| Methods |
Randomisation: no details
Blinding: double‐blind, but no details of method used
Number excluded: no details
Withdrawals: 2 (1 from each group due to extraneous viral infection)
Baseline characteristics: antibody levels to influenza A and B measured and baseline lung function tests |
| Participants |
Location: Houston, TX
Participants: 19 healthy adult volunteers with a history of asthma. 17 had data analysed, 11 given vaccine and 6 placebo
Asthma definition and severity: history of intermittent wheezing, 15 patients using intermittent or continuous bronchodilator therapy
Exclusion criteria: acute respiratory illness, allergy to egg, pregnancy |
| Interventions |
Vaccine type: intranasal bivalent (H3N2+H1N1) influenza A vaccine. 0.25 mL per nostril
Placebo: allantoic fluid, 0.25 mL per nostril |
| Outcomes |
Early: lung function tests on days 0, 3 or 4, and 7; performed in the mornings (no bronchodilators taken before testing). The authors regarded a reduction in forced expiratory volume in 1 second (FEV1) of 13% (or greater) from baseline to be clinically significant
Bronchodilator therapy and hospital admission were also reported |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Generated by statistical group in General Clinical Research Centre |
| Allocation concealment (selection bias) |
Unclear risk |
No details |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Double‐blind but no details of similarity between placebo and active vaccine |
| Blinding of outcome assessment (detection bias)
All outcomes |
Unclear risk |
No details |
| Incomplete outcome data (attrition bias)
All outcomes |
Unclear risk |
No drop‐outs reported |
