Informing the pandemic response: the role of the WHO's COVID-19 Weekly Epidemiological Update.

On 31 December 2019, the Municipal Health Commission of Wuhan, China, reported a cluster of atypical pneumonia cases. On 5 January 2020, the WHO publicly released a Disease Outbreak News (DON) report, providing information about the pneumonia cases, implemented response interventions, and WHO's risk assessment and advice on public health and social measures. Following 9 additional DON reports and 209 daily situation reports, on 17 August 2020, WHO published the first edition of the COVID-19 Weekly Epidemiological Update (WEU). On 1 September 2023, the 158th edition of the WEU was published on WHO's website, marking its final issue. Since then, the WEU has been replaced by comprehensive global epidemiological updates on COVID-19 released every 4 weeks. During the span of its publication, the webpage that hosts the WEU and the COVID-19 Operational Updates was accessed annually over 1.4 million times on average, with visits originating from more than 100 countries. This article provides an in-depth analysis of the WEU process, from data collection to publication, focusing on the scope, technical details, main features, underlying methods, impact and limitations. We also discuss WHO's experience in disseminating epidemiological information on the COVID-19 pandemic at the global level and provide recommendations for enhancing collaboration and information sharing to support future health emergency responses.

WHO's Investigations and Studies, Unity Studies: A global initiative creating equitable opportunities for enhanced surveillance, operational research, capacity building, and global knowledge sharing.

The World Health Organization's Unity Studies global initiative provides a generic preparedness and readiness framework for conducting detailed investigations and epidemiological studies critical for the early and ongoing assessment of emerging respiratory pathogens of pandemic potential. During the COVID-19 pandemic, the initiative produced standardized investigation protocols and supported Member States to generate robust and comparable data to inform public health decision making. The subsequent iteration of the initiative is being implemented to develop revised and new investigation protocols, implementation toolkits and work to build a sustainable global network of sites, enabling the global community to be better prepared for the next emerging respiratory pathogen with epidemic or pandemic potential.

Analysing the characteristics of a measles outbreak in Houaphanh province to guide measles elimination in the Lao People's Democratic Republic.

INTRODUCTION: In recent years, the incidence of measles has declined in the Lao People's Democratic Republic. However, an outbreak was reported in August 2014 in Houaphanh province, which was the biggest outbreak in the country since 2008. We describe the characteristics of this outbreak and outline critical interventions for the Lao People's Democratic Republic to achieve measles elimination. METHODS: Fever and rash cases in the Khouan and Samtai districts with an onset date from 1 September to 25 October 2014 were investigated. Active case finding and health facility record reviews were carried out. Appropriate samples from the individuals with suspected measles were tested to confirm the diagnosis. RESULTS: A total of 265 suspected cases including 12 deaths were reported from eight villages in the Khouan and Samtai districts. Forty-five individuals tested positive for measles IgM. Most of the confirmed patients were male (n = 28, 62%), less than 5 years old (n = 23, 51%) and from the Hmong ethnic community (n = 44, 98%). The majority of the people with suspected measles (n = 213, 80%) and all the confirmed ones were unvaccinated. A measles vaccination campaign conducted in the eight affected villages resulted in 76% coverage of the targeted population. DISCUSSION: Low routine coverage and measles occurrence among unvaccinated individuals indicate underimmunized areas. The geographical and sociodemographic characteristics of this outbreak highlight the need for tailored vaccination strategies to close the immunity gap. A sensitive surveillance system that is able to detect, notify, investigate and guide response measures, including a second measles dose in the routine immunization schedule, will be essential for the Lao People's Democratic Republic to attain its measles elimination status.

Trends in the incidence of acute watery diarrhoea in the Lao People's Democratic Republic, 2009-2013.

Diarrhoeal disease is the second leading cause of death in children under age 5 worldwide, with rotavirus being the main etiology. In the Lao People's Democratic Republic, acute watery diarrhoea (AWD) was introduced as one of the national notifiable diseases in 2004. We retrospectively reviewed the aggregate (n = 117 277) and case-based (n = 67 755) AWD surveillance data from 2009 to 2013 reported weekly from 1115 health facilities nationwide. Rotavirus rapid test data from all eight sentinel sites in Vientiane Capital in 2013 were also collected for analysis. The incidence of AWD ranged between 215 and 476 cases per 100 000 population and increased from 2009 to 2012 when it levelled off. The most affected age group was children under 5 who were about seven to nine times more likely to have AWD than the rest of the population (P < 0.0001). In children under 5, 74.8% of the cases were aged 0-24 months and AWD was 1.28 times more common in males (P < 0.0001). Among the 230 stool specimens tested in children under 5 in 2013, 109 (47.4%) tested positive for rotavirus. The increased AWD incidence over the study period may reflect a true increase in AWD or an improved sensitivity of the system. We recommend new mothers breastfeed up to two years after birth, which is known to reduce AWD morbidity and mortality in young children. We also recommend conducting rotavirus disease burden and cost-effectiveness studies to explore the benefits of introduction of rotavirus vaccine.

Introducing seasonal influenza vaccine in low-income countries: an adverse events following immunization survey in the Lao People's Democratic Republic.

OBJECTIVE: In 2012, Lao PDR introduced seasonal influenza vaccine in pregnant women, persons aged ≥50 years, persons with chronic diseases, and healthcare personnel. We assessed adverse events following immunization (AEFI). METHODS: We used a multistage randomized cluster sample design to interview vaccine recipients. FINDINGS: Between April and May 2012, 355,902 were vaccinated. Of 2089 persons interviewed, 261 (12·5%) reported one or more AEFI. The most commonly reported AEFIs were local reactions. No hospitalizations or deaths were reported; 16% sought medical care. Acceptance and awareness of vaccination were high. CONCLUSIONS: Following the introduction of seasonal influenza vaccine in Lao PDR, self-reported adverse events were mild.

National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings.

Although dengue has been a public health problem for several decades in the Lao People's Democratic Republic, the magnitude of the disease burden and epidemiological trends remain poorly understood. We analysed national dengue surveillance and laboratory data from 2006 to 2012 by person, place and time. Between 2006 and 2012, the annual dengue notification rate ranged between 62 and 367 cases per 100 000 population with an apparent geographical expansion of transmission throughout the country in recent years and concurrent co-circulation of all four dengue virus subtypes. An electronic database, called Lao People's Democratic Republic Early Warning Alert and Response Network, was introduced in 2008 to provide automated early warning for outbreaks and epidemics. Village outbreaks continue to be notified primarily through event-based surveillance, whereas the weekly indicator-based system provides systematic assessment of annual epidemic cycles. The dengue case data indicate a high and increasing burden of disease. Efforts now need to focus on using available data to prompt more effective outbreak response and to guide the design and implementation of intervention strategies.

National dengue surveillance in the Lao People's Democratic Republic, 2006–2012: epidemiological and laboratory findings

Although dengue has been a public health problem for several decades in the Lao People's Democratic Republic, the magnitude of the disease burden and epidemiological trends remain poorly understood. We analysed national dengue surveillance and laboratory data from 2006 to 2012 by person, place and time. Between 2006 and 2012, the annual dengue notification rate ranged between 62 and 367 cases per 100 000 population with an apparent geographical expansion of transmission throughout the country in recent years and concurrent co-circulation of all four dengue virus subtypes. An electronic database, called Lao People's Democratic Republic Early Warning Alert and Response Network, was introduced in 2008 to provide automated early warning for outbreaks and epidemics. Village outbreaks continue to be notified primarily through event-based surveillance, whereas the weekly indicator-based system provides systematic assessment of annual epidemic cycles. The dengue case data indicate a high and increasing burden of disease. Efforts now need to focus on using available data to prompt more effective outbreak response and to guide the design and implementation of intervention strategies.

Assessment of gender distribution in dengue surveillance data, the Lao People's Democratic Republic.

OBJECTIVE: Adolescent and young adult males account for a large proportion of dengue cases reported through national surveillance systems in the Western Pacific Region. To preliminarily assess the validity of these observed distributions, a field investigation was conducted in the Lao People's Democratic Republic's Savannakhet Province in November 2011. METHODS: Mixed quantitative and qualitative methods were used. Dengue surveillance data from Savannakhet Province, and aggregate hospital admission data from the Savannakhet Provincial Hospital for outpatients and inpatients were analysed by age and sex. Unstructured informal interviews were conducted with local health care workers, primary and secondary school officials and villagers. RESULTS: An excess of males was found among reported dengue cases in Savannakhet Province in the 15-49 year age group. Females in the same age group, however, were found to access health care more than their male counterparts. Qualitative assessments attributed this distribution to young females being more health-conscious and having greater health care-seeking behaviour. DISCUSSION: The excess of male dengue cases in the surveillance data appeared to be associated with a truly higher risk of dengue rather than greater health care access or health care-seeking behaviour by young men. This investigation indicated the importance of assessing the reported surveillance data within the context of health care utilization behaviour of the population under surveillance.

Seroprevalence of rubella and measles antibodies in Lao PDR.

BACKGROUND: Nowadays, measles and rubella epidemics still occur worldwide, particularly in developing countries. METHODS: The present study investigated seroprevalence of rubella and measles IgG antibodies by using a comercial enzyme immunoassay. The findings helped to understand the current status of these infections in school children in Vientiane Capital, Lao PDR. RESULTS: The seropositive rate for measles antibody was 97.6%. Most importantly, more than half of 411 healthy children (56.4%) were rubella seronegative and susceptible to acquired rubella infection. CONCLUSIONS: The results highlight a high proportion of rubella-seronegative children, suggesting that they are susceptible to rubella and face the risk of congenital rubella syndrome. It was the first study to report on seroprevalence of rubella in Vientiane Capital, Lao PDR.

Risk factors for protein-energy malnutrition in children under 5 years: study from Luangprabang province, Laos.

BACKGROUND: Laos is one of the poorest countries in which chronic malnutrition is highest. The aim of the present study was to determine the prevalence of and to identify risk factors associated with protein-energy malnutrition (PEM) in children under 5 years of age in Luangprabang province, Laos. METHODS: This cross-sectional study was undertaken from March to May 2004. Anthropometric measurements of 798 children were done and data were transformed into height-for-age, weight-for-age and weight-for-height ratios. Mothers were also interviewed with a semi-structured questionnaire. Anthropometric data were entered into Nutstat in Epi-Info 2000 and transferred to SPSS for analysis. RESULTS: There was a high prevalence of stunting, underweight and wasting, that is, 54.6%, 35%, and 6% respectively. It was also noted that children aged 12-23 months and Khmu ethnic children had a higher prevalence of stunting (65% and 66%) and underweight (45% and 40%), respectively. However, it was also found that boys were more prone to be stunted and underweight. Furthermore, restricted intake of meats, vegetables during illness, and low maternal education were main risk factors for child malnutrition in the study area. CONCLUSION: Socioeconomic-demographic factors, low maternal education, poor nutrition knowledge for mother and feeding practices for sick children are affecting children's health regarding stunting and underweight. It is recommended that an improvement in societal infrastructure, better maternal education and nutrition are needed to address the child malnutrition issue.

Health-care waste management in Lao PDR: a case study.

This study investigated the health-care waste (HCW) management at each health-care facility level at two selected sites in the Lao People's Democratic Republic (Lao PDR): Vientiane Municipality; and Bolikhamxay province. It focused on the amount of HCW, its segregation and the factors influencing HCW management, particularly segregation procedures. A high proportion of incorrectly segregated medical waste was found at each level of health-care facility. Re-segregation revealed 39, 62, 57 and 37% at national hospital, provincial hospital, district hospital and health centre level, respectively, was poorly segregated. The mean of generated HCW was 0.62 kg/bed per day (Vientiane Municipality) and 0.38 kg/bed per day (Bolikhamxay) at two study sites. A higher proportion of medical waste (MW) from the inpatient department at the primary health-care level was found. Thus, HCW management at primary health-care facilities needs more attention and should be better understood.