Browsing by Author "Chiu-Wan Ng"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- PublicationDengue Seroprevalence and Factors Associated with Dengue Seropositivity in Petaling District, Malaysia(2022)
;Rui Jie Ng ;Zhuo Lin Chong ;Mohd Hatta Abdul MutalipChiu-Wan NgDengue virus (DENV) infection is a major public health concern, posing huge economic and disease burdens globally. In Malaysia, the incidence of DENV infections has increased significantly over the years. Nevertheless, the passive surveillance mechanism applied may not capture the actual magnitude of DENV infection. There was also a paucity of community-based studies exploring DENV seroprevalence. This study aimed to determine the DENV seroprevalence and the associated factors among the urban population in Petaling district, Malaysia. A population-based cross-sectional study was conducted from 18 August to 26 October 2018 with 533 participants recruited. Blood samples were collected and analyzed for DENV seropositivity using a composite reference standard comprised of three dengue serological tests. Associated factors were identified by fitting Generalised Linear Mixed Models with binomial error structure and logit link function. DENV seroprevalence obtained was 79.0% (95% CI: 75.2–82.4%). The age-specific DENV seroprevalence showed an increasing trend with advancing age, from 22.7% (95% CI: 9.6–45.0%) for those aged below five years old to 94.9% (95% CI: 81.3–98.7%) for those aged ≥60 years old. Only age group and house level were found to be significant factors associated with DENV seropositivity. The odds of being DENV seropositive generally increased with age, from 13.43 (95% CI: 2.77–65.22) for the 5–9 years old age group to 384.77 (95% CI: 39.27–3769.97) for the ≥60 years old age group, as compared to those aged below 5 years old. For house level, those who lived on the first and second floor (OR: 8.98, 95% CI: 3.16–25.12) and the third floor and above (OR: 4.82, 95% CI: 1.89–12.32) had greater odds of being DENV seropositive compared to those living on the ground floor. This study demonstrated the persistently high DENV seroprevalence among the urban population in Petaling district, which could be useful to evaluate dengue control measures taken and estimate more accurate disease incidence. The associated factors with DENV seropositivity identified could also contribute to undertaking more targeted preventive and control measures. - PublicationDiagnostic accuracy and utility of three dengue diagnostic tests for the diagnosis of acute dengue infection in Malaysia(2020)
;Zhuo Lin Chong ;Shamala Devi Sekaran ;Hui Jen Soe ;Devi Peramalah ;Sanjay RampalChiu-Wan NgBackground: Dengue is an emerging infectious disease that infects up to 390 million people yearly. The growing demand of dengue diagnostics especially in low-resource settings gave rise to many rapid diagnostic tests (RDT). This study evaluated the accuracy and utility of ViroTrack Dengue Acute - a new biosensors-based dengue NS1 RDT, SD Bioline Dengue Duo NS1/IgM/IgG combo - a commercially available RDT, and SD Dengue NS1 Ag enzyme-linked immunosorbent assay (ELISA), for the diagnosis of acute dengue infection. Methods: This prospective cross-sectional study consecutively recruited 494 patients with suspected dengue from a health clinic in Malaysia. Both RDTs were performed onsite. The evaluated ELISA and reference tests were performed in a virology laboratory. The reference tests comprised of a reverse transcription-polymerase chain reaction and three ELISAs for the detection of dengue NS1 antigen, IgM and IgG antibodies, respectively. The diagnostic performance of evaluated tests was computed using STATA version 12. Results: The sensitivity and specificity of ViroTrack were 62.3% (95%CI 55.6–68.7) and 95.0% (95%CI 91.7–97.3), versus 66.5% (95%CI 60.0–72.6) and 95.4% (95%CI 92.1–97.6) for SD NS1 ELISA, and 52.4% (95%CI 45.7–59.1) and 97.7% (95%CI 95.1–99.2) for NS1 component of SD Bioline, respectively. The combination of the latter with its IgM and IgG components were able to increase test sensitivity to 82.4% (95%CI 76.8–87.1) with corresponding decrease in specificity to 87.4% (95%CI 82.8–91.2). Although a positive test on any of the NS1 assays would increase the probability of dengue to above 90% in a patient, a negative result would only reduce this probability to 23.0–29.3%. In contrast, this probability of false negative diagnosis would be further reduced to 14.7% (95%CI 11.4–18.6) if SD Bioline NS1/IgM/IgG combo was negative. Conclusions: The performance of ViroTrack Dengue Acute was comparable to SD Dengue NS1 Ag ELISA. Addition of serology components to SD Bioline Dengue Duo significantly improved its sensitivity and reduced its false negative rate such that it missed the fewest dengue patients, making it a better point-of-care diagnostic tool. New RDT like ViroTrack Dengue Acute may be a potential alternative to existing RDT if its combination with serology components is proven better in future studies. - PublicationEstimating excess mortalities due to the COVID‑19 pandemic in Malaysia between January 2020 and September 2021(2023)
;Vivek Jason Jayaraj ;Diane Woei-Quan Chong ;Kim-Sui Wan ;Noran Naqiah Hairi ;Nirmala Bhoo-Pathy ;Sanjay RampalChiu-Wan NgExcess mortalities are a more accurate indicator of true COVID-19 disease burden. This study aims to investigate levels of excess all-cause mortality and their geographic, age and sex distributions between January 2020-September 2021. National mortality data between January 2016 and September 2021 from the Department of Statistics Malaysia was utilised. Baseline mortality was estimated using the Farrington algorithm and data between 1 January 2016 and 31 December 2019. The occurrence of excess all-cause mortality by geographic-, age- and sex-stratum was examined from 1 January 2020 to 30 September 2021. A sub-analysis was also conducted for road-traffic accidents, ethnicity and nationality. Malaysia had a 5.5–23.7% reduction in all-cause mortality across 2020. A reversal is observed in 2021, with an excess of 13.0–24.0%. Excess mortality density is highest between July and September 2021. All states and sexes reported excess trends consistent with the national trends. There were reductions in all all-cause mortalities in individuals under the age of 15 (0.4–8.1%) and road traffic accident-related mortalities (36.6–80.5%). These reductions were higher during the first Movement Control Order in 2020. Overall, there appears to be a reduction in all-cause mortality for Malaysia in 2020. This trend is reversed in 2021, with excess mortalities being observed. Surveillance of excess mortalities can allow expedient detection of aberrant events allowing timely health system and public health responses.