OBJECTIVES : Pneumococcal disease, caused by Streptococcus pneumoniae, causes severe invasive pneumococcal disease (IPD) including meningitis, bacteremia and bacteremic pneumonia. V114, a 15-valent pneumococcal conjugate vaccine (PCV) containing the 13 serotypes in PCV13 and 2 additional serotypes (22F and 33F) is under development. The objective of this study is to quantify the health and economic burden of V114-type IPD in New Zealand children.

METHODS : A Markov model was developed to simulate V114-type IPD cases and deaths in a hypothetical unvaccinated birth cohort in New Zealand over 20 years. Inputs, including base-case pre-PCV era epidemiological inputs, were obtained from the published literature. In post-PCV analysis, pre-PCV era inputs were applied to PCV7 serotypes only, whereas pre-PCV10 and current-day inputs were used to estimate PCV10 not PCV7 type (PCV10-PCV7), and V114 not PCV10 (V114-PCV10) disease, respectively. Costs were estimated from a societal perspective (2017 NZD) and discounted at 3.5%.

RESULTS : In the pre-PCV analysis, 183 V114-type IPD cases would occur in a New Zealand birth cohort over 20 years: 152 (83%) attributable to PCV7 serotypes, 9 (5%) to PCV10-PCV7 serotypes, and 22 (12%) to V114-PCV10 serotypes. V114 serotypes were associated with 7 IPD deaths. Total costs were $6.4 million NZD. In the post-PCV analysis, V114-type IPD increased to 219 cases of which 20 (9%) were PCV10-PCV7 serotypes and 47 (21%) were V114-PCV10 serotypes. Compared to the pre-PCV analysis, the additional cases attributable to PCV10-PCV7 and V114-PCV10 serotypes were mainly caused by serotypes 1, 3, and 19A. Costs of V114-type IPD increased to $6.8 million NZD.

CONCLUSIONS : PCV7 serotypes cause most IPD-related morbidity and costs and should be retained in investigational PCVs. Serotypes contained in PCV10 and PCV13 also contribute to IPD morbidity and cost. Expanding coverage to non-vaccine serotypes can prevent additional disease.