Serotype distribution of invasive Streptococcus pneumoniae in Canada during the introduction of the 13-valent pneumococcal conjugate vaccine, 2010.

A baseline serotype distribution was established by age and region for 2058 invasive Streptococcus pneumoniae isolates collected during the implementation period of the 13-valent pneumococcal conjugate vaccine (PCV13) program in many parts of Canada in 2010. Serotypes 19A, 7F, and 3 were the most prevalent in all age groups, accounting for 57% in <2 year olds, 62% in 2-4 year olds, 45% in 5-14 year olds, 44% in 15-49 year olds, 41% in 50-64 year olds, and 36% in ≥65 year olds. Serotype 19A was most predominant in Western and Central Canada representing 15% and 22%, respectively, of the isolates from those regions, whereas 7F was most common in Eastern Canada with 20% of the isolates. Other prevalent serotypes include 15A, 23B, 12F, 22F, and 6C. PCV13 serotypes represented 65% of the pneumococci isolated from <2 year olds, 71% of 2-4 year olds, 61% of 5-14 year olds, 60% of 15-49 year olds, 53% of 50-64 year olds, and 49% of the ≥65 year olds. Continued monitoring of invasive pneumococcal serotypes in Canada is important to identify epidemiological trends and assess the impact of the newly introduced PCV13 vaccine on public health.