Chicken pox cases up despite vaccine

Texas recorded a 41 percent increase in cases of chicken pox from 2005 to 2007, despite an eight-year-old requirement that children be vaccinated before they can enter kindergarten.

Texas enacted the vaccine requirement for the 2000-2001 school year, but has not mandated a booster for children between the ages of 4 and 6.

A federal advisory committee recommended last year that children get the second dose, after an initial dose at age 1. Texas Department of State Health Services officials said they will study the booster this spring to decide if it too should be required in schools and day care centers.

San Antonio pediatrician Dr. Dianna Burns said she has started seeing a few cases of the virus this season, which normally lasts from late winter through spring. She said most parents agree when she offers the booster.

"The problem is, we've had a shortage of the chickenpox vaccine," Burns said. "That hit us just about at the beginning of school. We've had to prioritize to make sure everybody had at least one dose, so we prioritize toward the front."

Chicken pox, known medically as varicella, is a viral illness marked by a low-grade fever and small blisters that break open and crust. Children with the virus are normally asked to stay home from school for a few days while they're contagious.

Shirley Schreiber, director of health services with the Northside Independent School District in San Antonio, said vaccinated students who get chicken pox end up staying home the same number of days as they would have without the vaccine.

"Parents would get very frustrated when the youngsters would come down with a case and it would be a milder case of varicella, because they had been vaccinated," she said.

In Bexar County, the number of recorded chicken pox cases grew from 420 in 2003 to 520 in 2006 and 861 last year.

"Most of the time, we ask them: 'Did you get the vaccine?'" said Roger Sanchez, an epidemiologist with the San Antonio Metropolitan Health District. "Virtually all of them say yes."

The vaccine has been successful at reducing the severity of chicken pox, said Dr. Marietta Vazquez, an assistant professor of pediatrics at Yale School of Medicine.

"No vaccine is 100 percent effective," Vazquez said. "We know that the vaccine is extremely effective in preventing severe cases. What we now see are very mild cases. But what we do know — what we are almost 100 percent certain — is that the solution to that is another dose of the vaccine."

Schreiber said she hopes the booster vaccine becomes mandatory, which could help reduce the number of "breakthrough episodes."

The federal advisory committee's recommendation of the booster last year resulted in high demand and some delays in shipping of the vaccine, said Dr. Nalini Saligram, director of global communications for the drug company Merck.

The company has increased production and the vaccine is available, Saligram said.