"Any time we see numbers go down we're excited about that," said Rebecca Ward, health education director at the Utah Department of Health. "But we have to keep in mind that pertussis is cyclic, and an ongoing battle. I can't say we've turned a corner."
Pertussis tends to come in waves and poses a quandary for infectious-disease-control experts, because it could have been eradicated.
Last year's outbreak wasn't limited to Utah. The state's rate of infection was higher than the national average, but other states had it worse, including neighboring Colorado, which declared it an epidemic.
Inadequate immunization is the primary culprit, said Ward. Children entering school are required to be vaccinated against the disease, with five doses of the DTaP vaccine, though some seek waivers.
Also, a recent study found that the DTaP vaccine may not be as effective as previously thought.
It appears to wear off after the fifth dose, which is given between the ages of 4 and 6, making older children more vulnerable, according to the New England Journal of Medicine.
For this reason, the U.S. Centers for Disease Control and Prevention (CDC) recommends booster shots for incoming seventh-graders and for adults as well. Mothers are told to get vaccinated with each pregnancy.
Last year the Salt Lake County Health Department ran a series of television ads urging parents, grandparents and adult caregivers of newborn babies to get the DTaP vaccine. Whooping cough is most dangerous, and lethal, for children under the age of 1 because they're too young to be fully immunized.
County-run clinics and Harmon's, which sponsored the stopwhoopingcough.org campaign, saw their DTaP vaccinations double, the county says.
Primary Children's Medical Center, however, reports no decline in the number of children hospitalized for pertussis.
And the five-county, southwestern region of the state has seen no relief, particularly in the polygamist community of Hildale in Washington County.
Last year the Southwest Utah Public Health Department documented 41 cases of whooping cough, said the agency's spokesman David Heaton.
This year to date, there have been 85 cases, more than half of them from the Hildale area, and mostly among unimmunized children, he said.
"I don't think it's a bona fide religious belief, more of a cultural resistance," said Timothy Larsen, a pediatrician in St. George. "Parents, members of the [Fundamentalist Church of Latter-Day Saints] faith, will say it's just something they don't do because it's not natural."
Whether spiking cases in southern Utah could trigger another statewide outbreak is hard to say, said Larsen. "It could be that we're lagging behind the rest of the state."
Pertussis is nicknamed for the violent coughing that follows symptoms similar to that of a mild cold or fever. The coughing can force air out of the lungs, causing the sick to inhale with a loud "whooping" sound.
But not everyone makes that characteristic sound, said Larsen, who notes, "If your kid has a cold (with a persistent cough) it's never a bad idea to get them checked out [and tested] by your pediatrician."
Stop whooping cough
Antibiotics may shorten the time that someone is contagious. But the Centers for Disease Control and Prevention say the best way to prevent pertussis is to get vaccinated. There are vaccines for infants, children, preteens, teens and adults.
The Utah Department of Health publishes a list of vaccination sources at http://www.immunize-utah.org.
Sources: Utah Department of Health and U.S. Centers for Disease Control and Prevention