Whooping cough is on the rise in eight metro Atlanta counties, state health officials are warning.

As of Saturday, 95 cases of whooping cough — also known as pertusis — have been reported in Clayton, Cobb, DeKalb, Douglas, Fulton, Gwinnett, Newton, and Rockdale counties. That compares to 51 cases during the same time period last year, according to the Georgia Department of Public Health.

"Though we have not seen a substantial increase in the number of whooping cough cases statewide, the increase in whooping cough cases in highly populated metro Atlanta is of concern," state epidemiologist Cherie Drenzek said in a statement.

The increase is similar to national trends as the United States appears to be headed for its worst year for whooping cough in more than five decades, officials said. Nearly 18,000 cases have been reported nationally so far — more than twice the number seen last year, health officials said.

Whooping cough, a highly contagious respiratory illness spread by coughing and sneezing, affects people of all ages, but is most serious in infants, health officials note. It brings cold-like symptoms, followed by a long, severe cough that can last for weeks or months. Sometimes a "whoop" sound occurs while gasping for breath during a coughing episode. However, the sound is not always present.

Adolescents and adults often get a much milder case of whooping cough and may not realize they have the disease, though they can still spread it, officials said.

"This disease can be very serious for young babies, who often get whooping cough from adults and other family members. Most infected infants must be hospitalized," said J. Patrick O'Neal, M.D., state director of health protection.

Health officials reccommend whooping cough vaccines for all children and adults, as the shots children receive wear off over time, officials said. Those age 11 and older should get a whooping cough booster, called Tdap, they said. It's especially important for those in close contact with babies younger than 12 months. This includes parents, siblings, grandparents, healthcare providers, and child care providers, officials said.