[ad_1]
LONDON
In a major study, researchers said infection peaks early in Covid-19 patients, highlighting the need to quickly identify and isolate cases before the virus spreads.
The systematic review and meta-analysis of three human coronaviruses, published in The Lancet Microbe journal, suggests that people infected with coronavirus are more likely to be highly infectious in the first week after onset of symptoms.
The report used a meta-analysis to evaluate 98 studies on Covid-19, SARS and MERS.
Researchers studied all three diseases to determine why Covid-19 spread faster than previous diseases.
“This is the first systematic review and meta-analysis that has comprehensively examined and compared the viral load and spread of these three human coronaviruses,” study lead author Muge Cevik of the University of St. Andrews said. UK.
“It provides a clear explanation of why SARS-CoV-2 spreads more efficiently than SARS-CoV and MERS-CoV and is much more difficult to contain,” Cevik added.
The researchers included 98 studies that had five or more participants, cohort studies and randomized controlled trials, 79 focused on SARS-CoV-2, 73 of which included hospitalized patients only, eight on SARS-CoV and 11 on MERS-infection. CoV. .
From these studies, the authors calculated the mean duration of viral RNA spread and examined changes in viral load and the success of isolating live virus from different samples collected during an infection.
Analysis of the results of the SARS-CoV-2 studies showed that the mean time to spread of viral RNA in the upper respiratory tract, lower respiratory tract, faeces and serum was 17 days, 14.6 days, respectively. 17.2 days and 16.6 days.
The longest length of time that RNA clearance lasted was 83, 59, 35, and 60 days, respectively.
Of the eleven studies that attempted to isolate live virus, all eight studies included that respiratory samples used were able to grow viable viruses within the first week of illness.
Studies that also measured RNA viral load, these have shown a link between successful isolation of live virus with viral load levels.
No studies included in this systematic review were able to successfully isolate live virus beyond day nine of symptoms in any type of specimen, despite persistently high viral RNA loads.
These results suggest that in clinical practice, it may not be necessary to repeat the PCR test to believe that a patient is no longer infectious, as this may remain positive for much longer and does not necessarily indicate that they could be passing the virus to others.
“In patients with non-severe symptoms, their period of contagion could instead be counted as 10 days from symptom onset,” Cevik noted.
IANS
[ad_2]
Source link
