COVID Re-Infection or Something Else? A Case Report

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 100 million people so far globally with few cases of reinfection reported [1, 2]. Most people with coronavirus disease 2019 (COVID-19) develop antibodies after resolution of acute infection, however the exact duration of these antibodies and the extent to which it may indicate a protective immunity to SARS-CoV-2 in humans is unknown [2, 3]. We report an unusual case of probable asymptomatic reinfection with SARS-CoV-2 while still having antibodies present.

Case Presentation: A 39-year-old healthy female healthcare professional in New York City had severe myalgia, generalized body weakness, cough, and subjective fever (maximum axillary temperature 99.8F) in March of 2020. The patient was not tested for COVID-19 initially because there was no documentation of fever ≥100F and restriction of testing due to limited availability. Conservative management with analgesics and hydration was done and symptoms subsided after 7 days. One week later (April 2020), multiple family members became sick with COVID-like symptoms and tested positive to SARS-CoV-2 by polymerase chain reaction (PCR). Patient was then screened with SARS-CoV-2 RT-PCR (Roche Cobas 6800) due to close household contact and was positive. Routine COVID-19 antibody testing (Roche Cobas Elecsys) offered to hospital staff on a voluntary basis a month later and again 4 months later (September 2020) during annual employee health screening were both positive. In January 2021, the patient was tested due to mandatory return-to-work screening after out-of-state travel and was found to be positive by both PCR and antibody (Table 1). At that time, patient was completely asymptomatic but was required to quarantine. Six days later, she repeated both tests in an urgent care facility at which time SARSCoV-2 RNA PCR (Roche Cobas) was negative while the IgG antibodies (Abbott Alinity i) remained positive. A respiratory viral panel for SARS-CoV-2 RNA PCR and influenza A and B (Roche Cobas) done three weeks later as part of the prerequisites for clinical rotation in a different hospital was also negative.

Conclusion:The asymptomatic index case had antibodies at the time she re-tested positive to SARS-CoV-2 10 months after first testing positive. This may be a case of re-infection in which the presence of antibodies kept the patient symptom-free. Less likely, she may have been carrying viral particles in her nose for 10 months as there was no documented negative test in the interim. There are no published reports of such prolonged carriage of virus [4]. Furthermore, prolonged detection of viral particles does not translate to infectivity [4, 5]. The repeat positive test could also have been a false positive. Polymerase chain reaction cycle thresholds may prove helpful to clinicians to determine the significance of a positive PCR test.