Pneumococcal vaccines for preventing otitis media.

Background: Acute otitis media (AOM) is one of the most common diseases in early infancy and childhood. Long term effects of recurrent episodes of otitis media, rapid emergence of drug resistant bacteria associated with AOM worldwide and huge estimated direct and indirect annual costs associated with otitis media have emphasized the need for an effective vaccination program to prevent episodes of AOM.
Objectives: The object of this review was to assess the effect of pneumococcal vaccination in preventing AOM in children up to 12 years of age.
Search Strategy: We searched the Cochrane Acute Respiratory Infection Group specialised register (last update, 26th April 2001), the Cochrane Library (Issue 4, 2000), MEDLINE (January 1966-August 2000) and reference list of all studies and review articles retrieved. We also contacted two vaccine manufacturers and first or corresponding authors of some included studies.
Selection Criteria: Randomised controlled clinical trials of pneumococcal vaccination with prevention of AOM as outcome in children aged 12 years or younger and a follow-up of at least six months.
Data Collection and Analysis: Five reviewers independently assessed trial quality and two reviewers extracted data. Two study authors were contacted.
Main Results: Eight trials on pneumococcal polysaccharide vaccine (PPV) and two trials on pneumococcal conjugate vaccine (PCV) were included. The highest efficacy of PPV was found in children aged 24 months and older: the rate ratio after adjustment for study was 0.833 [95%CI: 0.625-0.970]. The PPV has little effect on the prevention of AOM in children without documented prior episodes of AOM and only a moderate effect in the group of children with documented AOM episodes prior to vaccination. The results of the two PCV trials in healthy infants, which followed children from the age of two months until two years of age, could not be pooled because of lack of data. Both studies showed that the risk of recurrent disease decreased with 9% in the group of children receiving the PCV together with other childhood vaccinations at 2,4,6 and 14 months of age: Study Black et al 2000 : risk ratio=0.91[95%CI:0.86-0.96]; Study Eskola et al 2001: risk ratio=0.90 [95%CI:0.73-1.12].
Reviewer's Conclusions: Based on the currently available results of the effectiveness of pneumococcal vaccination for the prevention of AOM, a large scale use of pneumococcal vaccination for this indication is not recommended. The results of currently ongoing trials could provide more information whether pneumococcal vaccines are effective in specific high-risk (otitis-prone) populations.