As the United States grapples with rising measles cases and outbreaks in several states, another vaccine-preventable disease is quietly spreading throughout the country. “This is a troublesome trend.”Last year, there were 285 cases of measles for all of 2024. A type of bacterial infection, whooping cough is spread through respiratory droplets when an infected person coughs or sneezes. Nationwide, there were 35,435 cases of whooping cough in 2024, compared with 7,063 in 2023, according to a provisional surveillance report from the CDC. Around a third of infants under six months old who came down with whooping cough in 2024 required hospitalization.