Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 19, Number 11—November 2013
Dispatch

Incidence of Influenza A(H1N1)pdm09 Infection, United Kingdom, 2009–2011

Saranya SridharComments to Author , Shaima Begom, Alison Bermingham, Katja Hoschler, Walt Adamson, William Carman, Maria D. Van Kerkhove, and Ajit Lalvani
Author affiliations: Imperial College London, London, UK (S. Sridhar, S. Begom, M.D. Van Kerkhove, A. Lalvani); Public Health England, Colindale, UK (A. Bermingham, K. Hoschler); West of Scotland Specialist Virology Centre, Glasgow, Scotland, UK (W. Adamson, W. Carman)

Main Article

Table 2

Risk factors for natural infection with influenza A(H1N1)pdm09, United Kingdom*

Risk factor Second pandemic wave (Sep 2009–Apr 2010)
Third pandemic wave (Aug 2010–Apr 2011)
Infection status, no.(%)
Unadjusted
Adjusted†
Infection status, no. (%)
Unadjusted
Adjusted†
None Natural‡ Total OR (95% CI) p value OR (95% CI) p value None Natural‡ Total OR (95% CI) p value OR (95% CI) p value
Total 210 (86.4) 26 (10.7) 242 119 (80.4) 28 (19.6) 148
Sex
M 95 (87.2) 14 (12.8) Ref 53 (85.5) 9 (14.5) 62 Ref
F 121 (91.9) 12 (9.0) 0.67 (0.30–1.52) 0.34 0.68 (0.30–1.58) 0.37 66 (76.7) 20 (23.3) 86 1.78 (0.75–4.24) 0.19 1.67 (0.69–4.26) 0.28
Age group, y 0.99 (0.95–1.03) 0.6 0.98 (0.93–1.02) 0.29
18-25 75 (91.5) 7 (8.5) 82 Ref Ref 33 (80.5) 8 (19.5) 41 Ref
26-40 98 (89.1) 12 (10.9) 110 1.31 (0.49–3.49) 0.59 53 (74.7) 18 (25.4) 71 1.40 (0.55–3.58) 0.48
41-55 30 (85.7) 5 (14.3) 35 1.79 (0.53–6.07) 0.35 23 (88.5) 3 (11.5) 26 0.54 (0.13–2.25) 0.39
>56 10 (90.9) 1 (9.1) 11 1.07 (0.12–9.64) 0.95 7 (57.1) 0 7
Not known 4 (80.0) 1 (20.0) 5 3 (100.0) 0
Titer at start of season 0.98 (0.97–1.01) 0.23 0.92 (0.86–0.99) 0.04
<8 140 (88.5) 18 (11.5) 158 Ref Ref 61 (70.1) 26 (29.9) 87 Ref
8–32 49 (89.1) 6 (10.9) 55 0.95 (0.36–2.54) 0.92 23 (88.5) 3 (11.5) 26 0.31 (0.08–1.11) 0.07
>32 27 (93.1) 2 (6.9) 29 0.58 (0.13–2.63) 0.48 35 (100) 0 35

*Ref, referent; –, cannot be calculated.
Adjusted for the other covariates. In the logistic regression undertaken the dependent variable was infection status and age, sex and titer at the start of the season were the independent variables. The results shown are from a single run, and no other model was fitted. Hosmer Lemeshow goodness-of-fit statistic showed an adequate fit for the logistic regression models fitted to the second wave and the third wave data (Hosmer Lemeshow statistic was 4.69 ,p = 0.58 for the second wave and 5.54, p = 0.59 for the third wave).
‡Natural infection indicates incident infection among those susceptible at the beginning of the wave.

Main Article

Page created: October 31, 2013
Page updated: October 31, 2013
Page reviewed: October 31, 2013
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external