Gov. Chris Gregoire has announced an emergency action to slow the spread of whooping cough (pertussis) in the state. I recently declared that whooping cough had reached epidemic levels in Washington. If the pace continues, we’re headed toward the highest number of reported cases here since the early ‘40s.

And that’s just the tip of the iceberg. Only 10-12 percent of cases are reported because many teens and adults don’t get sick enough to go in for medical treatment and testing.

Whooping cough is highly contagious. It causes cold-like symptoms, spreads by coughing and sneezing, and can last for weeks. It’s a miserable illness for teens and adults but very serious for babies who often catch it from relatives and other adults. Sadly, it has taken the lives of four Washington babies in the last two years and hospitalized dozens more.

Our new public service announcement features a Snohomish County mom who lost her newborn daughter to whooping cough. It’s a sobering reminder of just how serious whooping cough can be, and it encourages vaccination.

Prevention is key! Whooping cough vaccine is recommended for all kids and adults. It’s widely available at clinics, pharmacies and doctor offices. Everyone age 11 and older should get a whooping cough booster called Tdap. We’re buying 27,000 doses of Tdap for adults who otherwise can’t afford it. Gov. Gregoire joined me in urging health-care professionals to get vaccinated and to vaccinate their patients.

Younger kids must complete a series of five doses of DTaP vaccine by age 7 for full protection. Good health manners also help prevent the spread of whooping cough, like covering your cough and staying home when you’re sick.

Immunization exemptions have also played a role in the epidemic. Our state has the highest school immunization exemption rate in the nation at 6.2 percent, compared with a national average of about 2 percent. So, there are pockets of unvaccinated people vulnerable to getting and spreading diseases like measles and whooping cough.

There’s a lot of misinformation about vaccines, especially online. It’s hard to tell the difference between what’s reliable and what isn’t.

One way the state is helping parents get reliable information is through the new immunization exemption law. It requires parents to talk with a health-care provider before exempting their child from immunizations required for school entry. The health-care professional must sign a form verifying the parent or guardian received vaccine benefit and risk information.

We want parents to get reliable and trusted information about vaccines from their health care provider. It’s also important for parents to know that their child, if not immunized, may be excluded from school or child care during an outbreak.

To find an immunization clinic, contact your health care provider or local health agency. All recommended vaccines are offered at no cost to all kids under 19 through health-care provider offices participating in the state’s Childhood Vaccine Program. Health-care providers may charge an office visit fee and a fee to give the vaccine, called an administration fee. People who cannot afford the administration fee can ask the health-care provider to waive the cost. Most health-insurance carriers will cover the whooping-cough vaccine; adults should double-check with their health plan.

Making sure you’re current on your whooping-cough vaccine is the best way you can help protect the vulnerable in our communities — the babies that are too young to be fully immunized.

Mary C. Selecky is the Washington State Secretary of Health.