Presentación de trabajos libres (Libro de resúmenes on-line)

Objetivo

El ensayo clínico de Fase 3 en curso SMART (MK-1654-007, NCT04938830) está evaluando la seguridad y tolerabilidad de clesrovimab en lactantes con mayor riesgo de enfermedad grave por virus respiratorio sincitial (VRS). Este análisis interino se centra en la seguridad en diferentes subgrupos predefinidos según la condición del participante, la edad y el peso en la primera temporada de VRS.

Materiales y métodos

Los lactantes elegibles para palivizumab que ingresaron a su primera temporada de VRS fueron aleatorizados 1:1 para recibir clesrovimab (105 mg) o palivizumab mensual. La seguridad y tolerabilidad se evaluaron utilizando las tasas de eventos adversos (EA) reportados por subgrupo, incluyendo EA relacionados con la intervención, en el sitio de inyección solicitados, sistémicos solicitados, y EA graves (EAG) en todos los participantes aleatorizados que recibieron la intervención del estudio.

Resultados

Las proporciones de participantes que experimentaron cualquier EA fueron generalmente comparables entre los grupos de intervención a través de los diferentes subgrupos (Tabla 1). Ningún EAG estuvo relacionado con la intervención del estudio. También se presentarán análisis de subgrupos por grupo de edad y peso.

Conclusiones

Los resultados de seguridad fueron generalmente comparables entre los grupos de clesrovimab y palivizumab en las categorías de subgrupos predefinidos en la primera temporada de VRS, consistentes con la población general. Se considera como limitación un pequeño número de participantes en ciertos subgrupos.

Tabla 1. Resumen de seguridad de clesrovimab vs. palivizumab en lactantes de alto riesgo para la enfermedad por VRS: Resultados interinos del ensayo de fase 3 (MK-1654-007, SMART) en la temporada 1 de VRS

Objetivo
En 2019, se inició un Observatorio de los Programas Nacionales de Inmunizaciones (PNI) de América Latina con el fin de analizar ycomparar su situación mediante un Ranking anual. El objetivo del presente estudio fue construir el Ranking correspondiente al 2023 ycomparar su evolución respecto de las ediciones anteriores.
Métodos
Se recopiló información de los sitios web oficiales de los ministerios de salud, OMS, OPS y UNICEF de 19 países de la región, y seentrevistaron a los responsables de los PNI. Se ponderaron indicadores vinculados a distintos dominios: vacunas de calendario endiferentes etapas de la vida, en situaciones especiales, antigripal, COVID-19 y aspectos programáticos. El Ranking se construyó en baseal puntaje final alcanzado por cada PNI expresado como porcentaje relativo al máximo posible (puntaje absoluto del país*100/puntajemáximo posible).
Resultados
Durante 2023, diez países realizaron cambios en sus calendarios, siendo El Salvador el país con más incorporaciones. Cuatro países introdujeron vacuna COVID-19; uno incluyó VPH en mujeres, otro incluyó varones y dos pasaron a dosis única; dos incorporaron hepatitis A; tres adicionaron alguna dosis más de IPV; dos introdujeron vacuna hexavalente acelular; uno incorporó varicela y otro meningococo 4CmenB.
Aunque el 53%, 63% y 74% de los países informó en 2023 algún incremento de coberturas vacunales (CV) para DTP1, DPT3 y SRP1,respectivamente, sólo cinco alcanzaron la meta del 95% para dichas vacunas trazadoras. La vacunación del primer año de vida y los aspectos programáticos resultaron los dominios más fortalecidos en la mayoría de los países. La vacunación de curso de vida fue el más desatendido.
Chile lideró el Ranking general por quinto año consecutivo, alcanzando el 63% del puntaje máximo. La puntuación de los países restantes varió entre 56% (Uruguay) y 16% (Venezuela) (Figura). El Salvador, Paraguay y Ecuador ascendieron 13, 6 y 5 posiciones,mientras que Argentina, México y Panamá descendieron 8, 6 y 3 lugares, respectivamente. Al comparar 2023 con 2022, el puntaje relativo aumentó en 14 países y el promedio de la región creció 10%.
Conclusiones
El año 2023 se destaca por la incorporación de nuevas vacunas a calendario y por el incremento de CV en muchos países. Esta recuperación sigue siendo la principal meta de la región. La consolidación de la vacunación de curso de vida también es prioritaria en varios países. Este análisis busca motivar a los PNI a abordar los desafíos pendientes.

Introduction: Respiratory syncytial virus (RSV) is a leading cause of LRTI and hospitalizations in infants, especially during the first months of life. In Central America, where RSV imposes a substantial clinical and economic burden, assessing the value of maternal vaccination (MV) is therefore essential to inform health policy decisions.

Objective: To assess the health and economic impact of year-round MV with RSVpreF (at 32-36 wGA) versus no vaccination in children ≤1 year of age, using a cost-utility analysis from the perspective of the national public healthcare system.

Materials and methods: A Markov-type cohort model was adapted to simulate the clinical and economic outcomes of RSV in a national birth cohort over 1-year time horizon, stratifying infants by gestational age at birth and clinical risk. Clinical inputs include age-specific incidence rates and case fatality rates (obtained from local or regional/global literature). Demographic data, RSV monthly distribution, and MV coverage (maternal Tdap as proxy) were based on local sources. The base case analysed direct medical costs (2025 US$) of RSV-LRTI hospitalizations (estimated using a bottom-up microcosting approach informed by clinical experts), and quality-adjusted life years (QALYs) discounted at 3%. Notably, the cost inputs do not include expenditures related to complications arising from RSV infection, focusing solely on the direct management of acute episodes. Vaccine efficacy was based on the final analysis of the MATISSE trial. Model robustness was assessed using sensitivity and scenario analysis.

Results: With no intervention, there were a total of 4,399 RSV-LRTI hospitalizations and 71 RSV-related infant deaths, representing an annual cost of US$44.19 million (M). From a public healthcare perspective, RSVpreF was dominant, preventing more RSV-related illness and less costly compared with no vaccination. Assuming a 55.0% coverage, MV with RSVpreF prevented approximately 25.4% hospital admissions (n=1,116) and 21 RSV-related death in infants ≤1. Compared with no vaccination, the MV strategy gained 599 QALYs and produced net direct medical cost savings of US$213.540.

Conclusions: Compared with no vaccination, year-round RSVpreF MV against RSV was a dominant strategy,offering improved health outcomes and substantial cost-savings to the public healthcare system. These findings support its implementation as a priority public healthcare intervention to prevent RSV-related morbidity and mortality.

OBJECTIVE
To evaluate RSV immunization coverage and costs in Colombia, identifying optimization opportunities through analysis of newborn protection strategies, aligning with VIRALNET’s mission to enhance preventive healthcare and expand population coverage in Latin America.

METHODS
Analysis used official pharmaceutical market data (2020–2024), national birth statistics (445,011 births in 2024), and international pricing databases. Current investment and coverage with Palivizumab (5-dose regimen) were estimated from total milligrams sold (3,420,000 mg in 2024), divided by dose per infant. Two alternative models were evaluated: (1) Redeployment of current budget (US$25.8M) to single-dose Nirsevimab (US$233/dose); (2) Integrated approach using Nirsevimab plus maternal RSVpreF vaccination (US$49/dose). Infant protection numbers were calculated based on costs and required investments. Financial analyses used a 4,000 COP/USD exchange rate. Primary outcomes: infants protected, coverage rate, and cost per protected infant.

RESULTS
The current strategy protects 9,120 infants (2.05% of newborns) with US$25.8M, at a cost of US$2,834 per protected infant. Reallocation to Nirsevimab would protect 110,916 infants (24.9% coverage) with the same budget, increasing the protected population 12-fold. The integrated strategy—Nirsevimab (US$25.84M) plus maternal vaccination (US$16.37M)—would cover all 445,011 newborns at US$95 per infant, lowering unit cost by 29.8-fold. A total investment of US$42.21M (63% increase) would expand coverage 48.8-fold. Single-dose options allow complete protection with one healthcare visit, simplifying delivery and ensuring full immunization for each treated infant.

CONCLUSIONS
There are significant opportunities to improve RSV prevention in Colombia. Strategic reallocation could protect 12 times more infants without increasing budget. Universal newborn protection is feasible with 63% more investment, while transitioning to single-dose products lowers cost per infant by 96.6% and simplifies logistics. This model offers an actionable strategy for Latin American countries to maximize coverage using existing or moderately expanded resources. Surveillance, cost estimations, and modeling provide critical evidence for regional health policy decisions.

Introduction: RSV is a major cause of LRTIs and hospitalizations in infants, particularly early in life. In Latin American countries, RSV leads to significant pediatric illness and healthcare costs. Evaluating the economic and public health impact of a novel RSVpreF maternal vaccine (MV) will be important to reduce the morbidity and mortality in children ≤1 year of age.

Objective: To assess the clinical and economic outcomes of implementing a year-round MV strategy with RSVpreF (at 32-36 wGA) versus no vaccination, through a cost-utility analysis from a public healthcare perspective.

Materials and methods: A Markov-type cohort model was adapted to simulate the clinical and economic outcomes of RSV in a national birth cohort over 1-year time horizon (stratifying infants by gestational age at birth and clinical risk). Epidemiological inputs (age-specific incidence rates, case fatality rates) were obtained from regional/global literature. Demographic data, RSV monthly distribution, and MV coverage (maternal Tdap as proxy) were based on local sources. The base case analysed direct medical costs (2025 US$) of RSV-LRTI hospitalizations (estimated through a bottom-up micro-costing method with clinical expert input), life-years, and quality-adjusted life years (QALYs) discounted at 3%. Vaccine costs were sourced from PAHO’s Revolving Fund. Vaccine efficacy was based on the final analysis of the MATISSE trial. Model robustness was assessed using sensitivity and scenario analysis.

Results: With no intervention, there were a total of 614 RSV-LRTI hospitalizations and 4 RSV-related deaths, representing an annual cost of US$13.79 million (M). From a public healthcare perspective, RSVpreF was dominant, providing greater health benefits at lower costs than no vaccination. Assuming a conservative 67.6% coverage with RSVpreF and vaccinating 30,143 pregnant women (97.4% of infants protected), this strategy was projected to prevent 34% hospital admissions (n=208) and 1 RSV-related death in infants ≤1. Compared with no vaccination, the MV strategy gained 38 life-years and QALYs, saving US$2.91 M in direct medical costs (mainly from cases avoided between August and December).

Conclusions: Compared with no vaccination, year-round RSVpreF MV against RSV was a dominant strategy, offering improved health outcomes and substantial cost-savings to the public healthcare system. These findings support its implementation as a priority public healthcare intervention to prevent RSV.

Introduction: A country in Central America introduced PCV7 into its pediatric NIP in Jan 2009, transitioning to PCV13 in Aug 2011. Nonetheless, pneumococcal disease (PD) remains a significant economic and public health problem.

Objective: Anticipating the availability of PCV20, this analysis aimed to evaluate the cost-effectiveness (CE) of universal PCV20 introduction into a pediatric NIP compared with PCV13 and PCV15, as well as examining the financial implications of switching from PCV13 to PCV20, all under a 2+1 scheme.

Materials and methods: A Markov cohort model was developed from the public healthcare payer´s perspective to estimate the clinical (measured as life-years and quality-adjusted life years) and economic benefits of vaccinating a simulated cohort of infants <2 years of age over 10 years. Costs and health benefits were both discounted at an annual rate of 3%. Direct vaccine effect inputs were derived from PCV7 clinical trials (efficacy for noninvasive diseases) and PCV13 real-world data (invasive PD). Incidence of invasive PD, serotype distribution, and healthcare costs were collected from local sources. The study also used a budget impact (BI) model to estimate potential changes in expenditure resulting from adopting PCV20 over 3 years. Vaccine costs were taken from PAHO’s Revolving Fund; for PCV15, we used the PCV13 price, as PCV15 was not listed. Societal perspective was explored by including indirect costs (productivity loss). Model robustness was assessed using sensitivity analysis and scenario analysis. Costs are reported in US$ 2025.

Results: PCV20 was associated with greater reductions in PD incidence and associated deaths compared with PCV13 and PCV15 in the CE analysis. Despite its higher vaccination costs versus comparators, PCV20 achieved greater reductions in disease cases, leading to overall savings in disease costs and establishing PCV20 as the dominant strategy in every scenario analyzed (both from a public healthcare and societal perspective). Over 3 years, switching from PCV13 to PCV20 for infants <2 years (97.9% coverage) was associated with a reasonable BI relative to the overall healthcare utilization costs.

Conclusions: Compared with PCV13 and PCV15, immunizing infants with PCV20 was estimated to provide substantial health benefits and reduce overall costs over a decade. The analysis suggests that PCV20 may be the preferred option for universal introduction into the pediatric NIP compared to other strategies.