Senator Eliot Shapleigh - El Paso, Texas

Doctors' offices and emergency rooms across the Dallas area have been inundated this week with sick patients complaining of flu-like symptoms.

But a closer look reveals that the patients most often are children and young adults, seeking care alongside their distraught parents.

Since the swine flu, or H1N1 virus, first appeared in Texas in April, it has seemed to target the young and not the old.

"We're seeing very little disease in people who are 65 years and older with this particular virus," said Dr. Jeffrey Kahn, a pediatric infectious disease specialist at UT Southwestern Medical Center and Children's Medical Center Dallas.

The lopsided outbreak is sending pediatricians scrambling, filling up the emergency rooms at pediatric hospitals and draining many pharmacies of child-size doses of anti-viral medication.

"Influenza always spreads very freely among children," said Dr. John Carlo, medical director of the Dallas County health department.

"Classrooms are the highest density places for infections to spread, and children have lower immunity," he explained. "They also have less hygienic practices and tend to stay infectious longer, which gives them more time to infect other children."

That might explain why more than 70 percent of the confirmed swine flu cases in Dallas County have been in people under 25 years old.

So far, 52 percent of the swine flu cases in Dallas County that required hospitalization were patients 5 to 24 years old and an additional 20 percent were 4 and younger.

Normally, elderly people suffer the most severe flu symptoms and comprise 60 percent of the hospitalized cases. But this year, they are only 1 percent, according to statistics kept by the Dallas County Department of Health and Human Services.

People ages 25 to 49 made up 22 percent of the hospital cases, and those ages 50 to 64 were just 5 percent.

"Older individuals seem to have some pre-existing protection," Carlo said. "It could have been something that previously circulated in the 1960s or 1970s."

Kahn said he had reached the same conclusion.

"It could be that one of the viruses that circulated 60 years or so ago was immunologically similar to H1N1, so those people may have some immunity," he said.

That's why children will get the first doses of H1N1 vaccine, possibly as early as next week. The state health department has asked for 237,000 doses of FluMist, which will target 2- and 3-year-olds. Exactly when they will arrive is not known.

However, the Centers for Disease Control and Prevention announced Thursday that the first 600,000 doses of swine flu vaccine were heading to 25 large U.S. cities or states, including Texas.

"I don't think we'll promise any doses until we actually have them in our refrigerators," Carlo said.

As an indication of the onslaught of pediatric flu cases, the CDC also released 300,000 doses of children's Tamiflu from the Strategic National Stockpile.

The medicine was stockpiled to protect Americans in a public health emergency, such as a terrorist attack, earthquake or flu outbreak.

On Thursday, Texas received 22,000 doses of liquid Tamiflu for children, said Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases.

The medicine may not pass muster with most parents, however.

"Some of the liquid formulations of Tamiflu will have an expiration date that may have passed," Schuchat said. "But we want people to know that the FDA has extended the expiration dates of those courses, after careful testing."

Doctors are prescribing Tamiflu to children with severe flu symptoms or underlying medical problems in hopes of preventing bacterial infections, pneumonia or even death.

The age discrepancy applies even to the flu's mortality rate.

Of the five flu-related deaths reported in Dallas County, three have been children. The youngest victim was 3 and the oldest was 52.

"Children 2 and younger always get the worst flu. But we haven't seen that many this year," said Dr. Susanna Mendizabal, a pediatrician who works at Parkland Memorial Hospital's Oak West community clinic in South Dallas.

Oak West's pediatric waiting room was filled Thursday morning with crying babies and coughing toddlers and their anxious mothers.

"At some of our clinics, we've seen a large influx of patients, most of them pediatric," said Jessica Hernandez, vice president over Parkland's network of community clinics.

Parkland has had to shift physicians between its clinics to cover the rising number of pediatric cases. It also had to suspend doctor appointments to accommodate more walk-in patients who need immediate care. Two of its clinics implemented weekend hours to handle the overflow of patients.

"We are seeing so many patients that the doctors and nurses should be getting sick by now," Mendizabal said. "But for some reason, we're not."