Veenhoven R, Bogaert D, Uiterwaal C, et al. Lancet. 2003;361:2189–2195
Purpose of the Study.
To determine whether pneumococcal conjugate vaccine can prevent acute otitis media (AOM) among older children who have experienced previous episodes of AOM.
A total of 383 children (1–7 years of age) with ≥2 episodes of AOM in the year before study entry were studied.
Children recruited from a Netherlands general hospital and tertiary care hospital were randomized to receive either 7-valent pneumococcal conjugate vaccine followed by 23-valent pneumococcal polysaccharide or hepatitis A or B vaccines, in a double-blind trial. The randomization was stratified into 4 groups according to age (12–24 months versus 25–84 months) and the number of prior AOM episodes (from parental reports, with physician confirmation) (2 or 3 episodes vs ≥4 episodes). All children were monitored, via parental diaries and clinical examinations, for 18 months for the recurrence of AOM. Cultures of middle ear fluid and nasopharyngeal swabs were performed to assess the association of pneumococcal serotypes with AOM after vaccination.
Of the 383 children enrolled, 190 received pneumococcal vaccinations and 193 received control hepatitis vaccinations. A total of 474 episodes of AOM were diagnosed during the follow-up period after the final vaccination, with 275 recorded for 107 of the 186 children in the pneumococcal vaccine group (58%) and 200 recorded for 101 of 181 control subjects (56%). There was no decrease in AOM in the pneumococcal vaccine group, compared with the control group. Data from parental diaries indicated no differences between the pneumococcal vaccine group and the control group with respect to AOM symptom duration, symptom frequency, or use of treatment. Serial nasopharyngeal swabs obtained before and after vaccination in the pneumococcal vaccine group demonstrated a decrease in the conjugated vaccine serotypes but no overall decrease in the nasopharyngeal carriage of pneumococcus, compared with the control group.
There was no reduction in AOM episodes in the pneumococcal vaccine group, compared with the control group. Overall, there was no decrease in the carriage of pneumococcus.
Importantly, pneumococcal vaccination decreases the proliferation of conjugate vaccine serotypes and thus decreases nasopharyngeal carriage of the most frequent pneumococcal serotypes until children are older and immunologically more mature. Furthermore, the risk of older children developing recurrent AOM seems independent of receiving the pneumococcal vaccination. This study supports our current clinical practice of early childhood pneumococcal vaccination, without catch-up immunization of older children who might not have received the vaccine previously.