Which vaccine, developed in the 20th century, led to the global eradication of a major infectious disease?

Correct Answer: C

Rationale: The correct answer is C, the Smallpox vaccine. The Smallpox vaccine was developed in the 18th century by Edward Jenner and led to the global eradication of smallpox in the 20th century. The vaccine's effectiveness in preventing smallpox transmission played a crucial role in the eradication effort led by the World Health Organization. Choices A, B, and D are incorrect because while these vaccines are important in preventing diseases, none of them led to the global eradication of a major infectious disease like the Smallpox vaccine did.

Correct Answer: C

Rationale: The correct answer is C: Polio vaccine by Jonas Salk. The development of this vaccine in the mid-20th century led to a significant reduction in polio cases globally. Salk's inactivated polio vaccine was the first effective vaccine against polio and played a crucial role in controlling the spread of the disease. The other choices (A: Measles vaccine, B: Hepatitis B vaccine, D: Rubella vaccine) are important vaccines in their own right, but they did not have the same impact on reducing the incidence of polio worldwide as the polio vaccine by Jonas Salk.

Correct Answer: B

Rationale: The correct answer is B: Sanitation and disease prevention. In the 19th century, public health policies focused on improving sanitary conditions and preventing the spread of diseases. This principle was key in reducing mortality rates and improving overall population health. Centralized government control of healthcare (A) was not as prominent during this period. Nationalized healthcare systems (C) and universal vaccination programs (D) were not widely implemented or emphasized in the 19th century. Sanitation and disease prevention were foundational pillars in shaping public health policies during this era.

Correct Answer: C

Rationale: The correct answer is C: The eradication campaign initiated by the WHO. This campaign, led by the World Health Organization, aimed to eradicate smallpox globally through vaccination programs. The campaign's success in eliminating smallpox in 1980 highlighted the effectiveness of the smallpox vaccine. A: The Spanish Flu pandemic did not directly lead to the widespread use of the smallpox vaccine. B: The formation of the CDC did contribute to public health efforts, but it was not the main driver behind the widespread use of the smallpox vaccine. D: The discovery of penicillin revolutionized medicine, but it did not specifically lead to the widespread use of the smallpox vaccine.

Correct Answer: C

Rationale: The correct answer is C because during the Progressive Era, significant efforts were made to address public health issues, particularly for child welfare. Community health programs focusing on child welfare were established to improve living conditions, nutrition, and overall well-being of children. This was a crucial public health achievement as it aimed to reduce infant mortality rates and improve the health outcomes of children. A: The Social Security Act was not created during the Progressive Era; it was established in 1935 as part of the New Deal under President Franklin D. Roosevelt. B: The Centers for Disease Control and Prevention (CDC) was not established during the Progressive Era; it was founded in 1946 to address and prevent infectious diseases. D: The World Health Organization (WHO) was founded in 1948, after the Progressive Era, to address global health issues and promote public health worldwide.