Table 1. Case definitions, three international ILI definitions and one national ARI definition (used as inclusion criterion), GROG study, France, 2009–2014.
Definition | Type | Sudden onset | General symptoms | Respiratory symptoms |
---|---|---|---|---|
ECDC | ILI | Yes | At least one among: fever, feverishness, headache, malaise, myalgia |
At least one among: cough, sore throata, shortness of breath |
WHO | ILI | No | Fever ≥ 38 °C with onset within the last 10 days | Cough |
CDC | ILI | Yes | Fever ≥ 100° F (37.8 °C)b Absence of a known cause other than influenza |
At least one among: cough, sore throata |
GROG | ARI | Yes | At least one among: fever ≥ 38 °C, headache, weakness, myalgia, chills |
At least one among: cough, coryza, bronchitis, pharyngitis, shortness of breath, expectoration |
ARI: Acute respiratory illness; CDC: Centers for Disease Control and Prevention; ECDC: European Centre for Disease Prevention and Control; GROG: Groupes Régionaux d’Observation de la Grippe; ILI: influenza-like illness; WHO: World Health Organization.
a The sore throat symptom is not collected in the GROG network. For the purpose of this work, the variable was replaced by pharyngitis diagnosis.
b Fever is defined in the GROG network as a temperature fever ≥ 100.4°F (38.0 °C). For the purpose of this work, fever ≥ 100° F (37.8 °C) was replaced by fever ≥ 100.4°F (38.0 °C).