Higher-Valency Pneumococcal Conjugate Vaccines: An Exploratory Cost-Effectiveness Analysis in U.S. Seniors.

Introduction: Use of the 13-valent pneumococcal conjugate vaccine in nonimmunocompromised adults aged ≥65 years is controversial. Higher-valency conjugate vaccines (15-valent and 20-valent ) are under development; their potential cost effectiveness in older adults is unknown, particularly when potential indirect (herd immunity) effects from childhood vaccination are considered.

Methods: A Markov model estimated the cost effectiveness of current U.S. recommendations and alternative strategies using currently available and in-development pneumococcal conjugate vaccines in seniors. Separately, strategies using a hypothetical 20-valent vaccine adding the 7 most common disease-causing non-13-valent vaccine serotypes were considered. Sensitivity analyses were performed and alternative scenarios were examined. Data were gathered and the analyses were performed in 2020.

Results: In analyses considering only existing and in-development vaccines, sole 20-valent vaccine use cost $172,491/quality-adjusted life year gained compared with current U.S. recommendations under baseline assumptions (equal serotype effectiveness and no childhood vaccination indirect effects). Strategies using 15-valent vaccine were more costly and less effective. When 13-valent/20-valent vaccines were assumed ineffective against pneumococcal serotype 3 and 15-valent vaccine was fully effective, 15-valent vaccine cost $237,431/quality-adjusted life year gained. With indirect effects considered, 15-valent or 20-valent vaccine cost >$449,000/quality-adjusted life year gained. When adding hypothetical 20-valent vaccine under baseline assumptions, hypothetical 20-valent vaccine cost $139,348/quality-adjusted life year gained.

Conclusions: In-development pneumococcal conjugate vaccines may be economically unreasonable in older adults, regardless of serotype effectiveness assumptions, particularly when considering potential indirect effects from use of those vaccines in children. Adult vaccines containing high-risk serotypes not contained in childhood vaccines may be more promising.