Specific Viral Culprit Hard to Find in Otitis Media

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.

In 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.

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.

When there was a cold or ear infection among the children, a local sample was obtained and analyzed for specific bacteria and viruses, he explained, as he reported on the first three years and part of the fourth year of the study, which was partially supported by a grant from the National Institutes of Health.

One of the goals of this study was to assess the efficacy of potential strategies for otitis media prevention, he said.

We collected data from 102 families, including 213 subjects, he said. The average age of the subjects was 3.7 years; 110 were boys and 103 were girls. About 82.6 percent of the children were Caucasian; 11.3 percent were black. We detected viruses in 176 of the subjects, or 81 percent of those from whom samples were taken. We found that 114 of these subjects had one virus; 51 had two viruses; six had three viruses; one had four viruses; and four had five viruses. We found that 103 cases of otitis media were associated with virus.

Most of the children had infections with rhinoviruses. There were 140 children analyzed with rhinovirus upper respiratory infections and 62 of these children had otitis media (five of which were acute otitis media infections), or an association rate of 44%.

Dr. Alper said respiratory syncytial virus was identified in 27 subjects, 15 of whom had otitis media (5 acute cases), for an association rate of 56%. Eleven children were found to have influenza A infection, and eight of them had otitis media (3 acute cases), for an association rate of 73%. Five children had influenza B infection, with one of those children also having otitis media (20%). Twelve children were diagnosed with adenovirus infection, and six of them had otitis media (50%). Eighteen children were infected with coronaviruses, and seven of them had otitis media; and 11 children had parainfluenza viruses and four of them had otitis media.

Implications of the Study

Dr. Alper said the small numbers of nonrhinovirus infections made it impossible to determine if there was significance between a specific virus and the risk of developing otitis media.

Minor variations in antigens associated with different rhinovirus organisms makes it difficult to create an immunization vaccine to be effective against all strains, said Barry Hirsch, MD, Chairman of the Hearing Committee of the American Academy of Otolaryngology and Professor of Otolaryngology at the University of Pittsburgh Medical Center. These variations make each version of the virus different enough to make it unique so our immune system could not be induced to recognize it.

Dr. Hirsch said the take-home messages in Dr. Alper’s report are that kids with colds had a relatively high incident of otitis media, about 30 percent, and it could be asymptomatic, and secondly that the origins of the children’s colds were typically caused by rhinoviruses.

Additional reporting was contributed by Karen Shoffner.

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