Skip to main content
. 2015 Mar 3;33(10):1291–1296. doi: 10.1016/j.vaccine.2014.11.050

Fig. 1.

Fig. 1

Model of vaccine action. Note: S = susceptible, I = infected, R = recovered, VS = vaccinated susceptible, VI = vaccinated infected, VR = vaccinated recovered, λ = force of infection, γ = infectiousness period of measles, κ = coverage of measles vaccine for individuals vaccinated for the 1st time, τ = effectiveness of measles vaccine (85% for the first dose when vaccinating before one year of age, 95% after one year of age and 98% for two doses), κ2 = coverage of measles vaccine for individuals vaccinated for the 2nd time, through supplemental immunization activity (SIA) only (SIA coverage).