COVID-19 and Influenza Hospitalizations and the Role of COVID-19 Vaccination in the Post-pandemic Period: A Cross-sectional Study from Saudi Arabia

Background: The simultaneous spread of COVID-19 and seasonal influenza is an evolving healthcare challenge. This study examines the clinical characteristics of influenza and COVID-19 patients in Saudi Arabia and evaluates the impact of COVID-19 vaccination on hospital and ICU admission risks.

Methods: We conducted a cross-sectional study of 235 patients (113 with influenza and 122 with COVID-19) admitted between October 2023 and March 2024 to Saudi public hospitals. Data on demographic factors, comorbidities, vaccination status, and ICU admission were collected from medical records. Logistic regression models were used to investigate associations between COVID-19 vaccination and clinical outcomes, adjusting for potential confounders.

Results: Among the patients, 48.1 % were male, and 51.1 % were aged over 60 years. Among them, 80.0 % had received at least one COVID-19 vaccine dose; 6.8 % had one dose, 25.5 % had two doses, 46.4 % had three doses, and 1.3 % had four doses. COVID-19 patients had higher rates of comorbidities but lower rates of ICU admissions than influenza patients (18.0 % versus 5.3 %) and (7.4 % versus 13.3 %), respectively. COVID-19 vaccination was associated with a higher likelihood of receiving the seasonal influenza shot (OR [95 % CI] = 4.43 [1.29, 15.26]) and a lower likelihood of COVID-19 hospital admission (OR [95 % CI] = 0.39 [0.19, 0.81]) and ICU admission (OR [95 % CI] = 0.31 [0.12, 0.80]).

Conclusion: COVID-19 vaccination was significantly associated with a reduced risk of COVID-19 hospital admission and ICU admission in the post-pandemic period. These findings emphasize the importance of vaccination in mitigating severe outcomes from COVID-19 and influenza infections.