Before the availability of the pertussis vaccine, more than 270 000 cases and 10 000 deaths were reported annually in the United States. Mass immunization programs begun around the world in the 1940s almost eradicated childhood cases of the disease by the 1970s.
Yet in the last 2 decades, the number of cases of pertussis, or whooping cough, has been increasing in countries with high vaccination rates, particularly among 10- to 19-year-olds and infants younger than 5 months. Pertussis cases peak every 3 to 5 years, and the United States and other countries are in the midst of another upswing. According to the US Centers for Disease Control and Prevention (CDC), more than 21 000 cases were reported in 2010, the highest number since the 1950s.
Friedrich MJ. Research Aims to Boost Pertussis Control. JAMA. 2011;306(1):27-29. doi:10.1001/jama.2011.888