There are now 910 recorded cases of whooping cough in California, and health officials says those cases are growing.
As of June 15, five babies, all under three months of age, have died from the disease this year.
Experts say part of the problem has to do with parents not vaccinating their children. But what be a bigger issue is that the whooping cough vaccine does not last a lifetime and many people may not be getting their booster shots.
Without the booster, parents can become carriers and unknowingly infect their infants who have yet to develop immunity, even if they had the vaccine.