Introduction
Chronic hepatitis B (HBV) remains a major public health concern in Taiwan, where HBV seroprevalence reached 15-20% before the introduction of the national vaccination program in 1984. Chronic liver disease is known to negatively affect muscle mass and function, but the exact association between HBV infection and muscle mass is not fully understood. This study investigates the relationship between HBV infection and appendicular skeletal muscle mass (ASM) across age groups to better understand its impact on older populations.

Methods
This cross-sectional study included 2,917 participants undergoing health check-ups at a tertiary hospital in Taiwan. HBV infection was defined by the presence of HBV surface antigen. ASM was measured using dual-energy X-ray absorptiometry (DXA) and calculated as the sum of upper and lower limb muscle mass divided by height squared (kg/m²). Social and medical histories were collected through structured interviews conducted by trained nurses. Participants were stratified into two age groups (<50 years and ≥50 years). Group comparisons were performed using Chi-square tests for categorical variables and Student’s t-tests for continuous variables. Multivariate linear regression analyses were conducted to examine the associations between HBV and ASM in the two age groups.

Results
Across the participants in this study (mean age = 49.4 ± 12.0 years, 50.2% male), 10.5% were HBV positive. Among those ≥50 years old, HBV infection was significantly associated with lower ASM (unstandardized ß = -0.098 [95% CI: -0.179 to -0.016]). Other variables influencing ASM in this age group included age (p<0.001), male sex (p<0.001), body mass index (BMI) (p<0.001), total bilirubin (p<0.001), tea consumption (p<0.029), and regular exercise (p<0.001). In participants <50 years old, no significant association was observed between HBV and ASM (unstandardized ß = 0.016 [95% CI: -0.066 to 0.099]). Factors affecting ASM in this younger group included age (p=0.001), male sex (p<0.001), BMI (p<0.001), hemoglobin (p=0.004), and regular exercise (p<0.001).

Conclusion
Chronic HBV is independently associated with reduced muscle mass in those 50 years and older but not younger. Further studies are needed to uncover underlying mechanisms and to develop muscle mass screenings and preventative strategies in older individuals with chronic HBV.

Background:

Adult vaccine uptake remains notably low in many low-resource settings, yet its impact on public health responses during outbreaks is poorly explored. During the COVID-19 pandemic, many individuals in Sierra Leone made vaccine decisions for the first time in adulthood. Understanding how limited prior vaccine-decision experience affects uptake is critical to designing effective future immunization programs.

Methods:

This mixed-methods study was conducted in Freetown and Makeni, Sierra Leone, among three population groups: petty traders, pregnant women, and college students. Data collection included 435 online survey responses and 15 in-depth interviews. The study examined adult vaccine knowledge, COVID-19 vaccine decision-making, and the role of formal education and prior disease outbreak experience (Ebola) in influencing uptake.

Results:

Only 30% of participants reported being vaccinated for COVID-19. Uptake of other adult vaccines was similarly low, with tetanus (48%), yellow fever (25%), and influenza (7%) among the most reported. Many participants reported little to no prior experience receiving vaccines as adults, making the COVID-19 vaccine their first encounter with adult immunization. This lack of familiarity contributed to widespread uncertainty, hesitancy, and increased susceptibility to misinformation. Formal education was a strong predictor of COVID-19 vaccine uptake, with 51% of participants with more than high school education reporting vaccination compared to 21% of those with lower education levels. Additionally, barriers such as limited access to vaccination sites and personal autonomy were frequently cited in explaining decisions not to vaccinate.

Conclusion:

Findings suggest that limited exposure to adult vaccination prior to the COVID-19 pandemic played a significant role in the observed low uptake during the outbreak. This gap in routine immunization could hinder the success of future vaccination campaigns in the region. To address this, vaccine equity efforts in low-resource settings must not be limited to emergency response periods. Expanding access to adult vaccines during non-outbreak times can foster familiarity, build public trust, and lay a stronger foundation for timely, effective responses to future infectious disease outbreaks.

Context: Since 2023, dengue transmission has surged worldwide, with the Americas facing its largest epidemic since 1980. Over 4.1 million cases were reported, rising further in early 2024, prompting PAHO to issue an epidemiological alert. In response, the Dominican Republic’s Ministry of Health (MoH) launched the “National Plan for Dengue Prevention and Control” in March 2024. Focused on prevention, control, and education, the plan unites public and private sectors with communities to strengthen healthcare capacity, reduce cases, and improve vector control. This work explores the plan’s implementation and its role in dengue prevention.

Methods: The nationwide intervention followed PAHO’s Integrated Management Strategy for Dengue Prevention and Control. It included the Let’s Beat Dengue! campaign with the slogan “Eliminate, Clean, and Cover,” fumigation, mosquito breeding site elimination, health worker training, and the Anti-Dengue Family initiative, which empowered school students, teachers, and community leaders to become Anti-Dengue Heroes. The plan’s reach and dengue risk before and after the intervention were analyzed using monitoring reports, surveillance data, and population figures from the MoH and the National Statistics Office.

Results: From April 2024 to December 2024, 26,784 fumigations were conducted, 315,502 breeding sites eliminated, and 240,952 supplies distributed (including chlorine, water tank covers, and mosquito nets) across 8,325 sectors in all provinces and municipalities nationwide, impacting 1,048,907 households and 1,591,754 individuals. During this period (April–December 2024), compared to the same period in 2023, there were 578 confirmed dengue cases, down from 2,943 in 2023, reflecting an 80.4% reduction in dengue risk.

Conclusion: The intervention shows promising results, with a reduction in dengue cases observed. However, its effectiveness should be further evaluated using more structured methodologies and ongoing monitoring. These efforts underscore the importance of sustained funding, enhanced surveillance, and collaborative engagement across multiple levels, institutions, and sectors, including the community. Strengthening these initiatives could enhance the capacity to manage future dengue outbreaks and protect public health nationwide.