Surveillance To Track Progress Toward Polio Eradication - Worldwide, 2022-2023

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Global Health Security

Background:

• The global polio eradication program has significantly reduced wild poliovirus (WPV) cases by over 99.9% since 1988.
• WPV serotypes 2 and 3 have been eradicated, with only WPV type 1 (WPV1) still circulating endemically in Afghanistan and Pakistan.
• Surveillance for acute flaccid paralysis (AFP) and environmental sewage sampling are crucial for detecting poliovirus.

Purpose of the Study:

• To evaluate key performance indicators of polio surveillance systems in 28 priority countries during 2022-2023.
• To identify persistent surveillance gaps and inform strategies for strengthening polio detection capabilities.
• To assess progress towards global polio eradication goals.

Main Methods:

• Analysis of AFP surveillance data, including case detection and reporting rates.
• Review of environmental surveillance data from sewage samples for poliovirus detection.
• Evaluation of Global Polio Laboratory Network performance metrics.
• Data collection from 28 priority countries for the polio eradication program.

Main Results:

• No WPV1 cases were detected outside Afghanistan and Pakistan after August 2022.
• During 2022-2023, 71.4% of priority countries met national AFP surveillance indicator targets.
• An increase in the number of environmental surveillance sites was observed.
• Persistent national and subnational AFP surveillance gaps were identified, potentially due to reporting lags.

Conclusions:

• Maintaining high-quality surveillance systems is essential for achieving global polio eradication.
• Monitoring surveillance indicators is critical for identifying and addressing weaknesses in polio detection.
• Targeted strengthening of surveillance activities is necessary, especially in high-risk regions for poliovirus circulation.