Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against invasive pneumococcal disease in people aged 65 years and over in the North East of England, April 2006–July 2012

• Vaccine effectiveness of PPV23 estimated for ⩾65 year old IPD cases.
• Estimates calculated using the indirect-cohort method with a stratified analysis.
• Vaccine effectiveness of PPV23 for ⩾65 year olds moderately effective.
• PPV23 less effective for cases vaccinated over the age of 75 years.
• Individuals should receive PPV23 vaccination shortly after turning 65 years of age.

The 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended for all aged ⩾65 years in the UK to help reduce the burden of invasive pneumococcal disease (IPD). A total of 728 IPD cases aged ⩾65 years were diagnosed between 1 April 2006 and 31 July 2012 in the North East of England. Crude vaccine effectiveness (VE) estimates for PPV23 were calculated using the indirect-cohort method using a stratified analysis. VE for persons aged ⩾65 years was 28.5% (95% confidence interval: −17.4%, 56.5%). PPV23 was less effective in older age groups at IPD diagnosis and for those vaccinated at an older age. Estimates of VE published since the introduction of PPV23 appear to show a decrease in VE over time, possibly due to changes in demographics, circulating serotypes and vaccine formulation. An effective PPV23 vaccination programme should continue in those aged ⩾65 years in the North East of England.