Will the nucleic acid test be contagious? Expert authoritative interpretation

nucleic acid detection "fuyang", will also infect others? From the 22nd to the 23rd of this month, the Xicheng District of Beijing completed 1130,680 nucleic acid tests in batches, and found that one person was positive for initial screening. The officer was tested at the Shichahai Lotus Market TestIng Point at 16:39 on 22 January. Xicheng City subsequently reviewed the person found that it was a confirmed case diagnosed after entering Shanghai in August 2020 and cured, in line with the relevant provisions in October into Beijing, do not rule out the possibility of Fuyang.
The person has been transferred to a fixed-point hospital for further treatment, its close contacts for isolation observation and nucleic acid testing, involving environmental testing and disinfection of the site, related personnel and environmental samples nucleic acid test results are negative.In addition to beijing this case may be Fuyang patients, on January 24, Fushan County, Shanxi Province, found a confirmed case of rehabilitation after Fuyang, the patient is an immigrant, after the end of home medical observation isolation, nucleic acid test positive, was diagnosed as asymptomatic infected. On January 18, Guangdong Jieyang also found a case of asymptomatic importation of asymptomatic infected person Fuyang.why do you have a re-positive nucleic acid after recovery? Is Fuyang still contagious? How high is the proportion of Fuyang?
Zunyou, chief epidemiologist at the China Center for Disease Control and Prevention: Some of the relevant patients tested positive for nucleic acid in follow-up after discharge, and there are three possibilities for this phenomenon.
first, nucleic acid tests show false negative or false positive, such as two nucleic acid negative before discharge is false negative or follow-up nucleic acid positive, the result is false positive.
second, the virus is back in activity.
third, re-infection, for the first case, through multiple samples in multiple parts, can reduce the occurrence of false negative or false positive, for the second condition is not clear.
limited research suggests that the patient is less contagious, and no cases of transmission have been observed, and for a third case re-infection, the infectiousness is similar to that of other first-time patients. Overall, the proportion of patients who re-emerged as nucleic acid positive in follow-up was not high, at about 5%.