Poliovirus eradication in the Western Hemisphere demonstrated the effectiveness of vaccination campaigns and was achieved in which year?

• A. It was achieved in 1990, demonstrating the effectiveness of vaccination campaigns.
• B. It was achieved in 1994, demonstrating the effectiveness of vaccination campaigns.
• C. It has not been achieved.
• D. It was achieved in 1984, demonstrating the effectiveness of vaccination campaigns.

Answer: (B)

The main idea here is when the Western Hemisphere was officially declared free of endemic poliovirus transmission due to vaccination efforts. After years of intensive vaccination campaigns using oral polio vaccine and strengthened surveillance, PAHO/WHO certified the region polio-free in 1994. That certification reflects that there has been no ongoing transmission of wild poliovirus in the Americas for a sustained period, meeting strict elimination criteria. So the year that demonstrates the success of those vaccination campaigns in this region is 1994. Earlier years do not reflect the official certification, and the statement that it has not been achieved is incorrect because the polio-free status was declared in 1994.