Incidence of medically attended influenza among residents of Shai-Osudoku and Ningo-Prampram Districts, Ghana, May 2013 - April 2015.

Michael Preko Ntiri,Eve-Marie Benson,Ndahwouh Talla Nzussouo,Joseph Asamoah Frimpong,Erica Dueger,Marc-Alain Widdowson,Kwadwo Koram,Fatimah S Dawood,Michael Adjabeng,Meredith L Mcmorrow,Prince Parbie,William Ampofo,Edem Badji,Jazmin Duque

doi:10.1186/s12879-016-2078-x

Abstract

BackgroundInfluenza vaccination is recommended by the World Health Organization for high risk groups, yet few data exist on influenza disease burden in West Africa.MethodsWe estimated medically attended influenza-associated illness rates among residents of Shai-Osudoku and Ningo Pram-Pram Districts (SONPD), Ghana. From May 2013 to April 2015, we conducted prospective surveillance for severe acute respiratory illness (SARI) and influenza-like illness (ILI) in 17 health facilities. In 2015, we conducted a retrospective assessment at an additional 18 health facilities to capture all SONPD SARI and ILI patients during the study period. We applied positivity rates to those not tested to estimate total influenza cases.ResultsOf 612 SARI patients tested, 58 (9%) were positive for influenza. The estimated incidence of influenza-associated SARI was 30 per 100,000 persons (95% CI: 13-84). Children aged 0 to 4 years had the highest influenza-associated SARI incidence (135 per 100,000 persons, 95% CI: 120-152) and adults aged 25 to 44 years had the lowest (3 per 100,000 persons, 95% CI: 1-7) (p < 0.01). Of 2,322 ILI patients tested, 407 (18%) were positive for influenza. The estimated incidence of influenza-associated ILI was 844 per 100,000 persons (95% CI: 501-1,099). The highest incidence of influenza-associated ILI was also among children aged 0 to 4 years (3,448 per 100,000 persons, 95% CI: 3,727 – 3,898). The predominant circulating subtype during May to December 2013 and January to April 2015 was influenza A(H3N2) virus, and during 2014 influenza B virus was the predominant circulating type.ConclusionsInfluenza accounted for 9% and 18% of medically attended SARI and ILI, respectively. Rates were substantive among young children and suggest the potential value of exploring the benefits of influenza vaccination in Ghana, particularly in this age group.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-2078-x) contains supplementary material, which is available to authorized users.

Highlights

Influenza vaccination is recommended by the World Health Organization for high risk groups, yet few data exist on influenza disease burden in West Africa
A review of seasonal influenza epidemiology in sub-Saharan Africa found that 10% of outpatient acute respiratory cases and 7% of children hospitalized with acute respiratory infection (ARI) tested positive for influenza [2]
Study population Between May 1, 2013 through April 30, 2015, there were 801 severe acute respiratory illness (SARI) patients among Shai-Osudoku and Ningo Pram-Pram Districts (SONPD) residents, 612 (76%) of which were tested for influenza

Summary

Introduction

Influenza vaccination is recommended by the World Health Organization for high risk groups, yet few data exist on influenza disease burden in West Africa. A review of seasonal influenza epidemiology in sub-Saharan Africa found that 10% (range: 1%-25%) of outpatient acute respiratory cases and 7% (range: 1%-16%) of children hospitalized with ARI tested positive for influenza [2]. There are 24 World Health Organization (WHO) designated National Influenza Centers in Africa and 10 African countries regularly report influenza surveillance data to the Global Influenza Surveillance and Response System (GISRS) [6]. Despite these advances, there are few data describing influenza disease burden in West African countries

Methods

Results

Discussion

Conclusion