Here are some guidlines to follow from Pundit&Pundette:
To protect your children watch out for the symptoms, and hie thee to a doctor to get antibiotics for the whole family (vaccinated or not) if you suspect pertussis. If caught early enough, antibiotics may mitigate the coughing, which is typically extreme and long-lasting. Antibiotics will kill the bacteria and prevent spreading to your other family members. Be sure to tell the doc that you've been exposed to a confirmed case. There are different tests, but the one used by our doctor is a culture by nasal swab and can take as long as 14 days for a result.
Our daughter's culture was negative after 6 days but positive by day 14. The doctor started her on antibiotics the day she was tested. Our doctor said people are no longer contagious after 24 hours of antibiotics. When the test came back the doctor decided to give her another course of antibiotics. Probably not necessary but I didn't turn it down.
It seems to me that many doctors aren't very familiar with the symptoms, testing, or treatment. They're looking for asthma, allergies, bronchitis, croup, or pneumonia. My impression is that pertussis isn't on their radar. I suspect it's more common than they believe and often goes undiagnosed.
Week one: A cough. May be very frequent. Cold symptoms may accompany it. From website linked below:
runny nose, sneezing, low-grade fever, or a mild, occasional cough, similar to the common cold.
After that: Paroxysmal stage, when cough develops into long, spasmodic coughing fits. The "whoop" occurs when the victim tries to inhale. (Whoop is not always present, and babies in particular may not whoop.) Coughing fits may feature choking and vomiting.
Read more here:
Forewarned is forearmed.