Innovative strategies developed to mitigate the impact of COVID-19 pandemic on polio surveillance in Nigeria, 2020

Introduction

following the spread of the COVID-19 pandemic to Nigeria, the Federal Government of Nigeria restricted human and vehicular movements to curb the spread of the disease. This action had a negative impact on Acute Flaccid Paralysis (AFP) surveillance, with a resultant reduction in the number of AFP cases reported. This paper describes the impact of the COVID-19 pandemic on poliovirus surveillance in Nigeria and the proactive interventions by Nigeria´s polio program to mitigate the impact of COVID-19 on polio surveillance.

Methods

nine innovative strategies were implemented in all 774 Local Government Areas (LGA) of the 36 states and Federal Capital Territory (FCT) of the country. These strategies were developed by the national surveillance officers and operationalized by sub-national surveillance officers with different strategies starting at different epidemiological weeks from week 14 to 23, 2020. Many of the strategy innovations were technology-based and included: the use of mobile phones to send the AFP case definition and video by WhatsApp or by SMS, the use of state-specific toll-free numbers and Mobile Telephone Network (MTN) (mobile service provider) CallerfeelTM to community informants (CI) who were the main targets of the interventions to increase case detection and reporting. Others included the use of abridged e-surveillance integrated supportive supervision (ISS) checklists, virtual monthly DSNO meetings, and batched AFP stool specimen transportation network.

Results

compared to the same period in 2019, the cumulative rate of AFP case detection and reporting had gradually declined from 39.1% in January to 16.7% before the commencement of the interventions in week 20, 2020. However, the detection and reporting increased by 57.% from week 20 to week 47 compared to the same period in 2019. This is because with COVID-19, hospital visitation dropped, and the sick remained in the communities, so the CI network was relied on to detect and report AFP cases. The cumulative proportion of AFP cases reported by community informants as of week 47 increased from 13% in 2018 to 21% in 2020. This indicates an increase of 38%. Thirty-five AFP cases were detected and reported using the MTN Caller Feel strategy, while 15 cases were reported through state-specific toll-free numbers.

Conclusion

the implementation of the innovative strategies was able to mitigate the low AFP case detection and reporting observed at the initial stage of the COVID-19 pandemic. The use of technology facilitated reaching the CI network, which was more instrumental in detecting and reporting the cases.

Experience and findings from surveillance peer review in Nigeria, August 2017-May 2019

Introduction

acute flaccid paralysis (AFP) surveillance is the gold standard of the Global Polio Eradication Initiative (GPEI) for detecting cases of poliomyelitis and tracking poliovirus transmission. Nigeria's AFP surveillance performance indicators are among the highest in countries of the World Health Organization (WHO) African Region. The primary AFP surveillance performance indicators are the rate of non-polio AFP among children and the proportion of timely, adequate specimen collection. The surveillance working group of the National Emergency Operations Centre assessed the quality of AFP surveillance data in some reportedly high-performing states.

Methods

we conducted a retrospective review of AFP surveillance performance indicators in Nigeria for 2010-2019. We also reviewed data in reports from four groups of surveillance peer reviews and validation visits (conducted by in-country GPEI partners) during August 2017-May 2019 in 16 states with high primary AFP surveillance indicators; the validation visits reviewed clinical information and the dates of specimen collection and onset of paralysis with caretakers.

Results

there were consistently increasing AFP surveillance primary performance indicators during 2010-2016, followed by declines during 2017-2019. From the data for 16 states with peer reviews conducted from August 2017-May 2019, overall concordance of reported and "true" (validated) AFP indicator data in peer review investigations was highly variable. True AFP concordance ranged from 58%-100%, and stool timeliness concordance ranged from 56%-95%. The most common clinical causes of reported AFP cases that were not true AFP were spastic paralysis, malaria, sickle cell disease, and malnutrition. All the states that participated in peer reviews developed surveillance improvement plans based on the gaps identified.

Conclusion

Nigeria has highly sensitive AFP surveillance according to reported primary AFP performance indicators. The findings of peer reviews indicate that the AFP surveillance system needs to be strengthened and well-supervised to enhance data quality.

Implementing a robust adverse event of special interest surveillance for novel oral polio vaccine type 2 rollout, Nigeria, March-July 2021

Introduction

novel oral poliovirus vaccine type 2 (nOPV2), designed to be more genetically stable than Sabin-strain oral poliovirus vaccine type 2 (mOPV2), is a new and key component of the Global Polio Eradication Initiative's strategy to combat outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2). The World Health Organization´s (WHO´s) emergency use listing (EUL) requires extensive safety monitoring for Adverse Event of Special Interest (AESI) in its use. We implemented AESI active surveillance to monitor the safety of the nOPV2 in Nigeria.

Methods

a cross-sectional assessment was conducted in Nigeria during March-June 2021 in 117 local government areas (LGAs) across 6 states and the Federal Capital Area with confirmed cVDPV2 transmission. We conducted active searches for nOPV2 AESI in all health facilities. Suspected events were ascertained, and vaccination and clinical data abstracted. Events were classified using WHO causality assessment algorithm. Data were analyzed using Epi info7.

Results

total of 234 adverse events were reported after 21,997,300 doses of nOPV2 were administered, giving a crude reported incidence of 1 in 94,000 doses of nOPV2. Altogether, 221 of the 234 (94%) adverse events were classified. For 166 AESI ascertained to occur following a dose of nOPV2, the corrected crude incidence rate was 1 in 133,000 doses; 4 of the adverse events, were classified as consistent with casual association with nOPV2 vaccination.

Conclusion

we found that nOPV2 had a low incidence of AESI following nOPV2 campaigns and no new or unexpected adverse event was reported. Safety monitoring should be sustained for early detection of signals and uncommon adverse events.

Enhancing acute flaccid paralysis surveillance system towards polio eradication: reverse cold chain monitoring in Nigeria, 2017 to 2019

INTRODUCTION

Highly sensitive acute flaccid paralysis (AFP) surveillance is critical for detection of poliovirus circulation and documentation for polio-free certification. The reverse cold chain (RCC) is a system designed to maintain stool specimens in appropriate temperature for effective detection of poliovirus in the laboratory. We monitored the RCC of AFP surveillance in Nigeria to determine its effectiveness in maintaining viability of enterovirus.

METHODS

A descriptive cross-sectional study was conducted from November 2017 to December 2019. We included AFP cases from 151 Local Government Areas and monitored RCC of paired stool specimens from collection to arrival at laboratories. The national guideline recommends RCC temperature of +2 to +8°C and a non-polio enterovirus (NPENT) detection rate of ≥10%. We analyzed data with Epi Info 7, and presented results as frequencies and proportions, using Chi-square statistic to test for difference in enterovirus isolation.

RESULTS

Of the 1,042 tracked paired stool specimens, 1,038(99.6%) arrived at the laboratory within 72 hours of collection of second specimen, 824(79.1%) were maintained within recommended temperature range, and 271(26%) yielded enteroviruses: 200(73.8%) NPENT, 66(24.4%) Sabin, 3(1.1%) vaccine derived poliovirus type 2 and 2(0.7%) mixture of Sabin and NPENT. The NPENT and Sabin rates were 19.2% and 6.7% respectively. Twenty-five percent of 824 specimens maintained within recommended temperature range, compared with 29.8% of 218 specimens with temperature excursion yielded enteroviruses (P=0.175).

CONCLUSION

the RCC of AFP surveillance system in the study area was optimal and effective in maintaining the viability of enteroviruses. It was unlikely that poliovirus transmission was missed during the intervention.