Thursday, Dec. 6, 2007 | After five students erupted in chickenpox Tuesday in El Cajon, public health doctors urged parents to immunize their kids — not once, but twice.

All five kids had been injected with one dose of chickenpox vaccine, a requirement to enter California schools. And all had fallen ill, surprising El Cajon parents who thought they’d staved off chickenpox with a single shot.

As chickenpox pops up in San Diego County schools, parents are learning the limits of the varicella vaccine. All California students get a single dose of the shot before enrolling in public schools, unless their parents object for religious or personal reasons. The Centers for Disease Control and Prevention now recommend a second dose to quash chickenpox, but schools don’t require it.

Outbreaks still erupt in classrooms, sickening kids who’ve been immunized once to the illness. Countywide, at least 26 children have gotten chickenpox since June. Among them, at least 15 had received a single dose of the vaccine, according to news reports and school staff. (Poway Unified, which reported 10 chickenpox cases, could not be reached by press time to confirm how many of the infected students were immunized.)

“When the vaccine first came out, we were all told, ‘This vaccine is terrific! … One shot would probably last you for decades,’” said Dr. John Bradley, director of the division of infectious diseases at Children’s Hospital of San Diego. Bradley sits on an American Academy of Pediatrics committee that sets national policy for vaccinations. “Then we started seeing breakthrough cases, chickenpox in kids who’d been immunized. And that was puzzling. We thought everyone would be protected.”

Thumbing through kids’ medical records, school nurse Rosemary Jaworski estimated that half her students got two chickenpox shots, and half got only one. Countywide, nearly 90 percent of children ages 1 to 3 are immunized, according to a 2006 CDC study. The survey doesn’t note whether the children received one dose of vaccine, or two.

“I see less and less chickenpox, and the few cases I see are very, very mild,” said Jaworski, who’s spent 22 years tending to kids at Horton Elementary School in San Diego. Minus chickenpox, her hours are filled fixing other small crises: The allergic girl who accidentally ate kiwi. The uninsured boy who needs a low-cost root canal, but can’t find a willing dentist. When she can, Jaworski ducks out to the lunchroom, and goads kids to eat more greens. Chickenpox doesn’t top her to-do list.

But when chickenpox does erupt, Jaworski said, parents of immunized kids are startled.

“Parents say, ‘Why did I do that, if they’re going to get it anyway?’” she said.

Newspapers and television crews have noted four school outbreaks this year, in Santee, Cajon Valley, Carlsbad and Poway. This year isn’t unique, said Dr. Wilma Wooten, a county public health officer. Five schools reported outbreaks in 2006, two in 2005, and one in 2004. More cases likely went unreported: Schools are only required to notify health authorities if five or more students are sick.

Scientists note that when immunized kids get chickenpox, they suffer fewer lesions and shorter illness than children who never got the vaccine. Dire brain and liver infections triggered by the pox “have basically been eliminated, with just a single dose,” Bradley said.

But the shot is no guarantee against infection, and loses power with time.

“The feeling now is that one dose wanes,” said Dale Parent, president of the California School Nurses Organization. Parent also works as a health services coordinator for Chula Vista Elementary School District. “A second dose is really necessary to prevent the kids from having varicella altogether.”

As the pox persists, scientists question the efficacy of the chickenpox vaccine, approved by the FDA a dozen years ago. Some tout a second dose, which slims a child’s risk of long-term infection from roughly 15 percent down to 2 percent. Scientists who tracked immunized kids for a decade found that kids with two injections were three times less likely to get chickenpox than kids who got a single shot. Last June, the CDC ramped up its recommended dose from one to two chickenpox shots.

But some doctors question whether the cost of chickenpox vaccine outweighs the benefits, especially if kids need a double dose. Physicians pay $74.56 for a single vial of chickenpox vaccine, more than triple the cost of Hepatitis B vaccines. Chickenpox is a relatively low-risk illness, and rarely fatal.

Unlike any other state-mandated shot, California law allows the state to skip chickenpox vaccines if its yearly budget can’t provide for them.

If governments pay for multiple doses of chickenpox vaccine, they lose resources better spent on riskier diseases, argued Dr. Sydney Spiesel, a Yale Medical School professor.

Economically, “it’s hard to justify,” Spiesel said. The illness’ main cost is to employers, who lose workers when their kids fall ill. Calculating that expense is tricky, he said. “And the cost of the vaccine hasn’t really come down.”

Chickenpox vaccine may also have a hidden cost, Spiesel said. Long after the illness subsides, chickenpox lies dormant in the child’s cells, he said. Unless the person is exposed to chickenpox again, boosting their immunity, the pox may later re-emerge as shingles, a painful rash that afflicts adults. If all kids are immunized, Spiesel said, adult patients don’t encounter the pox, and may need even more boosters to stave off shingles.

“When you adopt a universal use policy, you are then going to drive the disease into atypical groups where it can have many more complications,” said Barbara Loe Fisher, co-founder and president of the National Vaccine Information Center, a group that opposes mandatory vaccinations. “And with chickenpox, that’s what we’ve seen.”

Dr. Bradley, whose American Academy of Pediatrics committee recommends a second chickenpox shot, counters that immunized kids are less likely to develop shingles themselves. What’s more, he said, at-risk adults can artificially hike their immunity by getting a shingles shot. A year ago, the CDC recommended the injection for seniors age 60 and older.

“When we immunize kids, we’re preventing active chickenpox … We didn’t know what impact it would have on (shingles),” Bradley said. “And we still don’t. We’ve got 50 years to wait on that one.”

Dr. Howard Taras, who consults San Diego Unified schools on medical issues, also backs the chickenpox vaccine. Yet Taras is also unsure whether the second shot is worth the price. One injection stops chickenpox in about 70 percent of children, he said. A second injection would only cover the remaining kids, who are already less susceptible to the most savage strains of chickenpox.

“It’s really not as critical,” Taras said. “The first vaccine is very important, no question. But the second one is a reasonable question, in terms of expense.”

Few families pay upfront for immunizations. Health insurers usually pay for school-required shots, and uninsured families in San Diego can get free school vaccines through the county’s Infant Immunization Initiative, which doles out shots from a trailer on Oceanview Boulevard. Since an advisory committee to the CDC approved a second dose of chickenpox, the booster is free through the state’s Vaccines for Children program.

Ultimately, whether or not a child gets a second chickenpox shot comes down to “the attitude of where they go for care,” Jaworski said.

State laws that dictate which shots students need have lagged behind doctors’ research. Legislators might cut the delay by tying state requirements to the CDC’s advice, Parent said. But sooner isn’t necessarily better, she cautioned. Some critics worry that states have rushed to adopt vaccines before considering their side effects — in the case of chickenpox, a potential swell in shingles.

For Jaworski, the bottom line is simple: One less illness to fret about. As she darts into her office, preparing to prick a school volunteer’s arm for tuberculosis, chickenpox is a distant worry.

“Chickenpox?” Jaworski said. “It’s probably one of the few things we don’t deal with anymore.”

(Correction: The original version of this story misspelled “varicella” in the third paragraph. We regret the error.)

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