Hospital discharges-based search of acute flaccid paralysis cases 2007\u20132016 in Italy and comparison with the National Surveillance System for monitoring the risk of polio reintroduction

Paola Stefanelli,Concetta Amato,Gabriele Buttinelli,Stefano Fiore,Stefano Fontana,Stefania Bellino

doi:10.1186/s12889-019-7617-0

Paola Stefanelli, Concetta Amato + Show 4 more

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https://doi.org/10.1186/s12889-019-7617-0

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Abstract

BackgroundAcute flaccid paralysis (AFP) surveillance has been adopted globally as a key strategy for monitoring the progress of the polio eradication initiative. Hereby, to evaluate the completeness of the ascertainment of AFP cases in Italy, a hospital-discharges based search was carried out.MethodsAFP cases occurring between 2007 and 2016 among children under 15 years of age were searched in the Italian Hospital Discharge Records (HDR) database using specific ICD-9-CM diagnostic codes. AFP cases identified between 2015 and 2016 were then compared with those notified to the National Surveillance System (NSS).ResultsOver a 10-year period, 4163 hospital discharges with diagnosis of AFP were reported in Italy. Among these, 956 (23.0%) were acute infective polyneuritis, 1803 (43.3%) myopathy, and 1408 (33.8%) encephalitis, myelitis and encephalomyelitis. During the study period, a decreasing trend was observed for all diagnoses and overall the annual incidence rate (IR) declined from 5.5 to 4.5 per 100,000 children. Comparing NSS with HDR data in 2015–2016, we found a remarkable underreporting, being AFP cases from NSS only 14% of those recorded in HDR. In particular, the acute infective polyneuritis cases reported to NSS accounted for 42.6% of those detected in HDR, while only 0.9% of myopathy cases and 13.1% of encephalitis/myelitis/encephalomyelitis cases have been notified to NSS. The highest AFP IRs per 100,000 children calculated on HDR data were identified in Liguria (17.4), Sicily (5.7), and Veneto (5.1) Regions; regarding the AFP notified to the NSS, 11 out of 21 Regions failed to reach the number of expected cases (based on 1/100,000 rate), and the highest discrepancies were observed in the Northern Regions. Overall, the national AFP rate was equal to 0.6, therefore did not reach the target value.ConclusionsAFP surveillance data are the final measure of a country’s progress towards polio eradication. The historical data obtained by the HDR have been useful to assess the completeness of the notification data and to identify the Regions with a low AFP ascertainment rate in order to improve the national surveillance system.

Highlights

Acute flaccid paralysis (AFP) surveillance has been adopted globally as a key strategy for monitoring the progress of the polio eradication initiative
Among children aged less than 15 years, due to AFP based on the following ICD-9-CM codes as indicated in primary or secondary diagnoses [6]: 045.0X “Acute paralytic poliomyelitis specified as bulbar”
A decreasing trend was observed for all diagnoses during the study period, and overall the annual AFP incidence rate (IR) declined from 5.5 to 4.5 per 100,000 children

Summary

Introduction

Acute flaccid paralysis (AFP) surveillance has been adopted globally as a key strategy for monitoring the progress of the polio eradication initiative. The World Health Organization (WHO) recommends countries to monitor cases of acute flaccid paralysis (AFP), which is the main clinical picture of a poliovirus infection, and the poliovirus (PV) circulation, to provide accurate data for the development of appropriate prevention and control strategies [1]. Until the PV transmission is not interrupted, all countries remain at risk of virus importation, through population movements. In response to the ongoing importations of poliovirus in polio-free countries, the WHO Director General on 5th May 2014 declared the international spread of wild poliovirus to be a public health emergency of international concern [3]

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