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 3. Clinical predictors of influenza in hospitalized patients, Vadu, India, May 2009–April 2011

Signs and symptoms, by patient age No. of patients positive for influenza virus/no. tested (% positive)
RR P
with symptom/sign without symptom/sign
Patients aged < 5 years (n = 337)
Symptoms
    Fever (reported) 34/299 (11.4) 5/24 (20.8) 0.55 0.227
    Cough 30/221 (13.6) 9/101 (8.9) 1.52 0.269
    Sore throat 20/153 (13.1) 19/170 (11.2) 1.17 0.628
    Nasal discharge 24/199 (12.1) 15/124 (12.1) 1.00 0.983
    Earache/discharge 0/3 (0.0) 39/320 (12.2) 0.695
    Fast breathing 4/43 (9.3) 33/268 (12.3) 0.76 0.634
    Lethargy 0/6 (0.0) 39/317 (12.3) 0.481
    Inability/refusal to feed 3/37 (8.1) 36/285 (12.6) 0.64 0.489
    Vomiting 10/133 (7.5) 29/190 (15.3) 0.49 0.047
    Diarrhoea 7/120 (5.8) 32/203 (15.8) 0.37 0.011
    Seizures 1/11 (9.1) 38/312 (12.2) 0.75 0.874
Signs
    Fever (> 38.0 °C) 38/265 (14.3) 5/64 (7.8) 1.84 0.192
    Tachypneaa 0/0 43/332 (13.0) 1.000
    At least one IMCI danger signb 5/56 (8.9) 34/265 (12.8) 0.70 0.469
Patients aged ≥ 5 years (n = 2842)
Symptoms
    Fever (reported) 595/2732 (21.8) 13/46 (28.3) 0.77 0.352
    Chills/rigor 550/2553 (21.5) 68/274 (24.8) 0.87 0.273
    Cough 497/1791 (27.8) 121/1036 (11.7) 2.38 0.000
    Sore throat 361/1162 (31.1) 257/1664 (15.4) 2.01 0.000
    Nasal discharge 391/1243 (31.5) 227/1584 (14.3) 2.20 0.000
    Earache/discharge 7/16 (43.8) 609/2808 (21.7) 2.01 0.090
    Headache 532/2514 (21.2) 86/313 (27.5) 0.77 0.027
    Muscle aches 452/2061 (21.9) 166/766 (21.7) 1.01 0.900
    Chest pain 16/64 (25.0) 602/2761 (21.8) 1.15 0.572
    Shortness of breath 23/78 (29.5) 551/2317 (23.8) 1.24 0.314
    Vomiting 111/492 (22.6) 507/2334 (21.7) 1.04 0.711
    Diarrhoea 42/225 (18.7) 575/2601 (22.1) 0.84 0.289
    Seizures 0/8 (0.0) 618/2819 (21.9) 0.174
    Confusion 0/4 (0.0) 618/2822 (21.9) 0.416
Signs
    Fever (> 38.0 °C) 488/2208 (22.1) 123/585 (21.0) 1.05 0.627
    Tachypneac 574/2661 (21.6) 41/157 (26.1) 0.83 0.241
    Respiratory distressd 8/47 (17.0) 0/0 1.000

IMCI, Integrated Management of Childhood Illness; RR, relative risk.

a Defined as respiratory rates, in breaths per minute, of > 60, > 50 and > 40 for children aged < 2 months, 2–12 months and 1–4 years, respectively.

b Inability to drink or breastfeed, vomiting of everything, convulsions, lethargy/unconsciousness, chest in-drawing or stridor in a calm child.

c Defined as a respiratory rate of ≥   20 breaths per minute.

d Defined as stridor, crepitation, wheeze or reduced air entry.