Fig. 5
From: Asymptomatic transmission and the resurgence of Bordetella pertussis
Comparing disease-free weeks in pre- and post-vaccination scenarios. Panel a shows the proportion of disease-free weeks (fade-outs) per year for the 50 US states in the pre-vaccine (1920–1945, black points and line) and post-vaccine (2006–2013, blue points and line) eras. Lines indicate best-fit exponential curves. Panel b shows the mean duration of consecutive disease-free weeks in both eras