Outbreaks among the unvaccinated are a predictable consequence of falling immunization rates. But even vaccinated adults may be vulnerable to some illnesses.
There were more than 32,000 cases of whooping cough in 2024, the highest tally in a decade. In California alone, the disease struck 2,000 people between January and October last year.
More than 60 infants younger than 4 months were hospitalized in the state. One died.