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.

The optimal condition for Moringa oleifera root barks extraction was determined using response surface methodology and Box-Behnken Design. The actual optimal condition of the factors was 65 o C, ethanol 60%, 40 (mL/g) liquid-to-solid ratio with 240 minutes extraction time. The enrichment of phenolic compounds sharply affected the antioxidant, and inhibitions of α-amylase enzyme, as well as, the anti-inflammatory effect of the extract from M. oleifera root barks. The extract in the optimal condition exhibited better 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and α-amylase inhibitory activities than those of positive controls.Also, the extract showed weak hydroxyl free radical scavenging and nitric oxide (NO) production inhibitory effects. These revealed a simple and promising method for the preparation of bioactive products from the root bark of M. oleifera.

Ovarian cancer is a primary global health concern, often diagnosed at advanced stages with limited treatment options and poor prognosis. Natural products have emerged as potential sources of safe and effective therapies. From the seeds of Myristica fragrans Houtt. (nutmeg), 24 compounds, including neolignans and diarylnonanoid derivatives, were isolated and structurally elucidated. The cytotoxic activities of these isolated metabolites against cisplatin-sensitive and resistant human ovarian cancer cell lines were evaluated. In particular, myrifragranone C (23) exhibited cytotoxicity against all test cancer cell lines A2780, TOV-112D, and SK-OV3 with IC50 values of 14.1, 16.9, and 33.4 μM, respectively. Furthermore, compound 23 induced the death of A2780 and SK-OV3 cancer cells via apoptosis. Western blotting revealed that compound 23 significantly increased the expression of cleaved caspase-3 and poly-ADP ribose polymerase and promoted apoptosis via the mitogenactivated protein kinase signaling pathway. Our findings may provide a preliminary understanding of the antiovarian cancer effect of the active compound myrifragranone C as a potential treatment using natural products.

Endophytic fungi are promising sources for the production of podophyllotoxin-an important anticancer compound, replacing depleted medical plants. In this study, the endophytes associated with Dysosma difformis-an ethnomedicinal plant species were isolated to explore novel sources of podophyllotoxin. Fifty-three endophytic fungi were isolated and identified by morphological observation and ITS-based rDNA sequencing, assigning them to 27 genera in 3 divisions. Fusarium was found the most prevalent genus with a colonization frequency of 11.11%, followed by Trametes (9.26%) and Penicillium (7.41%). Phylogenetic trees were constructed for the endophytic fungi community in two collection sites, Ha Giang and Lai Chau, revealing the adaptation of the species to the specific tissues and habitats. Cytotoxic activity of endophytic fungal extracts was investigated on cancer cell lines such as SK-LU-1, HL-60, and HepG2, demonstrating strong anti-cancer activity of six isolates belonging to Penicillium, Trametes, Purpureocillium, Aspergillus, and Ganoderma with IC 50 value of lower than 10 10 µg/mL. The presence of podophyllotoxin was indicated in Penicillium, Trametes, Aspergillus and for the first time in Purpureocillium and Ganoderma via high-performance liquid chromatography, which implied them as a potential source of this anticancer compound.

Objective: To investigate the cause of a botulism outbreak in several provinces in Viet Nam in 2020. Methods: An initial investigation was conducted to confirm the outbreak and to form hypotheses about the potential causes, followed by a case–control assessment of the plausible causative food item. Collected food samples were tested to identify the pathogen, and mouse bioassays were performed. Control measures were introduced to stop the outbreak and to prevent similar events in the future. Results: Twelve people in six southern provinces of Viet Nam were identified as having symptoms of botulism, of whom 11 were in critical condition requiring breathing support. A history of foods eaten in the 4 days before illness onset indicated that all the cases had eaten a tinned vegetarian pate, and a case–control assessment showed that this was significantly associated with the outbreak, with an odds ratio of 35.2 (95% confidence interval: 3.4–infinity). Clostridium botulinum type B was detected in three of eight pâté samples collected from the houses of cases. In the mouse bioassay for the toxicity of the pâté samples, all the mice died with clinical symptoms of botulism. Discussion: A tinned vegetarian pate was the plausible cause of a botulism outbreak in Viet Nam in 2020. Revision of food safety regulations to improve quality control of tinned foods to prevent future outbreaks is recommended.

Objective: Female sex workers (FSWs) are at high risk of human papillomavirus (HPV) infections and cervical cancer due to their high number of sexual partners. The objectives of this study were to determine the prevalence of HPV and identify risk factors for high-risk HPV infection among FSWs in Hanoi and Ho Chi Minh City (HCMC), Viet Nam. Methods: A cross-sectional study was conducted in Hanoi and HCMC between December 2017 and May 2018. We surveyed and screened 699 FSWs aged ≥18 years for HPV infection and abnormal cytology. A multivariable modified Cox regression model was used to determine risk factors for high-risk HPV infection. Results The overall prevalence of any HPV, high-risk HPV and HPV-16/18 infection in the 699 FSWs was 26.3%, 17.6% and 4.0%, respectively, and were similar in both cities. Multiple infections were identified in 127 participants (69.0%).HPV-52 was the most prevalent (7%), followed by HPV-58 (6%). Abnormal cytology was detected in 91 participants (13.0%). FSWs who are divorced (adjusted prevalence ratio [aPR]: 1.96, 95% confidence interval [CI]: 1.01–3.81), widowed (aPR: 3.26, 95% CI: 1.49–7.12) or living alone (aPR: 1.85, 95% CI: 1.01–3.39) were associated with a higher prevalence of high-risk HPV infection.

Objectives: Asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and test re-positivity after a negative test have raised concerns about the ability to effectively control the coronavirus disease 2019 (COVID-19) pandemic. We aimed to investigate the prevalence of COVID-19 asymptomatic and pre-symptomatic infections during the second wave of COVID-19 in Viet Nam, and to better understand the duration of SARS-CoV-2 infection and the dynamics between the evolution of clinical symptoms and SARS-CoV-2 test positivity among confirmed COVID-19 cases. Methods: We conducted a cohort analysis on the first 50 confirmed cases during the second COVID-19 wave in Viet Nam using clinical, laboratory and epidemiological data collected from 9 March to 30 April 2020. Kaplan-Meier estimates were used to assess time to clearance of SARS-CoV-2 infection, and log-rank tests were used to explore factors related to time to SARS-CoV-2 infection clearance. Results: Most cases (58%) had no typical signs or symptoms of COVID-19 at the time of diagnosis. Ten cases (20%) were re-positive for SARS-CoV-2 during infection. Eight cases (16%) experienced COVID-19 symptoms after testing negative for SARS-CoV-2. The median duration from symptom onset until clearance of infection was 14 days (range: 6–31); it was longer in re-positive and older patients and those with pre-existing conditions. Conclusion Asymptomatic and pre-symptomatic infections were common during the second wave of COVID-19 in Viet Nam. Re-positivity was frequent during hospitalization and led to a long duration of SARS-CoV-2 infection.

A new compound, 3β-acetoxylanosta-7,9(11),24-triene-26-al (3), and seven known compounds (1 – 2 and 4 – 8) were isolated from Ganoderma tropicum (Jung.) Bres. collected in Tay Nguyen, Vietnam. The structures of these compounds were determined by one- and two-dimensional nuclear magnetic resonance spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and high-resolution ESI-MS, and by comparison with literature data. All of the isolated compounds were tested for nitroblue tetrazolium (NBT) reduction activity in Saccharomyces cerevisiae-stimulated RAW 246.7 cells. Among them, compounds 2 – 4 and 6 – 8 enhanced the NBT reduction in a dose-dependent manner.

A new compound, 3β-acetoxylanosta-7,9(11),24-triene-26-al (3), and seven known compounds (1 – 2 and 4 – 8) were isolated from Ganoderma tropicum (Jung.) Bres. collected in Tay Nguyen, Vietnam. The structures of these compounds were determined by one- and two-dimensional nuclear magnetic resonance spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and high-resolution ESI-MS, and by comparison with literature data. All of the isolated compounds were tested for nitroblue tetrazolium (NBT) reduction activity in Saccharomyces cerevisiae-stimulated RAW 246.7 cells. Among them, compounds 2 – 4 and 6 – 8 enhanced the NBT reduction in a dose-dependent manner.

Animals ; Antibodies, Neutralizing ; Blotting, Western ; Classical swine fever virus ; Classical Swine Fever ; Enzyme-Linked Immunosorbent Assay ; Genotype ; Mortality ; Spleen ; Swine ; Vaccines ; Vaccines, Subunit ; Vietnam ; Virulence