Whooping cough cases could reach 'epidemic levels'

Sonoma County's whooping cough outbreak may have started in south Sonoma County, but has rapidly spread and is nearing epidemic levels, according to health officials.

Karen Holbrook, Sonoma County's interim health officer, said cases of pertussis, commonly called whooping cough, began showing up last year in Marin County and this year health officials have seen an unusually high number of cases in south county. "Now it is geographically all over the county," she said.

The Sonoma County outbreak is a reflection of a statewide trend that has 2014 on pace to surpass 2010, when the disease was officially declared an "epidemic" by state health officials. In 2010, Sonoma County had 238 confirmed cases of the disease. Through March of this year, there have been 199 confirmed cases.

The Petaluma City Schools District could not provide the number of confirmed cases in the district, but Tricia Rast, director of special services, did acknowledge, "We're seeing more cases than last year."

The district has been diligent about following county recommendations to combat the spread of the disease, and has sent out its own advisories warning parents of the increase in pertussis cases. "We are trying to make parents aware of the disease and its symptoms," Rast said. "We want to make sure people have as much information as possible. We are advising that if anyone has any of the symptoms, they go to a doctor sooner rather than later."

She added that the district is also stressing that children who come down with symptoms stay home until they recover.

Holbrook said the majority of the cases reported in the county were among high school students, although several have also been found among junior high school students.

While the seems to be primarily among older students, Holbrook said a strong emphasis has been placed on protecting infants because they are the most susceptible to complications from the disease. "Babies are at the highest risk," she said. "Our focus is on protecting the infants."

Holbrook said the best prevention is for expectant mothers to get vaccinated. "It is the best way to get the antibodies to the baby," she said. Once the baby is born, everyone associated with the infant should be vaccinated and anyone with any whooping cough symptoms should stay away from the child.

In 2010, 10 infants died of pertussis, however none were in Sonoma County, which hasn't seen an infant die from the disease since 2007. Last year there was one reported infant death in California.

Holbrook said a spike in whooping cough was not unexpected nor unusual, but the severity of the outbreak is abnormal. "We are seeing people getting ill who had previously been vaccinated," she observed. "The immunity does wane over time. It is an illness that comes in waves every three to five years. We were set up for another peak, we just didn't expect it to be so severe."

She noted that the immunity could be wearing off for students who received their last booster shot in junior high school and that could explain why the outbreak seems to be centered in the high schools.

Health officials recommend children be vaccinated at ages 2 months, 4 months, 6 months and again between the ages of 15 to 18 months. A booster is recommended between the ages of 4 and 6 years, and in California, students are required to get another booster vaccine before they begin seventh grade.

Parents can opt out of the school vaccination requirement by filling out an exemption form. Rast said "the majority" of the students in the Petaluma City Schools District have been vaccinated for the disease.

Holbrook pointed out that, while the percentage of incidents of pertussis is higher among unvaccinated persons, the vast majority of confirmed cases involved people who were up to date with their vaccinations. County statistics show that among all conformed cases of whooping cough, 88 percent of the patients were up-to-date with their vaccinations, 8 percent were unvacccinated and 4 percent were unknown.

Holbrook cautioned that pertussis is highly contagious. According to public health officials, there are especially high rates of transmission among household and school contacts, especially among students participating in extracurricular team activities.

Pertussis is an infection of the respiratory tract caused by a bacteria that spreads when an infected person coughs or sneezes. In the early stages, symptoms include a runny nose, sneezing, low-grade fever and mild cough. This stage is followed by explosive coughing outbursts that can often end with a high-pitch whoop, which gives the disease it common name. The coughing spells can be accompanied by vomiting and fever persists throughout the illness. Although the disease is treatable, symptoms may persist for several weeks or even months.

Holbrook said if a child shows any signs of pertussis, they should be immediately checked by a physician, stay home from school and stay away from infants.

(Contact John Jackson at johnie.jackson@arguscourier.com)