Fig. 1: Population demographics and invasive pneumococcal disease (IPD) burden.

a Among individuals who are aged ≥ 55 years, the proportion/share in annual age groups in Brazil, England, Malawi and South Africa as estimated from their national censuses, based on five years rolling average smoothed population counts to control for demographic stochasticity. b Number of IPD cases in five year age bands in older adults stratified by serotype in Brazil (2015–2017), England (2016–2019), Blantyre Malawi (2016–2019) and South Africa (2015–2018), reported from at least four years post-infant PCV introduction in each country, c Serotype-specific reported and predicted IPD incidence per 100,000 population between 55 years and 90 years in Brazil, England, Malawi and South Africa. The black circle represents estimated IPD cases per 100,000 population, the vertical line through the circle represents a 95% uncertainty interval in estimated IPD case number, the curve line is the exponential model fit and the ribbon represents a bootstrapped 95% confidence interval for the fitted line. The red and black points for England represent estimated IPD cases in the presence and absence of PPV23 vaccination, respectively.