Big-time pertussis breakout

California has experienced its largest outbreak of pertussis, or whooping cough, in about 70 years, according to a report from the Centers for Disease Control and Prevention.

As of Nov. 26, 9,935 cases of whooping cough had been reported in California—about 26 cases per 100,000 people—with the highest incidence among Hispanic infants, at 207 cases per 100,000, according to California Healthline. The high rate among infants was likely because they’re too young to be vaccinated; despite recommendations that pregnant women in their third trimester receive the pertussis booster shot, only 17 percent of mothers whose infants were later infected had received it.

Infants, along with the elderly, are most susceptible to complications due to whooping cough. Of the 347 hospitalizations related to pertussis in California this year, 275 involved children younger than 1 year old.