The incidence of probable reinfection with SARS-CoV-2 and the frequency of post-COVID syndrome among convalescents from COVID-19 at the Frantz Fanon hospital, Bejaia University Hospital, Algeria

Summary The rate of reinfection with SARS-CoV-2 is low while post-COVID syndrome is increasingly present. The aim of this study is to estimate the incidence of probable SARS-CoV-2 reinfection and post-COVID complications in patients previously infected with the virus. Methods We included patients in the convalescence phase of a SARS-CoV-2 infection confirmed by RT-PCR into our study. Follow-up started from the 90th day after clinical recovery from the first episode of COVID-19 and extended over a period of 12 months, from September 20, 2020 to September 30, 2021. A total of 96 convalescents were included in the study. During this follow-up period, we also assessed the frequency as well as the most common symptoms of post-COVID syndrome in previously infected convalescents. Results Of the 96 convalescents included in our study, only four were identified as having been infected twice, thus representing 4.17% of the positive cases diagnosed during the follow-up period. The clinical presentation of these 04 cases was benign. This low incidence of reinfection with SARS-CoV-2 among convalescents indicates a relative reduction in reinfection among previously infected people and that the risk of hospitalizations and death has also been reduced, moreover, the frequency of post COVID syndrome was 57.3%. Among the different symptoms observed, fatigue turned out to be the most common symptom (47.9%). These results highlight the importance of long-term monitoring of COVID-19 convalescents, highlighting aspects of reinfection as well as persistent manifestations of post-COVID syndrome. Conclusion This study found that the risk of reinfection with SARS-CoV-2 remained considerably lower while post-COVID syndrome is increasingly common, clinical and virological analysis indicates a decrease in the rate of reinfection in recovered patients as well as the persistence of post-COVID symptoms in most convalescents. These data show that convalescent patients maintain functional antibody responses for at least 12 months after infection, suggesting a strong and durable response after symptomatic illness that may provide prolonged protection that may reduce the risk of reinfection.