Table 1.
Recurrent cases reported in literature.
| Reference | Patients (n°) | Days from recurrence of COVID-19 | Test for recurrence of SARS-CoV-2 positive | Kit type (sensitivity and specificity) | Clinical symptoms | Recurrence with neurological signs |
|---|---|---|---|---|---|---|
| Abdullah et al., 2020 | 27/138 pt | 11 days | Nasopharyngeal and oropharynx swabs for RT-PCR | No specified | 6 pts mild symptoms, 21 pts no clinical symptoms | |
| Alonso et al., 2020 | 26-year-old man | 1 month later | Nasopharyngeal and throat swabs for RT-PCR | Allplex™2019-nCoV Assay [sensitivity (95% CI) 98.2 (90.3–100.0) % specificity (95% CI) 100.0 (94.9–100.0)] | A more vigorous COVID-19 recurrence | |
| An et al., 2020 | 38/242 pts | 5–7 days | Digestive (anal swab) and respiratory RT-PCR tests for the S gene and for ORF genes. Ct ≤ 37.0 Next-generation sequencing of samples Specific total antibody IgG, IgA, and IgM |
QIAamp RNA Viral Kit (hyper-sensitive kit compares to commercial kit) | Fewer respiratory and digestive tract symptoms | |
| Bentivegna et al., 2020 | 1 pt | 23 days | Nasopharyngeal swab RT-PCR IgM seroconversion | No specified | Asymptomatic | |
| Bongiovanni et al., 2020 | 125/1,146 pts | Mean 19.9 (3–43) days | Nasopharyngeal swabs RT-PCR | No specified | Asymptomatic (96, 76.8%), general sign (25, 20.0%), and respiratory failure (4, 3.2%) | |
| Cao et al., 2020 | 8/108 pts | 6–28 days | Deep nasal cavity swab samples or throat swab samples RT-PCR | No specified | Asymptomatic | |
| Cento et al., 2020 | 264/2,521 pts after one negative results by RT-PCR assay | 20–30 days | Nasopharyngeal swabs RT-PCR Cts-values ≥ 24 |
No specified | No clinical symptoms | |
| Chae et al., 2020 | 1 pt | 6 days | Naso- and oropharyngeal swab RT-PCR | No specified | Ground-glass opacities in the right upper lobe | |
| Chen D. et al., 2020 | 46-year-old woman | 2 days after 2 negative tests | Oropharyngeal swab test RT-PCR | No specified | Respiratory symptoms had already improved | |
| Chen J. et al., 2020 | 81/1,067 pts | 7–10 days | Throat-swabs RT-PCR tests | No specified | 84.0% (68) mild, 14.8% (12) severe, and 1.2% (1) critical of the cases with pulmonary, liver, kidney, and myocardial damage | |
| Chen M. et al., 2020 | 6/11 pts | 6–27 days | Oropharyngeal swab RT-PCR | No specified | Mild to moderate | |
| Chen S. L. et al., 2020 | 189/1,282 pts | 28 days | Nasopharyngeal and anal swabs specimens RT-PCR ORF1ab and N genes |
Catalog no. DA0931; DaAn Gene, Guangzhou, China (unavailable) | Cough (15.87%), Diarrhea (0.53%), Dyspnea (3.70%) | Fatigue (1.06%), Myalgia (1.06%), |
| Chen Y. et al., 2020 | 4 pts | 3 days after discharge | Nasopharyngeal, oropharyngeal, and anal swabs RT-PCR test | Kits from different manufacturers. No specified |
No clinical symptoms | |
| Crouwel et al., 2020 | 28-year-old female | 50 days | Nasopharyngeal swabs for the RT-PCR test | No specified | Diarrhea, nausea, coughing, sneezing | Headache, myalgia, anosmia, and dysgeusia |
| Deng et al., 2020 | 61 pts | Ranged from 3 to 35 days (median, 10 days) | Nasal and pharyngeal swab specimens, stool and sputum specimens RT-PCR | No specified | Mild 38 (62.3%) General 20 (32.8%) Severe 3 (4.9%) |
Headache 5 pts (8.2%) |
| Dou C. et al., 2020 | 1 pt | 15 days | Oropharyngeal swab RT-PCR | No specified | Asymptomatic | |
| Dou P. et al., 2020 | 2 pts | 17 days | Throat and anus swab RT-PCR | No specified | Asymptomatic | |
| Du et al., 2020 | 3/126 pts | 10–18 days | Nasopharynx and oropharynx swab RT-PCR targeting the ORF1ab gene and N gene Ct ≤ 37 |
Bio-Germ, Shanghai, China (sensitivity 96.15% specificity 100.0%) | Asymptomatic | |
| Duggan et al., 2021 | 1 pt | 10 days | Nasopharyngeal swabs for the RT-PCR test | No specified | Critical | |
| Fu et al., 2020 | 3 | 1–5 days | Nasopharyngeal swab RT-PCR; IgM and IgG antibodies | No specified | Asymptomatic | |
| Gao et al., 2020 | 70-year-old male patient | 15 days | Nasopharyngeal, blood, and rectal swab RT-PCR ORF1ab and N genes |
No specified | No symptoms | |
| Geling et al., 2020 | 24-year-old male | 7 days after discharge | Sputum specimen RT-PCR for ORF1ab and the N gene | No specified | No clinical symptoms | |
| Gidari et al., 2021 | 9 pts | 14–50 days | Respiratory samples RT-PCR for E gene, gene N Ct ≤ 40 |
Allplex™ 2019-nCoV Assay [sensitivity (95% CI) 98.2 (90.3–100.0) % specificity (95% CI) 100.0 (94.9–100.0)] | No clinical symptoms, retrosternal sense of weight | Headache, arthro-myalgias, asthenia, and insomnia |
| Gousseff et al., 2020 | 11 pts | 21–49 days after a symptom (quarantine) | Naso-pharyngeal swabs RT-PCR | No specified | Median duration of symptoms was 18 days for the first episode and 10 days for the second one | |
| Guo et al., 2020 | 27-year-old man | 3 days after discharge | Throat swab specimens A fluorescent immunochromatography detection kit specific to the IgM and IgG antibodies against SARS-CoV-2 |
Zhongshan Chuangyi Biochemical Engineering Co. (unavailable) | No clinical symptoms | |
| Habibzadeh et al., 2020 | 9/13 pts | 15–48 days | Nasopharyngeal swabs RT-PCR tested the E and RdRP genes | Invitrogen ChargeSwitch Total RNA Cell Kit, Invitrogen Co. (unavailable) | No clinical symptoms | |
| Hao et al., 2020 | 24/104 pts | Quarantine | Respiratory specimens (nasal/throat swab or sputum) RT-PCR tests of | No specified | No clinical symptoms | |
| He et al., 2020 | 1 pt | 8 days | Throat swab samples RT-PCR | No specified | Dry cough, arthralgia | Headache |
| Hu R. et al., 2020 | 11/69 pts | 14 days (range, 9–17 days). | Nasopharyngeal swabs RT-PCR | No specified | No clinical symptoms | |
| Huang et al., 2020 | 69/414 pts | Median 19 days, range 6–52 days | Nasopharyngeal and anal swabs qRT-PCR ORF 1ab and N genes. Ct ≤ 37 Antibody Chemiluminescent microparticle immunoassay kit IgM and IgG in plasma. |
QIAamp RNAViralKit (hyper-sensitive kit compares to commercial kit code. GZ-D2RM25, Shanghai GeneoD) | Respiratory symptoms including cough and increased sputum | |
| Jiang et al., 2020 | 6/35 pts | 9–10 days | Throat swabs or sputum samples for RT-PCR | No specified | 1 expectoration, nausea, 1 cough, 4 asymptomatic | 1 fatigue, sore muscles |
| Kang, 2020; KCDA, 2020 | 292/8,922 pts | 1–37 days | Nasopharyngeal swabs RT-PCR | No specified | Asymptomatic to minor symptoms | |
| Landi et al., 2020 | 6/29 pts | 13–24 days | Nasopharyngeal swabs RT-PCR | No specified | Asymptomatic or mild | |
| Lan et al., 2020 | 4 pts | 5–13 days | Throat swabs RT-PCR | BioGerm (sensitivity 96.15% specificity 100.0%) | Asymptomatic | |
| Li C. et al., 2020 | 15/85 pts | 9–30 days | Nasopharyngeal swabs RT-PCR | No specified | Two patients (13.3%) had cough, one (6.6%) had dyspnea | |
| Li J. et al., 2020 | 50-year-old man | Days 34 and 38 during quarantine | Nasopharyngeal swabs RT-PCR | No specified | No clinical symptoms | |
| Li Y. et al., 2020 | 6/13 pts | 6–14 days | Respiratory swabs qRT-PCR for RdRP, E, and N gene | Liferiver detection kit (sensitivity 90% specificity 100.0%) | Asymptomatic | |
| Ling et al., 2020 | 11/66 | 6–11 days | Oropharyngeal swab, stool, urine, and serum RT-PCR | Biosystems 251658240 7500 Real-Time PCR Systems (sensitivity 85.3% specificity 100.0%) | Asymptomatic | |
| Liu B. et al., 2020 | 8/47 pts | From 8 to 39 days after viral shedding | Anal and throat swab samples RT-PCR Antibodies against the spike glycoprotein (S); the receptor-binding domain (RBD); conserved heptad repeats (HR1–HR2) in the S2 domain; and the N, membrane (M), and E proteins. |
Kit from a different manufacturer (no specified) | No clinical symptoms | |
| Liu et al., 2020a | 9/51 pts | 7–14 days | Oropharyngeal-swab RT-PCR | BioGerm (sensitivity 96.15% specificity 100.0%) | Asymptomatic (6, 66.7%), mild (3, 33.3%) | |
| Liu F. et al., 2020 | 35-years old man | Positive during quarantine and returned positive after second quarantine (three hospitalizations) | Nasopharyngeal swabs RT-PCR E gene, RdRP gene, and N gene Ct ≤ 43 |
Liferiver detection kit (sensitivity 90% specificity 100.0%) | Mild clinical symptoms deteriorations | |
| Liu J. et al., 2020 | 15/62 pts | 14 days | Respiratory tract samples RT-PCR spike receptor-binding domain (S-RBD) and N spike protein as antigens. ORF1ab, NP genes fragments, Ct ≤ 38 COVID-19 IgG or IgM antibody |
BioGerm (sensitivity 96.15% specificity 100.0%) | Mild cases 5 (33.3%) Common cases 9 (60.0%) Severe cases 1 (6.6%) | |
| Liu T. et al., 2020 | 11/150 pts | 38 days, range 35–44 days | Throat swabs RT-PCR and serum IgM/IgG rapid test | BioGerm (sensitivity 96.15% specificity 100.0%) | No clinical symptoms reported | |
| Loconsole et al., 2020 | 48-year-old man | 30 days after 2 negative tests | Nasopharyngeal swab RT-PCR 2 targeting E-gene, RdRP-gene and N-gene | No specified | New symptoms, i.e., dyspnea and chest pain. | |
| Lu et al., 2020 | 87/619 pts | 2–19 days | Nasopharyngeal swabs, throat swabs and anal swabs RT-PCR and multiplex PCR sequencing including targeting the ORF1ab, N, RdRp, E. Microneutralization antibody assays for SARS-CoV-2 |
Three kits DAAN GENE (unavailable) BioGerm (sensitivity 96.15% specificity 100.0%) Liferiver detection kit (sensitivity 90% specificity 100.0%) |
Asymptomatic (77, 88.5%), mild (10, 11.5%) | |
| Luciani et al., 2020 | 69-year-old man | 41 days | Nose-pharyngeal swab RT-PCR | No specified | Fever, dyspnea, anemia | |
| Mardani et al., 2020 | 64-year-old woman | 21 days | Nasopharyngeal swabs RT-PCR | QiaSymphony; Qiagen, Hilden, Germany (hyper-sensitive kit compares to commercial kit) | Consciousness suddenly decreased, associated with respiratory distress | Meningoencephalitis |
| Mei et al., 2020 | 23/651 pts | 4–38 days | Nasopharyngeal and oropharyngeal swabs qRT-PCR immunochromatographic strip assay for anti-SARS-CoV-2 viral immunoglobulins | No specified | 15 (65%) were asymptomatic, 8 presented mild to moderate symptoms | |
| Peng et al., 2020) | 7 pts | During quarantine | Throat or anal swab on qRT-PCR | No specified | Milder symptoms | |
| Qiao et al., 2020 | 1/15 pts | 16 days | Throat swabs RT-PCR | No specified | Mild (itchy throat) | |
| Ravioli et al., 2020 | 2 pts | 14–21 days | Nasopharyngeal swab RT-PCR | No specified | Moderate (1, 50.0%) and death (1, 50.0%) | |
| Salcin and Fontem, 2020 | 62 year old female | 120 days | Nasopharyngeal swabs RT-PCR | No specified | Acute Respiratory Distress Syndrome | |
| Sen et al., 2020 | 5 pts | 5–43 days | Nasopharyngeal swabs RT-PCR | No specified | 1 pt asymptomatic/ 4 pts acute febrile illness | |
| Sharma et al., 2020 | 57-year-old man | 48 days | Nasopharyngeal swabs RT-PCR RdRp gene and E gene. Ct ≤ 30 Rapid COVID-19 IgM and IgG |
Cephpeid Xpert® Xpress (unavailable) | Fever, and a productive cough | Myalgia, headache |
| Fernandes Valente Takeda et al., 2020 | 6 pts health professionals | ranged from 53 to 70 days (median, 56.5 days) | Naso and/or oropharyngeal swab samples RT-PCR | No specified | Symptomatic second episode | 2 pts anosmia |
| Tian et al., 2020 | 20/147 pts | 17.25 days, ranging 7–47 days after discharge | RT-PCR ORF1ab gene and N gene |
DAAN GENE, Guangzhou, China (unavailable) | No clinical symptoms | |
| To et al., 2020 | 1 pt | 123 days | Respiratory specimens RT-PCR whole genome sequencing | LightMix® E-gene kit (highly sensitive, specificity 100%). | Asymptomatic | |
| Wang H. et al., 2020 | 1 pt | 15 days | Sputum, nasopharyngeal swabs RT-PCR | No specified | Mild | |
| Wang X. et al., 2020 | 8/131 pts | 7–30 days | Nose and throat RT-PCR ORF1b and N |
No specified | 2 pts fever, 6 pts no clinical symptoms | |
| Wong et al., 2020 | 21/106 pts | 13–16 days | Nasopharyngeal swab RT-PCR Orf1ab and N Ct <40 | BGI Genomics [sensitivity 88.2%e (78.1–94.8), specificity 100% (95.8–100)] | 1 a mild cough, 20 asymptomatic | |
| Wu F. et al., 2020 | 1 pt | 6 days | Throat swab RT-PCR | No specified | Mild | |
| Wu J. et al., 2020 | 10/60 pts | In-home 2-week quarantine | Nasopharyngeal and anal swab samples RT-PCR | No specified | 2 occasionally cought, 8 no clinical symptoms | |
| Xiao A. T. et al., 2020 | 15 of 70 patients | 45 days after symptoms onset | Throat swab samples or deep nasal cavity swab samples RT-PCR | Shanghai Huirui Biotechnology Co., Ltd. (unavailable) | No symptoms | |
| Xiao Y. et al., 2020 | 40/116 pts | During quarantine | Nasopharyngeal swab RT-PCR | Shanghai Huirui Biotechnology Co. (unavailable) | No symptoms | |
| Xie et al., 2020 | 22/161 pts | 1–14 days | Throat swabs and anal swabs RT-PCR | No specified | No data | |
| Xing et al., 2020 | 2/62 pts | 6–14 days | Throat swab samples RT-PCR for ORF1ab and N. Ct ≤ 37 |
BioGerm (sensitivity 96.15% specificity 100.0%) | Asymptomatic | |
| Yang et al., 2020 | 93/479 pts | 7-90 days | RT-qPCR Ct ≤ 40 IgM, IgG, and total antibody |
Zhongshan Daan Biotech. (sensitivity and specificity 100%) | 67 (72%) no symptoms, while 26 (28%) mild symptoms, including slight cough (18/93 [19%]) and chest tightness (3/93 [3%]). | |
| Ye et al., 2020 | 5/55 pts | 30 days | Throat swab samples qRT-PCR | No specified | Fever | |
| Yoo et al., 2020 | 1 pt | 14 days | Upper airway (nasopharyngeal swab), lower airway (sputum), urine, stool, saliva, and serum. qRT-PCR RdRP, N genes, and E gene Ct-values <35 |
Allplex™2019-nCoV Assay (Seegene Inc., Seoul, Korea) [sensitivity (95% CI) 98.2 (90.3–100.0) % specificity (95% CI) 100.0 (94.9–100.0)] | Mild | |
| Yuan B. et al., 2020 | 20/182 recovered patients | During a 14-day medical isolation | Blood, nasopharyngeal swabs, and anal swabs RT-PCR Antibody detection Ct-values <37 |
Bio-Germ, Shanghai (sensitivity 96.15% specificity 100.0%) | No clinical symptoms | |
| Yuan J. et al., 2020 | 25/172 discharged patients | 14 days, 5.23 ±4.13 days | Cloacal swab and nasopharyngeal swab samples RT-PCR Ct-value ≤ 40 |
AM1005; Thermo Fisher Scientific [sensitivity 85.3% (74.6–92.8) Specificity 100% (95.8–100)] | No clinical symptoms | |
| Zhang B. et al., 2020 | 7 pts | 7–11 days | Throat or rectal swabs RT-PCR | No specified | Asymptomatic | |
| Zhang J.-F. et al., 2020 | 1pt | 4 days | Throat swab sample RT-PCR | No specified | Asymptomatic | |
| Zhang R. Z. et al., 2020 | 4 pts | 14–21 days | Nasopharyngeal swab RT-PCR | No specified | Asymptomatic | |
| Zhao et al., 2020 | 7/14 pts | 7–17 days | Nasopharyngeal swab samples RT-PCR Ct-value ≤ 40 |
Zhongshan Daan Biotech (sensitivity and specificity 100%) | Asymptomatic | |
| Zheng et al., 2020 | 3/20 pts after hospital discharge | 7 days | Salivary tests RT-PCR and fecal nucleic acid (RNA) test | No specified | No symptoms | |
| Zhou H. et al., 2020 | 40-year-old male | 5 days after | Sputum or nasopharyngeal swab specimens RT-PCR ORF 1a/1b and nuclear gene Ct-values ≤ 40 |
No specified | Higher density of consolidation on chest CT | |
| Zhou X. et al., 2020 | 17/98 pts | 3–8.5 days | Oropharyngeal swab RT-PCR. Total exon sequencing | No specified | 12 fever, 8 cough, 1 diarrhea | 4 fatigue |
| Zhou Y. et al., 2020 | 53/257 pts | During quarantine | Throat swabs RT-PCR | No specified | Two patients developed clinical symptoms: one of the patients developed a cough, while the other patient had diarrhea |
RT-PCR, reverse transcriptase polymerase chain reaction; qRT-PCR, quantitative reverse transcriptase polymerase chain reaction; Ct, cycle threshold; ORF1ab, open reading frame1ab; N, nucleocapsid gene; E, envelope gene; RdRP, RNA-dependent RNA polymerase genes.