Skip to main content

Table 5 Univariable associations for recurrent IAV shedding using logistic regression and Cox’s regression for recurrent events

From: Longitudinal study of influenza A virus circulation in a nursery swine barn

Variable Ordinary logistic regression PWP-CP
OR 95% CI p-value HR 95% CI p-value
Study 1a
 H3N2_Ac,d 0.63 0.37, 0.09 0.10 0.87 0.77, 0.99 0.03
 H3N2_A2 1.63 1.13, 2.37 0.01 1.11 1.04, 1.17 0.01
 H3N2_Bc,e 0.49 0.21, 1.10 0.08 0.83 0.68, 1.01 0.72
 H3N2_B2 1.24 1.00, 1.53 0.04 1.04 0.99, 1.09 0.05
 H1N1_Cc,f 0.87 0.78, 0.96 0.01
 H1N1_homec,g 1.19 0.53, 0.97 0.03 0.82 0.84, 0.98 0.01
 Low heterologous H3N2 cluster Baseline Baseline
 High heterologous H3N2 clusterh 2.66 0.86, 8.24 0.08 1.15 0.91, 1.44 0.22
 Source    <0.01\\\    <0.01\\\
  Source 1 5.5 1.54, 19.6 0.01 2.58 2.14, 3.11 0.01
  Source 2 0.68 0.15, 3.08 0.62 1.34 1.02, 1.76 0.03
  Source 3 5.5 1.54, 19.6 0.01 2.16 1.77, 2.65 0.01
  Source 4 Baseline Baseline
  Source 5 1 1.96 1.39, 2.76 0.01
Study 2b
 H3N2_Bc,e 0.36 0.10, 1.27 0.11 0.67 0.46, 0.98 0.04
 H3N2_B2 1.15 0.96, 1.37 0.12 1.06 1.00, 1.12 0.03
  1. OR: Odds Ratio, PWP-CP: Prentice, Williams and Peterson conditional probability.
  2. \\\ p-value obtained by testing categorical variable using a partial likelihood test.
  3. a,bTwo distinct longitudinal studies were performed in nursery pigs.
  4. cEstimates based on variable representing an hemagglutinin inhibition titer for a specific strain divided by 10 and then log2 transformed.
  5. dMaternally derived antibodies as measured by using H3N2 strain heterologous to the resident strain in Study 1 (93.8% similarity in the hemagglutinin).
  6. eMaternally derived antibodies as measured by using H3N2 strain heterologous to the resident strain in Study 1 (97.9% similarity in the hemagglutinin).
  7. fMaternally derived antibodies as measured by using H1N1 virus broadly classified as classical H1N1 virus.
  8. gMaternally derived antibodies as measured by using H1N1 strain detected in the Study 2 (i.e. homologous strain).
  9. hGroupings obtained from the cluster analysis based on hemagglutinin inhibition titers of strains heterologous to the resident virus in Study 1.