SACRAMENTO -- California's growing whooping cough epidemic has claimed the life of a third infant, a tragic reminder that the very youngest are most at risk of hospitalization and death from the highly contagious bacterial disease, state health officials said Friday.
The officials continue to be alarmed that the number of cases has soared since Jan. 1, as the traditional peak month of July approaches. The number of cases is now at 4,558 -- almost double the 2,532 reported for all of 2013.
The year-old baby, who contracted the disease at 3 weeks of age, was from Sacramento County. Officials did not reveal the gender of the infant, citing privacy reasons.
The two other infants who died this year from whooping cough, also called pertussis, were from Placer and Riverside counties. One of those infants -- both 2 months old -- contracted the disease last year.
The deaths are troubling to state health officials, who last faced a whooping cough epidemic in 2010 that took the lives of 10 infants. Since then, no pertussis-related deaths had been reported until February.
"We are off to a really bad start in 2014,'' Dr. Gil Chavez, the state's epidemiologist, told reporters Friday.
Chavez said the infant deaths highlight the need for pregnant women to receive a pertussis vaccine during the third trimester.
"Vaccination of pregnant women is the most important thing that can be done,'' said Chavez, citing "good scientific evidence" showing that infants whose mothers are vaccinated against pertussis have the maximum protection against the disease.
Bay Area health officials echoed his words, though they said teenagers are coming down with the majority of pertussis cases. That's consistent with state figures showing that 84 percent of whooping cough cases so far this year have occurred in infants and children under 18, with the peak age after infancy at 15 years old.
"But we are most concerned with the babies," said Paul Leung, Contra Costa County's immunization program manager. "We have had five babies hospitalized with pertussis in 2014.''
He and other county health officials say they are using Facebook, Twitter and other social media outlets to alert parents about the epidemic, urging them and their children to get their shots at doctors' offices or, if they are uninsured, at county clinics for little or no cost.
"It's so important to vaccinate kids as they're entering middle school,'' said Dr. Sara Cody, Santa Clara County's health officer.
But she too is worried more about the babies. Three-quarters of those under age 6 months who contracted pertussis this year had to be hospitalized, she noted.
Health officials say that pregnant women who are inoculated pass immunity to their unborn babies that protect them until they can be vaccinated.
The first dose of pertussis vaccine can be given as early as 6 weeks of age. Children need four more doses of pertussis vaccine by kindergarten. And in California, seventh-graders must receive the vaccine under state law.
Unlike the flu virus, which usually surfaces in the winter, pertussis historically occurs from May to September, peaking in July, Chavez said.
Statewide, Sonoma, Napa and Marin counties have had the highest whooping cough rates.
Chavez and others attribute the current whooping cough epidemic to its three-to five-year cycle and a corresponding use of "acellular" pertussis vaccines, which cause fewer reactions than the whole-cell vaccines that preceded them. But they don't protect as long, lasting only three to five years.
The disease may also have spread in some areas because some Californians have chosen not to get vaccines for themselves or children because of religious or personal beliefs.
A state law that took effect on Jan. 1, however, requires parents who exclude their children from immunization requirements to submit a signed statement that they received information about the risks and benefits of vaccines from a health care professional.
Leung said one reason for the preponderance of pertussis cases among teens may be linked to those about to start seventh grade who have not received a vaccine. For older teens, he said, it may be because their seventh-grade vaccine has worn off.
Dr. Scott Morrow, San Mateo County's health officer, said that "it's helpful" that many teenagers are out of school and "not in larger congregate settings where it can spread faster.'' But Morrow noted that many students are attending summer school or camps.
When a case is reported to his department, he said, the person is removed immediately from their school or camp. And anyone who has had contact with that individual is checked for their vaccine history because pertussis "can go like wildfire'' if the kids are not vaccinated, he said.
The disease affects a person's airways and is spread easily through the air when people cough or sneeze.
Leung, the Contra Costa County health official, said it can start like a common cold with a runny nose, sneezing, cough and low-grade fever. The cough lasts for one to two weeks and then slowly gets worse, turning to coughing fits or spells that cause vomiting, gagging or a loud gasp, sometimes like a "whoop," that can last for up to 10 weeks.
Contact Tracy Seipel at 408-920-5343. Follow her at Twitter.com/taseipel.
Alameda County: 155
City of Berkeley: 34
Contra Costa County: 169
* Marin County: 156
Monterey County: 71
* Napa County: 106
San Benito County: 1
San Francisco: 26
San Mateo County: 47
Santa Clara County: 222
Santa Cruz County: 48
Solano County: 89
* Sonoma County: 552
* Sonoma, Napa and Marin counties have the highest whooping cough rates in the state
Source: California Department of Public Health
HOW TO PREVENT WHOOPING COUGH
To prevent pertussis, state public health officials recommend:
Pregnant women receive a pertussis vaccine booster during the third trimester, even if they've received it before.
Infants be vaccinated against pertussis as soon as possible. The first dose is recommended at 2 months of age but can be given as early as 6 weeks during pertussis outbreaks. Children need five doses of pertussis vaccine by kindergarten.
California seventh-grade students receive the pertussis vaccine booster as required by state law.
Adults receive a one-time pertussis vaccine booster, especially if they're in contact with infants or if they are health care workers who may have contact with infants or pregnant women.
Source: California Department of Public Health