Flu vaccines may protect against AOM

Block SL. Pediatr Infect Dis J. 2011;30:203-207.

Influenza vaccines may be effective in protecting children from acute otitis media associated with influenza, according to a new review study.

Infectious Diseases in Children Editorial Board member Stan L. Block, MD, of Kentucky Pediatric and Adult Research in Bardstown Ky., along with researchers from Turku Hospital’s department of pediatrics in Finland, and MedImmune reviewed eight previously published studies of influenza vaccines in which influenza-associated AOM was identified as a secondary endpoint. Most of the studies compared the live-attenuated influenza vaccine (FluMist, MedImmune), the trivalent influenza vaccine (TIV) and a placebo.

The researchers noted 290 children with AOM of a cohort of 24,046 children. In a pooled analysis of six placebo-controlled trials, LAIV efficacy was about 85%, meaning that AOM was noted in about 0.4% of LAIV recipients compared with 2.9% of children who received placebo. This trend was even more pronounced in children aged older than 2 years. TIV efficacy was about 54%, meaning that about 1.2% of children who received TIV had AOM.

“In placebo-controlled trials, among children who acquired influenza despite vaccination, AOM was diagnosed in 10.3% of LAIV recipients and 16.8% of placebo recipients, representing a 38.2% (95% CI, 11-58.2) relative reduction in the development of AOM,” the researchers wrote.

AAP guidelines encourage the prevention of otitis media by “reducing known risk factors,” and influenza puts children at increased risk for AOM-associated morbidity, the researchers wrote. They added: “LAIV recipients who contracted breakthrough influenza illness despite vaccination developed AOM at a significantly lower rate than did unvaccinated children who developed influenza.”

The current study confirms data collected from several other recent, large randomized studies that examined the effectiveness of LAIV against AOM when compared with TIV or placebo.

“The fact that LAIV provides a high level of protection against influenza-associated AOM is expected, given the efficacy of the vaccine against influenza illness,” Block and colleagues wrote.

Disclosure: MedImmune provided grant funding for the study.

Jerome O. Klein

Use of influenza virus vaccine is part of the strategy for reducing the incidence of acute otitis media (AOM). But is one vaccine preferable to others? Block and colleagues reviewed the results of randomized double-blind controlled trials, including six trials comparing live-attenuated influenza vaccine (LAIV) and placebo and two trials comparing LAIV and trivalent inactivated influenza vaccine (TIV). Infants aged 6 to 23 months and children aged 24 months to 83 months were included in the analyses. But since LAIV is not currently approved in the US for children younger than aged 2 years, the most important data to consider now are those for the older age group. The results suggest that children who received LAIV had fewer episodes of AOM than those who received placebo and fewer episodes of AOM than those who received TIV. We need more data to be persuaded that LAIV is preferred to TIV for prevention of AOM, particularly in children with severe and recurrent disease. If the benefit of intranasal LAIV for prevention of the AOM is confirmed, the results would suggest that future vaccines for prevention of upper respiratory tract pathogens be tested in intranasal formulations.

– Jerome O. Klein, MD
Infectious Diseases in Children Editorial Board member

Disclosure: Dr. Klein reports no relevant financial disclosures.

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