Which outcome measures progress toward polio eradication?

• A. Non-polio AFP rates
• B. Vaccination coverage
• C. Interruption of wild-type poliovirus transmission
• D. All of the above

Answer: (D)

Progress toward polio eradication is measured using multiple, complementary indicators that together show how close we are to stopping transmission. Non-polio AFP rates reflect how sensitive and effective the surveillance system is at detecting acute flaccid paralysis events, ensuring that poliovirus infections don’t go unnoticed. Vaccination coverage indicates the level of immunity in the population; high coverage reduces the number of susceptible children and interrupts transmission chains. The interruption of wild-type poliovirus transmission is the actual epidemiological milestone showing that the virus is no longer circulating in the community. Because each measure provides essential, different insight—surveillance quality, population immunity, and real transmission status—all of the above together best represent progress toward eradication.