Invasive Pneumococcal Disease Following the Introduction of 13-Valent Conjugate Vaccine in Children in New York City From 2007 to 2012.

IMPORTANCE: Invasive pneumococcal disease (IPD) is a leading cause of pneumonia, meningitis, and bacteremia in children. In March 2010, a 13-valent pneumococcal conjugate vaccine (PCV13) was introduced to the routine childhood immunization schedule. The PCV13 contains 6 serotypes not included in the previously recommended 7-valent pneumococcal conjugate vaccine, including serotype 19A, the predominant cause of IPD prior to the introduction of PCV13.

OBJECTIVES: To describe changes in the epidemiology and incidence of IPD in children younger than 5 years in New York City (NYC) after the introduction of PCV13 and assess PCV13 coverage in NYC.

DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of population-based IPD surveillance data of the general population residing in NYC between January 1, 2007, and December 31, 2012. Invasive pneumococcal disease cases were identified by laboratory reporting of positive pneumococcal cultures from a normally sterile body site in NYC residents younger than 5 years. Isolates were serotyped. Participants included 468 cases younger than 5 years with IPD reported through routine surveillance to the NYC Department of Health and Mental Hygiene.

MAIN OUTCOMES AND MEASURES: Absolute differences and percentage changes in IPD incidence before and after the introduction of PCV13 by serotype grouping, age, and race/ethnicity. The number of PCV13 doses administered to children younger than 5 years was calculated using the NYC immunization information system.

RESULTS: There were 468 IPD cases from 2007 to 2012. The incidence of IPD decreased by 69.6% (95% CI, -79.3% to -55.5%) from 21.0 cases per 100 000 (2007-2009 mean) pre-PCV13 to 6.4 cases per 100 000 (2011-2012 mean) post-PCV13. Estimates of disease caused by serotypes included in the PCV13 decreased by 82.5% (95% CI, -90.0% to -69.3%), including a 79.7% reduction in serotype 19A (95% CI, -89.0% to -62.4%). Reductions in IPD incidence were seen in all age groups, with the largest reduction in children younger than 12 months (80.4%; P = .005). Incidence decreased significantly in all racial/ethnic groups. The percentage of children younger than 5 years in NYC with 1 or more doses of PCV13 increased from 47.8% in 2010 to 89.8% in 2012.

CONCLUSIONS AND RELEVANCE: The incidence of IPD in NYC children younger than 5 years and, particularly, the incidence of IPD caused by serotype 19A decreased dramatically following the introduction of PCV13, with reductions among all age and racial/ethnic groups. This represents a significant achievement for public health immunization programs and underscores the importance of achieving high immunization coverage.