METHODS: A total of 2598 serum samples (1417 urban samples, 1181 rural samples) were randomly collected from adults ages 35-74 y. The presence of the dengue IgG antibody and neutralising antibodies to dengue virus (DENV) 1-4 was determined using enzyme-linked immunosorbent assay and the plaque reduction neutralisation test assay, respectively.
RESULTS: The prevalence of dengue IgG seropositivity was 85.39% in urban areas and 83.48% in rural areas. The seropositivity increased with every 10-y increase in age. Ethnicity was associated with dengue seropositivity in urban areas but not in rural areas. The factors associated with dengue seropositivity were sex and working outdoors. In dengue IgG-positive serum samples, 98.39% of the samples had neutralising antibodies against DENV3, but only 70.97% of them had neutralising antibodies against DENV4.
CONCLUSION: The high seroprevalence of dengue found in urban and rural areas suggests that both urban and rural communities are vital for establishing and sustaining DENV transmission in Malaysia.
METHODS: COVID-19 samples that tested positive by reverse transcription polymerase chain reaction and with cycle threshold values <30 were obtained throughout Malaysia. Sequencing of SARS-CoV-2 complete genomes was performed using Illumina, Oxford Nanopore, or Ion Torrent platforms. A total of 6163 SARS-CoV-2 complete genome sequences were generated over the surveillance period. All sequences were submitted to the Global Initiative on Sharing All Influenza Data database.
RESULTS: From June 2021 to January 2022, Malaysia experienced the fourth wave of COVID-19 dominated by the Delta variant of concern, including the original B.1.617.2 lineage and descendant AY lineages. The B.1.617.2 lineage was identified as the early dominant circulating strain throughout the country but over time, was displaced by AY.59 and AY.79 lineages in Peninsular (west) Malaysia, and the AY.23 lineage in east Malaysia. In December 2021, pilgrims returning from Saudi Arabia facilitated the introduction and spread of the BA.1 lineage (Omicron variant of concern) in the country.
CONCLUSION: The changing trends of circulating SARS-CoV-2 lineages were identified, with differences observed between west and east Malaysia. This initiative highlighted the importance of leveraging research expertise in the country to facilitate pandemic response and preparedness.