Objectives: Since the COVID-19 pandemic, the potential for vaccines to reduce pressure on health care systems has received much attention. However, evaluation of how vaccination may impact health system pressure is hindered by lack of a formal definition and measurement framework. We developed an approach for defining health system pressure and measuring its impact in healthcare settings and applied this approach to respiratory syncytial virus (RSV) and Clostridioides difficile (C. difficile) infections.

Methods: We conducted a targeted literature review and assessed hospital guidelines for prevention and control of RSV and C. difficile infections in hospital settings in Germany, Italy, and the UK. The definition and framework were tested via semi-structured interviews among healthcare professionals.

Results: Health system pressure can be generally defined as resource utilisation given a pre-set usable capacity. Its impact can be measured as the opportunity cost of actions taken to prevent or mitigate pressure. Actions to prevent or mitigate pressure due to RSV or C difficile can be classified by their impact on staff (labour resources), stuff (non-labour resources and materials), and structure capacity. Increased staffing needs drive RSV pressure during the RSV respiratory season and are considered to be extremely likely and extremely costly by 75% of the interviewees. C. difficile pressure is driven by the activation of outbreak-induced infection control protocols, which are likely to affect every capacity dimensions according to over 60% of the interviewees, and lead to large costs of infrastructure needed to isolate patients. In general, actions to mitigate pressure are associated with higher costs than actions used to prevent pressure before it occurs.

Conclusions: This research describes a novel definition and framework for health system pressure. Further development and application of this framework may enable HTA bodies to describe and measure the potential impact of vaccination on health care systems.