A spike in pertussis, commonly called whooping cough, triggered a statewide alert recently to health care providers to redouble vaccination efforts with patients of all ages to protect babies and people with weak immune systems.

Lake County has three confirmed cases with 10 others linked to the confirmed cases, and Missoula County has two confirmed. Jody White, Community Health Services director, said Flathead County has no confirmed cases yet at this time.

"We have had cases in the past year," she said.

Laboratories have confirmed pertussis in Blaine/Fort Belnap, Custer, Hill, Lewis & Clark and Rosebud counties. According to the state alert, increasing numbers of cases have been confirmed since mid-August of the highly contagious respiratory tract disease that can pose a deadly threat to infants.

White said at least nine babies have died in California from pertussis since spring.

"Our concern is mainly for infants who are not old enough to be immunized," she said. "What we want to do is proactively immunize those who could carry the disease."

According to information from the Centers for Disease Control and Prevention, whooping cough is most contagious before the coughing starts. Many infants get infected by their parents or others who don't know they have the disease.

White said anyone with direct contact with infants needs to make certain they have an up-to-date vaccination. This includes new mothers and other family members, including grandparents coming to interact with a new baby.

She said the mothers who haven't been immunized should receive the vaccine as soon as possible after giving birth. White said several grandparents have come into the health department to get the combination tetanus-diphtheria-pertussis (Tdap) vaccine in anticipation of visiting a new grandchild.

"That's really wonderful," she said. "Ideally, they should get it two weeks ahead of time but it's still worthwhile if they have less time before a visit."

According to White, people 65 and over need to consult with their health care provider since the vaccine isn't licensed for this age group. She said that California has waived this restriction due to a statewide epidemic of pertussis.

Babies can't receive the vaccine until at least six weeks. Generally, infants get five doses of Tdap at 2, 4, 6 and 15 to 18 months old, and then receive another booster in kindergarten at 4 to 6 years old.

White said medical experts once thought that this provided lifetime immunity, but research has shown otherwise.

"Immunity starts to wane by middle school," White said. "That's part of the reason we do a Tdap booster in seventh grade."

She said another booster as an adult is also recommended. Couples planning a pregnancy should get a vaccination beforehand for the best protection.

Health care providers as well as health departments offer the combination vaccine. Flathead City-County Health Department provides Tdap for adults for $50.

"We do have a program they can request information about if they are not able to pay the full amount," she said. "We have a limited amount of vaccine available. We don't want anyone to forego vaccine because of inability to pay."

White said many cases of pertussis go unreported because people assume that they have bronchitis or a common cold. Like a cold, whooping cough starts with a runny nose or congestion, sneezing and maybe a mild cough or fever.

Within one to two weeks, severe coughing begins. The CDC website reports that infants and children cough violently until all air leaves their lungs and they're forced to inhale, which makes the whooping sound.

Over half of babies under 1 year of age who get pertussis end up in the hospital.

"For most people, it's an annoying illness," White said. "But for an infant or a person who is immunocompromised, it can be life threatening."

For more information, people may call Flathead City-County Health Department at 751-8101.

Reporter Candace Chase may be reached at 758-4436 or by e-mail at cchase@dailyinterlake.com.