LANSING - Michigan saw a significant increase in reported cases of pertussis (whooping cough) in the second half of 2008 compared to the first half of the year, prompting officials to remind parents and doctors of the importance of vaccinating infants as well as teens and adults against this serious disease.

As of the end of December, a total of 307 cases had been reported in Michigan, although that number is subject to change as work continues to finalize case investigations. More than twice as many cases (210) were reported in the July-December period compared to the first half of the year (97). In 2007 there were 292 pertussis cases reported in Michigan.

"Pertussis is a vaccine-preventable disease, and that's why the single most important thing parents can do is get their infants vaccinated and follow the schedule for booster doses," said Janet Olszewski, director of the Michigan Department of Community Health.

Pertussis is a respiratory infection caused by bacteria that spread easily among persons in close contact, such as members of the same household. The illness starts as cold-like symptoms - runny nose, sneezing, mild cough - and at that point is indistinguishable from many other upper respiratory illnesses. A week or two later, the cough worsens, becoming a series of severe, intermittent coughing fits, which make it difficult for the patient to get a breath. Children may make a strange "whoop" noise as they finally catch a breath, which is where the illness gets its nickname of whooping cough. The bouts of coughing may end in vomiting and often leave the patient exhausted.

While the provisional 2008 total of pertussis cases in Michigan is close to the 2007 total, the increase seen in the latter half of 2008 is troubling for Michigan's youngest residents.

"A chief concern is that we're seeing more cases among babies, and they're at greatest risk of developing a severe case of pertussis, which can result in death," said Greg Holzman, chief medical executive for the MDCH. "It is absolutely critical that infants get all of their vaccine doses on schedule to give them as much protection as possible. It's also important that family members of young babies get a pertussis vaccine booster so they are protected from illness and don't pass pertussis to infants."

Infants should receive four doses of pertussis vaccine by the time they are 18 months old, and a routine booster dose is recommended for children before starting kindergarten. It's also critical that parents realize there are boosters for adolescents and adults that contain tetanus, diphtheria, and pertussis (Tdap), as vaccine protection can fade with time.

Pre-teens going to the doctor for their regular check-up at age 11 or 12 should get a dose of Tdap. Adults who didn't get Tdap as a pre-teen or teen should get a dose, as should adults who are healthcare workers or who care for infants.

Various studies have shown infants often get pertussis from other family or household members. The illness is most serious in babies, especially those under 6 months of age whose small lungs and respiratory systems are less able to manage the assault of the bacteria on their airways.

While those diagnosed with pertussis should be treated with an appropriate antibiotic, vaccination against the disease is the best way to control it and prevent Michigan residents from contracting it in the first place.

For more information about immunizations, go to www.michigan.gov/immunize.