In L.A. County, there have been 148 suspected cases so far, 70 of which have been confirmed in a lab. And experts expect it to exceed the number of cases last year.
In an average year, L.A. County has one or no deaths from pertussis, but this year two infants have died from it.
Infants under a year are at the highest risk for developing the most severe and possibly even fatal complications.
"Babies when they get to that stage they are at high risk of having apnea," said California Department of Public Health director Dr. Mark Horton. "That can lead to a lesser blood flow to their brain. It can lead to seizures and death."
A recent study showed 41 percent of infants with whooping cough got it from a sibling. Thirty-eight percent got it from their mother and 17 percent from their father.
"If you are immunized as an adult then you are not at risk of being infected. And since most infants acquire the infection from adults the more likely we can save babies," said Dr. Horton.
All the more reason children between the ages of 4 and 6 should get immunized against it. It is also important to make sure kids get a booster shots during their preteen years.
Teens or adults who haven't had a pertussis booster should get one, especially if they live in a household with an infant.
One possible factor in the rise of whooping cough can be attributed to parents who don't want to vaccinate their kids.
Besides immunizations, make sure kids cover their coughs to help prevent the spread of whooping cough. Basic hygiene, like hand washing, helps too.
If you or your child develops a cough that's accompanied by a whooping sound or vomiting, contact your doctor right away.