Children are heading back to school as California's whooping cough epidemic keeps spreading, a worrisome combination that has prompted health officials in at least one county to warn that unvaccinated students could be sent home if an outbreak occurs.
More than 200 new confirmed and suspected cases of the illness were tallied in the past week, bringing the state total this year to 3,311 cases as of Aug. 24. The figure released Wednesday marks a sevenfold increase from the same period last year and the most cases since 1958.
An eighth death was recorded by state health officials last week. All the fatalities involved babies under 3 months old. This year's total now matches those in 2005, the most recent peak year.
A typical case of whooping cough, also known as pertussis, might appear similar to a common cold, starting with a cough and runny nose for one to two weeks and followed by weeks or months of rapid coughing fits that sometimes end with a whooping sound. Fever is rare.
San Francisco County parents were warned in letters last week that children could be required to stay home if they aren't up-to-date with vaccines during a possible outbreak.
Last spring, too many San Francisco children with whooping cough were being sent to school by parents and allowed to remain in classes by school officials, despite weeks of obvious illness, said San Francisco Communicable Disease Control and Prevention Director Dr. Susan Fernyak.
"Schools did the best they could, but they're understaffed and have a lot of different priorities," Fernyak said.
Los Angeles County public health director Dr. Jonathan Fielding said the decision to pull vulnerable students from school would be made carefully.
"It's really important that kids be in school if they don't have a specific reason to be excluded, and we don't want parents to have to give up workdays," Fielding said.
Whooping cough infections tend to peak in August and September, but reporting of cases by counties tends to lag, said Ken August, a spokesman for the California Department of Public Health. That makes it difficult to know if the state's epidemic is currently at it's peak.
In the event of an outbreak, all county health officials are authorized to send unimmunized children home, August said.
An analysis by The Associated Press showed that 127 of the 7,174 public and private schools in California reported 2009 whooping cough immunization rates of 50 percent or less for kindergartners.
Typically, babies go through a series of vaccinations and receive booster shots between ages 4 and 6 and again after age 10.
In 2009, the parents of about 2 percent of kindergartners in California, or 10,280 students in all, signed personal belief exemptions, meaning they had refused some or all immunizations based on religious or personal beliefs.
Many parents use the exemptions because they fear vaccines could cause autism.
The TDAP vaccine against whooping cough, tetanus and diphtheria is free of the additive thimerosal, a preservative containing mercury that has been the subject of a long-running public debate about whether it can cause autism.
A federal ruling in March said there was no connection between autism and thimerosal.