This year, more than a third of whooping cough cases have been among people 11 to 19 years old. For this reason, the C.D.C. recommends that children get a booster shot at 11 or 12 years old.

Heartbreak in Mexico: 45 babies have lost their lives to whooping cough. Most were not vaccinated, and the number of infections keeps climbing.

However, officials said there is a concerning rise in local whooping cough cases. “We are seeing about 230% increase in the number of [whooping cough] cases,” said Dr. Anita Kurian, Deputy ...