New York City ? Outbreaks of whooping cough in four states are a sign the sometimes-fatal disorder has made a comeback despite mandatory vaccinations for children of school age, public health officials said Wednesday.

Whooping cough, or pertussis, is a highly infectious condition marked by an unstoppable urge to cough.

“Just as we have been reminded that tuberculosis is still with us, we are seeing the re-emergence of pertussis, a bacterial respiratory infection,” said Dr. Len Horovitz, a pulmonary specialist at Lenox Hill Hospital in Manhattan. “Children who have not been adequately vaccinated with the standard DPT vaccine are at risk, as are adults whose immunity to the bacterium may have faded over decades.”

Even though the number of cases diagnosed this year is lower than in 2006, many have occurred within the past several weeks in outbreaks in several states, including Pennsylvania, South Carolina, Wisconsin and Ohio.

A Colorado baby died last month, after coughing to death from an infection once considered a disease of a bygone era.