Regional and Temporal Dynamics of Dengue in Mexico (2020-2024): A Comprehensive Epidemiological Analysis

Dengue remains a major public health concern in Mexico, with incidence and clinical burden increasing substantially in recent years. Using national surveillance data from 2020 to 2024, this study provides a comprehensive overview of the changing epidemiological landscape, with an emphasis on geographic distribution, temporal trends, serotype dynamics, and disease severity. Over this period, Mexico saw an almost fivefold increase in dengue cases, reaching over 123,000 confirmed infections and 426 deaths in 2024, the highest annual number recorded. Seasonal patterns shifted, with sustained transmission extending into unusual winter months from late 2023. Serotyping data revealed a shift in predominant virus serotypes, with DENV2 predominating until 2022, DENV1 peaking in 2021, and DENV3 rising sharply from 2022 onward, becoming dominant in 2023 and almost exclusive by 2024. This shift coincided with a sustained rise in dengue with warning signs (from 16.9% in 2020 to > 42% in 2023-2024) and higher hospitalisation rates, while severe dengue remained below 5%. Although DENV3 dominated nationally, DENV1 and DENV2 persisted in specific states, and DENV4 circulated sporadically, particularly in southern and northern regions. Several traditionally low-prevalence states experienced atypical outbreaks, underscoring the potential for sudden epidemic expansion. Climatic analysis showed a consistent positive association between temperature and DENV3 prevalence, with precipitation effects varying by year. Odds ratio analysis suggested serotype-specific differences in severity across years. These findings underscore the heterogeneous and dynamic nature of dengue transmission in Mexico and highlight the need for regional surveillance, prevention, and clinical preparedness strategies.