In a prospective study, researchers have found that most otitis media infections are associated with rhinovirus upper respiratory infections-making the prospect of a vaccine to prevent the ear infections remote.
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December 2008In the ongoing clinical trial among families recruited through the University of Pittsburgh and the University of Virginia, doctors said that using standard statistical methods they were unable to distinguish which virus, if any, would be worthy of being targeted to prevent otitis media.
Because of the large number of rhinovirus strains, it is unlikely that a vaccine will be developed in the near future, said Cuneyt Alper, MD, Professor of Otolaryngology at the University of Pittsburgh School of Medicine, who presented the study findings at the 23rd annual meeting of the American Society of Pediatric Otolaryngology at the Combined Otolaryngology Spring Meeting.
Instead, Dr. Alper suggested that prevention measures be focused on children who are at risk of developing otitis media. The research pinpointed several risk factors for the families that participated in the study.
Risk Factors
Dr. Alper said that children who have had bouts of otitis media in the past have a 2.6-fold risk of having another otitis media infection. That increase reached statistical significance at the p = 0.03 level, he said.
Minor variations in antigens associated with different rhinovirus organisms makes it difficult to create an immunization vaccine to be effective against all strains.-Barry Hirsch, MD
Another risk factor uncovered through his study was that children who spent considerable time outside the home-such as at day care centers-as opposed to being home with a parent also had an increased risk of developing otitis media. There was a 2.4-fold risk for these children, also a significant finding (p = 0.034).
Dr. Alper also found that children who were breast-fed had a 3.7-fold risk of suffering otitis media (p = 0.02).
In his presentation, Dr. Alper described his work among 140 families. Each family had a minimum of two children in residence, and the children ranged in age from 12 months to five years. They were followed for seven months-October through April.
Daily home tympanometry was performed by parents, who also kept daily home diaries. The children underwent pneumatic otoscopy weekly or whenever upper respiratory infections or otitis media was present.
It is known that at least 50 percent of otitis media is preceded by viral infections, Dr. Alper said. Somewhere between 20 percent and 40 percent of infections lead to otitis media.
Relationship of Viruses to Otitis Media
He said that a number of potential factors lead from an upper respiratory viral infection to otitis media, including increases in bacterial colonization, activation of inflammatory cascades, swelling of the nasopharynx, blockages of orifices, and genetic predisposition, which can all translate into otitis media.