Background

Efficacy trials in next generation pediatric PCVs are not feasible given the high PCV coverage rate in this population. Immunogenicity trials demonstrate non-inferiority to current PCVs but do not provide insight on vaccine effectiveness (VE).

Methods

VE estimates of Merck’s pediatric 15-valent PCV VAXNEUVANCE™ (PCV15) against IPD were predicted with pooled immunogenicity data from randomized controlled trials using a previously published methodology¹. VE estimates were used as inputs for a dynamic transmission model² to predict serotype specific breakthrough disease incidence over 10 (simulated) years of a PCV15 immunization program in the United States. Predicted breakthrough disease incidence for PCV13 was estimated using real-world VE^{3, 4} over the same time horizon.

Results

Compared to values observed in the literature for PCV13, median predicted serotype specific PCV15 VE values are higher or similar for serotypes 4, 9V, 14, 18C, 19F, 23F, 3, 5, 7F, and are lower for STs 1, 6A, 6B, and 19A.

Overall, lower predicted incidence of PCV13-type breakthrough IPD occurs under a PCV15 program vs. PCV13 over 10 years. Breakthrough IPD incidence for PCV13 serotypes (excluding ST3) under a PCV15 program is similar to those expected for PCV13 despite lower VE for some STs. Breakthrough incidence of ST3 drops substantially in the year after implementation of a PCV15 program and remains low over 10 years.

Conclusions

Predicted PCV15 VE may result in lower breakthrough disease incidence of ST 3, and similar incidence for other PCV13 serotypes.

¹ ISPOR EU 2021; ² Submitted ISPPD 2022; ³ Moore 2016; ⁴ Whitney 2006