ABSTRACT
Background: The possibility of recurrence in COVID-19 is very rare and hence mostly underdiagnosed. In the face of pandemic, this can lead to circulation of the virus like a hidden iceberg. Better understanding about this topic can improve our knowledge of the COVID-19 pathogenesis and ways to control the transmission. Case presentation: A 41 year old male with no known comorbidities was admitted five times during a period of 7 months each time after being detected RTPCR positive for SARS-CoV-2 and more symptomatic than previously. He had no contact with other COVID-19 patients and was asymptomatic in between admissions. Despite this, he did not develop antibodies against SARS- CoV-2. Later on, he was diagnosed with thymoma on biopsy of the anterior mediastinal mass. Patient’s condition deteriorated on last hospitalization and he died, despite the treatment. Here we present an interesting report on multiple times recurrent COVID-19 infection, probably a case of reactivation and different plausible explanations on the role of thymoma. Conclusion: Acknowledging the potential of SARS-CoV-2 to cause recurrence is very important during the pandemic as a part of the long term transmission mitigation. The case report shows that previous infection does not guarantee complete immunity from COVID-19, especially in immuno-compromised patients. Hence, despite the status of prior infection, vulnerable individuals who recovered from COVID-19 should be under surveillance.