The effect of COVID-19 vaccination and associated factors on duration of hospitalisation among severe COVID-19 patients admitted in an Intensive Care Unit of a Tertiary Hospital, Cape Town, South Africa

Introduction: The SARS-CoV-2 pandemic caused unprecedented morbidity and mortality among populations globally. Definitive public health prevention strategy was needed to curtail the pandemic. This study aimed to assess the effect of COVID-19 vaccination on duration of hospitalization among COVID-19 patients admitted to the Intensive care unit (ICU) of a tertiary hospital in South Africa. Methods: Data for this study were collected from the medical records of patients 18 years and older with confirmed SARS-CoV-2 diagnosis admitted to the ICU. Data collection period was from February 2021 to December 2021. A total of 72 patients’ data were collected and entered into Research Electronic Data Capture (REDCap) database. Variable included were “admission and discharge date, clinical parameters including severity of illness index, biochemical and hematological tests indices, Age, and gender of the patient, and estimated BMI score. Data were and analysed using Stata statistical software for data analysis version 18. Univariable and multivariable regression models were constructed and factors with p<0.05 were considered significantly associated with duration of hospitalization. Results: The mean of the participants age was 51 years. Patients who received COVID-19 vaccination and developed a breakthrough -SARS-Cov2 infections were discharged from ICU within 7 days of admission while the non-vaccinated patients stayed longer than 7 days. Of the 72 patients 54/75 (75%) were discharged earlier, while 18/75 (25%) stayed longer, p<0.05. Non-vaccinated patients were 1.27 times at risk of longer hospitalization compared to vaccinated patients. Factors associated with duration of hospitalization in ICU on univariate analysis included “partial pressure of carbon dioxide (PCO2) (p = 0.021), bicarbonate (HCO3) (p = 0.037), duration of ventilation (p = 0.02), administration of sedatives (p = 0.01), Long COVID-19 diagnosis (p = 0.021) as well as and inotropes (p < 0.001). On multivariable regression analysis, Obesity (Adjusted Relative Risks [aRR]: 5.74, 95% confidence interval [CI]: 2.24 – 14.68, Long COVID-19 diagnosis [aRR]: 2.17, 95% CI: 1.22 – 3.86, and number of days on sedation [aRR]: 1.26, 95% CI: 1.00 – 1.59)) were significantly associated with duration of hospitalization in the intensive care unit. Discussion: COVID-19 vaccination reduced the duration of ICU admission among severely ill COVID-19 patients. Patients who were obese, those with long COVID diagnosis, and on sedatives were all more likely to have longer hospitalization in the ICU. Increasing access to COVID-19 vaccination and booster dosing to sustain a fully vaccinated population remains key preventive strategy to minimize morbidity and mortality to SARS-Cov2 infection in our populations. Conclusion: Expanding access to COVID-19 vaccination as well as monitoring patients with break-through SARS-Cov2 infections who present to hospital with these identified risk factors will help to reduce length of illness, reduce cost associated with long hospitalization and improve outcome among severely ill COVID-19 patients.