Timeliness of contact tracing among flight passengers during the COVID-19 epidemic in Vietnam.

BACKGROUND: International air travel plays an important role in the global spread of SARS-CoV-2, and tracing of close contacts is an integral part of the public health response to COVID-19. We aimed to assess the timeliness of contact tracing among airline passengers arriving in Vietnam on flights containing COVID-19 cases and investigated factors associated with timeliness of contact tracing. METHODS: We included data from 2228 passengers on 22 incoming flights between 2 and 19 March 2020. Contact tracing duration was assessed separately for the time between the date of index case confirmation and date of contact tracing initiation (interval I), and the date of contact tracing initiation and completion (interval II). We used log-rank tests and multivariable Poisson regression models to identify factors associated with timeliness. RESULTS: The median duration of interval I and interval II was one (IQR: 1-2) and 3 days (IQR: 2-5), respectively. The contact tracing duration was shorter for passengers from flights where the index case was identified through mandatory testing directly upon arrival (median = 4; IQR: 3-5) compared to flights with index case detection through self-presentation at health facilities after arrival (median = 7; IQR: 5-8) (p-value = 0.018). Cumulative hazards for successful tracing were higher for Vietnamese nationals compared to non-Vietnamese nationals (p < 0.001). CONCLUSIONS: Contact tracing among flight passengers in the early stage of the COVID-19 epidemic in Vietnam was timely though delays occurred on high workload days. Mandatory SARS-CoV-2 testing at arrival may reduce contact tracing duration and should be considered as an integrated screening tool for flight passengers from high-risk areas when entering low-transmission settings with limited contact tracing capacity. We recommend a standardized risk-based contact tracing approach for flight passengers during the ongoing COVID-19 epidemic.

After action review of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, in 2020.

Surveillance is the backbone of any response to an infectious disease outbreak, and comprehensive evaluation of surveillance systems is crucial. However, structured evaluations of surveillance systems during the COVID-19 pandemic are scarce. We conducted an after action review (AAR) of the performance of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, during 2020 using the COVID-19-specific AAR methodology developed by the World Health Organization in combination with guidance from the US Centers for Disease Control and Prevention (CDC). We conducted a stakeholder survey, document reviews, and key informant interviews with staff from Quang Ninh CDC's COVID-19 surveillance system. The COVID-19 surveillance system was based on the pre-existing surveillance system in the province. The system's strengths were early preparation for emergency response, strong governance and central coordination, and multidisciplinary collaboration. Stakeholders agreed that the system proved useful and adaptive to the fast-evolving COVID-19 situation but was weakened by overly complex systems, redundant administrative processes, unclear communication channels, and lack of resources. Overall, the surveillance systems in Quang Ninh province proved effective in containing COVID-19 and adaptive in a fast-changing epidemiological context. Several recommendations were made based on identified areas of concern that are of relevance for COVID-19 surveillance systems in Vietnam and similar settings.

After action review of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, in 2020.

Surveillance is the backbone of any response to an infectious disease outbreak, and comprehensive evaluation of surveillance systems is crucial. However, structured evaluations of surveillance systems during the COVID-19 pandemic are scarce. We conducted a after action review (AAR) of the performance of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, during 2020 using the COVID-19-specific AAR methodology developed by the World Health Organization in combination with guidance from the US Centers for Disease Control and Prevention (CDC). We conducted a stakeholder survey, document reviews, and key informant interviews with staff from Quang Ninh CDC's COVID-19 surveillance system. The COVID-19 surveillance system was based on the pre-existing surveillance system in the province. The system's strengths were early preparation for emergency response, strong governance and central coordination, and multidisciplinary collaboration. Stakeholders agreed that the system proved useful and adaptive to the fast-evolving COVID-19 situation but was weakened by overly complex systems, redundant administrative processes, unclear communication channels, and lack of resources. Overall, the surveillance systems in Quang Ninh province proved effective in containing COVID-19 and adaptive in a fast-changing epidemiological context. Several recommendations were made based on identified areas of concern that are of relevance for COVID-19 surveillance systems in Vietnam and similar settings.

Impact and effectiveness of Rotavin-M1 under conditions of routine use in two provinces in Vietnam, 2016-2021, an observational and case-control study.

Background: Half of diarrhea hospitalizations in children aged <5 years in Vietnam are due to rotavirus. Following introduction of a locally developed and licensed oral rotavirus vaccine, Rotavin-M1, into the routine immunization program in two Vietnamese provinces, Nam Dinh and TT Hue, we describe changes in rotavirus positivity among children hospitalized for diarrhea and calculate vaccine effectiveness against moderate-to-severe rotavirus hospitalizations. Methods: Active rotavirus surveillance among children <5 years began in December 2016 at sentinel hospitals in districts where rotavirus vaccine was introduced in December 2017. To estimate reductions in rotavirus detection, we calculated risk ratios comparing rotavirus positivity pre- and post-vaccine introduction. We used a test-negative case-control design to calculate vaccine effectiveness. Findings: From December 2016 to May 2021, 7228 children <5 years hospitalized for diarrhea were enrolled. Following introduction, Rotavin-M1 coverage was 77% (1066/1377) in Nam Dinh and 42% (203/489) in TT Hue. In Nam Dinh, rotavirus positivity among children <5 years significantly declined by 40.6% (95% CI: 34.8%-45.8%) during the three-year post-vaccine introduction period. In TT Hue, no change in rotavirus positivity was observed. Among children aged 6-23 months, a 2-dose series of Rotavin-M1 was 57% (95% CI: 39%-70%) effective against moderate-to-severe rotavirus hospitalizations. Interpretation: Higher vaccination coverage in Nam Dinh than TT Hue likely contributed to substantial declines in rotavirus positivity observed in Nam Dinh following rotavirus vaccine introduction. Robust vaccine effectiveness was observed through the second year of life. National rotavirus vaccine introduction with high coverage may have substantial impact on reducing rotavirus disease burden in Vietnam. Funding: Bill and Melinda Gates Foundation.

Using 'infodemics' to understand public awareness and perception of SARS-CoV-2: A longitudinal analysis of online information about COVID-19 incidence and mortality during a major outbreak in Vietnam, July-September 2020.

BACKGROUND: Trends in the public perception and awareness of COVID-19 over time are poorly understood. We conducted a longitudinal study to analyze characteristics and trends of online information during a major COVID-19 outbreak in Da Nang province, Vietnam in July-August 2020 to understand public awareness and perceptions during an epidemic. METHODS: We collected online information on COVID-19 incidence and mortality from online platforms in Vietnam between 1 July and 15 September, 2020, and assessed their trends over time against the epidemic curve. We explored the associations between engagement, sentiment polarity, and other characteristics of online information with different outbreak phases using Poisson regression and multinomial logistic regression analysis. We assessed the frequency of keywords over time, and conducted a semantic analysis of keywords using word segmentation. RESULTS: We found a close association between collected online information and the evolution of the COVID-19 situation in Vietnam. Online information generated higher engagements during compared to before the outbreak. There was a close relationship between sentiment polarity and posts' topics: the emotional tendencies about COVID-19 mortality were significantly more negative, and more neutral or positive about COVID-19 incidence. Online newspaper reported significantly more information in negative or positive sentiment than online forums or social media. Most topics of public concern followed closely the progression of the COVID-19 situation during the outbreak: development of the global pandemic and vaccination; the unfolding outbreak in Vietnam; and the subsiding of the outbreak after two months. CONCLUSION: This study shows how online information can reflect a public health threat in real time, and provides important insights about public awareness and perception during different outbreak phases. Our findings can help public health decision makers in Vietnam and other low and middle income countries with high internet penetration rates to design more effective communication strategies during critical phases of an epidemic.

Understanding the COVID-19 Infodemic: Analyzing User-Generated Online Information During a COVID-19 Outbreak in Vietnam.

OBJECTIVES: Online misinformation has reached unprecedented levels during the coronavirus disease 2019 (COVID-19) pandemic. This study analyzed the magnitude and sentiment dynamics of misinformation and unverified information about public health interventions during a COVID-19 outbreak in Da Nang, Vietnam, between July and September 2020. METHODS: We analyzed user-generated online information about five public health interventions during the Da Nang outbreak. We compared the volume, source, sentiment polarity, and engagements of online posts before, during, and after the outbreak using negative binomial and logistic regression, and assessed the content validity of the 500 most influential posts. RESULTS: Most of the 54,528 online posts included were generated during the outbreak (n = 46,035; 84.42%) and by online newspapers (n = 32,034; 58.75%). Among the 500 most influential posts, 316 (63.20%) contained genuine information, 10 (2.00%) contained misinformation, 152 (30.40%) were non-factual opinions, and 22 (4.40%) contained unverifiable information. All misinformation posts were made during the outbreak, mostly on social media, and were predominantly negative. Higher levels of engagement were observed for information that was unverifiable (incidence relative risk [IRR] = 2.83; 95% confidence interval [CI], 1.33-0.62), posted during the outbreak (before: IRR = 0.15; 95% CI, 0.07-0.35; after: IRR = 0.46; 95% CI, 0.34-0.63), and with negative sentiment (IRR = 1.84; 95% CI, 1.23-2.75). Negatively toned posts were more likely to be misinformation (odds ratio [OR] = 9.59; 95% CI, 1.20-76.70) or unverified (OR = 5.03; 95% CI, 1.66-15.24). CONCLUSIONS: Misinformation and unverified information during the outbreak showed clustering, with social media being particularly affected. This indepth assessment demonstrates the value of analyzing online "infodemics" to inform public health responses.

Carriage of Plasmid-Mediated Colistin Resistance-1-Positive Escherichia coli in Humans, Animals, and Environment on Farms in Vietnam.

Plasmid-Mediated Colistin Resistance 1 (mcr-1) was first reported in 2015 and is a great concern to human health. In this study, we investigated the prevalence of mcr-1 and mcr-1-positive Escherichia coli (MCRPEC) and the association in infection status among various reservoirs connected to livestock. The study was conducted in 70 poultry and swine farms in a commune in Ha Nam province, northern Vietnam. Samples were collected from farmers, food animals, domestic animals, and farm environments (flies and wastewater) for polymerase chain reaction (PCR) screening for mcr-1 gene and species identification of PCR positive isolates. Among 379 obtained mcr-1 positives isolates, Escherichia coli was the major identified, varying from 50% (2/4) in dog feces to 100% (31/31) in humans feces isolates. The prevalence of MCRPEC was 14.4% (20/139), 49.7% (96/193), 31.3% (25/80), 36.7% (40/109), 26.9% (18/67), and 3.9% (2/51) in humans, chickens, pigs, flies, wastewater, and dogs, respectively. The study identified association between MCRPEC infection status in humans and flies (OR = 3.4), between flies and chickens (OR = 5.3), and between flies and pigs (OR = 9.0). Farmers' age and farm livestock unit were also associated factors of MCRPEC infection status in humans (OR = 5.1 and 1.05, respectively). These findings bring new knowledge on antibiotic resistance in livestock setting and important suggestions on potential role of flies in the transmission of mcr-1 resistance gene.

Association of public health interventions and COVID-19 incidence in Vietnam, January to December 2020.

BACKGROUND: Vietnam implemented various public health interventions such as contact tracing and testing, mandatory quarantine, and lockdowns in response to coronavirus disease 2019 (COVID-19). However, the effects of these measures on the epidemic remain unclear. METHODS: This article describes the public health interventions in relation to COVID-19 incidence. Maximum likelihood estimations were used to assess containment delays (time between symptom onset and start of isolation) and multivariable regression was employed to identify associated factors between interventions and COVID-19 incidence. The effective reproductive numbers (Rt) were calculated based on transmission pairs. RESULTS: Interventions were introduced periodically in response to the epidemic. Overall, 817 (55.4%) among 1474 COVID-19 cases were imported. Based on a serial interval of 8.72 ± 5.65 days, it was estimated that Rt decreased to below 1 (lowest at 0.02, 95% CI 0-0.12) during periods of strict border control and contact tracing, and increased ahead of new clusters. The main method to detect cases shifted over time from passive notification to active case-finding at immigration or in lockdown areas, with containment delays showing significant differences between modes of case detection. CONCLUSIONS: A combination of early, strict, and consistently implemented interventions is crucial to control COVID-19. Low-middle income countries with limited capacity can contain COVID-19 successfully using non-pharmaceutical interventions.

Diversity and Ecology of Sand Flies (Diptera: Psychodidae), Potential Vectors of Leishmania in the Quang Ninh Province, Vietnam.

The study aims to make an update on the distribution and ecology of sand flies in the Quang Ninh province, Northern Vietnam, where Leishmania cases were reported in 2001. Seventeen sites were chosen in three districts of the province: Ha Long, Cam Pha, and Hoanh Bo. Phlebotomine sand flies were collected using 68 CDC light traps from May 30 to 3 June 2016. Captured specimens were transferred individually into Eppendorf tubes with 90% ethanol. The sand fly heads and genitalia were removed and were mounted in Euparal after successive different baths. Specimen identification was determined based on the morphology of the cibarium, pharynx, and/or male genitalia or female spermathecae. A total of 416 sand flies (125 females, 283 males) belonging to four genera were collected and 10 sand fly species were identified: Sergentomyia silvatica, Se. barraudi, Se. hivernus, Se. bailyi, Phlebotomus mascomai, Ph. stantoni, Ph. yunshengensis, Ph. betisi, Chinius junlianensis, Idiophlebotomus longiforceps. The Sergentomyia genus prevailed (79.7% of the collected sand flies), followed by the Phlebotomus genus (13.7%), the Chinius genus (6.1%), and the Idiophlebotomus genus (0.8%). Besides these well-defined taxa, five specimens, named sp1, showed unknown morphological characteristics, requiring further study. The majority of sand flies were collected in rock caves suggesting the cavernicolous character of the species in the Quang Ninh province. However, specimens were also collected in intra and peridomiciliary sites in which Ph. stantoni and Se. hivernus were found as the main species. It is worth noting that two Ph. stantoni were found in the house of a patient affected by Leishmania.

Dietary Carotenoid Intakes and Prostate Cancer Risk: A Case-Control Study from Vietnam.

The incidence of prostate cancer has increased in Vietnam, but there have been few studies of the risk factors associated with this change. This retrospective case-control study investigated the relation of the intake of carotenoids and their food sources to prostate cancer risk. A sample of 652 participants (244 incident prostate cancer patients, aged 64-75 years, and 408 age frequency-matched controls) were recruited in Ho Chi Minh City during 2013-2015. The habitual diet was ascertained with a validated food-frequency questionnaire, and other factors including demographic and lifestyle characteristics were assessed via face-to-face interviews by trained nurses. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression models. The risk of prostate cancer decreased with increasing intakes of lycopene, tomatoes, and carrots; the respective ORs (95% CIs) were 0.46 (0.27, 0.77), 0.39 (0.23, 0.66), and 0.35 (0.21, 0.58), when comparing the highest with the lowest tertile of intake (p for trend < 0.01). No statistically significant associations were found for the intake of α-carotene, ß-carotene, ß-cryptoxanthin, lutein, zeaxanthin, and major food sources of carotenoids. In conclusion, Vietnamese men with a higher intake of lycopene, tomatoes, and carrots may have a lower risk of prostate cancer. However, large prospective studies are needed in this population to confirm this finding.

Regional differences in the growing incidence of dengue Fever in Vietnam explained by weather variability.

Dengue fever is a major health problem in Vietnam, but its incidence differs from province to province. To understand this at the local level, we assessed the effect of four weather components (humidity, rainfall, temperature and sunshine) on the number of dengue cases in nine provinces of Vietnam. Monthly data from 1999 to 2009 were analysed by time-series regression using negative binomial models. A test for heterogeneity was applied to assess the weather-dengue association in the provinces. Those associations were significantly heterogeneous (for temperature, humidity, and sunshine: P < 0.001 heterogeneity test; for rainfall: P = 0.018 heterogeneity test). This confirms that weather components strongly affect dengue transmission at a lag time of 0 to 3 months, with considerable variation in their influence among different areas in Vietnam. This finding may promote the strategic prevention of dengue disease by suggesting specific plans at the local level, rather than a nationally unified approach.