RESUMO
BACKGROUND: Acute otitis media (AOM) nonresponsive to antibiotics is most commonly caused by antibiotic-resistant Streptococcus pneumoniae and Haemophilus influenzae. A strategy for treating these infections with parenteral ceftriaxone was adopted at the Children's Hospital Iceland. The 10-valent pneumococcal H. influenzae protein D-conjugate vaccine was introduced into the vaccination program in Iceland in 2011. The aim was to study its effect on the incidence of AOM with treatment failure. METHODS: This retrospective observational study included children who visited the Children's Hospital Iceland because of AOM or received ceftriaxone, regardless of indication from 2008-2015. Incidence rate was calculated for prevaccine (2008-2011) and postvaccine (2012-2015) periods using person-years at risk within the hospital's referral region. Incidence rate ratio of ceftriaxone treatment episodes of AOM was calculated using the Mantel-Haenzel method adjusting for age. Incidence risk ratio of ceftriaxone treatment if presenting to the hospital with AOM was calculated to adjust for rate of AOM visits. RESULTS: Visits for AOM decreased from 47.5 to 33.9 visits per 1000 person-years, incidence rate ratio (IRR) 0.86 (95% confidence interval [CI]: 0.81-0.91), P < 0.001. Fewer AOM episodes were treated with ceftriaxone, decreasing from 6.49 to 2.96 treatment episodes per 1000 person-years, with an overall Mantel-Haenzel adjusted IRR 0.45 (95% CI: 0.37-0.54; P < 0.001). This remained significant after adjusting for the decrease in AOM visits, IRR 0.53 (95% CI: 0.44-0.63; P < 0.001). CONCLUSIONS: Visits for AOM and ceftriaxone use decreased significantly after H. influenzae protein D-conjugate vaccine introduction. The observed decrease in ceftriaxone use is presumed to represent a decline in AOM with treatment failure, secondary to a decrease in resistant infections.
