Volume 17, Number 9—September 2011
Research
Seroepidemiologic Study of Pandemic (H1N1) 2009 during Outbreak in Boarding School, England
Sandra Johnson, Chikwe Ihekweazu
, Pia Hardelid, Nika Raphaely, Katja Hoschler, Alison Bermingham, Muhammad Abid, Richard G. Pebody, Graham Bickler, John T. Watson, and Éamonn O’Moore
, Pia Hardelid, Nika Raphaely, Katja Hoschler, Alison Bermingham, Muhammad Abid, Richard G. Pebody, Graham Bickler, John T. Watson, and Éamonn O’Moore
Table 1
Association of demographic characteristics, clinical illness, and interventions with study participants’ positive serologic test results during outbreak of pandemic (H1N1) 2009 at a boarding school, England*
| Variable |
No. participants |
No. (%) with positive serologic test result |
Odds ratio (95% CI) |
|---|---|---|---|
| Total | 353 | 143 (40.5) | |
| Demographics | |||
| Category | |||
| Students | 216 | 123 (56.9) | 7.74 (4.48–13.35) |
| Staff | 137 | 20 (14.6) | 1 |
| Age group, y | |||
| 13–15 | 90 | 46 (51.1) | 1 |
| 16–18 | 126 | 77 (61.1) | 1.50 (0.87–2.60) |
| 20–49 | 71 | 12 (16.9) | 0.19 (0.09–0.41) |
| >50 | 66 | 8 (12.1) | 0.13 (0.06–0.31) |
| Sex, staff only† | |||
| F | 71 | 5 (7.0) | 1 |
| M | 66 | 15 (22.7) | 3.88 (1.32–11.39) |
| Role, staff only‡ | |||
| Nonteaching | 93 | 6 (6.5) | 1 |
| Teaching | 43 | 14 (32.6) | 7.00 (2.46–19.90) |
| Clinical illness | |||
| ARI | |||
| No | 199 | 62 (31.2) | 1 |
| Yes | 141 | 77 (54.6) | 2.66 (1.70–4.16) |
| ILI | |||
| No | 277 | 95 (34.3) | 1 |
| Yes | 63 | 44 (69.8) | 4.44 (2.45–8.02) |
| Severity, n = 153§ | |||
| Mild | 81 | 38 (46.9) | 1 |
| Moderate and severe | 59 | 39 (66.1) | 2.21 (1.10–4.41) |
| Duration, d, n = 153§ | |||
| 1–2 | 14 | 6 (42.9) | 1 |
| 3–6 | 52 | 27 (51.9) | 1.44 (0.44–4.73) |
| 7–10 | 18 | 12 (66.7) | 2.67 (0.63–11.28) |
| >10 |
23 |
14 (60.9) |
2.07 (0.54–8.00) |
| Interventions | |||
| Took antiviral drugs | |||
| No | 96 | 48 (50) | 1 |
| Yes | 207 | 68 (32.9) | 0.49 (0.30–0.80) |
| Use of antiviral drugs: PEP vs. treatment dose | |||
| No antiviral drugs | 96 | 48 (50.0) | |
| PEP dose only | 187 | 56 (30.0) | 0.43 (0.26–0.71) |
| Treatment dose | 20 | 12 (60) | 1.5 (0.56–4.00) |
| Completion of PEP course of antiviral drugs¶ | |||
| No antiviral drugs | 96 | 48 (50.0) | 1 |
| Completed | 25 | 9 (36.0) | 0.56 (0.23–1.40) |
| Not completed | 159 | 45 (28.3) | 0.39 (0.23–0.67) |
| Seasonal influenza vaccine | |||
| No | 105 | 29 (27.6) | 1 |
| Yes | 230 | 106 (46.1) | 2.24 (1.36–3.69) |
*Categories in which the response was missing or unknown are shown in Table A1. CI, confidence interval; ARI, acute respiratory infection; ILI, influenza-like illness; PEP, postexposure prophylaxis.
†All students were male.
‡1 staff member was not included in the analysis because his occupation was unknown.
§Of those that self-reported ARI.
¶Excluding those who reported taking the treatment dose of antiviral drugs.
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