are the port of entry of SARS-CoV-2 in the upper respiratory tract,” SINC Wendtner clarifies.
Smyth considers the study “important despite limited number of patients,” due to a shortage of data from mild patients such as those provided by Wendtner and his team.
The fact that the viral load is so high in the throat shortly after the symptoms begin “helps explain why the virus is so infectious”, since it “can be transmitted by droplets of the upper respiratory tract before people are aware that it is infected “.
“[Los resultados] they support the use of simple throat swabs to diagnose infection, and underscore the efficient transmission of the virus when symptoms are mild,” adds University of Warwick researcher Lawrence Young, who has also not participated in the study. “Prolonged sputum ejection of viruses suggests patients should remain isolated at home after leaving the hospital.”
Source: Nature
