Author and date | Allocation concealment | Baseline influenza vaccination rate treatment group (%) | Baseline influenza vaccination rate control group (%) |
Difference 2% | Or less | ||
Abramson 2011 | Unclear | 43.4 | 44.4 |
Arthur 2002 | Unclear | 48.7 | 46.7 |
Barnas 1989 | Unclear | 5 | 5 |
Beck 1997 | No | 74 | 72 |
Clayton 1999 | Unclear | 0% for not vaccinated 100% for vaccinated |
0% for not vaccinated 100% for vaccinated |
Frank 2004 | Yes | 65 | 66 |
Ives 1994 | Unclear | 41.3 | 40.6 |
Karuza 1995 | Unclear | 47.5 | 46.5 |
Kiefe 2001 | Unclear | 40 | 40 |
Kim 1999 | Unclear | 79 | 80 |
Kouides 1998 | Unclear | 57.6 | 58 |
Krieger 2000 | Yes | 0% for not vaccinated 100% for vaccinated |
0% for not vaccinated 100% for vaccinated |
McCaul 2002 | Unclear | 0 | 0 |
McDowell 1986 | Unclear | 0 | 0 |
McMahon 1995b (McMahon Wyoming) | Unclear | Participants who received a personal letter 23.8 Participants who received a form letter 20.5 |
Participants who received no letter 21.6 |
Moran 1995 | Unclear | 16.7 | 16.6 |
Nuttall 2003 | Unclear | 0 | 0 |
Roca 2012 | Unclear | 50.9 | 49.1 |
Difference | 3% to 4% | ||
Dietrich 1989 | Unclear | 36 | 39 |
Herman 1994 | Unclear | 31.3 | 34.3 |
Lemelin 2001 | Unclear | 46.1 | 49.4 |
Lukasik 1987 | No | 7.3 | 4.5 |
MacIntyre 2003 | Yes | 61 | 64 |
McMahon 1995b (McMahon Montana 1994) | Unclear | Participants who received a personal letter 41.2 Participants who received a form letter 46 |
Participants who received no letter 42.3 |
Siriwardena 2002 | Unclear | 48.6 | 44.7 |
Difference | 5% or more | ||
Chan 2002 | Unclear | 31.8 solo 42.5 group practice |
37.8 solo 30.1 group practice |
Puech 1998 | Yes | 32 | 38 |
Marrero 2006 | Unclear | 36 | 14 |