JAMA Intern Med: Virus loads are similar in asymptomatic infected people and are recommended as key factors for prevention and control.

More than 19 million new crown cases have been confirmed globally, and WHO said in a recent statement that the outbreak is expected to last a long time.
in the many characteristics of the spread of the new crown virus, asymptomatic infected people how to understand the infectious, since the outbreak has been a concern.
the South Korean research team's new study, published in the Journal of the American Medical Association-Internal Medicine, adds important evidence for this.
analysis of a community-infected patients shows that the viral load in asymptomatic infected people is similar to that of asymptomatic patients, and recommends that public health measures be taken as a key factor in transmission.
team reviewed and analyzed data on 303 new coronavirus infections at a community isolation treatment center in Cheonan, South Korea, from March 6 to March 26, 2020. During
isolation, during the 8th, 9th, 15th and 16th days, health care workers collect samples of the upper respiratory tract (nasopharyngeal and pharynx swabs) and lower respiratory tract (sputum) of these infected persons for nucleic acid testing and as a reference for ending isolation.
of all 303 people (63.7 per cent) had symptoms during isolation, 21 (6.9 per cent) had symptoms during isolation and 89 (29.4 per cent) had no symptoms.
the average time from the detection of a new coronavirus infection to the ontest of symptoms is 15 days (quartile 13-20 days).
on the 14th and 21st days after detection of infection, the proportion of nucleic acid transficionality in asymptomatic infected persons was 33.7% and 75.2%, respectively, and the proportion of patients with symptoms was 29.6% and 69.9%, respectively, from the confirmed infection to the first medium time of genital genital inosis, 17 days and 19.5 days, respectively, in asymptomatic infected persons and patients with symptoms, respectively, with no significant difference.
nucleic acid testresults showed that the genetic sequences of the new coronavirus env protein (encoded envelope protein, envelope) and N protein (nucleocapsid) in the upper respiratory tract sample, or the gene sequence detection of the new coronavirus RdRp (RNA-dependent RNA polymerase) and N protein in the lower respiratory tract sample, were similar in both asymptomatic infected persons and patients with symptoms.
, from the time the infection is confirmed to the time of de-isolation, the viral load in the lower respiratory tract samples of asymptomatic infected people decreases more slowly than in patients with symptoms.
based on these data, the team suggests that "the spread of asymptomatic infected persons may be a key factor in community transmission, requiring population-based monitoring and timely isolation of asymptomatic infections."
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