Table 4.
First author, y | Setting | Age group or range | Underlying conditions | Associated respiratory infections | Hospitalization, in‐hospital complications, length of hospital stay, and mortality | Age‐adjusted |
---|---|---|---|---|---|---|
A vs B | ||||||
Hite, 2007 40 | Non‐hosp | <19 | ‐ | URTI: nr & ns | Hospitalization: nr & ns | Unclear |
LRTI: nr & ns | Mechanical ventilation: nr & ns | |||||
Length of hospital stay: nr & ns | ||||||
Death: nr & ns | ||||||
Irving, 2012 8 | Non‐hosp | All ages | ‐ | Pneumonia: 1.2 (0.5‐2.8) | Hospitalization: 1.2 (0.7‐2.4) | Yes |
A(H1N1)p vs B | ||||||
Gutiérrez‐Pizarraya, 2012 41 | Non‐hosp | >14 | Chronic cardiovascular disease: 1.1 (0.4‐3.1) | Pneumonia: 1.5 (0.7‐3.3) | Hospitalization: 1.6 (0.8‐3.3) | Unclear |
Chronic respiratory disease: 1.1 (0.5‐2.4) | ICU admission: 1.9 (0.6‐5.7) | |||||
Diabetes mellitus: 0.2 (0.04‐1.2) | Mechanical ventilation: 1.2 (0.4‐3.7) | |||||
Chronic renal disease: 0.8 (0.3‐2.8) | Death: 1.7 (0.6‐5.2) | |||||
Obesity: 0.9 (0.4‐2.3) | ||||||
Dawood, 2011 19 | Hosp | ≤17 | Any underlying condition: 2.0 (1.4‐3.1) | Pneumonia: 1.3 (0.8‐2.0) | ICU admission: 1.6 (0.9‐2.8) | Unclear |
A(H3N2) vs B | ||||||
Chaves, 2013 9 | Hosp | <18 | ‐ | ‐ | ICU admission or death: 1.01 (0.56‐1.82) | Yes |
Chaves, 2013 9 | Hosp | Adults | ‐ | ‐ | ICU admission or death: 0.91 (0.65‐1.27) | Yes |
Wie, 2013 44 | Non‐hosp | Adults | ‐ | ‐ | Hospitalization: 1.19 (0.59‐2.40) | Yes |
Cohen, 2014 30 | Hosp | All ages | Any underlying condition: nr & ns | ‐ | ICU admission: nr & ns | |
Mechanical ventilation: nr & ns | ||||||
Oxygen supplementation: nr & ns | ||||||
Length of hospital stay: 0.62 (0.45‐0.83) | ||||||
Death: nr & ns | ||||||
A(H1N1) vs A(H1N1)p | ||||||
Esposito, 201112 | Non‐hosp | <14 | ‐ | URTI: 0.88 (0.66‐1.16) | Hospitalization: 0.82 (0.59‐0.97) | Yes |
LRTI: 0.62 (0.39‐0.99) | Length of hospital stay: 0.18 (0.06‐0.56) | |||||
A(H1N1) vs A(H3N2) | ||||||
Esposito, 201112 | Non‐hosp | <14 | ‐ | URTI: 0.75 (0.50‐1.14) | Hospitalization: 0.70 (0.51‐0.96) | Yes |
LRTI: 0.59 (0.37‐0.93) | Length of hospital stay: 0.41 (0.15‐0.65) | |||||
A(H1N1)p vs A(H3N2) | ||||||
Esposito, 201112 | Non‐hosp | <14 | ‐ | URTI: 0.86 (0.43‐1.76) | Hospitalization: 0.96 (0.64‐1.72) | Yes |
LRTI: 0.79 (0.55‐1.11) | Length of hospital stay: 1.22 (1.03‐1.97) | |||||
Chaves, 2013 9 | Hosp | <18 | ‐ | ‐ | ICU admission or death: 2.19 (1.11‐4.33) | Yes |
≤18 | ‐ | ‐ | ICU admission or death: 2.21 (1.66‐2.94) | Yes | ||
Dangi, 2014 10 | Non‐hosp | All ages | Any underlying condition: nr & ns | ‐ | Unclear | |
Cohen, 2014 30 | Hosp | All ages | Any underlying condition: nr & ns | ‐ | ICU admission: nr & ns | Yes |
Mechanical ventilation: nr & ns | ||||||
Oxygen supplementation: nr & ns | ||||||
Length of hospital stay: nr & ns | ||||||
Death: nr & ns | ||||||
Kusznierz, 2016 33 | Hosp | All ages | ‐ | ‐ | ICU admission or death: 2.6 (1.0‐6.8) | Yes |
B Victoria vs B Yamagata | ||||||
Dangi, 2014 10 | Non‐hosp | All ages | Any underlying condition: nr & ns | ‐ | ‐ | Unclear |
Sočan, 2014 31 | Non‐hosp | All ages | Chronic cardiovascular diseases: 0.8 (0.2‐2.7) | Pneumonia: 0.8 (0.2‐3.1) | ‐ | Yes |
Chronic respiratory diseases: 1.6 (0.1‐17.2) | Bronchitis: 1.2 (0.4‐3.4) | |||||
Diabetes mellitus: 0.7 (0.2‐2.7) | ||||||
Chronic renal diseases: 1.3 (0.3‐6.0) | ||||||
Obesity: 1.1 (0.2‐6.1) |
ns, not statistically significant; nr, not reported; Hosp, hospital‐based studies; Non‐hosp, non‐hospital‐based studies; ICU, intensive care unit; LRTI, lower respiratory tract infection; URTI, upper respiratory tract infection. Bold value indicates the significant findings (p < .05).