In 2019, which of the following vaccine-preventable diseases had fewer than 100 cases in the United States?

In 2019, diphtheria reported fewer than 100 cases in the United States, making it a vaccine-preventable disease that was significantly controlled through vaccination efforts. This is reflective of the high level of immunization in the population, which has virtually eliminated many serious diseases that were once common.

Diphtheria is a bacterial infection that can cause severe respiratory issues and other serious health complications, but due to the widespread use of the diphtheria-tetanus-pertussis (DTP) vaccine, the incidence of this disease has drastically diminished in the U.S.

In contrast, diseases like measles and pertussis saw higher case counts in recent years due to various factors, including vaccine hesitancy and outbreaks in certain communities. Polio, while also effectively controlled in the U.S. due to vaccination, was reported to have a number of cases due to the ongoing global health challenges and rare vaccine-derived cases. Therefore, diphtheria stands out as the disease with fewer than 100 reported cases in that specific year.