Cost-utility of quadrivalent versus trivalent influenza vaccine in Brazil - comparison of outcomes from different static model types

ABSTRACT Background: Influenza burden in Brazil is considerable with 4.2-6.4 million cases in 2008 and influenza-like-illness responsible for 16.9% of hospitalizations. Cost-effectiveness of influenza vaccination may be assessed by different types of models, with limitations due to data availability, assumptions, and modelling approach. Objective: To understand the impact of model complexity, the cost-utility of quadrivalent versus trivalent influenza vaccines in Brazil was estimated using three distinct models: a 1-year decision tree population model with three age groups (FLOU); a more detailed 1-year population model with five age groups (FLORA); and a more complex lifetime multi-cohort Markov model with nine age groups (FLORENCE). Methods: Analysis 1 (impact of model structure) compared each model using the same data inputs (i.e., best available data for FLOU). Analysis 2 (impact of increasing granularity) compared each model populated with the best available data for that model. Results: Using the best data for each model, the discounted cost-utility ratio of quadrivalent versus trivalent influenza vaccine was R$20,428 with FLOU, R$22,768 with FLORA (versus R$20,428 in Analysis 1), and, R$19,257 with FLORENCE (versus R$22,490 in Analysis 1) using a lifetime horizon. Conceptual differences between FLORA and FLORENCE meant the same assumption regarding increased all-cause mortality in at-risk individuals had an opposite effect on the incremental cost-effectiveness ratio in Analysis 2 versus 1, and a proportionally higher number of vaccinated elderly in FLORENCE reduced this ratio in Analysis 2. Discussion: FLOU provided adequate cost-effectiveness estimates with data in broad age groups. FLORA increased insights (e.g., in healthy versus at-risk, paediatric, respiratory/non-respiratory complications). FLORENCE provided greater insights and precision (e.g., in elderly, costs and complications, lifetime cost-effectiveness). Conclusion: All three models predicted a cost per quality-adjusted life year gained for quadrivalent versus trivalent influenza vaccine in the range of R$19,257 (FLORENCE) to R$22,768 (FLORA) with the best available data in Brazil (Appendix A).

Costo-efectividad de la vacunación contra influenza pandémica en mujeres embarazadas en Colombia / Cost-effectiveness of vaccinating pregnant women against pandemic influenza in Colombia

OBJETIVO: Estimar la relación costo-efectividad de la vacunación contra influenza pandémica A (H1N1) 2009 en mujeres embarazadas en Colombia durante la segunda onda de la pandemia. MÉTODOS: Se construyó un árbol de decisiones que simulaba los resultados sanitarios (muertes y años potenciales de vida perdidos, APVP) en dos cohortes de mujeres embarazadas, una vacunada y otra sin vacunar. Los parámetros del modelo fueron extraídos de la literatura científica y los costos se estimaron a partir de un estudio previo. Se calcularon razones de costo-efectividad incrementales (RCEI). RESULTADOS: La vacunación de embarazadas contra influenza pandémica habría evitado entre 4 664 y 15 741 consultas ambulatorias y entre 119 y 401 hospitalizaciones. Los costos de atención evitados serían de US$ 249 530 a US$ 842 163. Para el escenario base, vacunar embarazadas sería costo-efectivo (RCEI/APVP evitado US$ 7 657). Esta RCEI fue sensible a la letalidad de la enfermedad; en escenarios de baja letalidad la vacunación no sería costo-efectiva en Colombia. CONCLUSIONES: La vacunación en embarazadas contra influenza pandémica es costo-efectiva en un escenario de alta mortalidad. La evidencia existente de que las mujeres embarazadas tienen mayor riesgo de presentar complicaciones y de que la vacuna es segura justificaría su uso en embarazadas.

OBJECTIVE: Estimating the cost-effectiveness ratio of vaccinating pregnant women against the 2009 pandemic influenza A (H1N1) in Colombia during the second wave of the pandemic. METHODS: A decision tree was constructed, which simulated the health results (deaths and years of potential life lost [YPLL]) in two cohorts of pregnant women; one vaccinated, the other unvaccinated. The model's parameters were drawn from scientific literature and costs were estimated on the basis of a previous study. Incremental cost-effectiveness ratios (ICER) were calculated. RESULTS: Vaccinating pregnant women against pandemic flu would have prevented between 4 664 and 15 741 outpatient visits and between 119 and 401 hospitalizations. Between US$ 249 530 and US$ 842 163 in costs of care would have been avoided. For the base scenario, vaccinating pregnant women would be cost-effective (ICER/YPLL avoided US$ 7 657). This ICER was responsive to the disease's fatality rate; vaccina tion would not be cost-effective in Colombia in scenarios with a lower fatality rate. CONCLUSIONS: Vaccinating pregnant women against pandemic influenza is cost-effective in a scenario with a high mortality rate. The existing evidence that pregnant women are at increased risk of complications and that the vaccine is safe would justify its use in pregnant women.

Costo efectividad de la vacunación contra influenza en menores de 2 años y mayores de 65 años en Colombia / Cost effectiveness of influenza vaccination in children under 2 years old and elderly in Colombia

Objetivo: Estimar la carga de enfermedad asociada a influenza y modelar el impacto epidemiológico y económico de la introducción de la vacuna para influenza en Colombia. Métodos: Se realizó un estudio de evaluación económica completa de la introducción de la vacuna de influenza en dos grupos poblacionales. Los desenlaces seleccionados en menores de dos años fueron la frecuencia de enfermedad respiratoria (ERA), consultas y hospitalizaciones por ERA. En mayores de 65 años se adicionaron las muertes y hospitalizaciones por enfermedad cardiosvascular y cerebrovascular. Resultados: En el escenario sin vacunación, el virus de influenza produciría anualmente 4 300 casos, 2 700 consultas, 900 hospitalizaciones y 230 muertes por ERA en menores de dos años. En mayores de 65 años, se presentarían anualmente 670 muertes por neumonía, 1 150 muertes por enfermedad cardiovascular y 720 muertes por enfermedad cerebrovascular relacionadas con influenza. El costo efectividad de la vacuna en menores de dos años oscila entre US $ 1 900 y US $ 2 967 por muerte evitada mientras que para mayores de 65 años la razón de costo efectividad seria costo ahorrativa. Conclusiones: Los resultados del presente estudio apoyarían la decisión del Ministerio de la Protección Social y algunas Secretarias de Salud de introducir la vacunación en Colombia para menores de dos años y mayores de 65 años.

Objective Estimating the burden of disease associated with influenza virus season and modelling the epidemiological and economic impacts of introducing an inactivated vaccine to Colombia. Methodology A complete economic evaluation was done in children aged less than 2 and adults aged over 65. The outcomes evaluated in the under 2-year olds included: the yearly number of cases of acute respiratory infection (ARI), medical visits, hospitalisations and deaths by ARI. The outcomes measured in adults were the number of yearly deaths and hospitalisations due to cardiocirculatory diseases (CCD). Results Influenza infection in children under 2 years old not having had vaccination may cause 4,300 cases, 2,700 medical visits, 900 hospitalisations and 230 deaths by ARI yearly. Amongst the elder group, influenza infection would be associated with 670 deaths by pneumonia and 1,870 deaths from CCD. The incremental cost effectiveness ratio (ICER) for flu vaccination among children under 2 ranged from USD$ 1,900 to USD$ 2,967 per averted death. ICER was cost saving in adults aged over 65. Conclusions This study's results supported the Colombian Ministry of Health's initiative for introducing yearly flu vaccination amongst small children and older adults in Colombia.

Eficacia y seguridad de la vacuna influenza en niños: detrás de la evidencia / Effectiveness and safety of influenza vaccine in children

La infección por virus Influenza es una enfermedad respiratoria aguda que se asocia a una elevada tasa de morbilidad y mortalidad. Todos los niños son susceptibles de desarrollar la infección, por lo que la mejor estrategia de prevención podría ser la vacunación universal pediátrica. Tradicionalmente,han sido reconocidos ciertos sujetos de mayor riesgo de desarrollar complicaciones. Si bien existe mucha evidencia que demuestra que la vacuna anti-influenza puede prevenir síntomas respiratorios, hospitalizaciones y muertes; recientemente, algunas publicaciones han mostrado resultados conflictivos revelando inconsistencias en las actuales indicaciones en términos de eficacia y efectividad. El presente artículo, revisa la evidencia publicada en torno a esta interesante controversia médica.

Evaluación económica de la vacuna contra la influenza aplicada al personal de salud que atiende pacientes oncológicos hospitalizados / Economic evaluation of influenza vaccine applied to health personnel attending hospitalised oncological patients

Objetivos Analizar, desde la perspectiva del pagador, el costo efectividad de la vacunación contra influenza al personal de salud que tiene contacto estrecho con los pacientes oncológicos hospitalizados en Colombia. Métodos Mediante un árbol de decisión, se identificó la relación de costo-efectividad de la aplicación de esta vacuna al personal de salud que tiene contacto estrecho con los pacientes oncológicos hospitalizados. La perspectiva es la del pagador. Los costos se valoraron en unidades monetarias y la efectividad se mide por la reducción en días de hospitalización de pacientes oncológicos como resultado de la disminución en las probabilidades de contraer el virus por la vacunación al personal de salud. Resultados Vacunar contra la influenza al personal de salud que tiene contacto estrecho con los pacientes oncológicos hace que, al ahorrar un día de estancia hospitalaria, simultáneamente se ahorren $ 2 978 000 (US$ 1 324). Conclusiones Vacunar contra la influenza al personal de salud que tiene contacto estrecho con los pacientes oncológicos es costo efectivo para una probabilidad de contagio del personal de salud que no ha sido vacunado mayor o igual a 0,02.

Objective Performing a cost-effectiveness evaluation of influenza vaccine for health workers coming into close contact with oncological patients from the payer's point of view. Methods As no evidence was found for influenza vaccine effectiveness in oncological patients, the cost-effectiveness of applying the vaccine to health workers coming into close contact with oncological patients was calculated by means of a decision tree; the payer's point of view was adopted. Costs were evaluated in monetary units and effectiveness was measured by the reduction in length of hospital stay for cancer patients as a result of lesser probability of catching the disease because of vaccinating the health workers. Results Vaccinating health workers coming into close contact with cancer patients led to savings of $2 978 000 (US$1 324) per day of stay saved. Conclusions Vaccinating health workers coming into close contact with cancer patients proved cost-effective, returning health worker contagion probability higher than or equal to 0.02.

Vacunación contra influenza para adultos mayores en México: consideraciones económicas / Influenza vaccination in the elderly population in Mexico: economic considerations

OBJETIVO: Presentar una estimación de los costos y resultados de salud que podrían obtenerse en México con la introducción de un programa de vacunación contra influenza en los adultos de 65 años de edad y más. MATERIAL Y MÉTODOS: Entre junio y octubre de 2004, en Cuernavaca, Morelos, México, se elaboró un modelo para estimar el número de años de vida que se pierden por problemas de salud ocasionados por la influenza y el porcentaje de los que podrían salvarse mediante la vacunación por influenza en adultos de 65 años de edad y más, así como el costo asociado a la atención de casos de influenza y el costo potencial de la vacunación, para obtener el costo neto por año de vida salvado. RESULTADOS: Utilizando dos escenarios de efectividad de la vacuna, se estimó un total de entre 7 454 y 11 169 años de vida que podrían salvarse mediante la vacunación de todos los adultos mayores en México a un costo de entre 13 301 y 21 037 pesos por año. DISCUSION: Si bien no se comparó con otros usos alternativos de los recursos, la intervención evaluada tiene un costo por año de vida ganado significativamente menor al producto interno bruto per cápita de México, lo que sugiere que es costo efectivo llevar a cabo la vacunación contra influenza en adultos de 65 años de edad en México.

The efficacy and effectiveness of influenza vaccination among Thai elderly persons living in the community.

OBJECTIVE: To determine the efficacy and cost-effectiveness of influenza vaccination in the Thai elderly living in an urban community. MATERIAL AND METHOD: The study design was a stratified, randomized, double blind, placebo-controlled trial. A total of 635 participants aged 60 years and older living in an urban community was randomized to receive an influenza vaccine or tetanus toxoid as a placebo injection. All participants were followed up 4-6 weeks in the community for influenza-like illness and treatment received, hospitalization and death for one year. A hemagglutination inhibition (HI) test for influenza virus antibody of all participants was done on the day of vaccination as well as 1 month, 5 months, and 12 months after the vaccination. Main outcome measures were immune response rate and protective titer, influenza-like illness, serological influenza, treatment received for influenza-like illness and their expenses, hospitalization and death during the study period. RESULTS: The immune response rate of vaccinations was 97.1% and protective titer for A (H1N1) and A (H3N2) strains were 96.4 and 98.6%, respectively. The incidence of influenza-like illness was 4.83% in the vaccine group compared with 10.88% in the placebo group. The relative risk reduction was 56% (95% CI = 14 to 77%). The survival analysis also showed that vaccinations significantly reduced the incidence of influenza (p = 0. 009). The number needed to prevent one episode was 17 persons (95% CI = 9 to 71 persons). The adverse reactions of vaccinations were mild and tolerable. However, the number of treatments received for influenza-like illness and their cost were not significantly different between the two groups. None of the subjects had pneumonia nor needed hospitalization during the study period. Seven participants died during the year of follow up, but not from influenza. CONCLUSION: In Thai elderly living in the community, influenza vaccination reduced the incidence of influenza-like illness by half, but not the number of treatments received for influenza-like illness, their cost, and its serious complications. In the year of the study, considering the cost of vaccines and the numbers needed to prevent one episode of infection from the provider's viewpoint, it may not be cost-effective to recommend that all Thai older persons living in the community should receive influenza vaccination annually. Vaccination recommendation for the elderly should be promptly implemented in expectation of a severe epidemic in Thailand.

Economic evaluation of influenza vaccination in Thai chronic obstructive pulmonary disease patients.

To determine the cost-effectiveness and cost-benefit of influenza vaccination in chronic obstructive pulmonary disease (COPD) patients the authors conducted a stratified randomized, double-blind, placebo-controlled trial from June 1997 to November 1998 at a university hospital in Thailand. A total of 125 COPD patients were stratified based on their FEV1 as mild COPD (FEV1 > or = 70% predicted), moderate COPD (FEV1 50-69% predicted) and severe COPD (FEV1 < 50% predicted) and in each severity stratum they were randomized to the vaccine group (received intramuscular injection with purified trivalent split-virus vaccine containing A/Texas/36/91 (H1N1), A/Nanchang 1933/95 (H3N2) and B/Harbin 107/94) or the placebo group (received intramuscular injection with vit B1). Number of episodes of acute respiratory illness (ARI) related to influenza (clinical ARI + a serum hemagglutination inhibition antibody titre of 38 or greater and a four fold titre increase in convalescent serum compared to acute serum) as well as severity of each ARI (outpatient treatment, hospitalization or required mechanical ventilation) and costs of treatment (direct medical costs comprised real drug costs from the hospital dispensary in outpatient cases and real charges in hospitalization cases) were collected and analyzed for the cost-effectiveness and cost-benefit of influenza vaccination. The incidence of influenza-related ARI in the study year was 27 per cent in the placebo group and 6.4 per cent in the vaccine group (relative risk [RR] 0.24, vaccine effectiveness 76%). The incidence was 27.3 per cent, 23.5 per cent and 29.2 per cent in mild, moderate and severe COPD respectively in the placebo group and 4.3 per cent, 12.5 per cent, and 4.3 per cent in the mild, moderate and severe COPD respectively in the vaccine group (RR 0.16, 0.53 and 0.15; vaccine effectiveness 84%, 47%, and 85% respectively). The incremental cost-effectiveness ratios demonstrated that for every 100 patients with mild COPD whom the authors decided to vaccinate, the cost would be 24,840 baht more and would prevent 18.2 outpatients, 4.8 hospitalizations and 0 patient from mechanical ventilation due to ARI related to influenza. Likewise, the authors would have prevented 5.1 outpatients, 5.9 hospitalizations, 5.9 mechanical ventilation and 20.8 outpatients, 3.9 hospitalizations, 8.3 mechanical ventilation for every 100 moderate COPD and every 100 severe COPD patients vaccinated respectively. More than 90 per cent of the costs of treatment of influenza-related ARI were costs of hospitalization and for patients with moderate and severe airflow obstruction, more than 90 per cent of these costs were attributed to the costs of treating the patients who required mechanical ventilation. Predicted cost savings for every 100 mild COPD, 100 moderate COPD and 100 severe COPD patients vaccinated were 125,629 baht, 538,184.3 baht, and 680,647.1 baht respectively. In conclusion: Influenza vaccination is highly effective in the prevention of acute respiratory illness related to influenza virus infection in COPD, regardless of severity of airflow obstruction. Vaccination is more cost-effective in preventing mechanical ventilation episodes and more cost-benefit in patients with more severe airflow obstruction. Influenza vaccination should be recommended to all patients with COPD with the higher priority provided to patients with more severe airflow obstruction.