The epidemiology of invasive pneumococcal disease in older adults from 2007 to 2014 in Ontario, Canada: a population-based study

In Ontario, pneumococcal conjugate vaccines (PCVs) have been sequentially introduced into the publicly funded childhood vaccination program since 2005. A 23-valent polysaccharide pneumococcal vaccine (PPV23) has been routinely recommended for adults aged 65 years and older since 1996. To determine the effect of herd immunity, we examined the epidemiology of invasive pneumococcal disease in adults aged 65 years and older.