Fast and Sensitive Real-Time PCR Detection of Major Antiviral-Drug Resistance Mutations in Chronic Hepatitis B Patients by Use of a Predesigned Panel of Locked-Nucleic-Acid TaqMan Probes.

We developed a novel real-time PCR assay that simultaneously evaluates 11 major nucleos(t)ide antiviral (NA) drug resistance mutations (mt) in chronic hepatitis B patients (CHB), including L180M, M204I/V, and V207M (lamivudine [LMV] resistance), N/H238A/T (adefovir [ADF] resistance), which are circulating in Vietnam; and T184G/L, S202I, and M250V (entecavir [ETV] resistance) and A194T (tenofovir resistance), which have been recently reported in several studies across the globe. We detected drug-resistant mt in hepatitis B virus (HBV) samples using our predesigned panel of allele-specific locked-nucleic acid (LNA) probes. Our assay had a high sensitivity of 5% in a low-HBV DNA population of ≥5 × 103 IU/ml and was validated in a cohort of 130 treatment-naive children and 98 NA-experienced adults with CHB. Single-point mt for LMV and ADF resistance were detected in 57.7% and 54.1% of the child and adult samples, respectively, with rtV207M (children, 42.3%; adults, 36.7%) and rtN238T/A (children, 15.4%; adults, 16.3%) being the most frequent mt in these populations. Multiple-point mt, including rtL180M-rtM204V- rtN238A and rtL180M-rtM204I, were identified in only two children, resulting in LMV-ADF resistance and reduced ETV susceptibility. In conclusion, this assay accurately identified the mt profile of children (98.4%) and adults (91.2%) with CHB, which is comparable to established methods. This fast and sensitive screening method can be used for the detection of major NA-resistant mt circulating in developing countries, as well as providing a model for the development of similar mt-detection assays, especially for use in nonhospitalized patients who need their results within half a day, before starting treatment.

A case study of an influenza vaccination program for health care workers in Vietnam.

BACKGROUND: In 2017, the Vietnam Ministry of Health conducted a demonstration project to introduce seasonal influenza vaccination to health care workers. A total of 11,000 doses of influenza vaccine, single-dose prefilled syringes, were provided free to HCWs at 29 selected hospitals, clinics, and research institutes in four provinces: Hanoi, Khanh Hoa, Dak Lak and Ho Chi Minh City. METHODS: Before the campaign, a workshop was organized to discuss an implementation plan including technical requirements, cold chain, uptake reporting, and surveillance for adverse events following immunization. All sites distributed communication materials and encouraged their staff to register for vaccination. Following immunization sessions, sites sent reports on uptake and adverse events following immunization. Left-over vaccine was transferred to other sites to maximize vaccine use. RESULTS: The average uptake was 57% for all health care workers, with 11 sites achieving 90% and above. These 11 sites were small with less than 500 staff, including 5 primary hospitals, 3 preventive medicine units, and 2 referral hospitals. Among the six biggest sites with over 1000 staff, four sites had the lowest uptake (14-47%). Most of the high-uptake sites were from the central to the south; only one site, a referral hospital, was from the north. After redistribution of left-over vaccine, only 130 vaccine doses (1.2%) were not used and destroyed. Based on factors that affected uptake, including registration levels, differing communication strategies, availability of vaccination, and commitment by health facility leaders, we recommended ways to increase health care worker coverage; recommendations to improve reporting adverse events following immunization were also made. CONCLUSIONS: The project demonstrated that it was feasible to conduct influenza vaccination campaigns among health care workers in Vietnam. Improvements in promotion of registration, more intense pre-planning, especially at larger facilities, and wider, more consistent availability of communication materials will result in increased efficiency and coverage in this program's future expansion.

Predictors for dioxin accumulation in residents living in Da Nang and Bien Hoa, Vietnam, many years after Agent Orange use.

Agent Orange (AO) was the main defoliant used by the US in Vietnam from 1961 to 1971; AO was contaminated with dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD). Three major dioxin "hot spots" remain from previous AO storage and use at former US bases at Bien Hoa, Da Nang, and Phu Cat, posing potential health risks for Vietnamese living on or near these hot spots. We evaluated potential risk factors contributing to serum TCDD levels in Vietnamese residents at and near contaminated sites in Da Nang and Bien Hoa, Vietnam. We used multiple linear regression to analyze possible associations of blood dioxin concentrations with demographic, socioeconomic, lifestyle, and dietary risk factors for residents living on or near these hot spots. For the Da Nang study, fish farming on the site, living on property flooded from monsoon rains, and age were among the factors showing significant positive associations with serum TCDD concentrations. For the Bien Hoa study, fish farmers working at this site and their immediate family members had significantly higher serum TCDD concentrations. Our results suggest that water-related activities, especially fish-farming, at the hot spots increased the risk of exposure to dioxin.