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A New Vaccine Targets Sometimes Fatal Bacteria

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TIMES HEALTH WRITER

Parents of infants and toddlers should start making room for yet another vaccination in their children’s already packed immunization schedule.

The new vaccine, approved by the U.S. Food and Drug Administration in February, protects against the serious, sometimes deadly bacteria responsible for many cases of childhood meningitis, pneumonia and bacteremia.

Each year, Streptococcus pneumoniae causes 700 cases of meningitis, an infection of the brain and spinal column, and 17,000 cases of bacteremia, an infection of the bloodstream. It is also the major cause of infectious pneumonia in young children and is behind hundreds of thousands of childhood ear infections annually. The illnesses are collectively referred to as pneumoccoal infections.

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The vaccine, called Prevnar, is a long-awaited achievement, says Dr. Henry Shinefield, co-director of the Kaiser Permanente Vaccine Study Center in Oakland, where the studies on the vaccine were conducted.

“Of the cases of meningitis each year, 5% of children die and 20% are left with mental retardation or deafness,” he says. “It’s an ugly disease. Prevnar is a very effective vaccine in children who have invasive disease.”

Prevnar does not arrive on the marketplace free of controversy, however. Although all young children could benefit from it, experts say, its $58-per-shot price tag prompted the government to recommend it only for those age 2 and under.

Moreover, adults may be gun-shy about any new vaccine after the last vaccine to be routinely recommended--Rotashield, to prevent the diarrheal disease rotavirus--was linked to 15 cases of bowel obstruction and was pulled from the market last year.

“It’s possible that people might be afraid of another vaccine, but that would be unfortunate because Prevnar is a very important vaccine,” says Dr. Ben Schwartz, of the National Immunization Program at the U.S. Centers for Disease Control and Prevention.

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According to a Centers for Disease Control and Prevention committee of vaccine experts, Prevnar should be given to all infants at 2, 4 and 6 months of age, with a booster shot administered between 12 and 15 months. Most of the deaths and serious complications from pneumococcal disease are in children under age 2, notes Schwartz.

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For children ages 2 to 5, who would need only a single shot, the committee created guidelines to help decide whether Prevnar is worth the cost. But the guidelines are complicated and vary by risk group.

Those in the high-risk group, for whom the vaccine is “recommended,” include children with sickle cell disease, HIV infection, chronic illness or weakened immune systems.

Those in the moderate risk group, for whom the vaccine should be “considered,” include all children 24 to 35 months, and Native American and African American children. Pneumococcal disease rates are higher in these ethnic groups.

Children who attend day care are also considered at moderate risk, because rates of serious pneumococcal infection among children in day care are two to three times higher than in other healthy children the same age.

The guidelines are the most complicated of all the childhood vaccines and have irritated some doctors and health experts.

“Anything we recommended was criticized on some basis: cost, political reasons, scientific,” says Dr. Margaret Rennels, a pediatrics professor at the University of Maryland School of Medicine and a member of the advisory panel. “[The decision] is really up to the pediatrician and the family.”

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Besides sparing children from infections, the vaccine is highly valued for its ability to help curb the use of the antibiotics used to treat pneumococcal disease. Within the last decade there has been a stunning increase in the rate of antibiotic resistance to S. pneumoniae, according to a recent study.

There are more than 80 known strains of S. pneumoniae, which is spread by droplets of respiratory tract secretions through kissing, sneezing or coughing. The vaccine protects against the seven most common strains in infants.

Perhaps the best candidates for the vaccine among low-risk children ages 2 to 5 are those who have chronic ear infections, experts note.

Although Prevnar was approved for the prevention of serious pneumococcal disease (meningitis, bacteremia and pneumonia), clinical trials showed the vaccine led to a modest 8% reduction in the incidence of inner ear infections in children with a history of the disorder.

Still, with an estimated 24 million doctor visits each year for childhood ear infections, even an 8% decline would be significant, says Shinefield.

“People should not think of this as an ear infection vaccine because they’ll get the vaccine and they’ll still get ear infections and they’ll think it’s a lousy vaccine,” he says. “But if you are talking about cutting 8% among 27 million visits per year, that’s a lot.”

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Moreover, kids with the worst ear infection rates tend to benefit the most from the vaccine, according to data from the clinical trials. Vaccinated children with chronic ear infections had a 25% less chance of needing ear tubes--which help drain fluid from the inner ear to prevent infection--compared with similar unvaccinated children.

The placement of ear tubes is the single most common surgical procedure for kids under age 5, with about 500,000 surgeries a year.

Curbing pneumococcal disease should also make a dent in the nation’s health care tab. The disease in children alone is estimated to cost the nation $1.5 billion a year.

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It’s still not clear, however, whether health insurance plans will cover the vaccine for children ages 2 to 5, although most are expected to cover the four shots needed for children under 2.

Parents and pediatricians will have to weigh the vaccine’s benefits against its cost, the pain involved and any personal fears parents have about vaccine safety.

Rennels and other experts say that parents should not fear a repeat of the rotavirus fiasco, because Prevnar is a very different vaccine--similar to the hib vaccine, which has a good safety record.

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The rotavirus vaccine was an oral vaccine made with live virus; Prevnar is made from a portion of the killed virus. In Prevnar’s clinical trials, there were no cases of serious side effects from the vaccine, although about one in 10 children suffered from mild fever and many had soreness at the injection site.

Parents who are concerned about all the shots their infants require should discuss how the vaccines can be administered to minimize the number of shots required in one visit, experts suggest. And, several combination vaccines are being investigated to combine vaccines in a single shot.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

When Is Your Child’s Next Shot?

This is the 2000 U.S. Childhood immunization schedule approved by the Advisory Committee of Immunization Practices, the American Academy of Pediatrics and the American Academy of Family Physicians. Any dose not given at the recommended age shouldn’t be given as a “catch-up” immunization at any subsequent visit when indicated and feasible.

Birth to 2 months: Hepatitis B

1 month to 4 months: Hepatitis B

2 months to 6 months: Diptheria, Tetanus, Pertussis; H. influenzae, type b; Polio; S. pneumoniae

6 months to 18 months: Hepatitis B; Polio

12 months to 18 months: H. influenzae type b; Varicella

12 months to 15 months: Measles, Mumps, Rubella; S. pneumoniae

4 to 6 years: Diptheria, Tetanus, Pertussis; Polio; Measles, Mumps, Rubella

24 months to 12 years: Hepatitis A (in selected areas of the U.S.)

11-12 years: Hepatitis B; Measles, Mumps, Rubella; Varicells (if previously recommended doses were missed or given earlier than the recommended minimum age)

11-16 years: Tetanus and Diptheria toxoids (recommended at 11 to 12 years of age if at least five years have passed since the last dose)

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Source: American Academy of Pediatrics

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