Table 2.
NS1 results in primary and secondary acute dengue casesa
| Days since the onset of symptoms | No. of NS1-positive samples/total no. of samples (%) |
||
|---|---|---|---|
| Santos 2002 | Goiânia 2005 | Santos 2010 | |
| Primary infection | |||
| 1–3 | 2/2 (100) | 15/16 (93.7) | 2/4 (50) |
| 4–5 | 6/7 (85) | 18/19 (94.7) | 19/25 (76) |
| 6–7 | 6/7 (85) | 19/19 (100) | 8/14 (57) |
| 8 | 1/1 (100) | 5/7 (71.4) | 3/5 (60) |
| Total | 15/17 (88) | 57/61 (93.4) | 32/48 (67) |
| Secondary infection | |||
| 1–3 | 6/9 (66) | 12/19 (63.1) | 39/108 (36) |
| 4–5 | 10/16 (62.5) | 24/33 (72.7) | 8/76 (11) |
| 6–7 | 19/331 (61) | 31/37 (83.7) | 7/48 (15) |
| 8 | 5/10 (50) | 12/14 (85.7) | 0/28 (0) |
| Total | 40/66 (60) | 79/103 (76.6) | 54/260 (38) |
a
Results are according to days of disease in a cohort of 82 samples from the Santos 2002 outbreak, 164 samples from Goiânia 2005 and 308 samples from Santos 2010 (71 samples from the current outbreak could not be classified into primary or secondary dengue due to the absence of IgG before 4 days of symptoms). All cases included in this analysis had the dengue diagnosis confirmed by IgM and/or were RNA positive.