2.Possible association between recent migration and hospitalisation for dengue in an urban population: A prospective case-control study in northern Vietnam
Ataru Tsuzuki ; Vu Trong Duoc ; Toshihiko Sunahara ; Motoi Suzuki ; Nguyen Hoang Le ; Yukiko Higa ; Lay-Myint Yoshida ; Futoshi Hasebe ; Tran Vu Phong ; Noboru Minakawa
Tropical Biomedicine 2014;31(4):698-708
A prospective case–control study was conducted in urban districts in Hanoi,
northern Vietnam to evaluate the effect of migration on the risk of hospitalisation for dengue
in a Vietnamese urban population. We enrolled laboratory-confirmed dengue patients aged
>18 years who were hospitalised in local hospitals in November and December 2010. Four
neighbourhood-matched controls for each case were recruited within a week of hospitalisation.
Sociodemographic data were collected by interviews, and the number of immature and adult
mosquitoes within household premises was counted by entomological survey. Matched-pair
analyses were conducted using conditional logistic regression models. Among 43 cases and
168 controls, 84% and 83% were migrants from rural areas, respectively. Although statistical
significance was marginal, recent migration (residing in study area for <5 years) independently
increased the risk of hospitalisation for dengue compared with inhabitants after controlling
for potential confounders (adjusted odds ratio [aOR] = 3.78; 95% confidence interval [CI] =
0.99–14.27), whereas longer-term migration (residing in study area for >6 years) did not
change the risk (aOR = 1.1; 95% CI = 0.30–4.05). Younger age (18–34 years) (aOR = 7.26; 95%
CI = 2.39–22.06) and higher adult Aedes aegypti infestation level within household premises
(aOR = 9.25; 95% CI = 1.68–51.09) were also independently associated with hospitalisation
for dengue. Recent migration from rural areas seems to increase the risk of hospitalisation for
dengue in urban populations in endemic areas. Further research including cohort study should
be done to confirm the impact of migration on the risk of dengue in urban areas.
3.First round of external quality assessment of dengue diagnostics in the WHO Western Pacific Region, 2013
Pok Kwoon Yong ; Squires Raynal C ; Tan Li Kiang ; Takasaki Tomohiko ; Abubakar Sazaly ; Hasebe Futoshi ; Partridge Jeffrey ; Lee Chin Kei ; Lo Janice ; Aaskov John ; Ng Lee Ching ; Konings Frank
Western Pacific Surveillance and Response 2015;6(2):73-81
Objective:Accurate laboratory testing is a critical component of dengue surveillance and control. The objective of this programme was to assess dengue diagnostic proficiency among national-level public health laboratories in the World Health Organization (WHO) Western Pacific Region.Methods:Nineteen national-level public health laboratories performed routine dengue diagnostic assays on a proficiency testing panel consisting of two modules: one containing commercial serum samples spiked with cultured dengue viruses for the detection of nucleic acid and non-structural protein 1 (NS1) (Module A) and one containing human serum samples for the detection of anti-dengue virus antibodies (Module B). A review of logistics arrangements was also conducted.Results:All 16 laboratories testing Module A performed reverse transcriptase polymerase chain reaction (RT–PCR) for both RNA and serotype detection. Of these, 15 had correct results for RNA detection and all 16 correctly serotyped the viruses. All nine laboratories performing NS1 antigen detection obtained the correct results. Sixteen of the 18 laboratories using IgM assays in Module B obtained the correct results as did the 13 laboratories that performed IgG assays. Detection of ongoing/recent dengue virus infection by both molecular (RT–PCR) and serological methods (IgM) was available in 15/19 participating laboratories.Discussion:This first round of external quality assessment of dengue diagnostics was successfully conducted in national-level public health laboratories in the WHO Western Pacific Region, revealing good proficiency in both molecular and serological testing. Further comprehensive diagnostic testing for dengue virus and other priority pathogens in the Region will be assessed during future rounds.
4.Occurrence of the Omicron variant of SARS-CoV-2 in northern Viet Nam in early 2022
Trang thi Hong Ung ; Phuong Vu Mai Hoang ; Son Vu Nguyen ; Hang Le Khanh Nguyen ; Phuong thi Kim Nguyen ; Dan Tan Phan ; Thanh Thi Le ; Anh Phuong Nguyen ; Thach Co Nguyen ; Futoshi Hasebe ; Mai thi Quynh Le
Western Pacific Surveillance and Response 2022;13(3):29-33
The Omicron variant caused a surge of infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Viet Nam in early 2022, signalling community transmission. We report on active whole-genome sequencing surveillance of positive SARS-CoV-2 samples collected at that time in northern Viet Nam from international arrivals and community clusters. We used an amplicon protocol developed with 14 polymerase chain reaction products and the Illumina iSeq 100 platform. Overall, 213 nasopharyngeal or throat swabs were analysed, of which 172 samples were identified with the Omicron variant. Of these, 80 samples were collected from community cases in February 2022, among which 59 samples were sublineage BA.2 and one sample was the recombinant XE variant. Our results indicated that Omicron had replaced Delta as the dominant variant in a very short period of time and that continuously conducting active whole-genome sequencing surveillance is necessary in monitoring the evolution and genomic diversity of SARS-CoV-2 in Viet Nam.