This is an age-structured transmission dynamic model of serogroup A Neisseria meningitidis (NmA) to investigate the impact of immunisation with MenAfriVac. Individuals may be susceptible, carriers, ill or recovered and in each of these states be vaccinated or unvaccinated, with vaccinated individuals having lower risks of infection (carriage acquisition) and disease. The model captures the key features of meningococcal epidemiology, including seasonality, age-specific carriage and periodic but irregular epidemics. Seasonality is implemented through seasonal forcing of the transmission rate, the extent of which varies stochastically every year.
Model name: MenA model
Modellers: Mike Jackson, Lucy McNamara
Institution: Kaiser Permanente Washington Health Research Institute and Centers for Disease Control and Prevention (CDC)
The model simulate the transmission of serogroup A Neisseria meningitidis (NmA) using an enhanced SIR-type model. This dynamic model is a set of partial differential equations describing the movement of the human population through different model states based on age (in months), immunologic protection against NmA colonization/disease (high/low/none), and NmA colonization/disease status (susceptible, colonized, or diseased). For computational efficiency, the model is implemented as a set of difference equations. Model parameters (other than demography) are defined based on the literature where possible or are estimated from NmA colonization and disease data.