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A Possible COVID-19 Reinfection Case in a Healthcare Professional

Erdinc Yavuz, Ese Basbulut

Euras J Fam Med 2021;10(1):36-40. doi:10.33880/ejfm.2021100107


Case Report


In these days when the effect of the COVID-19 pandemic is felt with all its severity, the findings of re-infection in people who have had COVID-19 disease have led to some questions about the natural immunity against this disease. Here, we report a possible COVID-19 reinfection. The second episode confirmed by RT-PCR with a more severe clinical picture one month after an incidentally detected first episode with mild symptoms of a doctor working as a microbiologist at a training research hospital. While a 47-year-old female doctor was working in a tertiary hospital serving as a reference hospital for the diagnosis and treatment of COVID-19 patients, symptoms of sore throat, cough and runny nose appeared on October 25. The patient, with a history of chronic tendinitis, COPD, asthma and allergic rhinitis, attributed these symptoms to her previous clinical diagnosis and did not consider consulting a doctor or testing for COVID-19 due to the mild course of symptoms. SARS-CoV-2 Ig G antibodies were found to be positive in a screening study conducted on November 11 in the patient whose complaints resolved within a few days. RT-PCR performed thereafter was reported as negative. The RT-PCR test performed on December 2 of the patient who complained of fever and severe weakness, immediately after her colleague had COVID-19, was interpreted as positive. No signs of viral pneumonia were found in the thoracic CT when the cough complaint of the patient who received COVID-19 treatment did not improve. The patient's complaints regressed with the addition of phenocodine to her treatment, and the RT-PCR test on December 12 was reported as negative. Further analysis of the frequency and possible causes of COVID-19 reinfections will be needed in the near future.

Keywords: SARS-CoV-2, COVID-19, reinfection, coronavirus


The COVID-19 pandemic has now reached colossal magnitudes. As of early January 2021, more than 82 million cases and almost 1.8 million deaths were reported globally (1). A worrisome issue concerning patients who recovered from COVID-19 has been the possibility of reinfection (2). Although it was shown that neutralizing antibodies against Corona virus were rapidly produced after the infection, it was also reported that the antibody titers declined over time as early as in one or two months (3,4). The clinical importance of this decline is still unknown; however, a few possible reinfection cases were reported (5-9). These reports were criticized about whether these cases represented a real reinfection or simply a relapse or viral persistence (9-11). Recently, five studies using whole genome sequencing confirmed that the second episodes were due to a phylogenetically distinct SARS-coronavirus-2 strains suggesting that these were real reinfections (2,12-15).

We report here a 47-years-old female doctor working in a microbiology laboratory of a tertiary healthcare facility who presented with a second episode of clinical manifestations of COVID-19 one month later after recovery from her initial infection and tested negative for reverse transcriptase polymerase chain reaction (RT-PCR) from nasopharyngeal swabs suggesting a possible reinfection.


The patient was a 47-years-old female doctor working as a specialist at the microbiology laboratory of a research and training hospital. She had clinical history of chronic tendinitis, chronic obstructive pulmonary disease (COPD), asthma and allergic rhinitis but she was not taking any medication regularly. A written consent was obtained from the patient.

First episode

On October 25, her complaints of sore throat, cough and runny nose started. The patient, who attributed his cough to COPD and nasal discharge to allergic rhinitis, started to use N-acetyl cysteine. She also began to use echinacea, reishi, propolis, zinc, vitamin D, vitamin B and omega 3 for sore throat. She did not suspect COVID-19 due to lack of fever and fatigue and her complaints resolved in a few days. 

The patient had some laboratory testing on November 3 after a visit to her dietitian. Her hemogram parameters were in normal range. Of her biochemical parameters the following were found abnormal: aspartate aminotransferase (AST): 39 U/L (reference range 5-35 U/L), alanine aminotransferase (ALT): 69 U/L (reference range 5-35 U/L), C-reactive protein (CRP): 23 mg/L (reference range 0-5 mg/L), fasting blood glucose: 112 mg/dl (reference range 74-106 mg/dl), creatine kinase: 240 U/L (reference range 10-145 U/L), HDL cholesterol: 43 mg/dl (reference range 50-65 mg/dl). The patient, who attributed her elevated liver enzymes to supplements she used such as echinacea and reishi and elevated CRP to her chronic shoulder tendinitis, did not consult a doctor.

On November 11, as a participant to a clinical screening study she was tested for SARS-CoV-2 Ig G antibodies and found to be seropositive (result: 3.1, cutoff: 1.4, EUROIMMUN, Germany). More laboratory tests were performed and it was found that hemogram parameters and liver enzymes were in normal limits. CRP was 2.3 mg/L (reference range 0-5 mg/L), D-Dimer was 620 ng/ml (reference range

Second Episode

The patient’s colleague whom she worked in the same room was tested positive for SARS CoV-2 RT-PCR on November 19. She had a fever of 37.5 °C on November 26, and severe fatigue. On November 28 she had a cough and a runny nose. The patient, who thought that her antibodies would protect her from a SARS CoV-2 infection, did not seek medical assistance. However, on December 2 her coughs increased in severity and she had trouble at breathing and she consulted a doctor. Her SARS CoV-2 RT-PCR test was found to be positive in the oropharyngeal and nasal swab samples. In blood tests, hemogram parameters were within normal limits, CRP was within normal limits (3.34 mg/L, reference range 0-5) and liver enzymes were elevated; AST: 51 U/L ( reference range 5-35), ALT: 92 U/L (reference range 5-35). Her thorax computed tomography (CT) was reported as negative for viral pneumonia. 

The patient was treated with favipiravir, hydroxychloroquine, dipiridamol, LMWH, vitamin D, zinc and famotidine. The patient was followed-up at home. Her cough worsened. She reported coughing episodes especially when she was speaking. Her oxygen saturations ranged between 97%-99%. Since there was no reduction in her complaints on the 10th day of her RT-PCR test, the patient sought medical assistance again on December 12. A control thorax CT was ordered, and it was reported that there were subpleural retractions in the apex but findings were incompatible with viral pneumonia. Liver enzymes and otherbiochemical parameters, CRP values and hemogram analyze were found to be normal. A beclometasone dipropionate and formoterol fumarate dihydrate inhaler was prescribed started after a consultation with the pulmonologist. Two days later with no improvement in coughs phenocodine treatment was added. Her complaints decreased in 5-6 days. 

RT-PCR test for SARS-CoV-2 performed at December 12 was reported as negative. The SARS CoV-2 Ig G antibody test performed on December 16 (14th day of RT-PCR positivity) was negative for the Anti-SARS-CoV-2 ELISA Ig G test (EUROIMMUN, Germany). However, the test was repeated on December 23 (21st day of RT-PCR positivity) and seroconversion was seen.


Here we report a medical professional, a female doctor who seems to have two distinct episodes of SARS-CoV-2 infection more than a month apart. Recently, SARS-CoV-2 reinfection has been a topic of debate. Suspected reinfection cases were reported among medical professionals who were at an increased risk due to repeated exposure to Covid-19 patients (16). However, it was criticized that these cases could be prolonged viral shedding, relapse or true reinfection (10,11). Tomassini et al.(5) tried to set the criteria for the definition of SARS-CoV-2 reinfection as the patient should have an initial COVID-19 confirmed with a positive RT-PCR, a clinical recovery confirmed with a negative RT-PCR test and at least 28 days after the previous negative result another positive RT-PCR test. Our case did not meet these criteria due to lack of a positive RT-PCR test result at the first episode. However, there is evidence of Ig G antibodies to SARS-CoV-2 suggesting a previous infection. The test we used was reported to have 97.7% sensitivity and 99.6% specificity (17). 

Batisse et al. (18) reported 11 possible cases of COVID-19 reinfection.  Four of these cases were young healthcare workers without significant comorbidity at both episodes. However, the interval between episodes was very short and recovery was not confirmed by a negative RT-PCR test. They concluded that these healthcare workers with mild symptoms at both episodes could suggest a reinfection due to waning immune response from the first non-invasive infection. Similarly, the first episode in our case was with so mild symptoms that there was no reach for medical assistance or SARS CoV-2 testing. The incidental finding of Ig G antibodies suggested a previous infection. Interestingly, existence of these antibodies from the first infection did not prevent a second infection confirmed by a subsequent RT-PCR test.

De Brito et al. (16) recently reported two doctors working in a reference clinic for COVID-19 with two clinical episodes of COVID-19. The authors concluded that the only way to distinguish these two cases, whether these were reactivations of previous infections or true reinfections was to demonstrate that they were molecularly distinct viruses. Five studies from Hong Kong, Belgium, South America, USA and France addressing this problem by implementing whole genome sequencing of two isolated viruses at both episodes of suspected reinfections (2,12-15). All studies demonstrated that two distinct episodes were due to two different strains of the virus confirming reinfections. This may have important implications about protection of natural immunity from SARS-CoV-2 and vaccines. Further larger studies are required to determine the frequency of these reinfections and factors causing them.


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How to cite: Yavuz E, Basbulut E. A possible COVID-19 reinfection case in a healthcare professional. Euras J Fam Med 2021;10(1):36-40. doi:10.33880/ejfm.2021100107.

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