"This is exciting news for parents whose children suffer from frequent and painful ear infections," said Katherine Poehling, a pediatrician at Brenner Children's Hospital in North Carolina whose research appears this month in Pediatrics.

But a word of caution for Utah parents:

The strains of bacteria that typically cause Utah's pneumococcal diseases - from ear infections to meningitis - are unique, and are not targeted by the PCV7 vaccine, said Carrie Byington, a professor of pediatrics at the University of Utah.

Kids in Utah may benefit more from the vaccine's next generation - PCV13 - which will add the three strains of pneumococcal bacteria common in Utah, she said.

About 100 Salt Lake City children are expected to try PCV13 in a clinical trial scheduled from May through August.

Such a vaccine would be welcome news to parents like Patty Lisieski, whose 13-month-old son Diego Reyes Lisieski has suffered four ear infections in the past seven months.

"This last one has been the worst," she said. "He was actually falling over dizzy; his balance was off, I guess because of the fluid."

On Saturday morning, she took her toddler to see ear, nose and throat specialist Steven Miller to talk about whether it makes sense for Diego to get pressure-equalizing ear tubes.

Fluid is trapped in Diego's right ear, Miller explained, allowing germs that travel up his Eustachian tube to multiply in it. An ear tube would allow the fluid to drain, reducing the likelihood of infections.

Or, Lisieski could wait and see if her son's infections clear up this summer. "You're kind of in the driver's seat," the doctor said.

About 75 percent of children experience at least one ear infection before their third birthday, and nearly half of those children will go on to experience three or more ear infections, according to the Centers for Disease Control.

'Children have benefited'

Poehling and a team of researchers tracked 27,000 children in upstate New York and 150,000 children in Tennessee from birth to 2 years old. The children were born after the PCV7 vaccine was licensed by the FDA in 2000.

PCV7, also known as Prevnar, was designed to fight off pneumococcal diseases such as meningitis and blood infections. It is administered in four doses, from the time a child is 2 months old until the child is around a year old.

While it was hoped it would prevent ear infections, the vaccine's effectiveness was better than expected, Poehling found. The number of children who developed ear infections or received ear tubes shrank by 25 percent in New York and 16 percent in Tennessee.

Though the results are promising, the trend warrants careful monitoring, Poehling said.

PCV7 protects children against only seven of 90 known pneumococcal bacteria strains. Untargeted strains could begin occurring more frequently, rendering the vaccine less effective.

In the last year of the study "the benefits began to wane in Tennessee but not in New York," Poehling said, adding, "Children have benefited. You're not going to make it worse, but we may lose the benefits we see."

Many areas of the country are also seeing different strains of pneumococcal bacteria appearing, said Byington, who is also associate chairwoman for clinical research in the U.'s Department of Pediatrics.

Unique strains

In Utah, however, the strains that cause serious invasive pneumococcal disease - meningitis or pneumonia, for example - were different from the start.

It's unclear what this means for less-serious diseases, such as ear infections, also caused by the bacteria, because a study similar to Poehling's has not been conducted in Utah. However, Byington speculates that PCV7 helps prevent ear infections here - just not as effectively as in other parts of the country.

"That modest reduction [in ear infections in New York and Tennessee] may be more modest in our community just because we don't have the same serotypes," or strains, she said.

The strains here are closer to those found in Europe, Asia, Africa and Latin America.

"Although we do not know why the Utah serotypes are different from other parts of the U.S., this is an area of intense research at the University of Utah," Byington said.

The vaccine's manufacturer, Wyeth, recently announced that Utah will be one of 70 sites nationally where the next generation will be tested. The new version is expected to be licensed for use in the U.S. in the future.

"We're so excited to test the vaccine because we see the burden of invasive disease . . . and to see kids die of pneumococcal disease when there is a vaccine - that's really hard," she said.

In the meantime, Byington recommends that Utah parents still have their children inoculated with the PCV7 vaccine.

"I would just temper it with the fact that you may still see otitis media [ear infections] because we have different serotypes in our community," she said.

Lisieski is still deciding whether to opt for ear tube surgery for her son. She worries about continuing to give Diego antibiotics, to which he could develop a resistance. "I'm on the fence," she said. "I'd kind of like to wait and see."

lrosetta@sltrib.com

* Who was studied: About 27,000 children in New York and 150,000 children in Tennessee, from birth to 2 years old. The children were born after the approval of the PCV7 vaccine, which was aimed at protecting against meningitis and other serious pneumococcal diseases.

* What researchers found: The number of vaccinated children who developed frequent ear infections and/or received ear tubes declined by 16 percent in Tennessee and 25 percent in New York.

Source: Pediatrics