Immunization, Vaccines and Biologicals

WHO Consultation on respiratory syncytial virus (RSV) vaccine development

23-24 March 2015, Starling Hotel and Conference Center

Background and objectives

Background

Globally, RSV is responsible for over 30 million new acute lower respiratory infection episodes in children under five, resulting in more than 3.4 million hospital admissions associated with severe RSV disease each year. Over 90% of all RSV-associated deaths are estimated to occur in low and middle-income countries (LMIC). Currently, no licensed vaccine exists for RSV. Enhanced disease witnessed with a crude formalin-inactivated whole virus vaccine in the 1960s is an important historical background element. Recently there has been a resurgence of vaccine development, spurred onwards by major progress in vaccine science and understanding of protective immune responses that can be induced through vaccination. There were recently estimated to be 51 vaccine candidates in development, and long-lasting prophylactic monoclonal antibodies are also in the pipeline.

Since the greatest burden of disease is in infants and young children, WHO’s goal is to facilitate advancement of interventions that will prevent serious RSV morbidity and mortality in these age groups, and from the global perspective. With this in mind, two strategic goals for RSV vaccine development (noting that global disease burden is focused on low and middle income countries, LMIC) have been proposed:

  • maternal/passive immunization in order to prevent RSV disease in those under 6 months; and
  • active paediatric immunization in order to prevent RSV disease in infants and young children beyond the time window served by maternal immunization.

With multiple vaccine candidates and at least one second generation monoclonal antibody currently in clinical testing, and a robust preclinical pipeline, the global R&D community is seeking consensus and guidance with respect to acceptable clinical development and licensure routes. This meeting is the first step in a WHO process to provide guidance that aims to accelerate timelines to development and licensure of high quality, safe and effective RSV vaccines. WHO’s focus is on geographical areas where global disease burden is focused.

Meeting objectives

This is a first scoping meeting by WHO on the status of RSV vaccine development.

  • Provide guidance on clinical development pathways to support decision-making in low and middle income countries in accelerated timelines. The aim is to avoid inappropriate timelags between data for decision-making in high income countries vs data allowing decision-making in LMIC.
  • Agreed plan and timeline for development of consensus RSV efficacy endpoints and case definitions for preventive intervention trials in LMIC.
  • Identify key knowledge and capacity gaps that need to be addressed to facilitate product development, and frame these as global priority areas for inclusion in an RSV vaccine roadmap.