Table 1

Characteristics of influenza A(H3N2) confirmed cases (N = 226) and test-negative controls (N = 116) in target group for vaccination, cycEVA 2011–12 study (weeks 52/2011 – 14/2012), Spain
Variables Controls no./total no. (%)a A(H3N2) cases no./total no. (%)a P valueb
Median age (range years) 53 (3–87) 63 (3–93) 0.011
Age group (years)
  0–4 4/116 (3.2) 5/226 (2.2) 0.088
  5–14 8/116 (6.5) 14/226 (6.2)
  15–64 69/116 (58.5) 107/226 (47.3)
  ≥65 35/116 (31.8) 100/226 (44.2)
Sex: male 52/116 (46.9) 106/226 (46.9) 0.716
Any chronic condition reported 73/116 (62.9) 117/226 (51.8) 0.049
Pregnancy 3/116 (2.6) 6/226 (2.6) 0.970
Obesityc 6/116 (4.9) 12/226 (5.3) 0.957
Any hospitalization 4/116 (3.4) 11/226 (4.9) 0.544
Median GP visits (range number) 5 (0–32) 5 (0–32) 0.782
Smoker 23/115 (19.1) 25/223 (11.2) 0.046
Swabbing less 4 days 108/116 (93.1) 217/226 (96.0) 0.240
Median time since vaccination (range days) 109 (39–151) 116 (62–166) 0.432
Vaccine coverage
By seasonal vaccine
  Seasonal 2011-12 46/116 (39.7) 88/226 (38.9) 0.898
  Seasonal 2010-11 40/116 (34.5) 75/224 (33.5) 0.853
By age groups
  0–4 years 1/4 (25.0) 2/5 (40.0) 0.635
  5–14 years 1/8 (12.5) 2/14 (14.3) 0.907
  15–64 years 19/69 (27.6) 19/107 (17.8) 0.124
  ≥65 years 25/35 (71.4) 65/100 (65.0) 0.487

GP: general practitioners and paediatricians.

aCases and controls recruited between weeks 52/2011 – 14/2012 and with an interval between symptom onset and swabbing of less than eight days.

bNon parametric test of the median or Chi-square test or Fisher’s exact test, when appropriate.

cDefined as body mass index ≥ 40 kg/m2.

Jiménez-Jorge et al.

Jiménez-Jorge et al. BMC Infectious Diseases 2013 13:441   doi:10.1186/1471-2334-13-441

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