May 9, 1997

Vaccine research leads fight against ear infections

Vaccine research leads fight against ear infections

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Pediatric Infectious Diseases research nurse Barbara Culley examines three-year-old Millie Marlin's ears for otitis while Millie's mother, Stephanie, keeps track of one-year-old Evan Marlin.

One-year-old Evan Burnett probably thinks the bubble gum-pink bottle of amoxicillin is a staple of his diet.

In just four months of his short life, he has had six ear infections, or as his mother recalls, one long ear infection.

It's a common problem in many homes with young children. Crying. Fever. Sleepless nights. Missed work. Days and days of three-times-a-day antibiotics. The pattern seems to repeat itself over and over.

"I am totally exasperated," said Stephanie Burnett, Evan's mother. "He'd get an ear infection, and would be on medication for 10 days. We would have a follow-up exam scheduled but often have to come back in before the exam because his ears would be infected again," she said.

"It's very frustrating and hard on everybody," his mother said.

Evan is one of many children who has experienced repeated ear infections, known in the medical world as acute otitis media.

"It is felt to be the most common infectious disease and the most common reason that children go to their pediatrician each year," said Dr. Kathryn M. Edwards, professor of Pediatrics at Vanderbilt University Medical Center. "The projected cost of medically and surgically treating otitis media each year in the United States is $3 billion to $4 billion. It's a very important problem."

VUMC is an international leader in the fight against ear infections, playing a major role in finding a vaccine to prevent repeated bouts of otitis media. The Vanderbilt research is focusing on the most common cause of ear infections, the bacteria streptococcus pneumoniae, or pneumococcus.

"We've been interested in otitis for many years," Edwards said.

Twenty years ago, Drs. Sarah H. Sell, professor of Pediatrics, Emeritus, and Peter F. Wright, professor of Pediatrics, began evaluating the causes of ear infections in children and demonstrated the important role that viruses played in making children susceptible.

"They began some of the initial trials in the use of a vaccine to prevent ear infections," Edwards said.

One completed VUMC study has shown that the vaccine given at a private pediatrician's practice was safe and effective in producing antibody responses. More studies are currently in progress in the community involving larger groups of infants, Edwards said.

Currently, about 300 infants are being enrolled in this study in another private community practice. The study is looking at the role of the vaccine in eliminating the pneumococcus bacteria that live in the nose and throat and the vaccine's impact on the prevention of acute ear infections in young children.

In the study, two-, four-, and six-month-old infants are given the vaccine by shot, then nose cultures are obtained each time they come in for a well or sick-child visit. The cultures look for the presence of the bacteria in the child's mucus.

Future testing – two to three years down the road – may involve using a nasal vaccine, Edwards said.

But there is a problem making Vanderbilt's research more difficult – streptococcus pneumoniae is becoming increasingly resistant to antibiotics.

"We now have organisms growing in the nose and throat which are totally resistant to penicillin and penicillin-like drugs," Edwards said.

VUMC and other medical centers have worked with the Centers for Disease Control to devise new guidelines that are now being issued to private practices about the use of antibiotics to treat ear infections.

The new guidelines include restricting the use of antibiotics to situations in which they are clearly indicated and using much higher doses of antibiotics than used in the past.

"We know that the resistance of these bacteria to antibiotics is driven by excessive use of antibiotics, and we are working very hard to begin to implement programs of more appropriate use and to restrict use to situations in which they are clearly indicated," Edwards said.

"We're becoming increasingly concerned that we can't treat colds or runny noses with antibiotics because inappropriate uses of antibiotics are simply selecting for resistant strains and when we need to use antibiotics, they will be less effective," she said.

Edwards said that newer antibiotics discovered over the past few years do not hold much hope in fighting the resistance problem.

"The fact that resistance is growing is more of a reason to work on a vaccine. It's certainly a much better way. If we can prevent infections and restrict the use of antibiotics, we could potentially reverse this increasing resistance. It's much cheaper to prevent disease than to treat it," she said.

Edwards said the precedent has already been set by the development of vaccines that have successfully fought other pediatric infectious diseases for years.

"Much of pediatric disease is prevented now because of immunizations for many different vaccines," she said. "When I became a pediatric infectious disease specialist, I saw hemophilus meningitis, the most common cause of meningitis in young children. Now I've seen the virtual elimination of that disease. It's a remarkable testimony to how prevention is so much more effective than treatment.

"It makes me very excited that the same may indeed be doable with ear infections," she said. "It's the same kind of theoretical approach, the same basic science understanding, that we've seen with the hemophilus vaccine."