Allaying the fears of parents about vaccine side effects and motivating and educating others to have their children routinely immunized is the purpose of National Infant Immunization Week, which ends April 28th.

Widespread childhood immunization in the past decades has freed parents from fear. Polio, whose frequent outbreaks caused panic only 50 years ago, is now a distant memory in the United States, and smallpox has been wiped out around the world.

"We now have a generation of young parents who aren't familiar with these diseases," said Dr. Jane Siegel, professor of pediatrics at UT Southwestern. "They've never had to worry about polio. We have to learn from history."

Siegel, who specializes in pediatric infectious diseases, points out that several diseases remain far from wiped out:

* Pertussis (whooping cough) outbreaks are frequent.

* Thousands of children who had not been immunized contracted measles in 1989-91 outbreaks in U.S. urban areas, and an ongoing risk of exposure to measles remains in other countries and from foreign individuals entering the United States. In fact, a 1999 study published in the Journal of the American Medical Association reported that children who weren't immunized against measles were 35 times more likely to contract the disease than those who had received the vaccine.

Still, many parents remain wary of vaccines. Most recently, concerns have surfaced about Prevnar, which protects against such pneumococcal diseases as meningitis, pneumonia and bloodstream infection.

Fear of immunizations was heightened in 1999 when the vaccine for rotavirus, a form of intestinal flu that affects young infants, was pulled from use because of increased risk (1 in 5,000) of bowel obstruction following vaccination.

"It was unfortunate, but it was caught early by the ongoing safety monitoring systems," Siegel said. "Prevnar is a totally different type of vaccine. It is very similar to the other meningitis vaccine (Hib), which has proven to be extremely safe and effective. We can't draw any analogy between Prevnar and the rotavirus vaccine."

Siegel pointed out that research has found Prevnar to be safe. In a random study of 38,000 patients, adverse effects were limited mainly to low-grade fevers.

Some seizures had been reported in children who had also received the whole-cell pertussis vaccine, now replaced by the safer acellular pertussis vaccine. But even under the old whole-cell vaccine, the rate of seizure was much lower than what is found in more common and readily accepted vaccines.

Prevnar also has proven to be as much as 97 percent effective in reducing the incidence of pneumococcal illness, which remains a threat to children. In the first two months of this year, Children's Medical Center of Dallas treated 21 patients with pneumococcal disease, of whom six were found to have meningitis. Seventy percent of these infections were caused by types of pneumococcus that are contained in Prevnar. Eighty-five pneumococcal cases were reported at Children's in 2000, of which eight were meningitis.

Beyond the wariness some parents show toward certain vaccines, infectious disease experts fear that apathy in some parents could have deadly results. Even a small drop in immunization rates could lead to a resurgence of some diseases.

Childhood vaccines prevent 10 diseases: polio, measles, diphtheria, mumps, pertussis, rubella (German measles), tetanus, Haemophilus influenzae type b (Hib) -- a cause of meningitis, chicken pox and hepatitis B.

Also, Prevnar should be administered for children residing in high-risk areas with high rates of disease. Although hepatitis-A vaccine is not currently recommended for routine use, it is recommended in areas with high rates of disease. Those areas consist of most western states (but not all of Texas) and several localized areas, including Dallas-Fort Worth. All children aged 2 to 18 who live in Dallas County should receive the hepatitis-A vaccine.

More information on immunizing children is available from the National Network for Immunization Information at this URL and from the Centers for Disease Control at this URL.

(Editor's Note: Patients, parents, health care providers, researchers, journalists and policymakers can find a portal to scientific information about vaccines at this website.)

[Contact: Ione Echeverria, Brian Cofer]

25-Apr-2001