Since the outbreak of the new crown pneumonia outbreak, when some discharged patients were re-examined, the viral nucleic acid test results became positive again, referred to as "Fuyang". The cause of "Fuyang" cases and whether the "Fuyang" cases are contagious have aroused great public concern.

At a press conference held by the State Council ’s Joint Prevention and Control Mechanism on February 28, Guo Yanhong, Supervisor of the Medical, Political, and Medical Administration of the National Health and Health Commission, said that no cases of “Fuyang” had been transmitted to others. Zhong Nanshan, a high-level expert group leader of the National Health and Medical Commission and an academician of the Chinese Academy of Engineering, previously said that whether "Fuyang" patients would infect others still remains to be seen.

On March 5th, Zhang Xiaochun, deputy director of the Medical Imaging Department of Zhongnan Hospital of Wuhan University, told the Beijing News reporter that the phenomenon of "rejuvenation" increased in various places reflects the dilemma of the accuracy and efficiency of the current new crown pneumonia detection technology, and also reflects the medical community's concerns about the new crown. Pneumonia virus is still in the process of deepening awareness, "this process is destined not to be easy."

Zhang Xiaochun suggested that when the conditions are mature, multi-point nucleic acid testing and complementary testing methods can be used to start the discharge and isolation period to curb the increase in "Fuyang" cases.

"Fuyang" dates back to February 14

The earliest case of "Fuyang" can be traced back to February 14th. The couple in Ontario, Canada, both "Fuyang" 14 days after being discharged from the hospital. They were discharged on January 29 and January 31, respectively, and the clinical diagnosis was that they had recovered. However, 14 days after discharge, nasopharyngeal swabs in both cases were positive.

According to public reports from various places, since mid-to-late February 2020, the disease control departments of 6 provinces including Guangdong, Jiangsu, Tianjin, Sichuan, Hunan, and Hubei have announced the contents of the "Fuyang" case report. In addition, "Fuyang" cases have also been found in Canada and South Korea.

On February 25, Song Tie, deputy director of the Guangdong Provincial Center for Disease Control and Prevention, said that about 14% of patients who had been discharged from hospitals in Guangdong had a "rejuvenation" phenomenon. Li Yueping, director of the ICU of the Infectious Diseases Center of the Eighth People's Hospital of Guangzhou, said that they found 13 "Fuyang" patients during follow-up of discharged patients.

On February 28, a reporter from the Beijing News learned from the Center for Disease Control and Prevention of Xuzhou City, Jiangsu Province that on the 27th, one of the discharged patients in the city had a positive nucleic acid retest (asymptomatic). Three days before the positive retest, the case was released from quarantine and returned home.

On March 1, the official website of the Hainan Provincial Government reported that Hainan's first "Fuyang" patient was discharged again. At present, his body temperature has returned to normal for 5 days, and the throat swabs and fecal nucleic acid tests were negative twice (with an interval of more than 24 hours).

On February 27, researchers from Wuhan University Zhongnan Hospital published a paper in the top international medical journal "Journal of the American Medical Association", revealing a corner of the "Fuyang" phenomenon from a research perspective. In this thesis, 4 cases of patients recovered from New Coronavirus were used as observation samples. These 4 patients recovered positive for nucleic acid 5 to 13 days after discharge. All four were medical staff, and the severity of the disease was mild to moderate, ranging in age from 30 to 36 years.

The paper showed that one of the patients had two nucleic acid tests before being discharged, and the results were negative. CT also showed that his lung lesions were significantly improved, so he was discharged. The patient received strict home isolation after discharge and continued to take ostavir drugs for nearly a month. In early February, the patient was examined again before preparing to return to work. The CT results showed normal, but the nucleic acid test results were weakly positive on the first day and positive on the next day.

The researchers concluded in the paper that they may need to re-evaluate current discharge standards, release standards, and patient management issues.

On March 5, Xu Haibo, a professor of Medical Imaging at Zhongnan Hospital of Wuhan University, one of the authors of the paper, told the Beijing News reporter that there is no more effective method and standard for how to adjust the discharge standards in response to "Fuyang".

"We are still researching, there are no new results, and the results will be announced in time. At present, the implementation according to the plan announced by the National Health Commission is the best." Xu Haibo said.

Need to exclude "false negative" factors

In the "New Coronavirus Pneumonia Prevention and Control Plan (Sixth Edition)" issued by the National Health and Health Commission, the source of new coronary pneumonia infection is mainly patients with new coronavirus infection. Asymptomatic infection may also become the source of infection. The "New Coronavirus Pneumonia Prevention and Control Plan (Fifth Edition)" shows that in addition to the disappearance of clinical symptoms, patients with new coronavirus must also have two consecutive negative respiratory pathogen nucleic acid tests (sampling interval of at least 1 day) before they can be cured. Discharge; in addition, negative nucleic acid test results cannot rule out new coronavirus infection, and factors that may produce false negatives need to be ruled out.

"False negatives" have become an important factor in disturbing the diagnosis of patients before they are discharged or released from isolation. The New Coronary Pneumonia Prevention and Control Plan (Fifth Edition) appendix to the new guidelines for laboratory testing techniques for new coronary pneumonia has strict requirements on the type, method, packaging, and storage of specimen collection. Problems in any link may lead to " False negatives. "

Zhang Xiaochun told the Beijing News reporter that the two commonly used nucleic acid detection methods are anal swab and throat swab nucleic acid detection. The reason is that they are efficient and easy to operate, which is suitable for the current situation where there is a large demand for nucleic acid detection. However, these two methods are more limited in sampling: "The virus may not be in the pharynx and anus, but in other body tissues. In addition, the amount of virus in the discharged patient's body is small, and it may not be available during operation. There are even fewer samples. There are interference factors such as kit sensitivity and patient physical differences, so it is easy to show 'false negatives.'

"This is the contradiction between precision and efficiency." Zhang Xiaochun believes that "there are too many people to be investigated across the country, and it is difficult to take into account a large-scale investigation."

On February 18, Zhong Nanshan, an academician of the Chinese Academy of Engineering, also said at a press conference that the diagnosis using nucleic acid testing is correct, but it also depends on the material. If the sampling is not accurate, it will cause a large difference in results.

According to information from the National Health and Medical Commission Inspection Center, in the throat and swab sampling of the oral cavity and nasal cavity, since the new coronavirus is mainly in the deep part of the lung, it is far from the atmospheric tube, and the infected person has more dry cough and not much sputum. Respiratory virus content is relatively low, increasing the probability of "false negatives".

In Zhang Xiaochun's opinion, nucleic acid testing can only give a qualitative reference for infection, while CT image testing can directly reflect the lung condition, and to a certain extent can complement the nucleic acid testing. Zhang Xiaochun said that when the conditions are gradually mature, "two-pronged approach" or even "multi-pronged approach", pre-hospital testing in various ways is believed to effectively reduce the subsequent increase in "Fuyang" cases.

Discharge criteria in the seventh edition of the treatment plan. National Health Commission official website screenshot

Some patients rule out the possibility of reinfection after admission

Guo Yanhong said at a press conference held by the State Council's Joint Prevention and Control Mechanism on February 28 that the new crown pneumonia virus is a new virus, and its pathogenic mechanism, the overall picture of the disease and the characteristics of the course of disease need further understanding.

Zhang Xiaochun told the Beijing News reporter that from the current clinical experience, the new crown pneumonia virus can invade many organs of the human body, so the virus may exist in patients' blood, feces, pleural effusion, and cerebrospinal fluid. This is a multi-point detection method. Point me. Zhang Xiaochun believes that in addition to the routine swab swab and anal swab testing, the nucleic acid testing point should be determined in accordance with the clinical symptoms of the patient. This is helpful to prevent problems such as inaccurate sampling, insufficient sample size, and virus content at the sampling site that cannot reflect the whole. However, as with multiple detection methods, the implementation of multiple-point nucleic acid detection on a large scale will require more time per test.

Subject to the research progress of the New Coronavirus itself, the measures adopted by various regions for the "Fuyang" phenomenon are currently limited. The public information of the disease control departments in various places shows that the post-intervention intervention methods such as strengthening the follow-up of discharged patients and strengthening the monitoring of health status are still the main areas.

Regarding the experience of Hainan's "Fuyang" case being discharged again, Wu Biao, the person in charge of the disease control office of Hainan Provincial People's Hospital and deputy director of the infection department, introduced that after being hospitalized again, "Fuyang" patients were found to have produced IgG antibodies and IgM Has been negative, eliminating the possibility of re-infection. Hainan Provincial People's Hospital will perform nucleic acid testing of whole blood and feces before discharge from patients who meet the discharge standards of the National Health and Health Commission, and they will be discharged only after they are all negative. The hospital will strengthen follow-up and follow-up of discharged patients with new coronary pneumonia, and implement a 14-day free rehabilitation isolation and medical observation according to the designated place of the local disease control center.

From the day of discharge from the patient to 12 weeks after discharge, three return review nodes for the 4th, 8th, and 12th weeks were established for discharged patients. Focus on reviewing blood routine, blood biochemistry, finger pulse oxygen, new crown virus antibody, multi-site nucleic acid, chest CT and other items, carry out health guidance and health status monitoring, and achieve full-process management.

On the morning of February 22, Zhang Fuchun, deputy secretary of the Party Committee and chief physician of the Eighth People's Hospital of Guangzhou City, suggested at the conference that discharged patients should still be isolated at home and have meals at home. According to him, some patients appeared positive two weeks after being discharged. At present, it is not clear about the disease period and the time of drug use. To this end, all patients are required to return to the hospital for two weeks and four weeks for follow-up.

In addition to the strict follow-up mechanism, Zhang Xiaochun, deputy director of the Department of Medical Imaging of Zhongnan Hospital of Wuhan University, believes that the length of community isolation and home isolation for discharged patients can be considered. "Rehabilitated people need to be isolated at the community's isolation point for 14 days after returning from hospital isolation. During this period, they can get simple medical services. This time may be considered to be extended to 2 months, or even 3 months. The time window of observation. "Zhang Xiaochun suggested.

On March 4, the seventh edition of the diagnosis and treatment plan announced by the National Health and Medical Commission also changed the precautions after discharge. Considering that a small number of discharged patients had positive nucleic acid test retest results, in order to strengthen the health management and isolation of discharged patients, the "should continue to carry out 14-day self-health monitoring" to "should continue to carry out 14-day isolation management and Health monitoring. " This means that after being discharged, discharged patients still need to be monitored by medical staff for health monitoring, which is more stringent than previous self-tests.

Whether "Fuyang" patients are infected is inconclusive

Because "Fuyang" cases are mostly found in the re-examination after release from quarantine, whether free-moving "Fuyang" cases are contagious has become the most important point of "Fuyang" right now.

Guo Yanhong, Supervisor, Medical Administration and Hospital Administration, National Health and Health Commission, introduced the situation of "Fuyang". CCTV News Screenshot

The infectious knowledge of the current "Fuyang" cases is still under exploration, as is the current understanding of the new crown virus in the global medical community.

Vanessa Allen, head of medical microbiology at the Ontario Department of Health in Canada, said at a press conference that some genetic or viral residues were found in the test samples of "Fuyang" cases, but they are still currently The survival status of the virus cannot be determined from these residues, and it is not clear whether the patients with "Fuyang" are still infectious.

On February 27, Zhong Nanshan said that new crown pneumonia is a new infectious disease, and its transmission process is not known yet. At present, no absolute conclusion can be reached. However, according to the laws of microorganisms, as long as sufficient antibodies are produced in the patient's body, the patient will not be infected again. Whether such patients will be transmitted to others remains to be seen.

In Xu Haibo's opinion, a positive nucleic acid test in discharged patients may indicate that some recovered patients still carry the virus, but it is still unclear whether it is infectious.

Zhang Xiaochun believes that "Fuyang" may be due to the low amount of virus in the body when the patient was discharged for testing, which did not reach the level of positive nucleic acid test, so it could not be detected. After discharge, the virus in the body had multiplied and the virus content increased. To be able to be detected positive. This shows that after the isolation period, the virus in the body is still active, so it is necessary to prevent the infectiousness of "Fuyang" cases.

Wu Biao, the person in charge of the CDC of Hainan Provincial People's Hospital and deputy director of the infection department believes that patients discharged after reaching the national discharge standard are theoretically in the process of rehabilitation and the body's virus is in the process of elimination. If there is a positive nucleic acid test during the recovery period, as long as it is not a disease recurrence through comprehensive clinical judgment, it will not pose a great threat, and the possibility of becoming a new source of infection is also very small.

On February 25th, Li Yueping, director of the ICU of the Infectious Diseases Center of the Eighth People's Hospital of Guangzhou City, also introduced at the Guangdong province epidemic conference. Although the nucleic acid test of the "Fuyang" case was positive, it is technically difficult to distinguish between live virus and live virus. Dead virus. Therefore, for the prevention and control of viruses, we still need to guard against death.

"For the phenomenon of" Fuyang ", hospitals and individuals need to pay attention to prevention and control, but they don't need to be too panicked, and don't discriminate against patients discharged from rehabilitation." Zhang Xiaochun said, "What we have is a way to deal with it, but we need to do well at all levels. The trade-off is that there is a lot of room for improvement. "

Beijing News reporter Liu Haonan