Lander Willem, PhD

Wednesday 5 July, 19:30, AIMS Main Lecture Hall

Abstract: Background Respiratory syncytial virus (RSV) is a significant cause of acute lower respiratory infection in children under 5 years old, imposing a substantial global burden. Maternal vaccines and infant monoclonal antibodies (mAb) have emerged as promising preventive strategies and some a close to licensing. This talk focuses on assessing the cost-effectiveness of RSV prevention strategies in 72 GAVI-eligible countries and six European countries. Methods A static multi-country cohort model was employed to track RSV-related events from birth to 5 years of age, incorporating country- and age-specific demographic, epidemiological, and cost data. Disability-adjusted life years (DALYs) were used as primary health outcomes for GAVI-eligible countries, while quality-adjusted life years (QALYs) were used for European countries. Comparative analyses evaluated the costs and health effects of year-round maternal immunization, year-round mAb programs, and no program. Additional scenarios considered seasonal mAb administration and a catch-up program. Results In the 72 GAVI-eligible countries, the estimated RSV burden included 20.8 million cases, 1.8 million hospital admissions, 40 thousand deaths, 1.2 million discounted DALYs, and 611 million USD discounted direct costs for each birth cohort under the age of 5 years. Considering the assumed longer protection of mAb, but at higher costs, the optimal strategy varied depending on the willingness to pay (WTP) per DALY averted. Among the six European countries, a seasonal mAb program combined with a catch-up initiative was cost-saving in Scotland from the health care payer perspective and deemed cost-effective in other countries based on the national WTP threshold. From a societal perspective, accounting for leisure time lost, the seasonal mAb plus catch-up program was cost-saving in all countries except the Netherlands. ImplicationsOur findings assisted Gavi's decision to include maternal vaccines and infant monoclonal antibodies for RSV in their 2018 vaccine investment strategy. The choice between maternal immunization and mAb programs in European countries relied on factors such as protection level, duration, price, availability, and feasibility. We advocated for research efforts to accurately measure age-specific RSV-attributable hospitalizations in young children.

About: Lander Willem is an Assistant Professor at the University of Antwerp, Belgium, specializing in health economic evaluations within the domains of health care organization and public health campaigns. His research interests during his PhD and post-doctoral work focused on social contact patterns, individual-based modeling, and computational efficiency. In collaboration with SACEMA, he hosted three 5-day courses on individual-based modeling. Additionally, he serves as the principal investigator of an individual-based model for Belgium that explores the interplay between adaptive social behavior and close-contact disease transmission. Throughout his academic journey, he has transitioned from studying effectiveness to assessing cost-effectiveness. He has contributed to various projects concerning the burden of disease and health economics, including research on varicella-zoster virus (VZV), measles, influenza, pneumococcus, and respiratory syncytial virus (RSV). Notably, he has developed a platform for health economic evaluation in the R software, enabling high-performance multi-country modeling while incorporating state-of-the-art uncertainty analysis.