The viral load of the SARS-CoV-2 coronavirus appears to peak in the upper respiratory tract early in the disease, up to five days after the onset of symptoms, after which the SARS-CoV and MERS loads reach; this could also be the reason for the rapid spread of the kovid 19 pandemic.
To date, evidence of the SARS-CoV-2 virus indicates a nine-day pattern of infection. Since the study only examines confirmed cases, and not those that may be revealed, it cannot provide information on the recommended duration of quarantine.
Although it appears to have a similar virus load among people infected with SARS-CoV-2 coronavirus who develop symptoms and those who do not, most studies suggest that asymptomatic people can expel the virus faster and become less contagious in less time.
Although the genetic material of the SARS-CoV-2 virus can still be detected in respiratory or stool samples after a few weeks, no surviving virus could be found in the samples collected nine days after the onset of symptoms, according to three systematic studies and three meta-analyzes of human coronavirus. Published in Lancet Microben.
“The findings are consistent with research to find contacts that suggest most viral transmission events occur very early, especially in the first five days of symptoms, indicating the importance of isolating symptoms immediately after onset,” says Dr. Muge Cevik. St. Andrews University in the UK.
“We also need to make people aware of the range of symptoms associated with the disease, rather than the mild symptoms that may occur earlier in the infection, such as coughing or fever.”
The researchers included 98 studies with five or more participants, including cohort studies and randomized retrospective trials; Of these, 79 focused on SARS-CoV-2, eight on SARS-CoV, and 11 on MERS-CoV infection.
With the help of respiratory samples the viable virus multiplied in the first week of the disease. On the other hand, the studies performed in this systematic study were unable to successfully isolate the live virus in any type of sample after the ninth day of symptoms.
Several studies have successfully isolated live virus from fecal samples, and the role of oral and fecal transmission for SARS-CoV-2 is clear.
“These findings suggest that in clinical practice it may not be necessary to repeat PCR tests to find out that the patient is no longer contagious,” says Dr. Cevik.
The highest viral load of the SARS-CoV-2 RNA coronavirus was detected early in the disease, when symptoms appear or before the fifth day of symptoms. In contrast, viral loads reached SARS and MERS within a maximum of ten and 14 days, respectively, within seven to ten days of onset of symptoms.
Only twelve studies have reported asymptomatic people infected with the SARS-CoV-2 virus, and six of them have also investigated the extent to which people have expelled viral material from their bodies.
“Although viral RNA loads appear to be similar among asymptomatic and asymptomatic individuals, several studies suggest that asymptomatic individuals may expel viral material more rapidly from the body,” says Dr. Cevik.
Several studies have found that people with asymptomatic infection can get rid of the virus faster, and those who have no symptoms may say they can be as contagious as those with early symptoms, but they can be contagious in no time.
Research St. Researchers from the universities of Andrews, Edinburgh and Glasgow and hospitals in Edinburgh, Vishawa and Naples have done so.
Source: B92.net, Tportal.hr