The Colorado health department says at least 715 cases of whooping cough have been reported in the state so far this year.
The department says the 715 cases reported through Aug. 11 is far above the five-year average of 158 cases typically reported by this time of year.
State health department executive director Chris Urbina said Monday it's key for people who spend time around infants to be vaccinated against the respiratory disease because babies are too young to have received all the doses necessary to protect against it.
Health officials also are recommending the vaccine for pregnant women in the third or late second trimester and health care workers.
Whooping cough, or pertussis, can spread when an infected person coughs or sneezes.