Report of the WHO technical consultation on the evaluation of respiratory syncytial virus prevention cost effectiveness in low- and middle-income countries, April 7-8, 2022

Abstract

Policymakers often rely on impact and cost-effectiveness evaluations to inform decisions about the introduction of health interventions in low- and middle-income countries (LMICs); however, cost-effectiveness results for the same health intervention can differ by the choice of parameter inputs, modelling assumptions, and geography. Anticipating the near-term availability of new respiratory syncytial virus (RSV) prevention products, WHO convened a two-day virtual consultation in April 2022 with stakeholder groups and global experts in health economics, epidemiology, and vaccine implementation. The objective was to review methods, parameterization, and results of existing cost-effectiveness analyses for RSV prevention in LMICs; identify the most influential inputs and data limitations; and recommend and prioritize future data gathering and research to improve RSV prevention impact estimates in LMICs. Epidemiological parameters identified as both influential and uncertain were those associated with RSV hospitalization and death, specifically setting-specific hospitalization rates and RSV-attributable death rates. Influential economic parameters included product price, delivery costs, willingness-to-pay for health on the part of potential donors, and the cost of RSV-associated hospitalization. Some of the influential parameters identified at this meeting should be more precisely measured by further research. Other influential economic parameters that are highly uncertain may not be resolved, and it is appropriate to use sensitivity analyses to explore these within cost-effectiveness evaluations. This report highlights the presentations and major discussions of the meeting.

Keywords: Cost effectiveness; Global health; Monoclonal antibody; Respiratory syncytial virus; Vaccine.

Fig. 1

RSV Vaccine and mAb development pipeline. Note: Adapted from the from PATH Clinical Trial Tracker (as of September 21 2023) , .

Fig. 2

Hospitalized SARI cases, in-hospital CFR values and the estimated ratio of out-of-hospital to in-hospital deaths in Kenya and South Africa. Note: As the overwhelming majority of the RSV disease burden in children under the age of 1 in Kenya and South Africa is estimated to be due to RSV-associated deaths, the parameters that most strongly influence the burden reduction are the age-specific CFR of in-hospital and out-of-hospital severe cases and the efficacy and duration of RSV preventive interventions against severe RSV LRTI. More deaths within the window of effectiveness of the RSV preventive interventions will lead to a proportionally larger reduction in the total disease burden. A longer duration or higher efficacy of the effect against deaths will similarly lead to a proportionally larger reduction of the burden and thereby lower the DALYs averted, improving the cost-effectiveness of the interventions. The dose price of RSV preventive interventions will scale the cost-effectiveness of the interventions linearly. Figure reproduced from a previous publication .

Fig. 3

A) Univariate sensitivity analysis for Mali. Note: A series of univariate sensitivity analyses were conducted to assess the parameters whose variance has the largest influence on cost-effectiveness estimates for Mali. The parameter with the largest influence on the ICER across interventions is the inpatient case fatality rate (>300%). Parameters with moderate (<60%) influence include the probability of being hospitalized with RSV LRTI, probability of LRTI given RSV, age-based RSV attack rates, intervention product efficacy, and inpatient care costs. As deaths have the largest impact on cost-effectiveness estimates, case fatality rates are critically important inputs to capture accurately. Figure reproduced from a previous publication .

Fig. 4

Expected Value of Partially Perfect Information for Senegal (high incidence), Vietnam (low incidence), and Angola. Note: In Fig, three examples are presented to demonstrate the influential factors. The age-specific RSV hospitalization probability is the most influential factor for all countries. RSV incidence rate, hospital case-fatality ratio and community case-fatality ratio are also top influential factors. A few countries (like Angola) show that cost of outpatient care is an influential factor at low willingness-to-pay level (<1000 USD per DALY averted), because the cost of outpatient care is higher and more uncertain compared to other countries. However, at higher WTP levels, the top-ranking influential factors are the same as the other countries. Figure reproduced from a previous publication .