OBJECTIVES

Pneumococcal disease, caused by Streptococcus pneumoniae, causes severe invasive pneumococcal disease (IPD) including meningitis, bacteremia and bacteremic pneumonia. 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 Australian children.

METHODS

A Markov model was developed to simulate V114-type IPD cases and deaths in a hypothetical unvaccinated birth cohort in Australia over 20 years. Inputs, including base-case pre-PCV era epidemiological inputs, were obtained from published literature. In the post-PCV scenario, pre-PCV era inputs were applied to PCV7 serotypes only, whereas pre-PCV13 and current-day inputs were used to estimate PCV13 not PCV7 type (PCV13-PCV7), and 22F/33F disease, respectively. Costs were estimated from a societal perspective (2018 Australian dollars) and discounted at 5%.

RESULTS

In the pre-PCV era, 1,104 V114-type IPD cases would occur in an Australian birth cohort over 20 years: 978 (89%) attributable to PCV7 serotypes, 116 (11%) to PCV13-PCV7 serotypes, and 10 (1%) to 22F/33F. V114 serotypes would cause 14 IPD deaths. Total cost of V114-type IPD was $21 million AUD. In the post-PCV era, V114-type IPD increased to 1,259 cases, of which 256 (20%) were PCV13-PCV7 serotypes, and 25 cases (2%) were 22F/33F. The increase in PCV13-PCV7 serotypes were attributable to serotypes 19A (n=139, 99%), 1 (n=19, 13%), and 7F (n=12, 9%). In the post-PCV era, the total cost of V114-type IPD increased to $24 million AUD with serotypes 22F and 33F ($531,794 AUD) accounting for more cost than serotype 3 ($240,321 AUD).

CONCLUSIONS

PCV7 serotypes cause most of pneumococcal-related morbidity and total costs and should be retained in investigational PCVs. Specific PCV13 serotypes also contribute significantly to disease burden. Expanding coverage to non-vaccine serotypes can prevent additional morbidity and costs.