AB088. Predicting COVID-19 mortality risk across SARS-CoV-2 variants in Melaka, Malaysia: a 3-year retrospective study

Background: As of March 2023, over 761 million coronavirus disease 2019 (COVID-19) cases and 6.8 million deaths have been reported globally. Malaysia recorded over 5 million cases and 30,000 deaths within the same period. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with differing transmissibility, virulence, and immune escape properties has complicated pandemic control. This study investigates variant-specific mortality risk factors to support health system preparedness in future outbreaks in Melaka, Malaysia.

Methods: This retrospective ecological study utilized secondary surveillance data of confirmed COVID-19 cases reported in Melaka, Malaysia, from March 2020 to March 2023. Data were obtained from the Melaka State Health Department and included cases with confirmed SARS-CoV-2 variants. The collected variables included sociodemographic characteristics, comorbidities, clinical symptoms, vaccination status, and outcomes. A universal sampling method was applied, and the data were analyzed using SPSS software. Descriptive statistics were used to summarize case characteristics, followed by univariate and multivariate logistic regression analyses to identify factors independently associated with COVID-19 mortality

Results: Among 1,146 cases, the mean age was 48.2 years (±22.6 years), and 52.1% of the cases were male. Omicron was the most common variant (86.8%). Most cases were symptomatic (89.6%) and had at least one comorbidity (54.7%), with the most common conditions being hypertension (31.2%) and diabetes mellitus (24.1%). The overall mortality rate was 2.9%. Multivariate analysis identified several factors significantly associated with death: Delta variant infection [odds ratio (OR) =3.43; 95% confidence interval (CI): 1.07–11.03], age ≥65 (OR =2.66; 95% CI: 1.13–6.24), unvaccinated status (OR =4.36; 95% CI: 1.58–12.04), and shortness of breath (OR =4.39; 95% CI: 2.01–9.62).

Conclusions: This study highlights the elevated mortality risk associated with the Delta variant, advanced age, being unvaccinated, and respiratory distress. These findings underscore the importance of targeted vaccination, early identification of high-risk individuals, and adaptive health system planning to improve responses to future variant-driven outbreaks.

Keywords: Coronavirus disease 2019 (COVID-19); Melaka; severe acute respiratory syndrome coronavirus 2 variants (SARS‑CoV‑2 variants); health system preparedness; mortality