Whooping cough cases are on the rise across the state, with almost six times as many cases in the first 11 weeks of 2012 as the same time period in 2011.
State health officials have reports of 463 cases through March 17, compared with 82 by this time last year.
Pertussis cases also are on the rise in Benton and Franklin counties, which have seen 19 cases so far this year.
Dr. Amy Person, health officer for Benton and Franklin counties, said most of the reported Tri-City cases have been schoolchildren or people around them.
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A small outbreak was reported in some Kennewick schools in February, and Person said she has heard some recent reports of pertussis in Pasco schools.
Leslee Caul, spokeswoman for the Pasco School District, said the district has sent letters to parents explaining pertussis symptoms, and offering tips for prevention such as vaccination and hygiene practices.
The district also notifies the Benton Franklin Health District when a student is confirmed to have pertussis, she said.
Person said that many adults are unaware that the pertussis vaccine they received as a child or adolescent wears off over time, and getting the illness itself doesn't provide any immunity.
"We want to make sure adults and children over 10 are getting their boosters," Person said.
But even getting a pertussis shot won't guarantee someone won't get sick.
Michele Roberts, health promotion and communications section manager for the state's child immunization program, said the vaccine is about 80 percent to 85 percent effective, meaning some people who get vaccinated still may get the disease.
"Pertussis is not all about seeing disease in unvaccinated people," she said.
She said it still is important to get the vaccine because that can mean the person gets a much milder case of pertussis, and it offers protection to vulnerable infants who can't be vaccinated.
"Also, reported cases are only the tip of the iceberg," she said. "Many cases in teens and adults don't get reported because they don't seek medical attention, or their symptoms are so mild that providers don't suspect pertussis. The bottom line is that anyone with an ongoing cough should stay away from infants. And we need to increase awareness in adults that everyone should get a whooping cough booster."
Adults can get a pertussis booster from their doctor along with their 10-year tetanus booster.
Person said the increased number of cases in Benton and Franklin counties isn't abnormal, particularly as nearby counties were reporting outbreaks in late 2010.
Grant County experienced 57 cases, including one infant death, during a 16-month outbreak that started in late 2010. included one infant death. In the previous five years, Grant County reported one to four cases per year.
Benton County was seeing very few cases during Grant County's outbreak, but now is seeing activity while Grant County has had no reported cases in 2012.
"I think it ended up just being our time," Person said. "It ends up being everybody's time at some point."