Influenza testing trends in sentinel surveillance general practices in Victoria 2007 to 2014
DOI:
https://doi.org/10.33321/cdi.2017.41.2Keywords:
influenza, influenza-like illness, sentinel surveillance, primary health care, AustraliaAbstract
The Victorian Sentinel Practice Influenza Network conducts syndromic surveillance for influenza-like illness (ILI), with testing for laboratory confirmation of a proportion of cases at the discretion of general practitioners. The aim of this study was to evaluate the consistency of sentinel general practitioners' swabbing practice within and between influenza seasons. Aggregated, weekly, non-identified data for May to October each year from 2007 to 2014 were used to calculate the proportion of patients presenting with ILI (defined as cough, fever and fatigue), proportion of ILI patients swabbed and proportion of swabs positive for influenza. Data on the proportion of consultations for ILI and the proportion of ILI patients swabbed were aggregated into time-period quintiles for each year. Analysis of variance was used to compare ILI patients swabbed for each aggregated time-period quintile over all 8 years. Spearman's correlation and Bland-Altman analyses were used to measure association and agreement respectively between ILI proportions of consultations and swabs positive for influenza in time period quintiles within each year. Data were aggregated by year for the rest of the analyses. Between 2007 and 2014 there was a slight decrease in the proportion of positive tests and the proportion of ILI patients was generally a good proxy for influenza test positivity. There was consistency in testing within and between seasons, despite an overall testing increase between 2007 and 2014. There was no evidence for temporal sampling bias in these data despite testing not being performed on a systematic basis. This sampling regimen could also be considered in other similar surveillance systems. Commun Dis Intell 2017;41(1):E4–E9.
Downloads
References
Fielding JE, Regan AK, Dalton CB, Chilver MB, Sullivan SG. How severe was the 2015 influenza season in Australia? Med J Aust 2016.;204(2):60–61.
Kelly HA, Grant KA, Tay EL, Franklin L, Hurt AC. The significance of increased influenza notifications during spring and summer of 2010-11 in Australia. Influenza Other Respir Viruses 2013;7(6):1136–1141.
Clothier HJ, Atkin L, Turner J, Sundararajan V, Kelly HA. A comparison of data sources for the surveillance of seasonal and pandemic influenza in Victoria. Commun Dis Intell 2006;30(3):345–349.
Navarro-Mari JM, Pérez-Ruiz M, Cantudo-Muñoz P, Petit-Gancedo C, Jiménez-Valera M, et al. Influenza-like illness criteria were poorly related to laboratory-confirmed influenza in a sentinel surveillance study. J Clin Epidemiol 2005;58(3):275–279.
Moretti ML, Sinkoc V, Cardoso LG, Camargo GJ, Bachur LF, Hofling CC, et al. Lessons from the epidemiological surveillance program, during the influenza A (H1N1) virus epidemic, in a reference university hospital of Southeastern Brazil. Rev Soc Bras Med Trop 2011;44(4):405–411.
Sreng B, Touch S, Sovann L, Heng S, Rathmony H, Huch C, et al. A description of influenza-like illness (ILI) sentinel surveillance in Cambodia, 2006–2008. Southeast Asian J Trop Med Public Health 2010;41(1):97–104.
Baumbach J, Mueller M, Smelser C, Albanese B, Sewell CM. Enhancement of influenza surveillance with aggregate rapid influenza test results: New Mexico, 2003–2007. Am J Public Health 2009;99 Suppl 2:S372–S377.
Fielding JE, Grant KA, Tran T, Kelly HA. Moderate influenza vaccine effectiveness in Victoria, Australia, 2011. Euro Surveill 2012;17(11). pii: 20115.
Fielding JE, Miller ER, Adams J, Hawking B, Grant K, Kelly HA. Influenza surveillance in Victoria, 2006. Commun Dis Intell 2007;31(1):100–106.
Turner JL, Fielding JE, Clothier HJ, Kelly HA. Influenza surveillance in Victoria, 2005. Commun Dis Intell 2006;30(1):137–143.
Thompson DL, Baumbach J, Jungk J, Sewell CM, Smelser C, Landen M. Does outpatient laboratory testing represent influenza burden and distribution in a rural state? Influenza Other Respir Viruses 2013;7(5):686–693.
Carville KS, Grant KA, Sullivan SG, Fielding JE, Lane CR, Franklin L, et al. Understanding influenza vaccine protection in the community: an assessment of the 2013 influenza season in Victoria, Australia. Vaccine 2015;33(2):341–345.
Moore K, Black J, Rowe S, Franklin L. Syndromic surveillance for influenza in two hospital emergency departments. Relationships between ICD-10 codes and notified cases, before and during a pandemic. BMC Public Health 2011;11:338.
Haddock RL, Damian YS, Duguies LA, Paulino YC. Guam's influenza epidemic(s) of 2009. Hawaii Med J 2010;69(6 Suppl 3):50–51.
Thursky K, Cordova SP, Smith D, Kelly H. Working towards a simple case definition for influenza surveillance. J Clin Virol 2003;27(2):170–179.
Soper DS. DanielSoper.com Statistics Calculators. 2016. Available from: http://www.danielsoper.com/statcalc3/default.aspx Accessed on 17 February 2016.
Stangroom J. Spearman's rho calculator. 2016. Available from: http://www.socscistatistics.com/tests/spearman/Default.aspx Accessed on 5 December 2016.
AusVet Animal Health Services. EpiTools epidemiological calculators: Chi-squared test for trend. 2016. Available from: http://epitools.ausvet.com.au/content.php?page=trend Accessed on 18 February 2016.
Porta MS, International Epidemiological Association. Surveillance. In: A dictionary of epidemiology. 5th edn. Oxford; New York: Oxford University Press: 2008. p. 239.
Carman WF, Wallace LA, Walker J, McIntyre S, Noone A, Christie P, et al. Rapid virological surveillance of community influenza infection in general practice. BMJ 2000;321(7263):736–737.
Kaczmarek MC, Ware RS, Lambert SB. The contribution of PCR testing to influenza and pertussis notifications in Australia. Epidemiol Infect 2016;144(2):306–314.
Kelly H, Carville K, Grant K, Jacoby P, Tran T, Barr I. Estimation of influenza vaccine effectiveness from routine surveillance data. PLoS ONE 2009;4(3):e5079.
Turner J, Kelly H. A medical locum service as a site for sentinel influenza surveillance. Euro Surveill 2005;10(4):96–98.
Downloads
Published
How to Cite
License
Copyright (c) 2017 Communicable Diseases Intelligence
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
