Final answer:
The resurgence of measles can be attributed to waning herd immunity caused by factors such as global travel and pockets of low vaccination rates. Hilary Koprowski developed a vaccine for polio, a disease nearly eradicated alongside smallpox thanks to vaccination efforts. High vaccination rates are crucial for maintaining herd immunity against contagious viruses.
The correct option is B. Measles.
Step-by-step explanation:
Waning herd immunity has resulted in a resurgence of measles. Several factors contribute to the potential rise of measles cases in the United States, including global travel, local pockets of low vaccination rates, and the decreasing prevalence which may lead to misdiagnosis by physicians unfamiliar with the initial symptoms. Measles is a highly contagious virus that can quickly spread among populations that do not maintain high enough vaccination rates to ensure herd immunity.
The vaccine developed by Hilary Koprowski was designed to prevent polio, another viral disease that has been nearly eradicated thanks to successful vaccination campaigns. While smallpox has been completely eradicated, diseases like measles and polio still pose threats when herd immunity wanes.
The correct option is B. Measles.