Bulletin of the World Health Organization

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.