What are the three types of polio?

There are three types of wild poliovirus (WPV): wild poliovirus type 1 (WPV1), wild poliovirus type 2 (WPV2), and wild poliovirus type 3 (WPV3). While all three cause the same debilitating symptoms, including irreversible paralysis and potentially death, they are immunologically distinct. Importantly, WPV2 has been eradicated.

• Wild Poliovirus Type 1 (WPV1): This type, along with WPV3, remains a global concern requiring ongoing vaccination efforts for eradication.
• Wild Poliovirus Type 2 (WPV2): This type has been successfully eradicated globally, marking a significant achievement in public health.
• Wild Poliovirus Type 3 (WPV3): Also considered eradicated, as declared on World Polio Day in 2019 by an independent commission of experts.

While these three wild poliovirus types are the focus of eradication efforts, it's also crucial to understand that polio is classified differently based on symptom severity: abortive, nonparalytic, and paralytic polio. These classifications describe the presentation of the disease, not the specific virus type causing it. All three classifications can be caused by any of the three WPV types.

The successful eradication of WPV2 highlights the power of global vaccination programs. However, continued vigilance and vaccination are necessary to completely eradicate WPV1 and prevent the re-emergence of the disease from other sources.