key: cord-318592-08mjfs83 authors: Chen, L.; Zhang, Z.-Y.; Zhang, X.-B.; Zhang, S.-Z.; Han, Q.-Y.; Feng, Z.-P.; Fu, J.-G.; Xiao, X.; Chen, H.-M.; Liu, L.-L.; Chen, X.-L.; Lan, Y.-P.; Zhong, D.-J.; Hu, L.; Wang, J.-H.; Yin, Z.-Y. title: Clinical Characteristics of Recurrent-positive Coronavirus Disease 2019 after Curative Discharge: a retrospective analysis of 15 cases in Wuhan China date: 2020-07-04 journal: nan DOI: 10.1101/2020.07.02.20144873 sha: doc_id: 318592 cord_uid: 08mjfs83 In China, the patients with previously negative RT-PCR results again test positive during the post-discharge isolation period. We aimed to determine the clinical characteristics of these recurrent-positive patients. We retrospectively reviewed the data of 15 recurrent-positive patients and 107 control patients with non-recurrent, moderate COVID-19 treated in Wuhan, China. Clinical data and laboratory results were comparatively analyzed. We found that recurrent-positive patients had moderate disease. The rate of recurrent-positive disease in our hospital was 1.87%. Recurrent-positive patients were significantly younger (43(35-54) years) than control patients (60(43-69) years) (P=0.011). The early LOS (length of stay in hospital before recurrence) was significantly longer in recurrent-positive patients (36(34-45) days) than in control patients (15(7-30) days) (P =0.001). The time required for the first conversion of RT-PCR results from positive to negative was significantly longer in recurrent-positive patients (14(10-17) days) than in control patients (6(3-9) days) (P =0.011). Serum COVID-19 antibody levels were significantly lower in recurrent-positive patients than in control patients (IgM: 13.69 {+/-} 4.38 vs. 68.10 {+/-} 20.85 AU/mL, P = 0.015; IgG: 78.53 {+/-} 9.30 vs. 147.85 {+/-} 13.33 AU/mL, P < 0.0001). Recurrent-positive patients were younger than control patients. The early LOS (length of stay in hospital before recurrence) was significantly longer in recurrent-positive group than that in control group. COVID-19 IgM/IgG antibody levels were significantly lower in recurrent-positive group than those in control group, which might explain why the virus RNA RT-PCR was positive after the initial clinical cure(with three times of virus RNA RT-PCR negative). The virus might not be fully eliminated because of the lower IgG level and their later replicating might result in recurrent-positive virus RNA RT-PCR. In December 2019, an outbreak of a novel type of pneumonia caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) occurred in Wuhan, China [1] . The disease caused by this virus, which is known as coronavirus disease 2019 , is highly infectious and lethal. The COVID-19 epidemic was declared a "public health emergency of international concern" by the World Health Organization with a sampling interval of at least 24 h [5] . Patients who meet these criteria are isolated and kept under observation in the community for a further 14 days after discharge. Another RT-PCR test is conducted towards the end of the observation period, and if it is negative, the isolation and observation can be stopped, and the patient is finally allowed to go home. It has been found that during the post-discharge isolation and observation period, a few patients again show positive results on RT-PCR tests. We call these patients "recurrent-positive patients," and they must return to their designated hospital for further treatment. The management of recurrent-positive COVID-19 patients has become a research hot spot, and several questions related to this patient population need to be urgently answered. For instance, the proportion of recurrent-positive patients, the cause of recurrent positivity, the clinical characteristics and optimal management of recurrentpositive patients, and whether these patients are infectious all need to be determined. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. . https://doi.org/10.1101/2020.07.02.20144873 doi: medRxiv preprint Since March 11, 2020, 15 recurrent-positive patients have been admitted to our ward. In this study, we analyzed the clinical data and laboratory findings of these patients as compared with a control group. We aim to describe the clinical characteristics of recurrent-positive COVID-19 patients, and hope that our findings will help guide their evaluation and treatment. The study protocol was approved by the ethics committee of Optics Valley Branch of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, and oral consent was obtained from all enrolled patients. Tongji Hospital is one of the largest teaching hospitals located at the center of the COVID-19 epidemic in Wuhan City, Hubei Province. At the government's behest, Tongji Hospital is responsible for the management of COVID-19 patients. Our study team is from Xiamen, Fujian Province, and is providing healthcare services at Tongji Hospital during the COVID-19 epidemic. The study protocol was also approved by the ethics committee of Xiamen Zhongshan Hospital (No xmzsyyky 2020-098). All COVID-19 patients were diagnosed according to the medium-term guidelines issued by the WHO [6] . Based on published guidelines [7] , the diagnostic criteria for COVID-19 are as follows: (1) a positive real-time RT-PCR test for COVID-19, (2) high homology with a known COVID-19 sequence on viral gene sequencing, and (3) a positive IgM antibody assay for COVID-19 and an IgG level four times the initial value. Moderate disease is defined as fever, respiratory symptoms, and imaging analysis indicative of pneumonia. All the recurrent-positive patients enrolled in this study met the four aforementioned discharge criteria [5] . Recurrent-positive COVID-19 was defined as positive results on RT-PCR testing of a nasopharyngeal swab collected during the post-discharge isolation and observation period. We retrospectively reviewed the data of 15 patients with recurrent-positive COVID-19 as well as 107 control patients with (non-recurrent) COVID-19 who were treated in Tongji Hospita between February 10 and March 31, 2020. All clinical data of the patients were collected, including general data, hospitalization time, time required for the first, second, and third conversions of the RT-PCR results, symptoms, All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. The COVID-19 RT-PCR detection kit (S1002) and COVID-19 nucleic acid detection kit were purchased from Beijing Youkang Hengye Biotechnology Co. Ltd. After admission, the patients' oral and nasopharyngeal swabs were collected in the ward by trained, qualified nurses every Monday, Wednesday, and Friday morning. Two swabs were collected together in a virus-preservation tube. The SARS-CoV-2 nucleic acid genome was detected in the laboratory of Tongji Hospital. The open reading frame 1ab (ORF1ab) gene and the core shell protein gene N fragment were detected using realtime fluorescence RT-PCR. Positive detection was determined by reference to the operating standards for the COVID-19 RT-PCR detection method for clinical laboratories [7] [8] [9] . In addition to the two gene parameters, a typical S-type amplification curve with an amplification threshold ≤ 40 was required for a positive RT-PCR test result. If any one of these two parameters was positive, re-sampling and re-examination were performed. If any one of positive result was obtained on re-examination, the sample was determined to be positive for COVID-19. If the ORF1ab or N gene test result was in the gray area (suspicious), re-sampling and re-examination were performed. If the result was still in the gray area after re-examination, but the amplification curve showed obvious peaks, the sample was judged to be positive; otherwise, it was considered negative. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. . https://doi.org/10.1101/2020.07.02.20144873 doi: medRxiv preprint Serum samples were tested using the COVID-19 IgM and IgG antibody detection kits (chemiluminescence method) were purchased from Shenzhen Yahuilong Biotechnology Co. Ltd. and iflash3000 automatic chemiluminescence immunoassay. The quantitative detection of IgM and IgG in serum was carried out using a two-step indirect immunoassay. They have a positive correlation with the relative luminous intensity measured by the chemiluminescence analyzer, and the test results were assessed using the calibration coefficient of the product calibrator. Negative and positive results were defined as serum IgM and IgG concentrations of <10.0 Au/mL and >10.0 Au/mL, respectively. [10, 11] Statistical analysis SPSS v17.0 software was used for statistical analysis. Measurement data were tested for normality. Normally distributed measurement data were expressed as mean ± standard deviation and compared between groups by using the t-test. Non-normally distributed measurement data were expressed as median (interquartile range), and compared between groups by using the Wilcoxon rank sum test. Count data were expressed as percentages, and the χ 2 test was used for between-group comparisons. Taking a = 0.05 as the test standard, we deemed differences with P < 0.05 as statistically significant. As of March 30, 2020, we have treated 143 patients with suspected COVID-19. Among these 143 patients, 135 patients were confirmed to have COVID-19, including 15 patients with severe/critical illness, and 120 patients with moderate disease. Among the 135 COVID-19 patients, 2 patients died; both of these patients had severe disease at the time of admission, and died within 12 h after admission. Among the 120 patients with non-severe COVID-19, 15 patients had recurrent-positive results. One of these patients was discharged from our hospital, while the other patients were discharged from other department and transferred to our department from the isolated area. Since March 11, 2020, all 15 recurrent-positive patients were successively re-admitted to our hospital. All of these patients had non-severe disease before discharge as well as after the recurrent-positive results. The 15 patients include 8 women and 7 men. As of March 30, 2020, a total of 121 COVID-19 patients have been cured in our department, All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. . https://doi.org/10.1101/2020.07.02.20144873 doi: medRxiv preprint including 14 recurrent-positive patients from other hospital. Among these 107 patients, 2 patients had recurrent-positive disease, yielding an incidence rate of 1.87%. One of these patients has been resident in our ward, while the other was isolated in the community (i.e., not hospitalized). In addition to the 15 recurrent-positive patients, this study included 107 patients with moderate, non-recurrent COVID-19 as the control group. There were 48 women and 59 men in the control group; thus, the sex ratio did not significantly differ between (Table 1) . Lymphocyte count, hemoglobin, albumin, and glomerular-filtration rate (GFR) were all significantly higher in the recurrent-positive group than in the control group (P < 0.05). Inflammatory indexes (neutrophil percentage and C-reactive protein level) were significantly lower in the recurrent-positive group than in the control group (P < All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. . https://doi.org/10.1101/2020.07.02.20144873 doi: medRxiv preprint 0.05). Thus, the results of clinical evaluation were better in the recurrent-positive group than in the control group. In addition, the levels of COVID-19 IgG and IgM antibodies were significantly lower (P < 0.0001, P = 0.015, respectively) in the recurrent-positive group than in the control group (Table 2) . The levels of COVID-19 IgG and IgM were significantly lower in the recurrentpositive group than in the control group, with the difference being especially obvious in the case of IgG. For the 14 recurrent-positive patients who were transferred from other hospitals after being discharged, no COVID-19 IgG and IgM data were available. In the one patient who was re-admitted to our hospital, the level of COVID-19 IgM did not increase after the nucleic acid result had turned negative, but rather remained low. The IgG level was also low and continued to decrease, which may be related to the recurrent-positive status (Table 3 ). (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. . https://doi.org/10.1101/2020.07.02.20144873 doi: medRxiv preprint the recurrent-positive group, the average time required for the second conversion of the RT-PCR results (from negative to positive) was 10.20 ± 1.18 days. (7) In the recurrentpositive group, the time required for the third conversion of RT-PCR results (from positive to negative; 3.33 ± 0.33 days) was significantly shorter than that required for the first conversion (13.00 ± 1.73 days). (8) The duration of the initial hospitalization in the recurrent-positive group was significantly longer than the duration of hospitalization in the control group. (9) Each patient in the recurrent-positive group had 2 to 3 negative RT-PCR results prior to discharge. (10) No hormone therapy was used during the hospitalization in the recurrent-positive group. The laboratory diagnosis of COVID-19 relies on the detection of the virus on RT-PCR and the detection of anti-viral IgM/IgG antibodies. Because the RT-PCR test has a false-negative rate of 30%-50% [12] , the latest version of China's COVID-19 diagnosis and treatment guidelines recommend that a positive IgM antibody assay and an IgG level of four times the initial value can be used to diagnose COVID-19 [5] . This method can be used as a supplement to RT-PCR. An absence of or a decrease in COVID-19 IgM antibody and an increase in COVID-19 IgG antibody indicate that immunity to COVID-19 has been developed and that gradual recovery may successfully occur [13] [14] [15] . Since February 28, 2020, IgG and IgM antibodies against COVID-19 have been used as diagnostic biomarkers at Tongji Hospital. Our study found that the levels of these antibodies were significantly lower in the recurrent-positive group than in the (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. . https://doi.org/10.1101/2020.07.02.20144873 doi: medRxiv preprint issue. In conclusion, our study shows that it is important to monitor the infectious status of the recurrent-positive COVID-19 patients after their initial discharge from the hospital as well as after the treatment of the recurrent illness. To reduce the rate of recurrent-positive disease, we recommend the following measures: (1) for patients with a long course of treatment, severe symptoms, repeated treatment process, or hormone treatment, three or more consecutive, negative RT-PCR results should be used as the discharge standard. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted July 4, 2020. RT-PCR, real-time reverse transcription-polymerase chain reaction assay (of nasopharyngeal swabs) All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. 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No reuse allowed without permission.(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint this version posted July 4, 2020. . https://doi.org/10.1101/2020.07.02.20144873 doi: medRxiv preprint All rights reserved. No reuse allowed without permission.(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint this version posted July 4, 2020. . https://doi.org/10.1101/2020.07.02.20144873 doi: medRxiv preprint