The pertussis epidemic continue to spread in Yolo County with 23 new cases reported in the past two weeks, bringing the total this year to 70.
By comparison, Yolo County reported four cases in all of 2013, six in 2012 and five in 2011.
Most local cases involve elementary-school age children and teenagers, according to county health officer Dr. Constance Caldwell, but cases have been reported in patients ages 0 to 90.
“We have had a very small number of hospitalizations and no deaths,” Caldwell reported. “The biggest concern is exposure to young infants.”
Infants are at the greatest risk of hospitalization and death from the disease. They cannot begin the pertussis vaccination shot series until they are 6 weeks old.
Of the 156 pertussis hospitalizations throughout California this year, 62 percent were infants under the age of 4 months, according to the California Department of Public Health, and three infants have died.
Pregnant women are being urged to get the Tdap booster during the third trimester of pregnancy in order to pass on some protection to their infants. But of the 56 infant pertussis cases statewide for which the mother’s vaccination history was available, only six had received the Tdap vaccine during the third trimester, the state reported.
In addition to pregnant women, anyone who is in regular contact with young children should be vaccinated as well, health officials have said.
“This includes baby-sitters, older siblings, parents and grandparents,” the state’s health officer, Dr. Ron Chapman, said earlier this month.
California is in the midst of a pertussis epidemic, with 5,393 cases reported since January. Only five counties have reported higher incident rates than Yolo — Humboldt, Marin, Napa, Sonoma and Tehama counties.
Caldwell reported that pertussis has been seen throughout the Yolo County with no particular concentration in any city or area.
In Davis, there have been several reports in recent weeks of possible pertussis cases, including at Davis High School and Holmes Junior High School prior to the end of the school year in June. But neither the school district — which is operating summer school as well as a summer lunch program — nor the city of Davis — which operates numerous camps — has reported being affected.
Caldwell said the county Health Department reaches out to summer school and camp programs when they become aware of pertussis cases but does not recommend prophylactic antibiotics to children who may have been exposed.
Rather, children should be up to date on their immunizations and adults — particularly those in contact with infants — should receive boosters, officials said.
The symptoms of pertussis vary by age and can vary from very mild to severe.
For children, a typical case of pertussis starts with a cough and runny nose for one to two weeks. The cough then worsens and children may have rapid coughing spells that end with a “whooping” sound.
Young infants may not have typical pertussis symptoms and may have no apparent cough, but parents may describe episodes in which the infant’s face turns red or purple.
For adults, pertussis may simply be a cough that persists for several weeks.
According to the state public health department, pertussis is cyclical and peaks every three to five years as the number of susceptible people in the population increases due to waning of immunity following both vaccination and disease. The last epidemic in California occurred in 2010, however, the overall incidence of pertussis has increased since the 1990s.
Midway through 2014, California already has more pertussis cases than in any previous years except 1947, 1950 and 2010 and could well set a new record high by the end of December.
Broken down by age and ethnicity, Hispanic infants under the age of 1 have the highest incident rate, followed by white adolescents between the ages of 10 and 17. More cases have been reported among 15-year-olds than in any other age group.
The DTaP vaccine for young children and the booster for teens and adults are available at the Yolo County Health Department’s regular Monday immunization clinics. Those clinics take place on the first Monday of each month in West Sacramento, 500-B Jefferson Blvd., and on the second, third and fourth Mondays of each month in Woodland, 137 N. Cottonwood St.
Additionally, most primary care providers — including CommuniCare clinics, Woodland Healthcare, Sutter Davis, Kaiser and UC Davis — can provide pertussis vaccinations and boosters.
Call the county Health Department at 530-666-8562 for additional information.
— Reach Anne Ternus-Bellamy at email@example.com or 530-747-8051. Follow her on Twitter at @ATernusBellamy