Figure 1

Structure of dynamic transmission model with vaccination for MRSA infection in a hospital setting . This model structure is following the model structure in [23]. Related parameter definitions and mathematical details can be found in Tables 1 and 2. This is a basic framework focused solely on transmission and infection at patient population level in a hospital setting, and not aiming to model dynamic feedback between hospital and community, patient history (pre- or post-hospitalization), etc. Patients are flowing into the hospital at a rate Λ defined as number of patients admitted per time unit (e.g., number of admissions per day), with corresponding fractions denoted by λ flowing in each of the Susceptible/Colonized (CA-MRSA/HA-MRSA)/Infected (CA-MRSA/HA-MRSA) states, unvaccinated and vaccinated, respectively, upon admission. We assume that vaccination takes place adequately prior to hospital admission, so that patients can mount a protective immune response; we do not consider in-hospital vaccination of current patients, under the assumption that the duration of the hospital stay is likely too short to enable a significant vaccine-induced immune response. We also do not consider vaccine protection waning for vaccinated patients while in the hospital, assuming the vaccine effects last at least for the duration of the current hospital stay. ^¥ “*” indicates additional potential benefits of vaccination that can be considered in this type of modelling framework: (1) potential faster clearance in the vaccinated patients; (2) potential faster recovery from infection in the vaccinated patients (milder infections); (3) lower death rates in the infected vaccinated patients (milder infections). In the analyses performed here, we did not consider such enhanced vaccination effects, and all the related parameters are similar in the Unvaccinated and Vaccinated model components. The possibility of a vaccine impacting colonization [26–30] is taken into account as a potential reduction in the force of infection.