Improvements of acute flaccid paralysis and measles surveillance performances in response to outbreak of circulating vaccine-derived poliovirus (2021-2022): the case of Southwest Ethiopia Region, Ethiopia.

Introduction: following the detection of vaccine-derived poliovirus in 2019 in Ethiopia, response activities have been conducted including strengthening disease surveillance activities.

Methods: trend analysis study design of acute flaccid paralysis and measles surveillance data for the years 2021 and 2022 for Southwest Ethiopia Region was used. The non-polio acute flaccid paralysis (AFP) rate and stool adequacy rates were used to assess the AFP surveillance. Whereas the non-measles febrile rash rate was used to assess the measles surveillance.

Results: a total of 68 AFP cases in 2022 and 49 in 2021 have been reported as of week 41 and investigated for polio analysis. All cases were discarded in 2022 and 1 cVDPV was detected in 2021. The stool adequacy rate for 2022 was 96%; whereas, 94% in 2021. The annualized non-polio AFP rate was 4.8/100,000 for 2022 and 3.8/100,000 for 2021, which the former is much higher though both met the minimum expected rate in outbreak areas of 3/100,000. A total of 155 suspected measles cases in 2022 and 38 in 2021 have been investigated for IGM analysis. In 2022, 9 and 1 in 2021 Igm positive for measles were identified. The non-measles febrile rash rate for 2022 was 4.6/100,000; whereas, 1.2/100,000 for 2021.

Conclusion: there is an improvement in the sensitivity of AFP and measles surveillance for Southwest Ethiopia Region in 2022. Sustaining high-quality measles and AFP surveillance is suggested to maintain measles and polio-free statuses.