Top 5 Takeaways

1. Improved Surveillance: National AFP surveillance performance improved from 2020 to 2021 in many priority countries, especially in the WHO African Region.
2. Persistent Gaps: Despite improvements, substantial national and subnational surveillance gaps remain, hindering timely detection of poliovirus circulation.
3. Environmental Surveillance: Environmental surveillance detected cVDPV2 before confirmed AFP cases in several countries, highlighting its importance in poliovirus detection.
4. Impact of COVID-19: The COVID-19 pandemic disrupted polio vaccination and surveillance activities, leading to a decline in reported AFP cases and delays in stool specimen processing.
5. Global Polio Laboratory Network: The WHO Global Polio Laboratory Network played a critical role in poliovirus detection and monitoring, testing over 170,000 stool specimens in 2021.

Original Article Author and Citation

Corresponding Author

Amanda L. Wilkinson, lxq6@cdc.gov

Suggested Citation

Wilkinson AL, Diop OM, Jorba J, Gardner T, Snider CJ, Ahmed J. Surveillance to Track Progress Toward Polio Eradication — Worldwide, 2020–2021. MMWR Morb Mortal Wkly Rep 2022;71:538–544. DOI: http://dx.doi.org/10.15585/mmwr.mm7115a2

Summary

This report analyzes AFP surveillance data from 43 priority countries for 2020-2021, highlighting improvements in national surveillance performance, particularly in the WHO African Region. Despite these gains, significant gaps remain at both national and subnational levels, necessitating ongoing efforts to enhance surveillance and ensure timely detection of poliovirus circulation.

Methods

AFP surveillance quality was assessed using two key performance indicators: the nonpolio AFP (NPAFP) rate and the adequacy of stool specimen collection. Environmental surveillance involved systematic sewage sampling to detect poliovirus. Data were reviewed from 43 priority countries, focusing on those at high risk for poliovirus transmission.

Discussion

The COVID-19 pandemic negatively impacted polio surveillance, causing declines in AFP case reporting and delays in stool specimen processing. However, many countries showed improved surveillance performance in 2021. The detection of a WPV1 case in Malawi underscores the need for continuous high-quality surveillance globally. The updated Global Polio Surveillance Action Plan for 2022–2024 aims to address these challenges and guide improvements.

Conclusion

High-quality surveillance is essential for global polio eradication. Continuous monitoring and addressing surveillance gaps will enhance the sensitivity and timeliness of poliovirus detection, moving closer to the goal of eradication.

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