Genomic epidemiology demonstrates spatially clustered, local transmission of Plasmodium falciparum in forest-going populations in southern Lao PDR.

While there has been significant progress in controlling falciparum malaria in the Lao People's Democratic Republic (PDR), sporadic cases persist in southern provinces where the extent and patterns of transmission remain largely unknown. To assess parasite transmission in this area, 53 Plasmodium falciparum (Pf) positive cases detected through active test and treat campaigns from December 2017 to November 2018 were sequenced, targeting 204 highly polymorphic amplicons. Two R packages, MOIRE and Dcifer, were applied to assess the multiplicity of infections (MOI), effective MOI (eMOI), within-host parasite relatedness, and between-host parasite relatedness ([Formula: see text]). Genomic data were integrated with survey data to characterize the temporal and spatial structures of identified clusters. The positive cases were mainly captured during the focal test and treat campaign conducted in 2018, and in the Pathoomphone area, which had the highest test positivity and forest activity. About 30% of the cases were polyclonal infections, with over half of theses (63%) showing within-host relatedness greater than 0.6, suggesting that cotransmission rather than superinfection was primarily responsible for maintaining polyclonality. A large majority of cases (81%) were infected by parasites genetically linked to one or more other cases. We identified five genetically distinct clusters in forest fringe villages within the Pathoomphone district, characterized by a high degree of genetic relatedness between parasites (mean [Formula: see text] = 0.8). Four smaller clusters of 2-3 cases linked Moonlapamok and Pathoomphone districts, with an average [Formula: see text] of 0.6, suggesting cross-district transmission. Most of the clustered cases occurred within 20 km and 2 months of each other, consistent with focal transmission. Transmission clusters identified in this study confirm the role of ongoing focal parasite transmission occurring within the forest or forest-fringe in the highly mobile population.

Burkholderia pseudomallei Bacteria in Ornamental Fish Tanks, Vientiane, Laos, 2023.

In 2019, a melioidosis case in Maryland, USA, was shown to have been acquired from an ornamental fish tank contaminated with Burkholderia pseudomallei bacteria, likely derived from Southeast Asia. We investigated the presence of B. pseudomallei in ornamental fish tanks in the endemic area of Vientiane, Laos.

A Predictive Model for Thiamine Responsive Disorders Among Infants and Young Children: Results from a Prospective Cohort Study in Lao People's Democratic Republic.

OBJECTIVE: To develop a predictive model for thiamine responsive disorders (TRDs) among infants and young children hospitalized with signs or symptoms suggestive of thiamine deficiency disorders (TDDs) based on response to therapeutic thiamine in a high-risk setting. STUDY DESIGN: Children aged 21 days to <18 months hospitalized with signs or symptoms suggestive of TDD in northern Lao People's Democratic Republic were treated with parenteral thiamine (100 mg daily) for ≥3 days in addition to routine care. Physical examinations and recovery assessments were conducted frequently for 72 hours after thiamine was initiated. Individual case reports were independently reviewed by three pediatricians who assigned a TRD status (TRD or non-TRD), which served as the dependent variable in logistic regression models to identify predictors of TRD. Model performance was quantified by empirical area under the receiver operating characteristic curve. RESULTS: A total of 449 children (median [Q1, Q3] 2.9 [1.7, 5.7] months old; 70.3% exclusively/predominantly breastfed) were enrolled; 60.8% had a TRD. Among 52 candidate variables, those most predictive of TRD were exclusive/predominant breastfeeding, hoarse voice/loss of voice, cyanosis, no eye contact, and no diarrhea in the previous 2 weeks. The area under the receiver operating characteristic curve (95% CI) was 0.82 (0.78, 0.86). CONCLUSIONS: In this study, the majority of children with signs or symptoms of TDD responded favorably to thiamine. While five specific features were predictive of TRD, the high prevalence of TRD suggests that thiamine should be administered to all infants and children presenting with any signs or symptoms consistent with TDD in similar high-risk settings. The usefulness of the predictive model in other contexts warrants further exploration and refinement. TRIAL REGISTRATION: Clinicaltrials.gov NCT03626337.

Fine-scale maps of malaria incidence to inform risk stratification in Laos.

BACKGROUND: Malaria risk maps are crucial for controlling and eliminating malaria by identifying areas of varying transmission risk. In the Greater Mekong Subregion, these maps guide interventions and resource allocation. This article focuses on analysing changes in malaria transmission and developing fine-scale risk maps using five years of routine surveillance data in Laos (2017-2021). The study employed data from 1160 geolocated health facilities in Laos, along with high-resolution environmental data. METHODS: A Bayesian geostatistical framework incorporating population data and treatment-seeking propensity was developed. The models incorporated static and dynamic factors and accounted for spatial heterogeneity. RESULTS: Results showed a significant decline in malaria cases in Laos over the five-year period and a shift in transmission patterns. While the north became malaria-free, the south experienced ongoing transmission with sporadic outbreaks. CONCLUSION: The risk maps provided insights into changing transmission patterns and supported risk stratification. These risk maps are valuable tools for malaria control in Laos, aiding resource allocation, identifying intervention gaps, and raising public awareness. The study enhances understanding of malaria transmission dynamics and facilitates evidence-based decision-making for targeted interventions in high-risk areas.

Spatiotemporal patterns and association with climate for malaria elimination in Lao PDR: a hierarchical modelling analysis with two-step Bayesian model selection.

BACKGROUND: The government of Lao PDR has increased efforts to control malaria transmission in order to reach its national elimination goal by 2030. Weather can influence malaria transmission dynamics and should be considered when assessing the impact of elimination interventions but this relationship has not been well characterized in Lao PDR. This study examined the space-time association between climate variables and Plasmodium falciparum and Plasmodium vivax malaria incidence from 2010 to 2022. METHODS: Spatiotemporal Bayesian modelling was used to investigate the monthly relationship, and model selection criteria were used to evaluate the performance of the models and weather variable specifications. As the malaria control and elimination situation was spatially and temporally dynamic during the study period, the association was examined annually at the provincial level. RESULTS: Malaria incidence decreased from 2010 to 2022 and was concentrated in the southern regions for both P. falciparum and P. vivax. Rainfall and maximum humidity were identified as most strongly associated with malaria during the study period. Rainfall was associated with P. falciparum incidence in the north and central regions during 2010-2011, and with P. vivax incidence in the north and central regions during 2012-2015. Maximum humidity was persistently associated with P. falciparum and P. vivax incidence in the south. CONCLUSIONS: Malaria remains prevalent in Lao PDR, particularly in the south, and the relationship with weather varies between regions but was strongest for rainfall and maximum humidity for both species. During peak periods with suitable weather conditions, vector control activities and raising public health awareness on the proper usage of intervention measures, such as indoor residual spraying and personal protection, should be prioritized.

Antibiotic prescribing practices and antibiotic use quality indicators in Luang Prabang, Lao PDR: a point prevalence survey in a tertiary care hospital.

CONTEXT: The increase and global dissemination of antibiotic resistance limit the use of antibiotics to prevent and treat infections. Implementing antibiotic stewardship programs guided by local data on prescription profiles is a useful strategy to reduce the burden of antibiotic resistance. The aim was to determine the prevalence of antibiotic use and guideline compliance at Luang Prabang provincial hospital, Lao PDR. METHODS: A point prevalence survey of antibiotics was conducted among hospitalized patients admitted to Luang Prabang hospital (204 beds) in Lao PDR on May 25, 2023. All patients presenting at 8:00 AM were eligible. Sociodemographic data, indications for antibiotic use, and antibiotic prescriptions were collected from medical records using a paper-based questionnaire and entered into an electronic platform following WHO methodology. The prevalence of antibiotic use was determined. RESULTS: Out of the 102 patients included, 60(58.8%) were undergoing antibiotic treatment, of which 33(55.0%) received combination therapy, and 7(10.5%) had two indications for antibiotic use. The highest prevalence was in the surgical ward (14/15, 93%) followed by general paediatrics (18/27, 67%). Out of the 100 antibiotic prescriptions, 47(47%) were for community-acquired infections, 26(26%) for surgical prophylaxis, 13(13%) for hospital-acquired infections and 5(5%) for medical prophylaxis. Twenty(20%) antibiotics were prescribed for obstetrics and gynaecology prophylaxis, 17(17%) for intra-abdominal infections, and 10(10.0%) for pneumonia treatment as well as bone, and joint infections. The main antibiotics prescribed were ceftriaxone 36(34.6%), metronidazole 18(17.3%), ampicillin 8(7.7%), and gentamicin 8(7.7%). Only 2(3%) samples were sent to the laboratory, one of which showed a positive culture for Escherichia coli Extended Spectrum ß-Lactamase. According to the WHO Access Watch and Reserve classification, 55(52.9%) molecules belonged to the Access category, 47(49.1%) to the Watch category, and none to the Reserve category. Only 14.9% of antibiotic prescriptions were fully compliant with current guidelines. CONCLUSION: This study indicated a significant prevalence of antibiotic use and a very low compliance with guidelines at Luang Prabang provincial hospital, Lao PDR. This highlights an urgent need for comprehensive strategies at all levels to optimize antibiotic use in hospitals, emphasizing diagnostic improvements, and continued research to address the factors driving this excessive antibiotic usage and improve adherence to guidelines.

Health system utilization and perceived quality among adults in Lao PDR: evidence from a nationally representative phone survey.

BACKGROUND: The World Health Organization (WHO) defines quality health services as being effective, safe, people-centered, timely, equitable, integrated and efficient. It is critical to understand people's perspectives and care experiences to measure progress against these goals. However, many low- and middle-income governments do not routinely collect such information. In this study, we aim to measure health systems performance from the perspective of the adult population of users and non-users in Lao PDR. METHODS: Using the People's Voice Survey (PVS), a novel phone-based survey designed to integrate people's voices into primary care performance measurement, we conducted a cross-sectional survey of the general adult (18+) population in Lao PDR in 2022. We analyzed health care utilization patterns, user-reported quality of care, and coverage of key preventive health services. Data from the most recent MICS survey was used to create sampling weights generating nationally representative estimates. RESULTS: A total of 2007 adults completed interviews in approximately 3.5 months. About two thirds (65%) of respondents reported visiting a health facility in the past year and, of these, the majority (61%) visited a hospital as opposed to a health center or clinic. Among those that recently visited health facilities, 28% rated their experience as "poor" or "fair". 16% had unmet need for care and 12% reported discrimination during treatment in the past year. 12% of women over 50 years old reported receiving a mammogram and 59% of adults reported receiving blood pressure screening in the previous year. CONCLUSIONS: The study presents data from the first nationally representative survey in Lao PDR to measure health system performance. The results indicate that, despite progress towards universal coverage of health insurance in Lao PDR, significant gaps remain, particularly with respect to bypassing of primary care facilities, significant unmet need for care, experiences of discrimination, and overall low perceptions of quality of care.

Risk factors for anaemia among women and their young children hospitalised with suspected thiamine deficiency in northern Lao PDR.

Anaemia among women and young children remains a major public health concern. This secondary study describes the anaemia prevalence among young hospitalised children and their mothers in northern Lao People's Democratic Republic and explores possible nutritional causes and risk factors for anaemia. Hospitalised children (ages 21 days to <18 months) with clinical symptoms suggestive of thiamine deficiency disorders were eligible along with their mothers. Venous blood was collected for determination of haemoglobin, ferritin, soluble transferrin receptor (sTfR), retinol-binding protein (RBP), erythrocyte glutathione reductase activation coefficient (EGRac), thiamine diphosphate (ThDP) and acute phase proteins. Risk factors for anaemia were modelled using minimally adjusted logistic regression controlling for age. Haemoglobin results were available for 436 women (mean ± SD age 24.7 ± 6.4 years; 1.6% pregnant) and 427 children (4.3 ± 3.5 months; 60.3% male). Anaemia prevalence (Hb < 120 g/L for nonpregnant women and <110 g/L for pregnant women and children) was 30.7% among women and 55.2% among children. In bivariate analyses, biomarkers significantly associated with anaemia in women were ferritin, sTfR, RBP, EGRac and ThDP. Other risk factors for women were lower BMI, mid-upper arm circumference < 23.5 cm, lower education, lower socioeconomic index, food insecurity, Hmong ethnicity, not/rarely having attended antenatal care, not having taken antenatal iron-containing supplements and not meeting minimum dietary diversity. Risk factors for anaemia among children were older age, male sex, stunting, sTfR, ThDP and alpha-1-acid-glycoprotein. Anaemia was common among women and their hospitalised children and was associated with micronutrient deficiencies and socioeconomic, dietary and health care-seeking risk factors, suggesting that multiple strategies are required to prevent anaemia among women and children.

Novel estimation of African swine fever transmission parameters within smallholder villages in Lao P.D.R.

African Swine Fever (ASF) disease transmission parameters are crucial for making response and control decisions when faced with an outbreak, yet they are poorly quantified for smallholder and village contexts within Southeast Asia. Whilst disease-specific factors - such as latent and infectious periods - should remain reasonably consistent, host, environmental and management factors are likely to affect the rate of disease spread. These differences are investigated using Approximate Bayesian Computation with Sequential Monte-Carlo methods to provide disease parameter estimates in four naïve pig populations in villages of Lao People's Democratic Republic. The villages represent smallholder pig farmers of the Northern province of Oudomxay and the Southern province of Savannakhet, and the model utilised field mortality data to validate the transmission parameter estimates over the course of multiple model generations. The basic reproductive number between-pigs was estimated to range from 3.08 to 7.80, whilst the latent and infectious periods were consistent with those published in the literature for similar genotypes in the region (4.72 to 6.19 days and 2.63 to 5.50 days, respectively). These findings demonstrate that smallholder village pigs interact similarly to commercial pigs, however the spread of disease may occur slightly slower than in commercial study groups. Furthermore, the findings demonstrated that despite diversity across the study groups, the disease behaved in a consistent manner. This data can be used in disease control programs or for future modelling of ASF in smallholder contexts.

Estimating the delivery costs of COVID-19 vaccination using the COVID-19 Vaccine Introduction and deployment Costing (CVIC) tool: the Lao People's Democratic Republic experience.

BACKGROUND: The COVID-19 Vaccine Introduction and deployment Costing (CVIC) tool was developed to assist countries to estimate incremental financial costs to roll out COVID-19 vaccines. This article describes the purposes, assumptions and methods used in the CVIC tool and presents the estimated financial costs of delivering COVID-19 vaccines in the Lao People's Democratic Republic (Lao PDR). METHODS: From March to September 2021, a multidisciplinary team in Lao PDR was involved in the costing exercise of the National Deployment and Vaccination Plan for COVID-19 vaccines to develop potential scenarios and gather inputs using the CVIC tool. Financial costs of introducing COVID-19 vaccines for 3 years from 2021 to 2023 were projected from the government perspective. All costs were collected in 2021 Lao Kip and presented in United States dollar. RESULTS: From 2021 to 2023, the financial cost required to vaccinate all adults in Lao PDR with primary series of COVID-19 vaccines (1 dose for Ad26.COV2.S (recombinant) vaccine and 2 doses for the other vaccine products) is estimated to be US$6.44 million (excluding vaccine costs) and additionally US$1.44 million and US$1.62 million to include teenagers and children, respectively. These translate to financial costs of US$0.79-0.81 per dose, which decrease to US$0.6 when two boosters are introduced to the population. Capital and operational cold-chain costs contributed 15-34% and 15-24% of the total costs in all scenarios, respectively. 17-26% went to data management, monitoring and evaluation, and oversight, and 13-22% to vaccine delivery. CONCLUSIONS: With the CVIC tool, costs of five scenarios were estimated with different target population and booster dose use. These facilitated Lao PDR to refine their strategic planning for COVID-19 vaccine rollout and to decide on the level of external resources needed to mobilize and support outreach services. The results may further inform inputs in cost-effectiveness or cost-benefit analyses and potentially be applied and adjusted in similar low- and middle-income settings.

Risk mapping for Taenia solium: Applying multicriteria decision analysis in Lao PDR.

OBJECTIVES: Taenia solium is ranked the most significant global foodborne parasite and the leading cause of epilepsy in low and middle-income countries. Diagnostic challenges have hampered disease control efforts to date and WHO has called for the development of risk mapping tools to assist endemic countries. This study describes the application of multicriteria decision analysis to map the risk of T. solium in Lao PDR and acts as a case study for other endemic countries. METHODS: Multicriteria decision analysis was completed using census data on relevant risk factors in Lao PDR. Factors were weighted using an analytical hierarchy process. Village risk scores were calculated using a weighted linear combination and categorised using the Fisher-Jenks algorithm into low, medium, and high risk. District risk scores and categories were calculated using the mean village risk score for a district. Sensitivity analysis was completed by doubling and halving risk factor weights, one at a time, and assessing the standard deviation of scores and categories across all scenarios. RESULTS: A total of 2017 (23.7%) villages were classified as high risk, with 3312 (39.0%) medium and 3170 (37.3%) low risk. This resulted in 21 (14.2%) high-risk districts, 83 (56.1%) medium and 44 (29.7%) low-risk districts. The risk maps highlight two areas of interest which are high risk and low variation. The first is the northern province of Phongsaly, which is consistent with literature and anecdotal reports. The second is the southern Salavan and Xekong provinces, which have yet to be investigated in detail. CONCLUSIONS: Multicriteria decision analysis has provided a simple, rapid, and flexible approach to mapping the risk of T. solium in Lao PDR. The nature of the method means that it can be completed in any endemic country with available and appropriate risk factor data.

Low seroprotection against diphtheria and tetanus in Lao adolescents.

OBJECTIVES: There is currently no booster diphtheria or tetanus vaccine for Lao children before adolescence, despite international recommendations. We investigated seroprotection against diphtheria and tetanus among Lao adolescents. METHODS: Seven hundred seventy-nine serum samples were tested for anti-diphtheria and anti-tetanus antibodies. RESULTS: Overall, 25.8% of the adolescents had antibody titers corresponding to protection against diphtheria and 30.9% to sufficient immunity against tetanus. Female participants >16 years were more likely to be protected against diphtheria (p < 0.001) and tetanus (p < 0.029). CONCLUSION: Low protection against diphtheria and tetanus, possibly due to low vaccination coverage or antibody waning, suggests booster doses are warranted before adolescence.

Bionomics of malaria vectors in Lao PDR, 2018-2020: entomological surveillance as a key tool for malaria elimination.

BACKGROUND: The Lao PDR National Strategic Plan for malaria control and elimination for year 2021-2025 emphasizes the importance of routine entomological surveillance being conducted in areas with high transmission and in active malaria foci in elimination targeted areas. The collection of entomological surveillance data that is closely linked to recent epidemiological data is crucial for improving impact, as it contributes to the evidence package that supports operational and strategic decision-making of national malaria programmes, as they accelerate their last mile of elimination. METHODS: The Center for Malariology Parasitology and Epidemiology (CMPE) entomology team conducted entomological surveillance activities at 13 sentinel sites in 8 provinces and at active transmission foci sites from 2018 to 2020. The techniques used for the mosquito collection were indoor and outdoor human landing collections (from houses and from cultivation areas) and cattle baited net trap collections. RESULTS: There were 5601 Anopheles mosquito females captured and identified throughout the study, on both human and cow bait. They represented 15 different species or species complexes. The primary malaria vectors as well as the secondary vectors were present in all collection sites in the south, indicating that people living in these rural areas with high malaria incidence are exposed to the vectors. The vectors were highly zoophilic, but they still bite humans throughout the night with a high peak of activity before midnight, both indoors and outdoors. Overall, 17% of the malaria vectors were collected indoors when the people are sleeping. This confirms the importance of bed net use during the night. Thirty-two percent of primary and secondary vectors were collected outdoors at times when people are usually awake and outdoors, which shows that people are exposed to potentially infectious mosquitoes and the importance of personal protection at these times. The findings showed that residual transmission may occur outdoors in the villages, and outside the villages in cultivation fields and forested areas. Epidemiological data showed that transmission was higher in surveillance sites which were targeted as part of a malaria response rather than sentinel sites. CONCLUSIONS: Understanding where and how transmission is persisting, monitoring and mapping vector species distribution in areas with active transmission, monitoring biting trends, and designing evidence based and effective vector control interventions are critical to accelerating progress toward malaria elimination. In this context, the role of entomological surveillance combined with epidemiological data should be considered as a cornerstone in achieving malaria elimination.

Quality of routine health data at the onset of the COVID-19 pandemic in Ethiopia, Haiti, Laos, Nepal, and South Africa.

BACKGROUND: During the COVID-19 pandemic, governments and researchers have used routine health data to estimate potential declines in the delivery and uptake of essential health services. This research relies on the data being high quality and, crucially, on the data quality not changing because of the pandemic. In this paper, we investigated those assumptions and assessed data quality before and during COVID-19. METHODS: We obtained routine health data from the DHIS2 platforms in Ethiopia, Haiti, Lao People's Democratic Republic, Nepal, and South Africa (KwaZulu-Natal province) for a range of 40 indicators on essential health services and institutional deaths. We extracted data over 24 months (January 2019-December 2020) including pre-pandemic data and the first 9 months of the pandemic. We assessed four dimensions of data quality: reporting completeness, presence of outliers, internal consistency, and external consistency. RESULTS: We found high reporting completeness across countries and services and few declines in reporting at the onset of the pandemic. Positive outliers represented fewer than 1% of facility-month observations across services. Assessment of internal consistency across vaccine indicators found similar reporting of vaccines in all countries. Comparing cesarean section rates in the HMIS to those from population-representative surveys, we found high external consistency in all countries analyzed. CONCLUSIONS: While efforts remain to improve the quality of these data, our results show that several indicators in the HMIS can be reliably used to monitor service provision over time in these five countries.

Utilising abattoir sero-surveillance for high-impact and zoonotic pig diseases in Lao PDR.

National disease surveillance systems are essential to a healthy pig industry but can be costly and logistically complex. In 2019, Lao People's Democratic Republic (Lao PDR) piloted an abattoir disease surveillance system to assess for the presence of high impact pig diseases (HIPDs) using serological methods. The Lao Department of Livestock and Fisheries (DLF) identified Classical Swine Fever (CSF), Porcine Respiratory and Reproductive Syndrome (PRRS) and Brucella suis as HIPDs of interest for sero-surveillance purposes. Porcine serum samples (n = 597) were collected from six Lao abattoirs in March to December of 2019. Serological enzyme-linked immunosorbent assay (ELISA) methods were chosen for their high-throughput and relatively low-costs. The true seroprevalence for CSF and PRRS seropositivity were 68.7%, 95% CI (64.8-72.3) and 39.5%, 95% CI (35.7-43.5), respectively. The results demonstrated no evidence of Brucella spp. seroconversion. Lao breed pigs were less likely to be CSF seropositive (P < 0.05), whilst pigs slaughtered at <1 year of age were less likely to be PRRS seropositive (P < 0.01). The testing methods could not differentiate between seropositivity gained from vaccine or natural infection, and investigators were unable to obtain the vaccine status of the slaughtered pigs from the abattoirs. These results demonstrate that adequate sample sizes are possible from abattoir sero-surveillance and lifetime health traceability is necessary to understand HIPDs in Lao PDR.

Risk of low birthweight associated with the timing and frequency of antenatal care visits in Lao PDR: a retrospective cohort study.

BACKGROUND: Antenatal care (ANC) plays an important role in preventing low birthweight (LBW). Whereas the government of Lao People's Democratic Republic (Lao PDR) has committed to increasing the usage of ANC, little attention has been given to the early initiation of ANC. The present study assessed the influence of delayed and fewer ANC visits on LBW in the country. METHODS: This is a retrospective cohort study conducted at Salavan Provincial Hospital. Study participants were all pregnant women who gave birth at the hospital between 1 August 2016 and 31 July 31 2017. Data were collected from medical records. Logistic regression analyses were performed to quantify the relationship between ANC visits and LBW. We also investigated factors associated with inadequate ANC visits: first ANC visit after the first trimester or < 4 ANC visits. RESULTS: The mean birth weight was 2808.7 g [standard deviation: SD 455.6]. Among 1804 participants, 350 (19.4%) had babies with LBW, and 147 (8.2%) had inadequate ANC visits. In multivariate analyses, compared to participants with adequate ANC visits, those with ≥ 4 ANC visits and the first ANC visit after the second trimester, those with < 4 ANC visits, and those with no ANC visits had higher odds ratios (ORs) of LBW: 3.77 (95% confidence interval: CI = 1.66-8.57), 2.39 (95% CI = 1.18-4.83) and 2.22 (95% CI = 1.08-4.56), respectively. Younger maternal age (OR 1.42; 95% CI = 1.07-1.89), government subsidisation (OR 2.69; 95% CI = 1.97-3.68) and ethnic minority (OR 1.88; 95% CI = 1.50-2.34) were associated with increased risk of insufficient number of ANC visits after adjusting for covariates. CONCLUSIONS: Frequent and early initiation of ANC was associated with a reduction in LBW in Lao PDR. Encouraging childbearing-aged women to receive sufficient ANC at proper timing may lead to a reduction in LBW and improvement in short- and long-term health outcomes of neonates. Special attention will be needed for ethnic minorities and women in lower socioeconomic classes.

Association between environmental factors and dengue incidence in Lao People's Democratic Republic: a nationwide time-series study.

BACKGROUND: Dengue fever is a vector-borne disease of global public health concern, with an increasing number of cases and a widening area of endemicity in recent years. Meteorological factors influence dengue transmission. This study aimed to estimate the association between meteorological factors (i.e., temperature and rainfall) and dengue incidence and the effect of altitude on this association in the Lao People's Democratic Republic (Lao PDR). METHODS: We used weekly dengue incidence and meteorological data, including temperature and rainfall, from 18 jurisdictions in Lao PDR from 2015 to 2019. A two-stage distributed lag nonlinear model with a quasi-Poisson distribution was used to account for the nonlinear and delayed associations between dengue incidence and meteorological variables, adjusting for long-term time trends and autocorrelation. RESULTS: A total of 55,561 cases were reported in Lao PDR from 2015 to 2019. The cumulative relative risk for the 90th percentile of weekly mean temperature (29 °C) over 22 weeks was estimated at 4.21 (95% confidence interval: 2.00-8.84), relative to the 25th percentile (24 °C). The cumulative relative risk for the weekly total rainfall over 12 weeks peaked at 82 mm (relative risk = 1.76, 95% confidence interval: 0.91-3.40) relative to no rain. However, the risk decreased significantly when heavy rain exceeded 200 mm. We found no evidence that altitude modified these associations. CONCLUSIONS: We found a lagged nonlinear relationship between meteorological factors and dengue incidence in Lao PDR. These findings can be used to develop climate-based early warning systems and provide insights for improving vector control in the country.

Cost-effectiveness analysis of typhoid vaccination in Lao PDR.

BACKGROUND: Typhoid vaccination has been shown to be an effective intervention to prevent enteric fever and is under consideration for inclusion in the national immunization program in Lao PDR. METHODS: A cost-utility analysis was performed using an age-structured static decision tree model to estimate the costs and health outcomes of introducing TCV. Vaccination strategies combined with five delivery approaches in different age groups compared to no vaccination were considered from the societal perspective, using the Gavi price of 1.5 USD per dose. The vaccination program was considered to be cost-effective if the incremental cost-effectiveness ratio was less than a threshold of 1 GDP per capita for Lao PDR, equivalent to USD 2,535 in 2020. RESULTS: In the model, we estimated 172.2 cases of enteric fever, with 1.3 deaths and a total treatment cost of USD 7,244, based on a birth cohort of 164,662 births without TCV vaccination that was followed over their lifetime. To implement a TCV vaccination program over the lifetime horizon, the estimated cost of the vaccine and administration costs would be between USD 470,934 and USD 919,186. Implementation of the TCV vaccination program would prevent between 14 and 106 cases and 0.1 to 0.8 deaths. None of the vaccination programs appeared to be cost-effective. CONCLUSIONS: Inclusion of TCV in the national vaccination program in Lao PDR would only be cost-effective if the true typhoid incidence is 25-times higher than our current estimate.

Assessment of the underlying causes of adult deaths using a short version of verbal autopsy in Xaiyabouli Province, Lao People's Democratic Republic.

BACKGROUND: In developing countries, it is difficult to collect the data of the underlying cause of death (UCOD), especially when a death does not occur in a health facility. This study aimed to develop a short version of verbal autopsy (VA) and identify the UCOD of adults in Lao People's Democratic Republic (Lao PDR). METHODS: A short version of VA for deaths outside health facilities was developed. This study included all deaths of people aged 15 years old or older in Xaiyabouli Province in 2020. Socio-demographic factors, place of death, and UCOD of the deceased were collected from health facilities or from family members using a questionnaire including the short VA form. UCOD was compared between home deaths and hospital deaths, between the age group of 15-59 years old and the age group ≥ 60 years old, and between males and females. RESULTS: Of all the 1,235 deaths included in this study, 1,012 deaths (81.9%) occured at home and 223 deaths (18.1%) at hospitals. The most common UCOD was senility (13.3%), followed by heart/renal failure (10.5%), pneumonia (9.6%) and traffic accident (7.1%). Compared to hospital deaths, home deaths had more people who were females, 75 years old or older, and Lao-Tai. Home deaths had more deaths than hospital deaths due to accident/injury (16.0% vs. 8.1%), tumor (4.7% vs. 1.8%), and senility (16.2% vs. 0%); fewer deaths due to heart/renal disease (15.1% vs. 32.3%), respiratory disease (12.2% vs. 18.8%), liver/gastro-intestine disease (5.3% vs. 9.0%), and infection (3.1% vs. 14.3%). The age group of 15-59 years had more deaths in the categories of accident/injury (28.1% vs. 4.4%), liver/gastro-intestine disease (8.1% vs. 4.4%), infection (7.2% vs. 3.5%), and tumor (6.0% vs. 2.8%). Males had more deaths due to tumor (5.2% vs. 3.0%) and fewer natural deaths (11.2% vs. 15.9%) than females. CONCLUSIONS: The major UCOD category was heart/renal disease in the adult generation in Xaiyabouli Province. Cost-effective interventions based on the multisectoral noncommunicable disease prevention plan should be appropriately implemented. Mortality surveillance using the short VA tool should be conducted for all home deaths in Lao PDR.

Risk Factors of Preterm Delivery in the Lao PDR: Hospital-Based Matched Case-Control Study.

OBJECTIVE: To describe the risk factors among mothers in four central hospitals and two provincial hospitals in the Lao PDR, a lower-middle-income country in Southeast Asia. METHOD: The study used a hospital-based matched case-control design study. Purposive sampling was used to select 320 mothers (80 cases and 240 controls) from the six hospitals. Cases were mothers who had delivered a live newborn between 28 and 36 weeks and 6 days, while controls were mothers who had delivered a live newborn within 37 and 40 weeks. Data were collected through a review of medical records and face-to-face interviews using a structured questionnaire. Data were entered into EPI info (Version 3.1) then exported to the STATA programme (Version 14) for univariate and conditional multiple logistic regressions to identify risk factors for PTD at p ≤ 0.05. RESULTS: The mean maternal age of cases and controls was 25.2 (SD = 5.33) and 25.8 (SD = 4.37), respectively. In the multivariate analysis, factors with statistically significant relationships with PTD were the mother's religion (AOR: 3.01; 95% CI 1.24-7.26), the number of antenatal care visits (AOR: 3.39; 95% CI 1.6-7.18), having a pre-pregnancy maternal weight of less than 45 kg (AOR: 3.05; 95% CI 1.66-10.5), having had a premature preterm rupture of the membrane (AOR: 7.13; 95% CI 2.44-20.8) and vaginal bleeding during pregnancy (AOR: 6.89; 95% CI 3.02-15.73). CONCLUSIONS FOR PRACTICE: Improving capacity of the Laotian health system to provide quality ANC and increasing the number of ANC contacts is critical. This requires context specific strategies that also address the socio-economic factors, such as access to a nutritious diet, that contribute to PTD.