Application of early aberration reporting system (EARS) to seasonal influenza weekly report in Mexico (2007–2014)

Abstract

Purpose: Seasonal influenza is a serious re-emerging acute infectious diseases with its social and health impact. Understanding its temporal characteristics in different spatial perspectives is a priority in public health and disease surveillance due to its annual recurrent episodes causing significant health burden. However, national and state-level influenza temporal trends are not fully investigated yet. Therefore, we applied EARS methods o describe temporal trends of seasonal influenza in Mexico from 2007 to 2014 in different spatial level. Methods & Materials: The number of confirmed seasonal influenza cases are reported every week at the state level from 2007 to 2014 (except in 2009) in Mexico. We use Early Aberration Reporting System (EARS) methods (C1, C2, and C3 algorithms) to detect the signals from influenza outbreak as temporal trends investigation in two different spatial level: national level and state level. Results: At national level analysis, C1 method could catch up 22 signals, C2 method could catch up 73 signals and C3 method could catch up 116 signals during 2007–2014 seasonal influenza surveillance. At state-level analysis, C1 statistics could catch up total 570 signals in 32 states. Average number of signals from C1 statistics is 17.8 signals/state ranged from 11 to 28. C2 statistics could catch up total 1612 signals in 32 states. The average number of signals C2 statistics is 50.4 signals/state ranged from 31 to 67 signals. C3 statistics could catch up total 3163 signals in 32 states. The average number of signals from C3 statistics is 98.8 signals/state ranged from 72 to 120 signals.Tabled 1Number of C1 SignalsNumber of C2 SignalsNumber of C3 SignalsMinimum (per year)113173Maximum (per year)2867119Average(SD)17.8(4.09)50.4(10.6)88.5(14.6) Open table in a new tab Conclusion: National level surveillance system and its signals may not meet the state level outbreak signals. Public health professionals should understand the difference of seasonal influenza temporal trends. Public health professionals and governments should apply state-level surveillance system to provide better guidelines for seasonal influenza prevention and control.