The study found the outbreak in California had a lot do to with parents steering away from vaccines, mostly due to personal beliefs.
Local health officials say it's a reminder to learn as much as possible about vaccines before refusing them.
"In an infant, their airways are so small, they cough so hard that they make that sound of a whoop afterward as they're trying to struggle and breath air in," said Dr. Cynthia Brownfield, Heartland Health.
Dr. Brownfield said the symptoms of whooping cough are severe and can be deadly.
She adds that whooping cough is a disease that can be prevented with a vaccine. And health officials say both children and adults should get one.
"Babies aren't fully immunized against pertussis until they're six months old. So, if you're an adult who is around a baby, you need to be protected so that you're not carrying the disease without knowing it and passing it on to that infant that is not protected," said Stephanie Malita, St. Joseph Health Department.
"The disease is very hard on infants, they don't have a large enough airway to handle it. So, there hospitalization rate and death rate is much higher than the average adult," added Dr. Brownfield.
Despite that warning, some parents shy away from vaccines due to a fear of potential risks and personal beliefs.
"Many people have concerns about vaccines," said Dr. Brownfield.
A recent study - published in the Pediatrics Journal - links the largest whooping cough outbreak since 1947 to clusters of unvaccinated children.
The outbreak happened in California in 2010 when more than 9,000 were infected and 10 infants died.
The study confirmed what health officials suspected at the time - that the outbreak was the result of some kids not being vaccinated.
Health officials say parents should do their homework before deciding against vaccines.
"If you're choosing not to have your child immunized, do the research and have a good reason why you're not - not because you're hearing some snippet of someone saying I'm not getting my child immunized because of this or that," added Malita.
"Parents voice a whole bunch of different reason to be concerned for vaccines. What I usually let them know is that the American Academy of Pediatrics and the CDC are here to protect us. We live longer, our children live longer with less risk for hospitalization disease, we don't have the death rates like we did in the 1950s and 1940s," Dr. Brownfield said.
The T-DAP vaccine helps protect against whooping cough, also known as pertussis. It is recommended by the CDC for children, teens, new parents and anyone who comes in contact with infants.