California public health officials on Monday strongly urged elderly adults, children and pregnant women to get vaccinated against whooping cough, citing an epidemic in the state that is on track to be the worst in 50 years.
Nearly 1,500 cases of whooping cough have been reported statewide this year, nearly five times the number of cases last year, according to Dr. Gil Chavez, the state's epidemiologist.
Babies under 6 months old are the most vulnerable because even those vaccinated have yet to develop immunity, Chavez said.
Five infants have died of whooping cough so far this year, all under 3 months old. Two of the deaths were in Los Angeles County. A sixth possible infant death was still being investigated Monday in L.A. County, Chavez said.
Last year three infants died of the disease, one each in Los Angeles, Kern and San Bernardino counties. All of the whooping cough deaths since 1996 have been infants under 3 months old, according to Ken August, a spokesman for the California Department of Public Health.
As of July 16, L.A. County had reported 289 possible whooping cough cases for the year, including 73 confirmed infections and 54 likely infections, according to the Department of Public Health. The county 156 reported cases of whooping cough last year.
The highly contagious upper-respiratory infection, also known as pertussis, initially may be mistaken for a cold, becoming more serious as it escalates and often causing those infected to make a tell-tale "whooping" sound as they gasp for air.
Pertussis infections typically peak every five years, Chavez said. The last outbreak in California was in 2005, when 3,182 cases were reported statewide and eight infants died. Since then, a booster vaccine was developed for adolescents and adults.
"It's time for Californians to help us by getting vaccinated and protecting themselves," Chavez said.
The Department of Public Health on Monday expanded its vaccination recommendation to include children age 7 and older; adults age 64 and older; women before, during and immediately after pregnancy; and anyone who may have contact with pregnant women or infants.
Dr. Jack Chou, a Baldwin Park family physician, said he was "heartened" by the new recommendations.
"That will allow us to give this vaccine to grandparents who care for infants," said Chou, president of the California Academy of Family Physicians.
Dr. Dean Blumberg, an associate professor of pediatric infectious diseases at UC Davis, said three-quarters of infants who catch whooping cough get it from someone in their home.
"That's why it's important to make sure their siblings and caregivers are protected," Blumberg said.
Public health officials have been tracking whooping cough cases by county, patient age and ethnicity, Chavez said. They have seen more infections in counties such as Marin, where more parents have opted out of vaccinating children, he said. Latino infants are most likely to get whooping cough, more than twice as likely as white infants. Among adults, whites are most likely to get infected, followed by Latinos, Chavez said.
Chavez said the department has provided free vaccines to local hospitals and community clinics and held a series of meetings with ethnic media outlets in Northern, Southern and Central California to raise awareness about the importance of vaccinations.
Department officials said the booster vaccine is safe for pregnant women, is made from a dead virus and is preservative-free.