Publication date: Jun 10, 2026
COVID-19 represents a serious health concern leading to considerable morbidity and mortality worldwide. The repercussion of COVID-19 was expected to be more severe in middle- and low-income countries. Few studies have examined survival patterns across six successive pandemic waves. The objective of this study was to analyze the survival rates during the first six waves of the pandemic in the Monastir governorate (Tunisia) and identify mortality predictors of COVID-19. We conducted a prospective cohort study encompassing all COVID-19 patients admitted to healthcare facilities in Monastir between March 2020 and March 2022, spanning six full waves of infection. Patients were monitored throughout their hospital stay. Data were gathered using a questionnaire carefully filled out by trained residents. Survival analysis was performed to compare outcomes across the different waves. Cox model employing a stepwise variable selection approach in multivariate survival analysis was utilized to assess the risk factors associated with COVID-19 deaths. COVID-19 waves occurred between March 2020 and March 2022, resulting in a total of 58,861 infections, 5176 hospitalizations, and 1109 deaths in hospitals. The 30-day survival rate decreased progressively, reaching its minimum during W4 and W5 at 30. 6% and 29. 5%, respectively. The 30-day cumulative in-hospital mortality probability among COVID-19 hospitalizations was 57. 4%. Based on Cox multivariate analysis, W4 and W5 demonstrated the highest mortality risk, with W3 and W6 showing a moderate and comparable level of risk, while W2 exhibited the lowest risk. Independent prognostic factors for early hospital death were age over 75 years (HR 3. 44- 95% CI 2. 62-4. 52), cancer (HR 1. 90-95% CI 1. 17-3. 01), and neurological symptoms (HR 1. 30-95% CI 1. 04-1. 62). Fever (HR 0. 69- 95% CI 0. 60-0. 81) and digestive symptoms (HR 0. 73- 95% CI 0. 56-0. 94) were associated with lower observed mortality. Advanced age, cancer and neurological symptoms are associated factors for in-hospital mortality during COVID-19. Our findings emphasize the importance of early identification and need for targeted interventions for high-risk patients to optimize care and improve survival rates. This six-wave longitudinal analysis provides a comprehensive overview of temporal changes in survival and mortality risk across successive pandemic phases, offering valuable evidence to inform preparedness and response strategies in similar settings. Not applicable.
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| Concepts | Keywords |
|---|---|
| Healthcare | COVID-19 waves |
| Pandemic | Hospital |
| Tunisia | Mortality |
| SARS-Cov-2 | |
| Survival analysis | |
| Tunisia |