Table 1.
Relationship between detection of RSV RNA in nasal swabs during respiratory infections before age 24 months and RSV IgG antibody levels in sera at ages 13 and 24 months
| Case number(s) | Mean age (range) in months at RSV RNA detection(s) (<13 months) | RSV IgG at 13 months | Mean age (range) in months at RSV RNA detection(s) (13–24 months) | RSV IgG at 24 months | Change in mean EIA units | ||
|---|---|---|---|---|---|---|---|
| Mean EIA units (range) | Seropositivity rate or status | Mean EIA units (range) | Seropositivity rate or status | ||||
| Cases with a single RT–PCR confirmed RSV infection episode | |||||||
| 1–31 | 7·7 (0·8–13·5) | 32 (3–82) | 87% | n.d. | 49 (4–127) | 97% | +17 |
| 32–55 | Not detected | 0 (0–6) | 4% | 17·3 (13·1–24·7) | 52 (6–162) | 100% | +52 |
| Cases with two RT–PCR confirmed RSV infection episodes | |||||||
| 56 | 1·9 (group B) | 35 | Positive | 25·4 (group B) | 82 | Positive | +47 |
| 57 | 2·6 (group B) | 5 | Positive | 18·3 (group B) | 15 | Positive | +10 |
| 58 | 2·8 (group B) | 1·3 | Negative | 23·9 (group B) | 54 | Positive | +53 |
| 59 | 4·2 (group A) | 43 | Positive | 16·0 (group A) | 64 | Positive | +21 |
| 60 | 6·1 (group B) | 25 | Positive | 17·1 (group A) | 41 | Positive | +16 |
| 61 | 9·7 (group B) | 24 | Positive | 23·1 (group B) | 86 | Positive | +62 |
| 62 | 11·2 (group A) | 43 | Positive | 21·2 (group B) | 89 | Positive | +46 |
| 63 | 2·3, 12·3 (group B, A) | 30 | Positive | n.d. | 46 | Positive | +16 |
| 64 | 2·9, 9·7 (group A, A) | 10 | Positive | n.d. | 7 | Positive | −3 |
| 65 | 4·1, 10·4 (group n.d., B) | 41 | Positive | n.d. | 91 | Positive | +50 |
| Cases with three RT–PCR confirmed RSV infection episodes | |||||||
| 66 | 5·8, 7·4 (group n.d., A) | 21 | Positive | 18·3 (group A) | 49 | Positive | +28 |
RSV, Respiratory syncytial virus; EIA, enzyme immunoassay; n.d., not detectable.