Characteristics of Included Studies
Study and Year | Population and Season(s) | N | Influenza Prevalence, % | Country | Reference Standard | Comment |
---|---|---|---|---|---|---|
DIF=direct immunofluorescence; ED = emergency department; ELISA = enzyme-linked immunosorbent assay; ILI = influenza-like illness; NPV = negative predictive value; PCR = polymerase chain reaction; RSV = respiratory syncytial virus; RTI = respiratory tract infection. | ||||||
Govaert et al,13 1998 | Average-risk, unvaccinated primary care patients older than 60 y with ILI during 1991–1992 flu season | 1,838 (logistic regression); 1,791 (heuristics) | 6.6 | Netherlands | Increase in antibody titer | Any symptoms reported during study period were included; part of randomized trial of vaccination. |
Carrat et al,23 1999 | Primary care patients older than 1 y with ILI, RTI syndrome, and/or fever >38°C without signs of other infections during 1995–1996 flu season | 600 | 26 | France | DIF and ELISA; if disagreement, further testing with PCR and culture | Separate models created for H1N1 and H3N2 subtypes, and for all influenza. |
Monto et al,11 2000 | Adolescent or older with fever and ≥2 other symptoms (headache, myalgia, cough, or sore throat) during fall or winter of 1994–1998 | 3,744 | 66 | North America, Europe, southern hemisphere | Culture or increase in antibody titer (in some studies PCR or immunofluorescence) | High prevalence of influenza. Data from 6 randomized trials of zanamivir vs placebo. |
Boivin et al,12 2000 | Patients with ILI (fever ≥37.8°C and ≥2 other symptoms) seeking care at an outpatient clinic during 1998–1999 flu season | 100 | 79 | Canada | PCR and culture | – |
van Elden et al,10 2001 | Primary care patients with fever (≥38°C), ≥1 constitutional symptom (malaise, headache, myalgia, chills), and ≥1 respiratory symptom (coryza, sneeze, cough, sore throat, hoarseness) seeking care within 48 hr of onset during 1997–1998 flu season | 81 | 51 | Netherlands | PCR and culture | Only PCR results were used for model development. |
Zambon et al,19 2001 | Persons aged 12 y or older seen within 48 hr of onset of ILI as part of a multicenter international clinical trial of an influenza drug | 1,033 | 77 (any test positive); 67 (all 3 tests positive) | Europe, North America | PCR, culture, or increase in antibody titer | Reference standard was abnormal finding on all 3 tests. |
Walsh et al,21 2002 | Inpatients older than age 65 y or with underlying cardiopulmonary conditions with a respiratory diagnosis during 1999–2000 flu season | 332 | 18 | United States | Culture, rapid antigen test, increase in antibody titer, or PCR | A model with 2 variables (temperature >38°C and absence of dyspnea) reportedly did not discriminate well; results not reported by authors. |
Friedman and Attia,20 2004 | Children (0–17 y) seen in the ED with suspected ILI (fever and coryza, cough, headache, sore throat, or muscle aches) during 2002 flu season | 128 | 35 | United States | Culture | – |
Senn et al,7 2005 | Persons with ILI seeking care at an outpatient clinic during 1999–2000 flu season | 201 | 52 | Switzerland | Culture | Cutoff for logistic model presumably probability of influenza >50%. |
Stein et al,8 2005 | Consecutive adults with RTI in past 3 wk with cough, sinus pain, congestion/ rhinorrhea, sore throat, or fever seen in the ED during 2002 flu season | 258 | 21 | United States | PCR | Validated previously developed fever and cough rule.11 |
Ohmit and Monto,24 2006 | Study 1 (zanamivir): children aged 5–12 y with fever and duration of illness <36 hr during flu season Study 2 (oseltamivir): children aged 1–12 y with fever and cough or nasal symptoms, and duration <48 hr during flu season | Study 1: 468 Study 2 (1–4 y): 255 Study 2 (5–12 y): 221 | Study 1: 74 Study 2: 67 | United States | Culture and/or 4-fold increase in antibody titer (or PCR in zanamivir trial only) | Validated previously developed fever and cough rule.11 RSV infection excluded. Unable to calculate sensitivity, specificity, NPV from data for fever and cough rule. |
van den Dool et al,22 2008 | Adult inpatients in the general medicine, pulmonology, and infectious disease wards of a tertiary care hospital during 2006–2007 flu season | 264 | 8.7 | Netherlands | PCR | Included all patients regardless of symptoms; validated previously developed fever and cough rule.11 |