Prolonged SARS‐Cov‐2 shedding with rapid IgG antibody decay in a COVID‐19 patient: A case report

Abstract Background The coronavirus disease 2019 (COVID‐19) epidemic is still spreading rapidly around the world. Recent cases with prolonged severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) RNA detection have been successively reported, and the phenomenon of false‐negative real‐time polymerase chain reaction (RT‐PCR) results of SARS‐CoV‐2 RNA or “repositive” was also described in COVID‐19 patients. Methods We report a 69‐year‐old female patient with hypertension, suspected lung tumor, and previous history of total hysterectomy for hysteromyoma who presented with moderate COVID‐19 symptoms and was positive for SARS‐CoV‐2 RNA by RT‐PCR when she traveled from the USA to China. Results The patient required second and third re‐hospitalizations due to “repositive” SARS‐CoV‐2 throat swab test results during post‐charge solitary isolation and observation, and serum SARS‐CoV‐2‐IgG decayed rapidly before disappearing on illness Day 139 when the throat swab was still positive. The virus shedding lasted for at least 146 days (the last positive throat swab test result was on illness Day 146, and the first true‐negative test result was on illness Day 151) since her initial positive test. Conclusion Prolonged SARS‐CoV‐2 RNA viral shedding is prone to occur in an immunocompromised host, wherein changes in the host immune status can lead to repeated positive SARS‐CoV‐2 detection. Moreover, the SARS‐CoV‐2‐IgG may decrease rapidly and disappear before virus removal, indicating there may be certain limitations on the protective effect of the SARS‐CoV‐2 antibody, which deserves clinical attention.

disappearance before virus removal. This study was approved by the Fuzhou Pulmonary Hospital of Fujian Ethics Committee, and the patient provided an informed consent for case publication. CD3 + , CD4 + , and CD8 + T cells, were also noted. Arterial blood gas analysis showed an oxygen partial pressure of 80.6 mm Hg, a carbon dioxide partial pressure of 36.9 mm Hg, and an arterial oxygen saturation of 94.6%. Additionally, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and lactic dehydrogenase (LDH) levels gradually increased during hospitalization. Her human immunodeficiency virus antibody test was negative and procalcitonin (PCT) kept normal. Moreover, chest CT findings showed multiple patchy ground-glass opacities in both lungs, indicating viral pneumonia, and a nodular consolidation shadow (1.0 × 0.7 cm) with lobulated sign and spiculation in the dorsal lobe of the left lower lung (LLL-S 6 ), indicating suspected isolated lung tumor (Figure 2A). An additional bedside echocardiography showed aortic sclerosis, aortic valve thickening, normal left ventricular systolic function, and tricuspid regurgitation with mildly elevated pulmonary arterial pressure. Color Doppler ultrasonography of the whole abdomen revealed double renal cyst without other abnormalities; however, color Doppler ultrasonography of the neck suggested the possibility of nodular goiter without lymph node enlargement.

| C A S E INTRODUC TI ON
In this case, the patient was diagnosed with confirmed moderate COVID-19 following diagnostic criteria, 1 with a suspected early lung tumor and hypoxemia. She received antivirals with abidor and recombinant human interferon α-2b spray, as well as other therapeutic drugs, including traditional Chinese medicine, ulinastatin, thymalfasin, human granulocyte colony stimulating factor, and amlodipine, among others, with administered oxygen inhalation via nasal cannula at 2L/minute. After two days of treatment, the patient developed cough and expectoration, although her fatigue disappeared and ap- On illness Day 51 (the 14th day of the isolation observation after discharge), the patient's throat swab was found to be RP for SARS-CoV-2 RNA, although she had no symptoms of discomfort. She was then transferred to our hospital once more for solitary isolation on that same day. The patient's anti-SARS-CoV-2 IgG retest was positive, but her other laboratory results were normal. Chest CT this time showed continuous absorption of residual infection lesions in both lungs, and the suspected cancerous nodule in the LLL-S 6 was found to be slightly larger than before (1.2 × 0.9 cm). The patient was then given antiviral drug with recombinant human interferon α-2b  *Reference of IL-6 is 0-7 pg/mL; reference of CRP is <10 mg/L; reference of ESR is 0-20 mm/h; reference of WBC is 3.5-9.5×10 9 /L; reference of NEU is 1.8-6.3×10 9 /L; reference of PLT is 125-350×10 9 /L; reference of LYM is 1.1-3.2×10 9 /L; reference of SaO 2 is ≥95%; reference of LDH is 115-220 U/L; reference of CK is 24-190 U/L; reference of CK-MB is <3.61 ng/ml; reference of MYO is 28-72 ng/ml.  (Table 2). Elevated CK, CK-MB, and LDH levels with reduced T-lymphocyte subgroups were noted once again (Tables 1 and 2 and   Figure 1 and Table 2).  This case suggests prolonged virus shedding is prone to occur in an immunocompromised host [5][6][7]11 since changes in the host immune status can lead to repeated positive SARS-CoV-2 detections. A recent case report has confirmed that SARS-CoV-2 can persistently survive with repeat replication for more than five months after initial infection, 6 suggesting that some cases with prolonged virus shedding could be associated with prolonged infectivity. Therefore, for F I G U R E 2 Dynamics of Chest CT findings after illness onset. (A) On illness day 2, chest CT findings showed multiple patchy ground-glass opacities in both lungs, indicating viral pneumonia, and a nodular consolidation shadow (1.0 × 0.7 cm) with lobulated sign and spiculation in the dorsal lobe of the left lower lung (LLL-S 6 ), indicating suspected isolated lung tumor (arrow).

Day of illness
(B) On illness day 10, repeated chest CT showed progress of partial lesions with absorption in both lungs, and the suspected cancerous nodule in the LLL-S 6 was similar to previous findings. (C) On illness day 32, repeated chest CT showed significant absorption of infected lesions in both lungs, and the initial solid nodule in the LLL-S 6 remained similar to previous findings such patients, it is necessary to increase the frequency of SARS-CoV-2 nucleic acid testing and enhance post-discharge isolation management and health monitoring. 1 Notably, the IgG antibody titer in this case decayed rapidly at the early course of disease onset, and the antibody completely disappeared in less than five months before virus removal, indicating that there may be certain limitations on the protective effect of anti-SARS-CoV-2 antibodies, especially in immunocompromised hosts.

ACK N OWLED G M ENTS
We would like to thank the patient for her willingness to participate in this study, as well as the nurses and clinical staff who provided care for the patient in Fuzhou Pulmonary Hospital of Fujian.

CO N FLI C T O F I NTE R E S T
The authors declare that there is no conflict of interest.

AUTH O R CO NTR I B UTI O N S
JH conceived the study, drafted the study, and reviewed all drafts of the study. CL managed the data generation, data analysis, and drafted the study. XW helped to carry out clinical data collection.
MH helped to carry out laboratorial data collection. JH and CL contributed equally as senior authors. All authors read and approved the final study.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data used to support the findings of this study are available from the corresponding author upon request.