Objectives: Low-income and middle-income countries in Asia bear a disproportionate burden of particulate matter with an aerodynamic diameter of 2.5 micrometers or less (PM2.5) pollution, yet data remain scarce. This systematic review and meta-analysis aimed to quantify the association between PM2.5 exposure and the risks of coronavirus disease 2019 (COVID-19) infection and mortality in this vulnerable region. Methods: A systematic search was conducted in PubMed, Scopus, and other major databases for studies published up to December 31, 2024. We included observational studies reporting associations between PM2.5 and COVID-19 outcomes in low-income and middle-income Asian countries. Pooled effect sizes and 95% confidence intervals (CIs) were calculated using a random-effects model. The study was registered with PROSPERO (CRD42022316008). Results: Fourteen studies met the inclusion criteria. Separate analyses demonstrated statistically significant positive associations between PM2.5 exposure and COVID-19 infection for both short-term exposure (pooled risk ratio [RR], 1.12; 95% CI, 1.07 to 1.18) and long-term exposure (pooled RR, 1.41; 95% CI, 1.28 to 1.56). For mortality, the analysis identified a statistically non-significant positive association with short-term exposure (pooled RR, 1.37; 95% CI, 0.80 to 2.33). Substantial heterogeneity was observed across all analyses (I²>75%); however, sensitivity analyses confirmed that the findings for infection were robust. Conclusions Our findings provide robust evidence that PM2.5 exposure is a significant risk factor for COVID-19 infection in low-income and middle-income Asian countries. The available evidence was insufficient to establish a clear association with mortality. These results underscore the urgent need for strengthened air quality control policies as a critical component of public health strategies to mitigate the burden of respiratory pandemics.

Background: Dengue is a systemic, viral, mosquito-borne infection that continues to be a major public health issue in endemic regions in tropical and subtropical climates. Accurate tests for rapid diagnosis in point-of-care settings are important to reduce the fatality rates of severe dengue. We evaluated the diagnostic accuracy of the Standard M10 DENV 1-4 system (SD Biosensor, Gyeonggi, Korea), which is a cartridge-based, automated system that integrates nucleic acid extraction, reverse transcription-PCR (RT-PCR) amplification, and detection of dengue virus (DENV) serotypes. Methods: This was a retrospective diagnostic evaluation study. The index test, Standard M10 DENV 1-4, was evaluated using 320 dengue-positive and 279 dengue-negative archived samples. The reference tests were a combination of Centers for Disease Control and Prevention (CDC) DENV 1-4 real-time RT-PCR, dengue NS1 antigen and IgM antibody detection, and DENV whole-genome sequencing. Results: The overall sensitivity and specificity of Standard M10 DENV 1-4 were 94% and 100%, respectively. By serotype, the highest sensitivity was 100% for DENV-1, and the lowest was 82% for DENV-4. The overall between the CDC RT-PCR dengue serotyping method and the Standard M10 DENV 1-4 was 95%. Standard M10 DENV 1-4 RT-PCR had comparable sensitivity and specificity to CDC DENV RT-PCR. Conclusions Based on its commensurate performance to an established RT-PCR method combined with additional benefits of convenient storage and transport, easy use, and rapid processing, the Standard M10 DENV 1-4 system has potential for DENV detection and serotyping in point-of-care settings.