1.Within-household SARS-CoV-2 transmission and vaccine effectiveness in the first three COVID-19 school outbreaks in northern Viet Nam, September–December 2021
Trang Thu Vu ; Tu Huy Ngo ; Khanh Cong Nguyen ; Vu Thi Lan ; Cu Thi Bich Hanh ; Le Hong Son ; Huyen Thi Nguyen ; Hien Thi Nguyen ; Nghia Duy Ngu ; Duong Nhu Tran ; Duc-Anh Dang ; Florian Vogt ; Thai Quang Pham
Western Pacific Surveillance and Response 2024;15(3):19-30
Objective: The risk of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from schoolchildren to their household and the protective effects of vaccination in these settings remain poorly understood. We assessed the transmission dynamics of schoolchildren with SARS-CoV-2 within their households and the protective effects of coronavirus disease (COVID-19) vaccination among household members in Viet Nam.
Methods: We estimated the attack rate, vaccine effectiveness and adjusted risk ratio (aRR) of factors associated with SARS-CoV-2 transmission to household contacts of children confirmed to have COVID-19 who attended three schools in Ha Nam, Phu Tho and Thanh Hoa provinces between September and December 2021 using multivariable regression with household-level random effects.
Results: This retrospective cohort study included 157 children infected with SARS-CoV-2 and their 540 household contacts. The attack rate among household contacts was 24.6% (133/540). Overall, vaccine effectiveness among household contacts was 39% (95% confidence interval [CI]: -1 to -63), higher among males than females and higher in adults aged >40 years. COVID-19 transmission was greater among female household contacts compared with males (aRR: 1.35, 95% CI: 0.94 to 1.95), although not statistically significant, and highest among those aged 19–39 years (aRR: 2.51, 95% CI: 1.50 to 4.21). Fully vaccinated household contacts had significantly lower infection risk (aRR: 0.46, 95% CI: 0.26 to 0.84).
Discussion: We found substantial onward transmission of SARS-CoV-2 from schoolchildren to household members, and older people were more likely to be protected by vaccination. We recommend that schoolchildren and all household members living with schoolchildren receive at least two doses of a COVID-19 vaccine. Recognizing the role of schoolchildren in the onward transmission of COVID-19 is an important lesson learned by Viet Nam that can help not only in managing other outbreaks but also in protecting schoolchildren by predicting the progress of the outbreak and preparing for a timely response.
2.Large-scale salmonella outbreak associated with banh mi, Viet Nam, 2024
Tinh Huu Ho ; Phuong Hoai Hoang ; Lam Vo Thi Ngoc ; Minh Nguyen Dinh ; Dong Do Thanh ; Viet Nguyen Dinh ; O Phan Van ; Phuong Nguyen Thi Lan ; Thanh Nguyen Quoc ; Nhan Ho The ; Nhan Le Dinh Trong ; Chinh Van Dang
Western Pacific Surveillance and Response 2024;15(3):36-42
Objective: To investigate the cause of a foodborne outbreak that occurred in Dong Nai province, Viet Nam, in 2024, and implement control measures.
Methods: An initial investigation was conducted to confirm the outbreak, which was followed by epidemiological and environmental investigations to find the plausible causative food item. Clinical specimens and food samples were tested to identify the pathogen.
Results: A total of 547 symptomatic cases were recorded, of whom two were in severe condition requiring extracorporeal membrane oxygenation and ventilation, one of whom died. Among 99 interviewed cases, the mean incubation time was 9 hours (range 2–24 hours), with the main symptoms being fever, abdominal pain, diarrhoea and vomiting. All patients had eaten banh mi from a local bakery. Salmonella spp. were identified in food samples and clinical specimens. The bakery halted production, and the outbreak ended after 1 week.
Discussion: All the patients were exposed to only one food in common, which facilitated the investigation process. This outbreak is a reminder to small retailers and take-away shops of the importance of food safety management in preventing similar future outbreaks. All food handlers must comply with food hygiene principles, especially in hot temperatures, which boosts bacterial growth.
3.NO Production Inhibition of Lignans from Vietnamese Schisandra sphenanthera Rehd. et Wils. Fruits
Hong Khuyen THI PHAM ; Phu Chi Hieu TRUONG ; Khanh Huyen THI PHAM ; Dao Cuong TO ; Manh Hung TRAN ; Tu Nguyen THI THANH
Natural Product Sciences 2023;29(4):312-322
In the present study, bioactivity-guided extraction and isolation of the n-hexane fraction of the fruits of Vietnamese Schisandra sphenanthera led to the isolation of five dibenzocyclooctadiene lignans as gomisin N (1), schisandrin C (2), gomisin H (3), gomisin D (4), and gomisin C (5). All the isolates were tested for their inhibition of NO production in LPS-induced RAW 264.7 cells. Among them, compounds 4 and 5 showed weak inhibition of NO production with IC 50 values of 25.0 ± 1.6 and 24.8 ± 2.0 µM, respectively. Compound 1 exhibited NO production inhibition with an IC 50 value of 15.8 ± 2.1 µM, meanwhile, schisandrin C (2) showed the most potent inhibition with an IC 50 value of 8.5 ± 0.5 µM. In addition, compound 2 had a concentrationdependent inhibitory effect on the protein expression of the inflammatory enzymes iNOS and COX-2. Their physicochemical properties and ADMET data were predicted by in silico, indicating favorable drug-like properties as well as low acute oral toxicity. The results suggest that the fruit of S. sphenanthera and its phytochemical constituents might be used as anti-inflammatory agents.
4.Systematic sequencing of imported cases leads to detection of SARS-CoV-2 B.1.1.529 (Omicron) variant in central Viet Nam
Do Thai Hung ; Nguyen Bao Trieu ; Do Thi Thu Thuy ; Allison Olmsted ; Trinh Hoang Long ; Nguyen Duc Duy ; Huynh Kim Mai ; Bui Thi Thu Hien ; Nguyen Van Van ; Tran Van Kiem ; Vo Thi Thuy Trang ; Nguyen Truong Duy ; Ton That Thanh ; Huynh Van Dong ; Philip L Gould ; Matthew R Moore
Western Pacific Surveillance and Response 2022;13(4):82-85
As authorities braced for the arrival of the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), infrastructure investments and government directives prompted action in central Viet Nam to establish capacity for genomic surveillance sequencing. From 17 November 2021 to 7 January 2022, the Pasteur Institute in Nha Trang sequenced 162 specimens from 98 150 confirmed SARS-CoV-2 cases in the region collected from 8 November to 31 December 2021. Of these, all 127 domestic cases were identified as the B.1.617.2 (Delta) variant, whereas 92% (32/35) of imported cases were identified as the B.1.1.529 (Omicron) variant, all among international flight passengers. Patients were successfully isolated, enabling health-care workers to prepare for additional cases. Most (78%) of the 32 Omicron cases were fully vaccinated, suggesting continued importance of public health and social measures to control the spread of new variants.
5.Characteristics of severe malaria in hospitalized children in Ho Chi Minh City from 2012 to 2019
Ha, M.T. ; Ho, T.A.T. ; Nguyen, A.N. ; Nguyen, T.A.
Tropical Biomedicine 2021;38(No.3):371-376
In Vietnam, severe malaria is currently rare but is a life-threatening disease. It may be
misdiagnosed with other common diseases. This descriptive study aimed to characterize
severe malaria and its clinical aspects, as well as outcomes of infected pediatric patients
to improve case management. The case-series study was carried out based on medical
records of children aged between one month and 15 years with malaria diagnosed by blood
smear or rapid diagnostic test. Chi-squared test with the p values less than 0.05 were
considered statistically significant. There were 47 cases enrolled in the study. The prevalence
of severe malaria was 29.8% (57.1% in children under five). The morbidity was 71.4% in male
and 28.6% in female. Common clinical signs of severe malaria were fever (100%), severe
anemia (21.4%), hepatomegaly (85.7%), and splenomegaly (71.4%). Common biological
abnormalities in severe malaria were anemia, thrombocytopenia, increased liver enzymes,
and high CRP level. The severe malaria was mainly caused by P. falciparum (100%). The age
range for those infected with P. falciparum was 6.5 ± 4.5 years (min 0.3; max 14.9). The successful
rate of treatment was 92.9% with artesunate. Antimalarial treatment time was 9.0 (6 – 12)
days for severe malaria, which was twice as many as that for non-severe malaria (p = 0.067).
The current clinical and biological findings of severe malaria are different from those in
previous times, which make it easy to be overlooked. Therefore, it’s important to perform
malaria diagnostic tests when there’re clinical suggestions of severe malaria, including
fever, hepatomegaly or splenomegaly.
6.Anaplasma marginale and A. platys Characterized from Dairy and Indigenous Cattle and Dogs in Northern Vietnam
Nguyen Thi Hong CHIEN ; Thi Lan NGUYEN ; Khanh Linh BUI ; Tho VAN NGUYEN ; Thanh Hoa LE
The Korean Journal of Parasitology 2019;57(1):43-47
Anaplasma marginale and A. platys were detected and characterized (16S rDNA sequence analysis) from dairy and indigenous cattle, and the latter in domestic dogs in Vietnam. A phylogenetic tree was inferred from 26 representative strains/species of Anaplasma spp. including 10 new sequences from Vietnam. Seven of our Vietnamese sequences fell into the clade of A. marginale and 3 into A. platys, with strong nodal support of 99 and 90%, respectively. Low genetic distances (0.2–0.4%) within each species supported the identification. Anaplasma platys is able to infect humans. Our discovery of this species in cattle and domestic dogs raises considerable concern about zoonotic transmission in Vietnam. Further systematic investigations are needed to gain data for Anaplasma spp. and members of Anaplasmataceae in animal hosts, vectors and humans across Vietnam.
Anaplasma marginale
;
Anaplasma
;
Anaplasmataceae
;
Animals
;
Asian Continental Ancestry Group
;
Cattle
;
DNA, Ribosomal
;
Dogs
;
Humans
;
Phylogeny
;
Trees
;
Vietnam
7.Tuberculosis case notification data in Viet Nam, 2007 to 2012
Nhung Viet Nguyen ; Hoa Binh Nguyen ; Khanh Huyen Pham ; Cornelia Hennig
Western Pacific Surveillance and Response 2015;6(1):7-14
Tuberculosis (TB) remains a major cause of morbidity and mortality, and Viet Nam ranks 12 among the 22 high-TB burden countries. This study analyses surveillance data of the National Tuberculosis Control Programme in Viet Nam for the six-year period 2007 to 2012. During the study period, 598 877 TB cases (all forms) were notified, and 313 225 (52.3%) were new smear-positive cases. The case notification rate of new smear-positive cases was decreased, from 65 per 100 000 population in 2007 to 57 per 100 000 population in 2012; this decrease was observed for males and females in all age groups except males aged 0–14 and females aged 15–24 years. The male-to-female ratio of new smear-positive TB cases increased from 2.85 in 2007 to 3.02 in 2012. The average annual cure rate of new smear-positive cases was 90.3%. The high male-to-female ratio for new smear-positive TB cases in this notification data was lower than that from the 2007 TB prevalence survey in Viet Nam, suggesting a lower case detection for males. The decrease in new smear-positive case notification rates may reflect a decline in TB incidence in Viet Nam as several programmatic improvements have been made, although further research is required to increase case detection among young males and children.
8.Parasite egg contamination of water and air in a suburban area of Hanoi, Vietnam
Shinichi Noda ; Nguyen Thi Viet Hoa ; Shoji Uga ; Le Khanh Thuan ; Yoshiki Aoki ; Yasunori Fujimaki
Tropical Medicine and Health 2009;37(2):55-61
Contamination of water and air by soil-transmitted helminth eggs was investigated in a small village located in the suburbs of Hanoi, Vietnam. Water samples were collected from 29 households, two schools, two kindergartens, one restaurant, three ponds and 23 ditch sites during the rainy season. Water samples were also collected at the same places, except for one household and one restaurant, during the dry season. The water samples collected from households, schools, kindergartens and restaurant were comprised of well-water and rain-water. These samples included both water filtrated with sand and gravel and non-filtrated water. Two-liter water samples were examined for helminth eggs by either a centrifugation or flotation method. The contamination of air by helminth eggs was assessed by the method of Kroeger et al. (1992). Eggs in air were trapped on adhesive tapes hanging in rooms and in the area around 29 houses, two schools, two kindergartens, one restaurant and 18 utility poles.
Out of 63 water samples collected from households in the rainy season, helminth eggs were found in four water samples; one from non-filtrated well-water and three from filtrated well-water samples. The one non-filtrated water sample contained six eggs of Toxocara sp., while the three filtrated water samples contained one egg each of Trichuris sp., Trichiuris sp. and Taenia sp. No eggs were found in the water samples collected from schools, kindergartens or the restaurant in the rainy season. All water samples collected from ponds and ditches in the rainy season contained many helminth eggs. The eggs found were Ascaris sp., Trichuris sp., Toxocara sp., Ascaridia galli, hookworm, Taenia sp. and Fasciola sp. Examination of the adhesive tapes hanging in the air showed that four sites were contaminated by helminth eggs, i. e. one site near the house, two sites near the school and one site at a utility pole. The species of eggs found were Trichuris sp., Ascaridia galli and Taenia sp. The number of eggs found on tapes was only one or two. In the dry season, a few samples of well-water and rain-water collected from the residential area were contaminated with helminth eggs, and all samples collected from ponds and ditches contained many eggs of various species similar to those collected in the rainy season. The present study clearly indicates that, in our study area, the villagers were subject to infection from soil-transmitted helminthes directly and indirectly through water.
9.Study PML/RAR alpha fusion gene on 21 patients diagnosed with acute promyelocytic leukemia (AML \u2013 M3)
Phuong Minh Vu ; Vinh Quang Pham ; Hoa Khanh Bach ; Nhung Thi Hong Le ; Dung Thi My Tran ; Phuong Minh Nguyen
Journal of Medical Research 2008;58(5):18-24
Background: In Vietnam, there are a number of studies on the application of ATRA in treating acute promyelocytic leukemia (AML \u2013 M3) but they have still faced with certain difficulties. Objectives: (1). Study PML/RAR alpha fusion gene on the patients diagnosed with AML \u2013 M3. (2). Study the index of hematology of the PML/RAR alpha positive group. Subject and Method: 21 patients with acute promyelocytic leukemia (M3) were studied. All patients were examined with morphology, coagulation and cytogenetic tests and RNA were extracted from leukemic cells and PCR for PML/RAR alpha fusion transcript. Result and conclusion: PML/RAR alpha positive in 67% including 4 patients which were not discovered t(15; 17) by cytogenetic technique. Rates of three subtype (bcr1, bcr2 and bcr3) of PML/RAR alpha were 7 patients (50%), 3 patients (21,5%) and 4 patients (28,5%), respectively. WBC and bone marrow cells of PML/RAR alpha positive group were 5.08+/-3.87 and 155.82+/-106.21. D \u2013 Dimer level was 1954.89+/-1575.28; 93% of patients in the PML/RAR alpha positive group had DIC.
Acute promyelocytic leukemia
;
M3
;
PML/RAR alpha
10.Research on AML1/ETO fusion gene on 76 patients diagnosed with acute myelogenous leukemia
Phuong Minh Vu ; Vinh Quang Pham ; Hoa Khanh Bach ; Nhung Thi Hong Le ; Dung Thi My Tran ; Phuong Minh Nguyen
Journal of Medical Research 2008;59(6):10-16
Background: Chromosome mutation type t(8;21) has quite a high frequency in acute myelogenous leukemia, which accounted for about 15% among adult patients. From 2001, the WHO has a new classification for acute myelogenous leukemia based on genetic mutations. Form had AML1/ETO were arranged into genetic mutation group with better prognosis and ability to fully recover after chemotherapy with a high dose of cytarabin. Objective: Study AML1/ETO fusion gene on the patients diagnosed with Acute Myelogenous Leukemia (AML), as well as the clinical features and some haematologic parameters of the AML1/ETO positive group. Subject and methods: 76 patients with AML were treating in the National Institute of Hematology & Blood Transfusion and the Department of Hematology & Blood Transfusion of Bach Mai Hospital from April 2007 to July 2008. These patients were studied for clinical examination, morphology and RNA were extracted from leukemic cells and PCR for AML1/ETO fusion transcript was performed. Results and conclusions: The incidence of AML1/ETO positive in the AML patients was 24%. The incidence of AML1/ETO positive in AML-M2 was 28%. In the AML1/ETO positive group: median age was 26.94+/-9.22; rate of severe anemia, hemorrhage, fever, infection, hepatomegaly, splenomegaly, lymphadenopathy and gum hypertrophy was 44%, 33%, 28%, 11%, 44%, 28%, 17% and 6%, respectively. Median hemoglobin, WBC, platelet, bone marrow cell count, % blast in peripheral blood and in bone marrow was 84.41+/-28.97 g/l, 29.42+/-31.36 g/l, 42.12+/-33.83 g/l, 215.93+/-134.42 g/l, 56.21+/-26.58% and 65.14+/-16.12%, respectively.
acute myelogenous leukemia
;
AML1/ETO fusion gene


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