Chapel Hill, N.C. — Whooping cough is becoming a big health concern, particularly in California where they've seen more than 900 cases this year, up from 200 last year. Now, other states concerned about the spread.

With whooping cough, also known as Pertussis, very young children, under age 2 or 3, are at greatest risk. It has led to the deaths of five babies in California this year.

Having a cough is common, but whooping cough, especially in young children, is more severe.

“And what they do is they cough, cough, cough, cough and then they ‘whoooooop,’” said UNC Epidemiologist Dr. David Weber. “It's when they've been inspiring, after they've been coughing so much, they get that like ‘whooping’ sound.”

Weber, an infectious disease expert, says the cough becomes suspicious after it lasts more than three weeks. There may be vomiting after coughing and sometimes a fever. The disease is spread easily through families, in daycare environments and schools.

There has long been a vaccine for young children, a combination of tetanus, diphtheria and pertussis called DTAP. Now a newer vaccine is formulated for an older population, called TDAP.

“And so we're going to protect those young infants that get sick by immunizing adolescents, particularly around 11 to 12 and again, all adults, particularly under the age of 60, particularly those who deal with young children should be immunized,” Weber said.

The vaccine wears off after time, so check with your doctor about when to get a booster shot. If you think your child has whooping cough, go to your doctor. There's a simple swab test that can be done and sent off to a lab with results in a few days.

“It's very accurate,” said WRAL Health Team’s Dr. Allen Mask. “If you've got it, you can be prescribed antibiotics. If given early enough, it can lessen the severity of the illness. Even if it doesn't lessen the severity, it does make them non-infectious. The antibiotics can even be prescribed to members of a family where the disease is present, so it can prevent illness.”