TABLE IV.
Subgroup Characteristics of HRSV Isolated From Children Infected 3 Times
| Patterns of occurrence | No. of children infected 3 times | Interval of repeated infection 3 times | No. of children analyzed for clinical features | ||||
|---|---|---|---|---|---|---|---|
| More than one separate season | Two infections within a single season | Three infections within a single season | |||||
| A–A–A* | 5 | 2 | 2 | 1 | 4 | ||
| A–A–B | 4 | 1 | 2 | A–A (2)a | 1 | 4 | |
| A–B–A | 8 | 5 | 3 | A–B (2), B–A (1) | 0 | 7 | |
| A–B–B | 1 | 1 | 0 | 0 | 0 | ||
| B–B–B | 2 | 1 | 1 | 0 | 1 | ||
| B–B–A | 3 | 1 | 2 | B–A (2) | 0 | 2 | |
| B–A–B | 3 | 2 | 1 | A–B (1) | 0 | 1 | |
| B–A–A | 10 | 7 | 3 | B–A (3) | 0 | 10 | |
| A/B | 6 | 3 | First (1)b, Second (2) | 3 | Second (1), Third (2) | 0 | |
| Total | 42 | 23 | 17 | 2 | 29 | ||
*
The first letter designates the subgroup responsible for the first infection; the second letter, that for the second infection; and the third letter, that for the third infection. A/B indicates dual infection in the first, second, or third infection. The numbers in parentheses indicate the sample numbers for each pattern of occurrence in 2 infections within a single seasona, and dual-infected HRSV samples in the first, second, or third infectionb. The numbers in italics indicate children infected 3 times who were enrolled for the analysis of clinical features.