The mean number of office visits for otitis media in children younger than 5 years dropped significantly after the introduction of the 13-valent pneumococcal conjugate vaccine, according to findings published in the.
Previous studies have shown that more than half of children with otitis media (OM) have serotypes included in the PCV7 vaccine (4, 6B, 9V, 14, 18C, 19F, and 23F), wrote Xiaofeng Zhou, MD, of Pfizer, New York, and colleagues.
To assess the impact of PCV13, with the additional serotypes 1, 3, 5, 6A, 7F, and 19A, the researchers analyzed data from the U.S. National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey for three time periods: pre-PCV7 (1997-1999), after the introduction of PCV7 (2001-2009), and after the introduction of PCV13 (2011-2013).
Between the pre-PCV7 and PCV13 time periods, the researchers found significant reductions in the mean rates of OM visits of 48% and 41% among children younger than 2 years and younger than 5 years, respectively; reductions were 24% and 22%, respectively, when comparing PCV13 and PCV7. Ambulatory care visits for skin rash and trauma were not significantly different among the study periods.
Comparing the PCV7 and PCV13 time periods, the mean number of OM visits per 100 children declined from 84 to 64 per 100 children younger than 2 years, 41 to 34 per 100 children between ages 2 and 5 years, and from 59 to 46 per 100 children younger than 5 years.
The study findings were limited by several factors including the use of an ecologic study design, which was chosen to help reduce selection bias, but that did not show evidence of the field effectiveness of the PCV13 vaccine. Another limitation was the potential misclassification of patients with OM given clinician variability in diagnostic criteria, the researchers noted.
“Our results in this study, while not providing direct evidence of causality, nonetheless suggest a significant and positive impact of the PCV13 vaccination program on otitis media for children less than 5 years of age in the U.S., with further reductions in OM visits observed in PCV13 period following a decade of PCV7 use,” Dr. Zhou and associates said.
The investigators are employed by Pfizer, which funded the study.