LOS ANGELES -- State health officials are urging the elderly, pregnant women and children to get vaccinated against whooping cough now that an epidemic has been declared that could be the worst in 50 years.
As of July 16, at least 1,496 cases of whooping cough, or pertussis, have been found statewide, a fivefold increase over the same period last year, said California Department of Public Health epidemiologist Dr. Gil Chavez.
The prevalence of the highly contagious disease peaks in the summer months, according to Al Lundeen, a spokesman for the state Department of Health.
Still, Lundeen said, health officials have seen three times as many cases as expected for this time of year.
Five infants have died of whooping cough so far this year -- all under three months old. A sixth possible death in L.A. County is still be investigated.
Newborns under six months are the most vulnerable.
Earlier in the year, state officials said twice as many cases had been reported in the first quarter compared with the same period last year.
The disease peaks like this about every five years, according to health experts.
The last peak occurred in 2005 when California reported 3,182 cases, with 574 hospitalizations and seven deaths.
Most kids get five doses of the vaccine DTaP before kindergarten to prevent whooping cough, but those vaccines don't immunize them for life.
Health officials say most kids are once again susceptible to the disease by middle school.
A booster dose of the vaccine is recommended for people between the ages of 11 and 18, as well as for people who have contact with infants, who can't be immunized until two months of age.
A typical case starts with a cough and runny nose for one to two weeks, followed by weeks or months of rapid coughing fits that sometimes end with a whooping sound.
Fever is rare.
The California Department of Public Health on Monday recommended vaccinating not only infants but also children age 7 and older, adults age 64 and older, women of child-bearing age before, during and immediately after pregnancy, and anyone else who may have contact with pregnant women or infants.