Background: Acute otitis media (AOM) is a frequent complication of influenza in children. Vaccination is known to protect against influenza-associated AOM by preventing influenza illness. Live attenuated influenza vaccine (LAIV) is approved for use in eligible children ≥24 months of age.
Objectives: To estimate the efficacy of LAIV in preventing AOM associated with culture-confirmed influenza illness in children ≥24 months of age versus placebo and trivalent inactivated influenza vaccine (TIV).
Methods: Data were analyzed for the incidence of AOM in 6 randomized, double-blind, placebo-controlled trials in children 24-83 months of age (LAIV, n=4278; placebo, n=2784) and 2 randomized, double-blind, TIV-controlled trials in children 24-71 months of age (LAIV, n=2872; TIV, n=2903). Efficacy was measured against all influenza strains regardless of antigenic similarity in 10 influenza seasons for placebo-controlled trials and 2 seasons for TIV-controlled trials. In all studies, influenza was detected by viral culture, and AOM was diagnosed clinically by study investigators.
Results: The pooled efficacy of LAIV against influenza-associated AOM was 91.4% (0.3% vs 3.0% for placebo; P<0.001) and 61.2% (0.4% vs 1.0% for TIV; P=0.005). When analyzing only those children with culture-confirmed influenza illness, AOM was diagnosed in 11 of 145 (7.6%) LAIV recipients and 83 of 473 (17.6%) placebo recipients, for a 56.8% relative reduction of AOM (P=0.004). In TIV-controlled studies, AOM was diagnosed in 11 of 117 (9.4%) LAIV recipients and 29 of 251 (11.6%) TIV recipients, for a nonsignificant relative reduction of 18.6% (P=0.537).
Conclusions: Among children 24-83 months of age, this data suggests that LAIV substantially reduced the development of influenza-associated AOM compared with placebo and TIV. In addition to preventing influenza illness, LAIV significantly reduced the complications associated with breakthrough influenza among vaccinated children compared to placebo recipients by reducing the incidence of influenza-associated AOM. Sponsored by MedImmune.