Dengue virus infection-enhancement activity in neutralizing antibodies of healthy adults before dengue season as determined by using FcγR-expressing cells.

BACKGROUND: Antibodies are critical responses to protect the host from dengue virus(DENV) infection. Antibodies target DENV by two pathologic mechanisms: virus neutralization and infection enhancement. In dengue patients, the absence of neutralizing activity in the presence of FcγR implies that infection-enhancing activity hampers the neutralizing activity of antibodies, which could potentially lead to symptomatic presentations and severe clinical outcomes. METHODS: A total of 100 pair serum samples from adult healthy volunteers were obtained during the dengue season in Ha Noi in 2015 for evaluation of neutralizing and infection-enhancing activity. Additionally, 20 serum samples from acute secondary DENV infection patients were also used as the patient group in this study. PRNT was performed on BHK cells and FcγR-expressing BHK cell lines for all serum samples. RESULTS: Out of 100 residents, positive neutralizing antibodies (N.A) were found in 44.23 and 76.92% for DENV-1; 38.46 and 75% for DENV-2; 19.23 and 15.38% for DENV-3; and 1.92 and 9.62% for DENV-4 for pre and post-dengue season respectively. The percentage of post-exposure residents having positive responses against single, two, or more than three DENV serotypes were 38.46, 44.23 and 15.38%, respectively. A total of 34 residents were DENV seropositive before the dengue season and these individuals demonstrated further elevation of IgG antibodies after the dengue season. At the end of the season, 18 residents were confirmed to be new asymptomatic DENV infection cases. In both groups, N.A titers determined on BHK cells were higher than that on FcγR-expressing BHK cells. In heterotypic N.A responses, N.A titers to the infecting serotype from the samples obtained from pre-exposure group were significantly higher than those of the patient group. However, fold enhancement to the infecting serotypes from the samples in the pre-exposure group was substantially lower as compared to that of the patient group. CONCLUSION: Before and after the dengue season, serum samples from healthy volunteers demonstrated high levels of neutralizing antibodies and low or absence of infection-enhancement activity. The results suggest that while infection-enhancement activity hampers neutralizing activity of antibodies, high levels of DENV neutralizing antibodies set a critical threshold in facilitating the prevention of disease progression.

Progress toward universal health coverage in Vietnam: Evidence on dispensing trends of diabetes medications from 2015 to 2021.

AIMS: This study aims to investigate the trends in treatment coverage through dispensing diabetes medications in Vietnam from 2015 to 2021. The findings will serve to inform health policies to mitigate the health burden of Type 2 diabetes mellitus (T2DM). METHODS: We collected information on major antidiabetic medicines from General Department of Vietnam Customs and payments for antidiabetics via the National Health Insurance Program. We applied ordinary least squares models, accounting for economic and health outcome characteristics, to estimate the association between the annual mass of medications and related factors. RESULTS: Nationally, the total mass/doses of all antidiabetic drugs increased rapidly from 2015 to 2021, based on both databases. Metformin was the most frequently prescribed medicine, with the total mass increasing nearly threefold over the study period. Gliclazide, a Sulfonylureas drug, ranked second. In the multivariate regression analysis, a one-unit increase in adults with diabetes (in 1,000 s) was associated with 0.11 % (95 %CI = 0.0005; 0.0076) and 0.13 % (95%CI = 0.0007; 0.0242) higher mass of Metformin and Glimepiride, respectively. CONCLUSION: Our data suggested that policies changes were related to significant increase in antidiabetic medication dispenses in Vietnam. The high treatment coverage indicates impressive progress in achieving universal health coverage in Vietnam, meeting the UN Sustainable Development Goal (SDG).

Risk Factors and Protective Immunity Against Rabies in Unvaccinated Butchers Working at Dog Slaughterhouses in Northern Vietnam.

Vietnam is a rabies-endemic country where eating dog meat is customary. However, the risks of rabies transmission to dog slaughtering and processing workers have not been identified. This study aimed to determine the rabies neutralizing antibody (NTA) and risk factors in dog slaughterers to propose appropriate intervention methods for this occupational group. In 2016, a cross-sectional study on NTA against rabies virus and related factors was conducted among 406 professional dog slaughterers in Vietnam. The participants were interviewed using a structured questionnaire, and their sera were tested for rabies NTA by a rapid focus fluorescence inhibition test. Statistical algorithms were used to analyze the data. The results showed that most of the professional dog butchers (344/406 subjects, 84.7%) had no rabies NTA. Interestingly, 7.8% (29/373) had NTA without a rabies vaccination history. Over 5 years of experience as a dog butcher was positively associated with the presence of NTA in unvaccinated individuals (OR = 6.16, P = 0.001). The NTA in vaccinated butchers was present in higher titer and for longer persistence to those of other previously reported professionals, which is possibly as a result of multiple exposures to low levels of rabies virus antigens during dog slaughtering. Our study demonstrated that professional dog butchers in Vietnam are at a high risk of rabies virus infection, apart from those with common bite experiences. In countries where dog meat consumption is customary, rabies control and prevention activities should focus on safety during dog trading and slaughtering.

Rabies-infected dogs at slaughterhouses: A potential risk of rabies transmission via dog trading and butchering activities in Vietnam.

The study aimed to determine the status of neutralizing antibodies and rabies virus infection in dogs at slaughterhouses in Hanoi city from 2015 to 2017. A total of 2,376 pairs of blood and brain samples were collected from dogs at 92 slaughterhouses (8 large slaughterhouses and 84 small slaughterhouses) in 6 districts in Hanoi. Of the 1,500 dog samples from the large slaughterhouses where imported dogs were slaughtered, no dog brain samples were infected with rabies virus and no blood samples were positive for rabies neutralizing antibodies. Meanwhile, 7/876 (0.8%) of dog brain samples from small slaughterhouses in which slaughtered local dogs were positive for rabies virus and 26.4% had neutralizing antibodies against rabies virus. Analysis of the genetic characteristics of these rabies viruses showed that they all had a common origin with the domestic strains circulating in Northern Vietnam. Research results suggested that there was a potential risk of rabies transmission to humans through dog slaughtering activities in Vietnam. Vaccination for dogs should be strengthened, strictly implemented and frequently monitored to reach the rate of herd vaccination coverage as WHO's recommendation. Dog trading and slaughtering activities should be strictly monitored to minimize the risk of rabies transmission to humans.