Effectiveness of the 7-and 13-Valent Pneumococcal Conjugate Vaccines against Vaccine-Serotype Otitis Media

Background: Despite the demonstrated impact of pneumococcal vaccine (PCV) implementation on otitis media (OM), demonstration of real-life serotype-specific effectiveness of the 7-valent and 13-valent PCVs (PCV7 and PCV13) is lacking owing to the paucity of culture-positive cases. Furthermore, prelicensure PCV13 efficacy against OM was not studied. Methods: The study was conducted from October 2009 to July 2013. Case patients were children aged 5-35 months with OM (mostly complex OM [recurrent/nonresponsive, spontaneously draining, chronic with effusion]) from whom middle-ear fluid culture was obtained; controls were contemporary children with rotavirus-negative gastroenteritis in a prospective population-based rotavirus surveillance, from the same age group with similar ethnic distribution and geographic location. Vaccine effectiveness (VE) was estimated as 1 minus the odds ratio using unconditional logistic regression, adjusting for time since PCV implementation, age, and ethnicity. Results: A total of 223 case patients and 1370 controls were studied. Serotypes 19F and 19A together caused 56.1% of all vaccine-Type (VT) OM. VE of ≥2 PCV doses in children aged 5-35 months was demonstrated as follows: PCV7 against OM due to PCV7 serotypes, 57.2% (95% confidence interval, 6.0%-80.5%); PCV13 against OM due to PCV13 serotypes, 77.4% (53.3%-92.1%); PCV13 against OM due to the 6 additional non-PCV7 serotypes 67.4% (17.6%-87.1%); PCV13 against OM due to serotype 19F, 91.3% (1.4%-99.2%); and PCV13 against OM due to serotype 3, 85.2% (23.9%-98.4%). PCV7 and PCV13 VE against OM due to serotype 19A in children aged 12-35 months was 72.4% (95% confidence interval, 6.2%-91.9%) and 94.6% (33.9%-99.6%), respectively. Conclusions: PCV7 and PCV13 were effective against complex OM caused by the targeted serotypes.