Universal vaccination of children against hepatitis a in Chile: a cost-effectiveness study / La vacunación infantil universal contra la hepatitis a en Chile: análisis de la relación costo-efectividad

OBJECTIVE: To evaluate the healthcare and economic impact of routine hepatitis A vaccination of toddlers in Chile. METHODS: We used a dynamic model of hepatitis A infection to evaluate the impact of a two-dose vaccination program, administered at ages 12 and 18 months. The model incorporated the changing epidemiology of hepatitis A in Chile and the development of vaccine-induced herd immunity. Our analysis was conducted from the public payer perspective, and an estimation of the societal perspective was performed. Costs are expressed in 2005 U.S. dollars. RESULTS: Vaccination of toddlers rapidly reduced the healthcare burden of hepatitis A. In the base case (95 percent vaccination coverage, 100-year time horizon, 1 percent annual decrease in force of infection), the average number of infections fell by 76.6 percent annually, and associated deaths fell by 59.7 percent. Even at 50 percent coverage, the program reduced infection rates substantially. Routine vaccination of toddlers had economic as well as health benefits, saving $4 984 per life-year gained (base case scenario). The program became cost saving after 6 years, and its overall cost-effectiveness per life-year gained was largely unaffected by changes in disease-related costs, herd immunity, coverage rate, and annual decrease in force of infection. CONCLUSIONS: Routine vaccination of toddlers will reduce the rates of symptomatic hepatitis A and associated mortality. The two-dose schedule evaluated here will be less expensive than disease-related costs in the absence of vaccination from the sixth year of its implementation. These findings support the establishment of a routine vaccination program for toddlers in Chile.

OBJETIVO: Evaluar el impacto sanitario y económico de la vacunación sistemática de infantes contra la hepatitis A en Chile. MÉTODOS: Se empleó un modelo dinámico de hepatitis A para evaluar el impacto de un programa de vacunación de dos dosis administradas a los 12 y 18 meses. El modelo incorporó la epidemiología cambiante de la hepatitis A en Chile y la aparición de la inmunidad de grupo inducida por la vacuna. El análisis se realizó desde la perspectiva del financiador público y se hizo un estimado desde la perspectiva de la sociedad. Los costos se expresaron en dólares estadounidenses del año 2005. RESULTADOS: La vacunación de los infantes redujo rápidamente la carga de la hepatitis A para los servicios de salud. En la variante de base (cobertura de la vacunación: 95 por ciento; horizonte temporal: 100 años; reducción anual de la virulencia de la infección: 1 por ciento), el número promedio de casos se redujo anualmente en 76 por ciento y el número de muertes asociadas disminuyó en 59,7 por ciento. Incluso con una cobertura de vacunación de 50 por ciento, el programa redujo notablemente la tasa de infección. La vacunación sistemática de los infantes presentó beneficios económicos y sanitarios y ahorró US$ 4 984,00 por año de vida ganado (en el escenario base). El programa generó ahorros a partir del sexto año y la efectividad general en función del costo por año de vida ganado no se afectó por cambios en los costos relacionados con la enfermedad, la inmunidad de grupo, la cobertura de vacunación o la reducción anual de la virulencia de la infección. CONCLUSIONES: La vacunación sistemática de los infantes reduciría la tasa de hepatitis A sintomática y la mortalidad asociada. A partir del sexto año del programa, los costos de aplicar el esquema evaluado de dos dosis serían menores que los relacionados con la enfermedad si no se aplicara la vacuna. Estos resultados apoyan la implantación de programas de vacunación sistemática de infantes...

Influenza vaccination among the elderly in Bangkok.

This study aimed to determine the effectiveness of influenza vaccinations among the elderly in Bangkok in reducing influenza-like illness (ILI) and influenza-related complications. Using a non-randomized, controlled, prospective methodology, healthy, active people aged 60 years or more, living in the Bangkok Metropolitan Administration (BMA) area, were studied. The two study cohorts comprised 519 persons in the vaccinated group and 520 in the non-vaccinated group. The outcome under study was influenza-like illness (ILI), as reported by the study volunteers. The two groups were comparable for most socio-demographic characteristics, except for gender, level of education, marital status, and smoking habit. The age range was 60-88 years (mean: 68 years). Females outnumbered males in both groups, with ratio of female to male of 2.6:1 and 1.9:1 in the vaccinated and non-vaccinated groups, respectively. The top three co-morbidities among these groups were hypertension, diabetes mellitus, and heart disease, in that order. Only 1% of the volunteers reported lung disease as co-morbidity. During the 12-month study period, a total of 107 volunteers reported ILI in both groups, with 38 persons in the vaccinated group and 69 persons in the non-vaccinated group. There were 46 ILI episodes in the vaccinated group, and 86 in the non-vaccinated group, for a total of 132 episodes. The incidence rates rates of influenza in this population, therefore, were 8.9% for the vaccinated and 16.9% for the non-vaccinated groups; with a reduction in the rate of reported ILI and doctor visits of 8%. Vaccine effectiveness was rated at 47.6%, crude risk ratio at 1.9 (1.33-2.75), and adjusted risk ratio at 1.92 (95% CI: 1.25-2.95), after adjustment for gender, marital status, education, and smoking habit. No complications due to ILI were observed in this population during the study period. Hospitalizations during this period were due to non-ILI related causes, such as cancer and accident.