COVID-19 reinfection: A multicenter retrospective study in Saudi Arabia

There are limited direct data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) long-term immune responses and reinfection. This study aimed to evaluate the rate, risk factors, and severity of COVID-19 reinfection.

This retrospective cohort study included five hospitals across Saudi Arabia. All subjects who were presented or admitted with positive SARS-CoV-2 real-time polymerase chain reaction (RT-PCR) tests were evaluated between March 2020 and August 2021. Reinfection was defined as a patient who was infected followed by clinical recovery, and later became infected again 90 days post first infection. The infection was confirmed with a positive SARS-CoV-2 (RT-PCR). Four hundred and seventeen recovered cases but with no reinfection were included as a control.

A total of 35,288 RT-PCR-confirmed COVID-19 patients were observed between March 2020 and August 2021. Based on the case definition, (0.37%) 132 patients had COVID-19 reinfection. The mean age in the reinfected cases was 40.95 ± 19.48 (range 1-87 years); Females were 50.76%. Body mass index was 27.65 ± 6.65 kg/m²; diabetes and hypertension were the most common comorbidities. The first infection showed mild symptoms in 91 (68.94%) patients; and when compared to the control group, comorbidities, severity of infection, and laboratory investigations were not statistically different. Hospitalization at the first infection was higher, but not statistically different when compared to the control group (P = 0.093).

COVID-19 reinfection is rare and does not carry a higher risk of severe disease. Further studies are required, especially with the continuously newly emerging variants, with the unpredictable risk of reinfection.