Re-positive cases have appeared in many places. What is going on? Is it contagious?

Recently, many places across the country have reported reinfection cases of COVID-19, and "reinfection" has gradually become a hot topic among the people.

Why do patients test positive again after recovery? What is the reason for the re-test? Are those who test positive again contagious? ... With these questions, the reporter interviewed authoritative experts and industry insiders.

What is the situation of reinfected cases across the country?

Xicheng District, Beijing reported the results of the district's coronavirus nucleic acid test on the 24th, and one person tested positive in the initial screening. It is reported that this person was a confirmed case who returned to Shanghai from abroad in August last year and has been cured. He came to Beijing in October last year, but now the re-examination is positive. After recovering for so long, he still tested positive again? This further highlights the difficulty of epidemic prevention and control.

In fact, this is not the first time that a patient with COVID-19 has tested positive again after recovery.

On the same day that Xicheng District reported the case, Fushan, Shanxi also reported a re-positive asymptomatic infection. The person returned from abroad on December 16 last year, and the nucleic acid test result was positive the next day. He was later diagnosed as an asymptomatic infection and received treatment. After multiple nucleic acid tests, they were all negative, and he was discharged from the hospital on January 5. However, when the nucleic acid test of key populations in Fushan County, Shanxi Province was conducted on January 23, the result was positive, and he was isolated and treated on the 24th.

In addition, Zhejiang, Hebei and other places have also reported cases of COVID-19 re-infection this year. Re-infection has become a new "keyword" in epidemic prevention and control.

What is the reason for reinfection?

At present, the cumulative number of confirmed cases of COVID-19 worldwide has exceeded 100 million. Feng Zijian, deputy director of the Chinese Center for Disease Control and Prevention, said that with such a large-scale infection, very low-probability and relatively special cases will appear among the infected, and this phenomenon also occurs in other diseases.

Why did the patient relapse after being discharged from hospital?

Wu Zunyou, chief epidemiologist at the Chinese Center for Disease Control and Prevention, said there are three possible reasons for the re-positive phenomenon: one is a false negative or false positive in the nucleic acid test; the second is that the virus becomes active again; and the third is reinfection. For the first case, multiple samplings at multiple sites can reduce the occurrence of false negatives or false positives. For the second case, the mechanism is still unclear. For the third case, the infectiousness is similar to that of other patients infected for the first time.

Will those who have tested positive again infect others?

Feng Zijian, deputy director of the Chinese Center for Disease Control and Prevention, said that continued transmission due to reinfection is rare and does not play a big role in transmission.

In this regard, Chen Zhihai, deputy director of the Infection Center and director of the Second Infection Department of Beijing Ditan Hospital, agreed: "The patient's re-testing positive shows that there is a low level of virus replication in his body and its infectiousness is also very low." He said that based on the current research conclusions, patients will not carry the virus for life after recovery, and because the toxicity of the virus carried by re-tested patients is very low, no cases of re-infection of others have been found after re-testing positive.

How to deal with the phenomenon of reinfection?

"The issue of reinfection cannot be ignored, but it cannot be taken too seriously," said Zhang Boli, an academician of the Chinese Academy of Engineering.

In terms of testing, "through multi-faceted comprehensive testing, we can greatly increase the positive detection rate of quarantined personnel, reduce the missed detection rate, achieve early detection of positive cases, effectively reduce isolation pressure, and improve the management and control efficiency of close contacts." said Zhu Tongyu, director of the Shanghai Public Health Clinical Center.

It is reported that Shanghai has launched the management and follow-up of discharged patients with the novel coronavirus pneumonia.

Wu Jinglei, director of the Shanghai Municipal Health Commission, said that Shanghai has closed-loop transferred all discharged patients to isolation points in various districts for 14 days of centralized isolation. At the same time, the city-level designated hospitals will follow up on discharged patients. Cases with positive nucleic acid test results during the isolation period after discharge will be transferred to the city-level designated hospitals for reexamination in a closed loop, and centralized isolation and health observation will be carried out again after the nucleic acid test is negative.

At present, the global COVID-19 epidemic is showing a high incidence trend. Sporadic cases and clustered epidemics in local areas in my country have increased significantly, and the epidemic prevention and control situation is severe and complicated.

As the Spring Festival approaches, Zhang Boli recommends that people gather less during the Spring Festival and try not to arrange travel without special circumstances. "For those who spend the Spring Festival in their place of residence, try not to hold large gatherings. Maintaining social distance, wearing masks, washing hands frequently, ventilating frequently, staying up less late, and maintaining a healthy work and rest schedule are all very good practices."

Source: Xinhua Viewpoint

Reporter: Mu Tiecheng, Peng Yunjia, Gong Wen, Xia Ke

Producer: Zhou Nianjun Editors: Xu Xiangda, Chen Zixia

Internship: Lin Yujing, Guo Yunqi