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Table 2 Change in Emergency Department (ED) syndrome counts (relative risk (RR) and 95% CI) associated with a 1 unit increase in weekly laboratory counts, lagged by up to ± 4 weeks: Univariate analysis.

From: Evaluation of alternative respiratory syndromes for specific syndromic surveillance of influenza and respiratory syncytial virus: a time series analysis

ED syndrome outcome Lag1 (weeks) RR RSV (95%CI) RSV P-value RR influenza (95%CI) Influenza
P-value
Bronchiolitis -4 1.009 (1.004-1.013) 0.0001 1.007 (1.003-1.011) < 0.0001
  -3 1.015 (1.011-1.019) < 0.0001 1.003 (1.000-1.007) 0.075
  -2 1.021 (1.017-1.026) < 0.0001 0.998 (0.994-1.001) 0.221
  -1 1.025 (1.020-1.029) < 0.0001 0.999(0.995-1.003) 0.658
  0 1.031 (1.027-1.035) < 0.0001 0.999 (0.995-1.003) 0.586
  1 1.020 (1.016-1.024) < 0.0001 0.995 (0.990-0.999) 0.009
  2 1.018 (1.014-1.022) < 0.0001 1.000 (0.996-1.005) 0.815
  3 1.015 (1.011-1.019) < 0.0001 1.000 (0.995-1.004) 0.838
  4 1.015 (1.011-1.019) < 0.0001 0.998 (0.994-1.003) 0.461
Pneumonia -4 0.998 (0.995-1.001) 0.1088 1.004 (1.002-1.007) 0.0005
  -3 0.998 (0.995-1.001) 0.1611 1.007 (1.005-1.009) < 0.0001
  -2 1.001 (0.998-1.004) 0.4498 1.010 (1.008-1.012) < 0.0001
  -1 1.000 (0.997-1.003) 0.8307 1.011 (1.008-1.013) < 0.0001
  0 1.004 (1.001-1.007) 0.0043 1.009 (1.007-1.012) < 0.0001
  1 1.005 (1.002-1.008) 0.0008 1.007 (1.005-1.009) < 0.0001
  2 1.011 (1.008-1.014) < 0.0001 1.003 (1.000-1.005) 0.0303
  3 1.011 (1.008-1.013) < 0.0001 1.004 (1.002-1.007) 0.0011
  4 1.015 (1.012-1.018) < 0.0001 0.999 (0.996-1.001) 0.3567
Influenza - like -4 1.009 (1.001-1.016) 0.0285 0.994 (0.988-1.000) 0.0383
  -3 0.988 (0.981-0.996) 0.0031 1.011 (1.006-1.017) < 0.0001
  -2 0.984 (0.976-0.991) < 0.0001 1.029 (1.024-1.034) < 0.0001
  -1 0.984 (0.977-0.992) < 0.0001 1.047 (1.042-1.052) < 0.0001
  0 0.991 (0.984-0.998) 0.0129 1.041 (1.036-1.046) < 0.0001
  1 0.983 (0.976-0.990) < 0.0001 1.025 (1.020-1.031) < 0.0001
  2 1.006 (0.999-1.012) 0.1129 1.025 (1.020-1.031) < 0.0001
  3 1.002 (0.995-1.009) 0.5857 1.014 (1.008-1.020) < 0.0001
  4 0.996 (0.989-1.002) 0.2172 0.999 (0.993-1.005) 0.655
All acute respiratory infections -4 0.998 (0.997-0.999) < 0.0001 1.003 (1.002-1.005) < 0.0001
  -3 0.997 (0.996-0.998) < 0.0001 1.006 (1.005-1.007) < 0.0001
  -2 0.999 (0.998-1.001) 0.2516 1.008 (1.007-1.009) < 0.0001
  -1 1.002 (1.001-1.003) 0.0032 1.012 (1.011-1.013) < 0.0001
  0 1.004 (1.003-1.005) < 0.0001 1.010 (1.009-1.011) < 0.0001
  1 1.002 (1.001-1.003) 0.0053 1.007 (1.006-1.008) < 0.0001
  2 1.008 (1.006-1.009) < 0.0001 1.005 (1.004-1.006) < 0.0001
  3 1.007 (1.006-1.008) < 0.0001 1.003 (1.002-1.004) < 0.0001
  4 1.006 (1.005-1.008) < 0.0001 0.999 (0.998-1.000) 0.0876
All respiratory -4 1.000 (0.999-1.001) 0.5467 1.003 (1.002-1.004) < 0.0001
  -3 0.999 (0.998-1.000) 0.1499 1.005 (1.004-1.006) < 0.0001
  -2 1.001 (1.000-1.002) 0.2258 1.007 (1.006-1.008) < 0.0001
  -1 1.003 (1.002-1.004) < 0.0001 1.009 (1.008-1.010) < 0.0001
  0 1.005 (1.004-1.005) < 0.0001 1.007 (1.006-1.008) < 0.0001
  1 1.002 (1.001-1.003) 0.001 1.004 (1.004-1.005) < 0.0001
  2 1.006 (1.005-1.007) < 0.0001 1.003 (1.002-1.004) < 0.0001
  3 1.006 (1.005-1.006) < 0.0001 1.001 (1.000-1.002) 0.0198
  4 1.005 (1.004-1.006) < 0.0001 0.998 (0.997-0.999) < 0.0001
  1. 1A negative lag number refers to virus counts occurring after ED visits, while a positive lag number refers to virus counts occurring before ED visits.