Innovations in the Implementation of Polio Surveillance Enhancement Plan in Oyo State, Nigeria: Key Benefits, Lessons Learned, Challenges and Opportunities

Abstract
Background: Nigeria attained the milestone of being certified wild poliovirus free in the year 2020. However, a drop in the key performance indicators of polio surveillance system was across various Local Government Areas (LGAs) in Oyo State. This drop highlighted the need for an innovative way of enhancing polio surveillance in Oyo State. Methods: This study was conducted in four phases and each phase utilized a cross-sectional study design and purposive sampling technique to select eligible LGAs and participants. LGAs that met at least two of the set-out criteria (had not reported at least a case of Acute Flaccid Paralysis (AFP) 12 months preceding the survey, with decline in AFP case detection rate, had not met AFP key indicators, are densely populated, and has an international border) were selected. A concurrent mixed method of data collection was utilized, and quantitative data were collected with a semi-structured questionnaire administered using Computer Assisted Personal Interviews (CAPI) during community active case search, health facility retroactive case search (HFRACS). Qualitative data collection was done through Focus Group Discussion (FGD). Surveillance intensification activities were conducted over eight weeks period. Data were analyzed using Microsoft Excel Software; summarization was done using frequencies and percentages while presentation was done using charts and spot maps. Results: A total of 1277, 49, 259 and 632 settlements, households and health facilities respectively were visited across 24 (73%) LGAs in Oyo State. Of the 150 suspected AFP cases identified, 45 (30%) were rejected cases, 33 (22%) were missed cases and 72 (48%) were true AFP cases. Non-Polio AFP Rate (NP-AFP rate) increased from 2.7 to 6.9 (P < 0.0001) after the surveillance intensification, also, the Non-Polio Enterovirus (NPENT) isolation was increased by 40% (16% to 23%). At the end of the intensification activities, all LGAs in Oyo State had met the WHO recommended Non-Polio Acute Flaccid Paralysis (NP-AFP) rate of ≥3/100,000 population. Conclusions: Innovative strategies implemented in AFP surveillance across Oyo State have resulted in improvement in AFP surveillance performance indicators in the State. There is therefore the need for dynamic and innovative ways of conducting AFP surveillance to prevent poliomyelitis epidemics and to ensure maintenance of Nigeria polio free certification status.