Pneumococcal Serotype Replacement and Distribution Estimation (PSERENADE) Project

Challenge

• Need better understanding of epidemiology, distribution & regional variability of serotypes causing invasive pneumococcal disease (IPD)
• Serotype replacement has been observed to vary by setting. Previous global serotype replacement analysis did not include LMICs and reflected PCV7 experience.
• Global analysis needed to inform development of future pneumococcal vaccines & global/national vaccination policy around product choice & schedule

Approach

• The PSERENADE project is estimating the impact of long-term use of PCV on invasive pneumococcal disease, including on replacement disease caused by non-vaccine-type strains and indirect protection in unvaccinated adults. In collaboration with colleagues at University College London, the effect of age on immunogenicity of both PCVs and polysaccharide vaccines is being evaluated in older adults to inform policy on adult immunization programs.
• Summarize the global evidence on the impact of PCV10/13 on serotype-specific IPD incidence for all ages
• Describe distribution of serotypes causing IPD in mature PCV10/13 programs in children younger than 5 years of age
• IVAC presented results from the PSERENADE project and highlighted a summary of evidence from 29 surveillance sites in 22 countries showing that the routine use of pneumococcal conjugate vaccines, PCV10 and PCV13, in childhood immunization programs has significantly reduced disease in older adults.

Results

• All IPD declined following PCV10/13 use in both children <5 years and adults ≥65 years, driven by substantial declines in vaccine types, which were partially offset by increases in non-vaccine-type IPD.
• Net impact was greater for children than adults ≥65 years.
• Net impact for adults was heterogeneous across countries (some sites returned to near-baseline rates while meaningful declines were sustained at others).
• Serotype 6A decreased in all strata, suggesting 6B provides cross-protection, including herd effects, at PCV10 sites.
• Serotype 19A decreased at PCV13-sites, mitigating replacement disease after PCV7 use, but on average increased at PCV10-sites
• No clear impact on serotype 3 IPD was observed.
• Data from low-income & high-burden settings were limited.
• Results for meningitis cases were similar to all-IPD
• Higher-valency PCVs under evaluation target over half of the remaining IPD cases, but some prevalent serotypes are not included in known investigational products.