Declaration of interest
A Vyse, J Campling, C Czudek, G Ellsbury, D Mendes, R-R Reinert are employees of Pfizer, which has an interest in pneumococcal vaccines. M Slack works as a contractor for Pfizer, which has an interest in pneumococcal vaccines. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.