Does knowing the influenza epidemic threshold has been reached influence the performance of influenza case definitions?
Journal
PloS one
ISSN: 1932-6203
Titre abrégé: PLoS One
Pays: United States
ID NLM: 101285081
Informations de publication
Date de publication:
2022
2022
Historique:
received:
21
07
2021
accepted:
16
06
2022
entrez:
1
7
2022
pubmed:
2
7
2022
medline:
8
7
2022
Statut:
epublish
Résumé
Disease surveillance using adequate case definitions is very important. The objective of the study was to compare the performance of influenza case definitions and influenza symptoms in the first two epidemic weeks with respect to other epidemic weeks. We analysed cases of acute respiratory infection detected by the network of sentinel primary care physicians of Catalonia for 10 seasons. We calculated the diagnostic odds ratio (DOR) and 95% confidence intervals (CI) for the first two epidemic weeks and for other epidemic weeks. A total of 4,338 samples were collected in the epidemic weeks, of which 2,446 (56.4%) were positive for influenza. The most predictive case definition for laboratory-confirmed influenza was the WHO case definition for influenza-like illness (ILI) in the first two epidemic weeks (DOR 2.10; 95% CI 1.57-2.81) and in other epidemic weeks (DOR 2.31; 95% CI 1.96-2.72). The most predictive symptom was fever. After knowing that epidemic threshold had been reached, the DOR of the ILI WHO case definition in children aged <5 years and cough and fever in this group increased (190%, 170% and 213%, respectively). During influenza epidemics, differences in the performance of the case definition and the discriminative ability of symptoms were found according to whether it was known that the epidemic threshold had been reached or not. This suggests that sentinel physicians are stricter in selecting samples to send to the laboratory from patients who present symptoms more specific to influenza after rather than before an influenza epidemic has been declared.
Sections du résumé
BACKGROUND
Disease surveillance using adequate case definitions is very important. The objective of the study was to compare the performance of influenza case definitions and influenza symptoms in the first two epidemic weeks with respect to other epidemic weeks.
METHODS
We analysed cases of acute respiratory infection detected by the network of sentinel primary care physicians of Catalonia for 10 seasons. We calculated the diagnostic odds ratio (DOR) and 95% confidence intervals (CI) for the first two epidemic weeks and for other epidemic weeks.
RESULTS
A total of 4,338 samples were collected in the epidemic weeks, of which 2,446 (56.4%) were positive for influenza. The most predictive case definition for laboratory-confirmed influenza was the WHO case definition for influenza-like illness (ILI) in the first two epidemic weeks (DOR 2.10; 95% CI 1.57-2.81) and in other epidemic weeks (DOR 2.31; 95% CI 1.96-2.72). The most predictive symptom was fever. After knowing that epidemic threshold had been reached, the DOR of the ILI WHO case definition in children aged <5 years and cough and fever in this group increased (190%, 170% and 213%, respectively).
CONCLUSIONS
During influenza epidemics, differences in the performance of the case definition and the discriminative ability of symptoms were found according to whether it was known that the epidemic threshold had been reached or not. This suggests that sentinel physicians are stricter in selecting samples to send to the laboratory from patients who present symptoms more specific to influenza after rather than before an influenza epidemic has been declared.
Identifiants
pubmed: 35776716
doi: 10.1371/journal.pone.0270740
pii: PONE-D-21-23664
pmc: PMC9249166
doi:
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
e0270740Déclaration de conflit d'intérêts
The authors have declared that no competing interests exist.
Références
PLoS One. 2020 Jul 23;15(7):e0236267
pubmed: 32701976
Am Fam Physician. 2003 Jan 1;67(1):111-8
pubmed: 12537174
J R Soc Interface. 2018 Jul;15(144):
pubmed: 30045889
PLoS Comput Biol. 2017 Feb 3;13(2):e1005330
pubmed: 28158192
Influenza Other Respir Viruses. 2018 Mar;12(2):241-249
pubmed: 29152877
Clin Infect Dis. 2000 Nov;31(5):1166-9
pubmed: 11073747
Euro Surveill. 2017 Apr 6;22(14):
pubmed: 28422004
BMC Infect Dis. 2021 Jan 7;21(1):31
pubmed: 33413174
J Med Virol. 2018 Jul;90(7):1177-1183
pubmed: 29488229
Euro Surveill. 2015 Jun 04;20(22):21145
pubmed: 26062645
Epidemiol Infect. 2016 Apr;144(5):1045-51
pubmed: 26388141
JAMA. 2005 Feb 23;293(8):987-97
pubmed: 15728170
Rev Clin Esp (Barc). 2021 Dec;221(10):582-586
pubmed: 34839891
BMC Infect Dis. 2012 Jun 07;12:129
pubmed: 22676850
PLoS One. 2014 Feb 24;9(2):e89178
pubmed: 24586575
PLoS One. 2014 Jan 24;9(1):e84873
pubmed: 24475034
Epidemiol Infect. 2017 Jan;145(1):148-155
pubmed: 27691995
Aust N Z J Public Health. 2018 Feb;42(1):69-76
pubmed: 29281169
Infect Control Hosp Epidemiol. 2015 Mar;36(3):241-8
pubmed: 25695163