A Patient with Asymptomatic SARS-CoV-2 Infection Who Presented 86 Days Later with COVID-19 Pneumonia Possibly Due to Reinfection with SARS-CoV-2.

BACKGROUND Coronavirus disease 2019 (COVID-19) has radically changed the world, and promising vaccine trials are currently underway. The immune responses in asymptomatic and symptomatic individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are still under investigation, and data are evolving. While it is known that humoral and cell-mediated immune responses against SARS-CoV-2 are elicited, it is uncertain whether these responses protect against reinfection or that they provide definitive evidence of viral clearance. Very few cases have been reported in the literature regarding reinfection with SARS-CoV-2. CASE REPORT We present a case of a middle-aged man with asymptomatic SARS-CoV-2 infection who later developed mild symptomatic COVID-19 after a period of 3 months. The source of reinfection was likely from the community, which had a soaring burden of infection with the highest number of COVID-19 cases per million in the world at that time. The patient had 2 negative COVID-19 polymerase chain reaction (PCR) tests 2 weeks after the initial infection. During the second infection, a nasopharyngeal reverse-transcription PCR test and tests for the presence of COVID-19 immunoglobulin (Ig)M and IgG antibodies were all positive. CONCLUSIONS Reinfection with SARS-CoV-2 is a strong possibility. This case raises concerns that asymptomatic infections may not provide long-term protective immunity to all patients, which could make them susceptible to reinfection. Possible explanations for reinfection include an interval decrease in protective antibodies titers after SARS-CoV-2 infection that may be more prevalent in patients who had an asymptomatic infection. Other possibilities include viral reactivation after a prolonged carriage of the virus or delayed immune response.