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Vigilance with vaccines

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Special to The Times

Pediatricians and public health experts once worried about children whose families couldn’t afford vaccinations. Now they worry about children whose families deliberately forgo the shots.

Free immunization programs and aggressive outreach efforts have virtually ensured that all children can be protected against childhood diseases such as measles, mumps and chickenpox. But some parents believe that the vaccines are more dangerous than the diseases they’re designed to prevent.

Their refusal to immunize has the potential to affect many other families.

“I have a lot of close friends who haven’t immunized their kids,” says Los Angeles resident Patti Wolff, mother of 3-year-old Jack. Although Wolff has immunized her son, her friends’ decisions make her question her own choice. “It definitely gives me pause,” she says. “Every time Jack goes in for another vaccination, I feel stressed out and have to decide again whether getting the vaccine is a risk I’m willing to take.”

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It’s true that vaccines are not entirely without risk. The most common adverse reactions, however, are mild -- redness and tenderness at the site of the injection, fever and irritability. Serious reactions, such as seizures and nervous system damage, are exceptionally rare, and, according to the National Vaccine Program Office, the risk of death is so small that it’s hard to assess statistically. (Although many parents believe that vaccines cause autism, scientific evidence does not support this theory.)

Parents who fear the vaccinations realize that their children are unlikely to contract a disease such as measles or mumps. When adequate numbers of children are vaccinated, unimmunized children are protected, a phenomenon called “herd immunity.”

“Outbreaks of infectious illnesses occur because the bacteria and viruses that cause them have the ability to jump from one person to another,” says Bruce Gellin, director of the National Vaccine Program Office. “Vaccines create dead ends.”

In short, kids who take the small risk of having a vaccine protect those who don’t.

“It’s like a four-way stop sign,” says Gellin. “If you knew everybody else was going to stop, you wouldn’t have to.”

But that protective effect works only up to a point. It erodes when large numbers of parents decide against immunization. Like the situation at the four-way stop, if others choose to ignore the signs too, sooner or later there’s going to be a collision.

With vaccination coverage at its current level, around 80% nationally, herd immunity isn’t completely protective. One recent study found that children whose parents chose not to allow them to be vaccinated for personal reasons were 22 times more likely to contract measles and six times more likely to contract pertussis (whooping cough) than were vaccinated children.

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The community at large is then placed at risk. Unvaccinated people can act as a source of transmission for these diseases. In 1996, an unvaccinated high school student triggered an outbreak of more than 100 measles cases in Utah. Although the majority of cases occurred among unvaccinated children, 34 under-vaccinated children who had received only one dose of the measles vaccine, six infants who were too young to have received the measles vaccine and one fully vaccinated teenager were also affected.

In 2001, more than 21 Oregon elementary school children fell ill with chickenpox. The first three recognized cases all occurred in unvaccinated children.

The need to maintain high levels of immunization is one reason why all 50 states have passed laws requiring parents to immunize their children before enrolling them in school. All states, however, grant exemptions to children with medical conditions that prevent them from being immunized. Most states also permit exemptions for religious beliefs.

Some states take exemptions one step further, allowing parents to opt out of immunizing their children if it is against their philosophical or personal beliefs to do so. In California, parents can elect not to immunize without so much as an explanation.

Wolff is sympathetic toward those parents. “I understand it’s not an easy decision,” she says. “Everybody’s trying to make the right decision for their kid.”

Not all parents are as understanding. To some, the choice not to immunize is seen simply as freeloading. “It’s wrong. It’s really, really wrong,” says Los Angeles resident and father of three Bernie Cummings. He doesn’t feel that some children should reap the benefits of immunization without having to assume any of the risk. “It’s socially irresponsible,” says Cummings.

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Many experts agree. With immunization rates at their current level, they believe that there’s a relatively narrow margin of safety and not a lot of room for personal exemptions. For some of the more highly infectious illnesses, even small drops in vaccine usage might lead to outbreaks of disease -- disease with potentially significant risks. Measles, for example, kills one or two kids out of every 1,000 who contract it.

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Dr. Valerie Ulene is a board-certified specialist in preventive medicine practicing in Los Angeles. She can be reached at themd@att.net. The MD appears the first Monday of the month.

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