Risk of allergic sensitization after respiratory syncytial virus (RSV) bronchiolitis in infancy as reported by different studies
| First author [ref. no.] | Design | Patients/controls n | RSV-positive patients % | Age at bronchiolitis | Follow-up time yrs | End-point | Result at time of follow-up |
| Studies not demonstrating any increased risk at time of follow-up | |||||||
| Sims 48 | Case-control follow-up study | 35/35 | 100 | <12 months | 8 | Personal history of atopy | The prevalence of clinical features of atopy was similar in bronchiolitis and control groups |
| Pullan 49 | Case-control follow-up study (extension of 48) | 130/111 | 100 | 3.5 months | 10 | Eczema or rhinitis | No significant difference between RSV and control groups, 19% versus 15% |
| Mok 50 | Case-control follow-up study | 100/200 | 100 | 4.3 months# | 7 | Atopy | Atopic characteristics were similar between RSV and control groups, but figures not given |
| Carlsen 51 | Prospective case-control study | 51/24 | 61 | Median 6 months | 2 | Total IgE, eosinophil counts | No significant difference between index and control group in atopic eczema or urticaria, positive SPT, total IgE or eosinophil counts |
| Noble 52 | Prospective case-control study | 61/47 | 66 | All <12 months, mean 4 months | 9–10 | Positive SPT | No difference between bronchiolitis and control group, 31% versus 30% positive SPT |
| Stein 3 | Longitudinal cohort study | 100 | Lower RTI before age 3 yrs | Positive allergy SPT | No association between RSV lower RTI and subsequent atopic status by age 6 or 11 yrs | ||
| 155/272 | 6 | 37.4% (RSV) versus 39.7% (controls) | |||||
| 145/253 | 11 | 59.3% (RSV) versus 58.9% (controls) | |||||
| Kneyber 80 | Meta-analysis of three controlled studies 45, 48, 49 | 212/239 | 100 | All <12 months | Personal history of atopy | No significant difference between RSV and control groups 15% versus 17%, OR 0.7 (0.4–1.1) | |
| Studies demonstrating an increased risk at time of follow-up | |||||||
| Murray 53 | Prospective case-control study | 73/73 | 68 | All <12 months, mean 4 months | 6 | Personal atopy (eczema and/or SPT) | Personal atopy more prevalent in 1992 the bronchiolitis group, 37% positive versus 20.5% (controls)* |
| Sigurs 45 | Prospective case-control study | 47/93 | 100 | All <12 months, mean 3.5 months | 3 | Allergic sensitization more common in the RSV group | |
| 45/92 | Positive SPT (inhalants) | 13% (RSV) versus 1% (controls)¶, RR 12.3 (1.5–98.9) | |||||
| 44/92 | Any positive allergy test | 32% (RSV) versus 9% (controls)+, RR 3.7 (1.7–8.1) | |||||
| Sigurs 2 | Prospective case-control study | 100 | All <12 months, mean 3.5 months | 7.5 | Allergic sensitization more common in the RSV group | ||
| 44/89 | Positive SPT | 20% (RSV) versus 6% (controls)§, RR 3.6 (1.3–10.2) | |||||
| 44/86 | Any positive allergy test | 41% (RSV) versus 22% (controls)f, RR 1.9 (1.1–3.2) | |||||
RTI: respiratory tract infection
SPT: skin-prick test
IgE: immunoglobulin-E
OR: odds ratio
RR: relative risk
#: acute RTI
*: p<0.05
¶: p=0.005
+: p=0.002
§: p=0.014
f: P=0.039