Table 2.
Laboratory investigations of cases of Influenza-like illness (ILI) tested only for influenza.
| Author, date | Country, area, date of cases | N | % Influenza A | % Influenza B |
|---|---|---|---|---|
| CDC or WHO ILI definition | ||||
| Hirve 2012 [14] | Western India, 2012 | 3167 | 13% <5 years; 22% ≥5 years | 6 |
| Lee 2011 [15] | Singapore 2009 | Not stated | 17%a | |
| Nguyen 2013 [16] | Vietnam 2006–2010 | 29,804 | 14.5 | 7.3 |
| Radin 2012 [17] | 15 African countries 2006–2010 | 69860 | 21.7b | b |
| Not CDC or WHO ILI definition | ||||
| Barbara 2012 [27] | Canada 2008/9 | 176 | 11 | 10 |
| Chadha 2011 [32] | India 2004–2008 | 13928 | 2.5 | 1.9 |
| Chuang 2012 [33] | Taiwan 2009–2011 | 26601 | 21 | 3.9 |
| Fowlkes 2012 [29] | US 2009–2010 | 8747 | 23 | 0 |
| Mulpuru 2013 [28] | Canada 2009 | 391 | 12c | |
| Portuguese Laboratory 2011 [31] | Portugal 2009–11 | 62,089 (2009–10) 1512 (2010–11) | 42 (2009–10) 38 (2010–11) | 0.05 (2009–10) |
| Wei 2012 [34] | China 2009–2011 | 6143 | 20 | 6 |
| Woolpert [30] | US 2007–8 | 789 | 19 | 8 |
a
Only an influenza rate was stated, with Bayesian credible 95% confidence intervals 14–20% based on paired samples.
b
Only an influenza rate is reported. B was the predominant strain in 2006 and 2007 except South/Central Africa
c
Only an influenza rate is reported. The study was during the A(H1N1) epidemic.