PARENTING : Virus May Fall to Vaccine : Shot for chickenpox should be available soon, but there are unanswered questions about its effectiveness.

Spring may never be the same again in Shelley DeVito’s preschool classroom.

This year, as in years past, chickenpox has swept through the Woodland Hills Private School class, inspiring art projects, the reading of chickenpox literature and a countdown of the fallen.

The children “count down how many kids have it and how many we have left,” DeVito said.

But, thanks to a recently approved vaccine, preschool teachers and parents can look forward to far fewer cases of the highly contagious ailment, according to Tarzana pediatrician Joel Auerbach.

Auerbach expects the vaccine, approved March 17 by the Food and Drug Administration, to arrive in doctors offices within a month. A single shot of the vaccine is recommended for children ages 1 to 12, and two injections four to eight weeks apart in people 13 and older.

But there are still several unknowns about the long-awaited vaccine, said Dr. Eric Daar of Cedars-Sinai Medical Center’s division of infectious disease. One concerns the shot’s long-term effectiveness.

“Natural immunity we’re sure of,” said Daar.

While those who have had the pox have lifelong immunity, the vaccine is considered 70% to 90% effective. Nevertheless, trials of the vaccine found that vaccinated children who got the virus anyway suffered a mild case, he said.

There’s also a question about whether immunity among vaccinated children will wane in adulthood, when a case of chickenpox is typically more serious. Not just adults but teen-agers as well are at higher risk of a severe case of chickenpox.

Daar said a “generic” case may be characterized by “a dozen blisters and a little bit of fever.” But a severe case can cause “literally hundreds of blisters” in painful areas like the genitals, palms and soles of the feet.

While complications--particularly in healthy children--are rare, doctors said they can occur. These include infection of the lesions, pneumonia and the brain infections encephalitis and meningitis. Doctors said those at highest risk include “immune-compromised” people, such as those with cancer or AIDS, as well as pregnant women. The vaccine, which contains the live virus in a weakened form, is not an option during pregnancy.

Congenital varicella (chickenpox) syndrome can damage the fetus in the first trimester and cause possible malformation of organs and retardation. The fetus is damaged in “1% to 2%” of cases, pediatrician Auerbach said. An injection is available to pregnant women and others at high risk, soon after exposure to the virus. The varicella zoster immune globulin injection is a temporary prevention for the one exposure, Auerbach said.

Another danger during pregnancy is that in the course of delivery a baby can contract the virus from an infected mother. In the latter case, Daar said, mother and infant can be treated with the medication Acyclovir.

Parents may prefer that their child develop chickenpox immunity the old-fashioned way. But they may be left with no choice but to have their child vaccinated.

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According to Daar, “If parents would choose to go against a recommendation and not have their child immunized, there’s the chance the child would not become infected” as the number of cases dwindles with the new vaccine. “We’re left with the risk of lots of children who have never had the virus reaching adulthood.”

So parents will “have to gamble on the vaccine.” But, Daar added, it’s not such a bad gamble. “If it becomes clear that immunity wanes, boosting (additional shots at a later age to boost immunity) will work.”

Because chickenpox tends to hit its stride in spring, the vaccine may not arrive in time to prevent some children from becoming ill. Doctors offered some tips. Make the patient more comfortable with daily baths with an antibacterial soap; trim the child’s nails so the skin is not injured by scratching; give doses of children’s acetaminophen and antihistamines to relieve itching.

Daar listed some warning signs of rare complications. Confusion, lethargy or the inability to eat or drink could be tip-offs to “involvement of the brain.” Labored breathing is a sign of possible pneumonia, and “a lot of redness around the lesions” can mean infection.

To soothe children emotionally, Barbara Culverhouse of Studio City, a psychologist and mother of Erica, 8, recommends buying small red stickers. Erica, who had the pox when she was 3, “put them on her stuffed animals to commiserate.”

For the time being, the vaccination is not required by state law for school enrollment.

“It takes five or six years (after approval) before it becomes implemented as a requirement for enrollment,” said Nina Vassilian, senior health coordinator for the county Department of Health’s immunization program. She added that there is no “official timetable” when the vaccination will be available free of charge at county health clinics.

Lois Shepes, secretary at the Sherman Oaks Nursery School, was philosophical about the new vaccine.

“We’ll require it when we’re told to require it,” she said. “Kids have been getting chickenpox for years.”