Burden of Influenza in Latin America and the Caribbean: a Systematic Review and Meta-analysis

SAVY, VILMA; CIAPPONI, AGUSTÍN; BARDACH, ARIEL; GLUJOVSKY, D; ARUJ, PATRICIA; MAZZONI, AGUSTINA; GIBBONS, LUZ; ORTEGA-BARRIA, EDUARDO; COLINDRES, ROMULO

Conferencia; 2010 International Conference on Emerging Infectious Diseases; 2010

Introduction: Influenza is an acute respiratory illness responsible for severe morbidity and mortality worldwide. This systematic review aimed to study the incidence, etiology and healthcare resource usage for seasonal influenza in Latin America and the Caribbean (LA&C). Methods: A systematic search from 1980 to 2008 in MEDLINE, Cochrane Library, EMBASE, LILACS, generic and academic Internet searches, Ministries of Health, PAHO, regional proceedings, doctoral theses, reference lists of included studies and consulting experts yielded 1092 references, of which 31 articles were finally included. We also used important information from the book Health in the Americas, 2007 Edition, 10 reports from the Collaborative Group for epidemiological surveillance of influenza and other respiratory virus (GROG), and information retrieved from the WHO global flu database FLUNET. Arc-sine transformations and DerSimonian?Laird random-effects model were used for meta-analyses, using Stata® 9.0 and StatsDirect® softwares.Results: A total of 483,130 lab specimens from patients with suspected influenza were included. Influenza-like-illness (ILI) showed an annual rate of 36,080 (95% CI: 28,550?43,610) episodes reported per 100,000 persons-years. The prevalence of influenza virus out of total specimens received by influenza centers ranged between 4.66% and 15.42% with type A being more prevalent than type B, and A subtype H3 predominating. Deaths due to pneumonia and influenza were mainly seen in children under 5 years old (11.5% of total deaths for both genders) and in the elderly population (5.7% in women and 5.3% of deaths in men). Influenza had a substantial impact on the economy of the region. The mean length of stay at hospital due to influenza ranged between 5.8?12.9 days, total workdays lost due to ILI were 17?150 days and the mean direct cost at the time of discharge was US$ 1188 (international US$ 2009) per laboratory-confirmed influenza case. Conclusions: Our data show that seasonal influenza imposes a high morbidity and economic burden to the region. However, the vaccine-uptake rate has been low in this region. Population-based cohort studies are required to improve the knowledge about incidence and resource utilization, which would inform healthcare authorities for decision-making.