JACKSONVILLE, Fla. -- Experts say they have seen a rise in pertussis, or whooping cough, in Duval County.
It can start with a stuffy or runny nose and then in a week can turn into a really bad cough.
"You'll have a hard time breathing because you're coughing hard," said Duval County Health Department epidemiologist Karen Elliott.
The disease has infected 20 people in Duval County in the past nine months.
Elliott told Action News the number of cases this year keeps rising, similar to recent years.
"During the previous five years, we've seen about 30 for this time period," said Elliott.
Elliott said kids get vaccinated for school, but the vaccine usually wears off after five years, making adults more susceptible to catching the disease.
"It's fairly easily passed around because you have people coughing up bacteria," Elliott said.
It's even more easily passed to infants, who are too young to get the vaccine. For them, whooping cough can be deadly.
"Sometimes they have a cough, sometimes they don't. They may just have a period where they don't breathe, or turn blue," said Elliott.
Elliott recommended adults get the T-dap vaccine often, so they do not pass pertussis on to babies.
"It's one of those things where they're trying to create a better vaccine that may last longer," said Elliott.
She said no one has died from the 20 cases reported in Duval County.