| Study characteristics |
| Methods |
Experimental study conducted in Russia during the 1996 to 1997 influenza season, randomised, double‐blind, placebo controlled; random sample stratified by age and underlying health conditions. Follow‐up period was 20 January 1997 to 2 March 1997 |
| Participants |
602 nursing home residents (93 vaccinated with parenteral vaccine, 111 vaccinated with aerosol vaccine, and 109 controls); severely debilitated and immunosuppressed people were excluded; 41 to 95 years, median 73 years |
| Interventions |
Live cold‐adapted vaccine aerosol administered: A/Leningrad/134/17/57; B/Ann Arbor/60/69 parenteral vaccine: A/Texas/36/91; A/Nanchang/933/95; B/Harbin/7/94. Vaccine strains matched the circulating strains |
| Outcomes |
Laboratory‐confirmed influenza: positive swab or 4‐fold or greater increase in antibody titre |
| Notes |
No description of methods; 1 or 2 doses' efficacy was tested; data were extracted irrespective of the number of doses administered |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
High risk |
Random allocation sequence not described and the six groups have uneveven denominators |
| Allocation concealment (selection bias) |
Unclear risk |
Not described |
| Blinding (performance bias and detection bias)
All outcomes |
Unclear risk |
Not described |
| Incomplete outcome data (attrition bias)
All outcomes |
High risk |
Unexplained attrition both for efficacy and serological outcomes. Harms are not mentioned at all in the report. This is a particular problem in the use of live attenuated vaccines in elderly or infirm people |
