Presentation and Outcomes of the Covid- 19 Among the Vaccinated and Nonvaccinated Patients

Background: Previous infection or vaccination boosts up the body’s immune system. It may have a protective effect or an exaggerated immune response. Knowledge about the impact of vaccination or previous infection on the presentation and outcome of the new variant of COVID- 19 is scarce. Objectives: In this study, vaccine effectiveness, reinfection rate and severity prediction among vaccinated and non-vaccinated COVID-19 infected patients were assessed. Methods: This observational study was conducted in the COVID-19 unit of Dhaka Medical College Hospital. Three hundred forty-four patients who presented in the triage and were admitted to DMCH were enrolled as per inclusion criteria and were followed up for three months for outcome variables. Patients were divided into four groups by vaccination and previous infection. Results: Mortality was 18(14.6%), 10(14.3%), 14(22.6%), and 40(44.9%) in new COVID-19 in vaccinated, reinfection in vaccinated, new COVID-19 infection in unvaccinated, and reinfection in unvaccinated patients respectively. 5 (4.1%) of the newly infected vaccinated and 4 (6.5%) freshly infected unvaccinated, 14 (15.7%) reinfected unvaccinated patients were transferred to ICU for mechanical ventilation. The mean duration of the hospital stay was significantly (p<0.05) lower among the vaccinated group than in non-vaccinated patients. Conclusion: This study suggests that vaccination of previously infected people may be associated with reducing the adverse outcome of COVID-19 infection. J Dhaka Med Coll. 2022; 31(1) : 137-147