Once thought to be nearly eradicated, pertussis, the highly contagious respiratory disease also known as whooping cough, surged last year in many areas of California, with hundreds more cases reported in 2013 than in the previous year, state figures show.
In the greater Sacramento region, the largest bump in pertussis cases occurred in Placer County, which reported 79 cases in 2013, up from 11 cases in 2012. Sacramento County reported 65 cases, almost double the number in 2012. Yolo County was the only county in the region to see fewer pertussis cases in 2013: four, down from six the year before.
California health officials cite a variety of reasons for the uptick. A major contributor, according to the state, was declining immunity among children who had been vaccinated years earlier and had yet to get the booster shot recommended at ages 11 or 12.
Other factors include the cyclical nature of the disease and an increasing number of parents opting out of immunizations for their children.
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“Historically, there are increases in the incidence of pertussis every few years, as more people become susceptible to pertussis, primarily through waning immunity,” the California Department of Public Health said in an emailed statement.
Unlike the flu, pertussis has no specific season. Caused by the bacterium Bordetella pertussis, pertussis is distinctive for the symptomatic violent coughing that makes it hard to catch one’s breath. After a coughing fit, young children with pertussis often need to take deep breaths that make a “whooping” sound.
The disease typically affects infants and young children and, in babies younger than 1 year, can worsen quickly and be fatal. Coughing spells can last for 10 weeks.
Nationwide, 48,000 cases of pertussis were reported to the Centers for Disease Control and Prevention last year, more cases than in any other year after immunizations became widely available.
Pertussis has a cyclical nature and tends to peak every two to five years, health officials said. Statewide, reported pertussis cases rose from 1,023 in 2012 to 1,669 last year. Eighty-three percent of those cases were in children aged 7 to 16, according to state data.
All told, 99 patients were sick enough to end up in hospitals, some requiring extensive medical intervention. No deaths were reported last year.
Even with the recent rise in cases, the spread of pertussis is nowhere near levels reported in 2009-10, when California experienced an epidemic.
Olivia Kasirye, Sacramento County’s public health officer, said she recalls the severity of that epidemic. California saw more cases that year than it had in six decades, with 9,000 people coming down with the disease and 10 babies dying of it. All deaths and most hospitalizations occurred in infants younger than 3 months, with the highest disease rates hitting Latino infants.
“Babies who are really young do not have the protection they need against the disease,” Kasirye said. “They depend on the community for the protection. That’s one of the reasons we have pregnant women get immunized, so they can pass that immunity onto the baby.
“In 2009, we did have several babies who died. We hear of stories in adults who cough so hard they break ribs, but babies are the most vulnerable,” she said.
Kasirye said it’s important for adults and siblings who come in contact with infants to get vaccinated so they can avoid passing on the germs. That was one lesson learned from the 2009-10 epidemic: getting adults, middle school and high school students to take booster shots because the protection provided by earlier vaccines had worn off.
Another trend some suspect is contributing to pertussis’ spread is the increasing number of parents declining immunizations for their children, fearing risky side effects.
CDC officials acknowledge the pertussis vaccine can, in rare cases, have serious side effects. They include life-threatening allergic reactions, seizures, brain or nervous system diseases and fever over 105 degrees. But overall, according to the CDC, the disease poses greater risks, and immunizations are recommended.
Cindy Foxfoot has been a midwife in Nevada County for decades. She home-schooled her daughters and decided against immunizing them. In 1998, the girls came down with pertussis, developing the tell-tale cough. They recovered without complications after being kept at home for six weeks and now have naturally occurring immunity.
But Foxfoot, who has served on the board of directors for the California Association of Midwives, said she makes it a point to call attention to high pertussis rates in Nevada County, where more parents refuse vaccinations for their school-aged children than in any other county in California. The state Public Health Department put that figure at 21 percent; statewide the average is about 3 percent.
“Most people in Nevada County are well educated and are making their own informed decisions,” Foxfoot said. “But I tell all the families I work with that pertussis comes every year and to expect it.”
She also noted that many parents are less than enthusiastic about the newer vaccines since studies have shown the immunity wanes over time. Some parents say they’d prefer a single-disease vaccine against pertussis, but without the diphtheria and tetanus components that are included in the pertussis vaccine, Foxfoot said.
Either way, she said, “The high opt-out rate probably contributes to the high rate of pertussis in Nevada County.”
Nevada County ended up with a higher year-over-year increase per 100,000 residents than any other county in California: 70 cases in 2013 compared with five in 2012. Marin County ranked second, with 173 cases in 2013. Both counties are known for nurturing communities of back-to-the-earth-style parents who may favor organic, natural solutions over doctor-recommended pharmaceuticals.
“Nevada County did have a pertussis outbreak in 2013,” said Dr. Ken Cutler, the county’s health officer. “Evidence shows that pertussis outbreaks are more likely in communities with clusters of unvaccinated people.
“It is also clear that people who are unvaccinated are more likely than those who are vaccinated to get pertussis and to have more severe symptoms,” he said.
California is among 20 states that have allowed parents to exempt their children from public school immunization requirements by stating they have personal objections. A state law that went into effect this year now requires parents to obtain a doctor’s note as well, indicating they’ve been notified of the health benefits of immunizations.