Performance of case definitions used for influenza surveillance among hospitalized patients in a rural area of India
Siddhivinayak Hirve, Mandeep Chadha, Pallavi Lele, Kathryn E Lafond, Avinash Deoshatwar, Somnath Sambhudas, Sanjay Juvekar, Anthony Mounts, Fatimah Dawood, Renu Lal & Akhilesh Mishra
Volume 90, Number 11, November 2012, 804-812
Table 2. Influenza virus positivity among the patients enrolled in study, stratified by age and by clinical and other characteristics of the patients, Vadu, India, May 2009–April 2011
| Characteristic | Age < 5 years (n = 337) |
Age ≥ 5 years (n = 2 842) |
|||||
|---|---|---|---|---|---|---|---|
| No. positive/no. tested | Percentage positive | Pa | No. positive/no. tested | Percentage positive | Pa | ||
| Age (years) | 0.000 | 0.000 | |||||
| < 1 | 5/86 | 6 | NA | NA | |||
| 1–4 | 39/251 | 16 | NA | NA | |||
| 5–14 | NA | NA | 143/404 | 35 | |||
| 15–29 | NA | NA | 348/1426 | 24 | |||
| 30–44 | NA | NA | 83/554 | 15 | |||
| 45–59 | NA | NA | 33/279 | 12 | |||
| ≥ 60 | NA | NA | 14/179 | 8 | |||
| Sex | 0.511 | 0.010 | |||||
| Male | 24/201 | 12 | 411/1755 | 23 | |||
| Female | 20/136 | 15 | 210/1087 | 19 | |||
| Underlying medical condition | 0.000 | 0.039 | |||||
| None | 44/331 | 13 | 611/2754 | 22 | |||
| Asthma | 0/0 | 0 | 7/27 | 26 | |||
| Chronic lung disease | 0/0 | 0 | 1/8 | 13 | |||
| Cardiovascular disease | 0/1 | 0 | 2/19 | 11 | |||
| Diabetes | 0/0 | 0 | 0/26 | 0 | |||
| Tuberculosis | 0/0 | 0 | 1/6 | 17 | |||
| Neurological condition | 0/2 | 0 | 0/1 | 0 | |||
| Time from onset to specimen collection (days) | 0.296 | 0.039 | |||||
| 1–7 | 37/293 | 13 | 555/2487 | 22 | |||
| > 7 | 7/36 | 19 | 47/279 | 17 | |||
| Influenza type | 0.214 | 0.766 | |||||
| A(H1N1)pdm09 | 26/337 | 8 | 314/2842 | 11 | |||
| Seasonal influenza A/B | 18/337 | 5 | 307/2842 | 11 | |||
NA, not applicable.
a P-value for trend within each category.