Effects of a large-scale introduction of the pneumococcal polysaccharide vaccine among elderly persons in Stockholm, Sweden
In October 1998 Stockholm County launched a 3-year vaccination campaign with the 23-valent pneumococcal polysaccharide vaccine (PPV-23) directed towards all elderly persons. We analysed the impact of this campaign on the incidence and serotype distribution of invasive pneumococcal disease (IPD) in Stockholm County, where the vaccine coverage was 36%, as compared to Skane County, where no vaccinati