Extended Data Fig. 1: Potential effect of pneumococcal serotype replacement.
From: Childhood vaccines and antibiotic use in low- and middle-income countries
a, We compare the maximum estimate of the replacement disease associated with increased carriage of nonvaccine-type (NVT) pneumococci to the prevented burden of disease associated with vaccine-type (VT) pneumococci based on the approach described in the Methods section ‘Potential reduction in PCV10/13 effects owing to serotype replacement’. We plot the ratio of replacement-attributable NVT disease as a function of the relative pathogenicity of NVT and VT pneumococci. As this ratio may differ according to disease end point, the measure presented in a can be interpreted as end point agnostic. Estimates from two previous studies64, 65 of acute otitis media (AOM) and invasive pneumococcal disease (IPD) provide a range of 0.218–0.387 for the relative pathogenicity of NVT compared with VT pneumococci in these conditions. We plot estimates based on serotype replacement observations from three carriage studies in LMICs with continuous, prospective surveillance in place before and after PCV10/13 implementation35, 66, 70. b, We next illustrate the estimated ratio of replacement-attributable antibiotic-treated ARI to all-cause antibiotic-treated ARI among children aged 24–59 months, based on our estimates of the fraction of antibiotic-treated ARI attributable to VT pneumococci (Fig. 2). On the basis of the input values from the carriage and disease studies cited35, 64,65,66, 70, we infer that the maximum extent of antibiotic-treated ARI that replacement serotypes would account for would decrease to between 2.6% and 8.2% of the pre-vaccination incidence of all-cause antibiotic-treated ARI; this range is well below the estimated reduction associated with protection against VT pneumococci.
