A comparison of COVID-19 and post-COVID-19 syndrome among symptomatic and asymptomatic patients in Bangladesh: A retrospective cohort study.

Background: The differentiation between COVID-19 and post-COVID-19 syndromes is not properly defined as some patients remain asymptomatic for post-COVID-19. It can be characterized by several signs and symptoms. Risk factors related to post-COVID-19 remain unsolved. Here we aimed to differentiate post-COVID-19 patients among symptomatic and asymptomatic groups to check the percentage among them and the risk factors for post-COVID-19 and the association of different symptoms.

Methods: This study was conducted in Chittagong division, Bangladesh at different hospitals. Data were collected from the participants either by in person interview or online (email) or mobile phone calls. Follow up was done after 3 months to check the development of post-COVID-19 syndromes. Relevant data were taken, and symptomatic and asymptomatic patients were divided based on the presence and severity of specific symptoms.

Results: Our results showed that 41.88 % patients develop post-COVID-19 symptoms. Fever and Cough were classified as one of the factors of post-COVID-19, followed by dyspnea, fatigue, cough, rhinitis, sore throat, and muscular discomfort. On the other hand, age, respiratory distress, lethargy, duration of illness and severity were classified as risk factors for post-COVID-19. There was a significant difference between symptomatic and asymptomatic patients as only 16.3 % patients showed post-COVID-19 symptoms. Based on the severity grade, 80.7 % of patients had mild COVID-19. We also found that people with 'B' positive blood group had a higher chance of developing post-COVID-19 syndrome.

Conclusion: It was concluded that age, duration of illness, presence of respiratory distress, blood group, and disease severity are major risk factors for the development of post-COVID-19 syndrome.