Table 1.
Model serotype classes (STCs).
Table 2.
Age groups (AG) used in the model.
Fig 1.
Individuals are born into the non-colonized compartments and can move throughout the system during their lifetime. Upon carriage acquisition, individuals move to the colonized (with a single ST), co-colonized with two STs, or triple-colonized compartments. Colonized individuals can clear carriage of one ST at a time. A proportion of colonized individuals will develop a pneumococcal disease. Vaccination (right arm of flowchart) reduces the chance of carriage acquisition and disease development for vaccine STCs. Vaccine can wane over time, but vaccination history is tracked. The waned vaccine compartment consists of colonized, co-colonized, and triple-colonized individuals. Detailed model flowchart is provided in Figures S3–S5 in S1 Text.
Table 3.
Vaccine effectiveness against IPD by age and serotype class. (PCV20 was only considered for adult vaccination).
Fig 2.
Calibrated versus observed IPD incidence per 100,000 over time in children age groups.
Dashed lines: data; Solid lines: model outcome.
Fig 3.
Calibrated versus observed IPD incidence per 100,000 over time in adult age groups.
Dashed lines: data; Solid lines: model outcome. IPD = invasive pneumococcal disease; PCV7 = 7-valent pneumococcal conjugate vaccine; PCV13 = 13-valent pneumococcal conjugate vaccine; PCV15 = 15-valent pneumococcal conjugate vaccine; PPSV23 = 23-valent pneumococcal polysaccharide vaccine; ST3 = serotype 3; STCs = serotype classes; V116 = an investigational 21-valent pneumococcal conjugate vaccine.
Fig 4.
IPD incidence per 100,000 projected by the calibrated model.
Top: IPD burden, infants; Bottom: Overall IPD burden by age group. Vaccination in adults 18 + : 80% receive PCV20, 10% receive PPSV23, and 10% receive PCV15 + PPSV23. Vaccine coverage used in these projections is given by Figure S6 in S1 Text. Reduced IPD incidence in adults is a result of indirect protection of pediatric PCV15 vaccination. IPD = invasive pneumococcal disease; PCV13 = 13-valent pneumococcal conjugate vaccine; PCV15 = 15-valent pneumococcal; STs = serotypes; VE = vaccine effectiveness.
Fig 5.
IPD incidence (cases per 100,000) attributed to each STC grouped by vaccine in each model age group.
Model calibrated STC distributions and data at the start and end of calibration period (2000 and 2019 respectively), and model projected STC distributions after 10 years of PCV15 in infants. IPD = invasive pneumococcal disease; PCV7 = 7-valent pneumococcal conjugate vaccine; PCV13 = 13-valent pneumococcal conjugate vaccine; PCV15 = 15-valent pneumococcal conjugate vaccine; PPSV23 = 23-valent pneumococcal polysaccharide vaccine; ST3 = serotype 3; STCs = serotype classes.