Was there an outbreak of diphtheria in the 1940s?

Yes, there was a notable outbreak of diphtheria in the United States during the 1940s, particularly after the decline in vaccination rates during World War II. This outbreak highlighted the importance of immunization, as the disease can be prevented through vaccination. The increase in cases prompted public health campaigns to promote diphtheria vaccination, leading to a significant decrease in incidence in the following years.