ABSTRACT
Background: There is a lack of real-world evidence evaluating the disease outcomes and patient features in vaccinated coronavirus disease (COVID-19) cases. This study aimed to address this scientific need gap and also compare characteristics between the partially vaccinated and fully vaccinated COVID-19 patients in India. Methods: This observational cross-sectional study included data of adult patients diagnosed with COVID-19 at a tertiary care Indian hospital with a history of at least single-dose COVID-19 vaccination. Overall evaluation of patient features and disease characteristics was done. Patients were segregated into two groups based on vaccination status (partial or fully vaccinated), and characteristics were compared between these two groups along with COVID-19 outcomes. Results: Data of 403 vaccinated patients treated for breakthrough COVID-19 infection postvaccination was evaluated. The mean age was 47.7 ± 15.3 years (range: 19-87 years), with the majority being males (73.94%); 54.1% of evaluated cases were fully vaccinated; 74.93% of cases were asymptomatic. The majority of the symptomatic cases (60.39%) suffered from only mild-moderate symptoms; 72.7% of cases needed only home isolation, while only 1.99% died. A significantly higher number of partially vaccinated COVID-19 patients had severe COVID-19 pneumonia vs. fully vaccinated ones (14.59% vs. 5.96%, p < 0.05). The relative risk (RR) for the development of severe COVID-19 infection was 0.32 for the fully vaccinated subgroup, which was a significant finding (CI: 0.19-0.55, p < 0.05). Conclusion: The majority of vaccinated COVID-19 patients are asymptomatic or suffer from mild clinical features, which can be managed with home isolation. Fully vaccinated patients have a lower risk of developing severe COVID-19 infection in comparison to partially vaccinated cases.