Table 1. Characteristics of Included Studies.
| Source | Country | Participants | Dose, μg | Virus strains | Outcomes | Maximum follow-up, d | ||
|---|---|---|---|---|---|---|---|---|
| No. | Age, range, y | ID | IM | |||||
| Ansaldi et al,19 2013 | Italy | 47 | ≥60 | 15 | 15 | A/H1N1 (A/California/7/2009, A/Genoa/1/11, A/Genoa/6/11, A/Genoa/24/11), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, MFI, Sc, Sp | 90 |
| Ansaldi et al,18 2012 | France, Belgium, Lithuania, Italy | 50 | ≥60 | 15 | 15 | A/H3N2 (Wisconsin/67/05, Genoa62/05, Genoa03/07, Brisbane/10/07, Genoa02/07,Genoa03/06) | GMT, MFI, Sc, Sp | 21 |
| Arnou et al,20 2010 | France, Italy, Belgium, Lithuania | 1676 | 18-60 | 9 | 15 | A/H1N1 (A/New Caledonia/20/99),A/H3N2(A/Wisconsin/67/2005), B Strain (B/Malaysia/2506/2004) | AEs, GMT, MFI, Sc, Sp | 21 |
| Boonnak et al,21 2017 | Thailand | 221 | 60-88 | 15 | 15 | A/H1N1(A/California/07/09), A/H3N2 (A/Songhka/308/13), B Strain (B/Phuket/287/13) | AEs, GMT, Sc, Sp | 60 |
| Camiloni et al,22 2014 | Italy | 80 | 64−100 | 15 | 15 | A/H1N1 (A/California/7/09,A/Perugia/06/12, A/Perugia/20/12, A/Perugia/44/12, A/Perugia/50/12), A/H3N2 (A/Perth/16/09), B Strain (B/Brisbane/60/08) | GMT, MFI, Sc, Sp | 180 |
| Carter et al,23 2019 | US | 106 | 18-69 | 9 | 15 | A/H1N1 (A/California/04/2009), A/H3N2 (A/Victoria/361/2011, A/Texas/50/2012), B Strain (B/Texas/6/2011,B/Wisconsin/1/2010, B/Massachusetts/2/2012) | AEs, GMT, Sc | 21 |
| Chan et al,24 2014 | Hong Kong | 100 | ≥65 | 15 | 15 | A/H1N1 (A/Victoria/361/2011), A/H3N2 (A/California/7/2009), B Strain (B/Massachusetts/2/2012) | AEs, GMT, MFI, Sc, Sp | 180 |
| Chi et al,25 2010 | US | 130 | ≥65 | 9 | 15 | A/H1N1 (A/Solomon Islands/3/2006), A/H3N2 (A/Wisconsin/67/2005), B Strain (B/Malaysia/2506/2004) | AEs, GMT, Sp | 28 |
| Chuaychoo et al,26 2019 | Thailand | 80 | ≥60 | 9 | 15 | A/H1N1 (A/California/7/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, Sc, Sp | 365 |
| Chuaychoo et al,27 2016 | Thailand | 149 | 60-94 | 9 | 15 | A/H1N1 (A/California/7/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, Sc, Sp, Influenza infection | 28 |
| Chuaychoo et al,28 2010 | Thailand | 156 | 36-91 | 6 | 15 | A/H1N1 (A/New Caledonia/20/99), A/H3N2 (A/California/7/2004), B Strain (B/Malaysia/2506/2004) | AEs, GMT, Sc, Sp | 365 |
| Della Cioppa et al,29 2014 | Germany, Poland, Belgium | 257 | ≥65 | 6 or 12 | 15 or 30 | A/H3N2 (A/Uruguay/716/2007) | AEs, GMT, MFI, Sc, Sp | 22 |
| Esposito et al,30 2011 | Italy | 112 | ≥3 | 9 or 15 | 15 | A/H1N1 (A/California/7/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, MFI, Sc, Sp | 28 |
| Frenck et al,31 2011 | US | 1571 | 18-64 | 3, 6, or 9 | 15 | A/H1N1 (A/New Caledonia/20/99 IVR-116), A/H3N2 (A/Wyoming/03/2003 (an A/Fujian/411/2002-like strain), B Strain (B/Jiangsu/10/2003 (a B/Jiangsu/361/2002-like strain)) | AEs, GMT, MFI, Sc, Sp | 21 |
| Garg et al,32 2016 | Thailand | 80 | 18-60 | 15 | 15 | A/H1N1, A/H3N2, B Strain | AEs, GMT, MFI, Sc, Sp | 30 |
| Gorse et al,33 2013 | US | 3868 | 18-64 | 9 | 15 | A/H1N1 (A/Brisbane/59/07), A/H3N2 (A/Uruguay/716/2007 X-175CA), B Strain (B/Florida/04/2006 Yamagata-like) | AEs, GMT, Sc, Sp | 28 |
| Han et al,34 2013 | South Korea | 120 | ≥18 | 9 or 15 | 15 | A/H1N1 (A/California/7/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, Sc, Sp | 21 |
| Hung et al,35 2016 | China | 160 | 18-30 | 15 | 15 | A/H1N1 (A/California/07/2009, Prototype A/WSN/1933, A/HK/408027/09, A/H3N2 (A/Victoria/361/2011, A/HK/485197/14), B Strain (B/Massachusetts/2/2012), Others (B/HK/418078/11) | AEs, GMT, MFI, Sc, Sp | 21 |
| Hung et al,37 2014 | China | 93 | ≥21 | 15 | 15 | A/H1N1 (A/California/07/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, MFI, Sc, Sp, Influenza | 365 |
| Hung et al,36 2012 | China | 262 | ≥21 | 3 or 9 | 15 | A/H1N1 (A/California/07/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, MFI, Sc, Sp | 21 |
| Leung et al,38 2017 | US | 336 | 18-64 | NR | NR | A/H1N1 (A/California/07/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, MFI, Sc, Sp | 28 |
| Levin et al,46 2016 | NR | 370 | ≥65 | 7.5 or 15 | 15 | A/H1N1 (A/California/07/2009), A/H3N2 (A/Victoria/361/2011), B Strain (B/Wisconsin/1/2010) | AE, Sc, Sp | 90 |
| Levin et al,45 2014 | Switzerland | 280 | 18-60 | 3, 4.5, or 6 | 15 | A/H1N1 (A/SolomonIslands/3/2006), A/H3N2 (A/Wisconsin/67/2005), B Strain (B/Malaysia/2506/2004) | AEs, GMT, MFI, Sc, Sp | 21 |
| Nougarede et al,39 2014 | France | 80 | 18-40 | 9 | 15 | A/H1N1 (A/SolomonIslands/3/2006), A/H3N2 (A/Wisconsin/67/2005), B Strain (B/Malaysia/2506/2004) | AEs, GMT, MFI, Sc, Sp, influenza-like illness | 180 |
| Patel et al,40 2010 | US | 100 | 18-40 | 3 or 9 | 15 | H5N1 (A/Vietnam/1203/2004) | AEs, GMT,Sc, Sp | 28 |
| Seo et al,41 2014 | South Korea | 364 | ≥65 | 15 | 15 | A/H1N1 (A/California/7/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | AEs, GMT, MFI, Sc, Sp | 180 |
| Song et al,42 2013 | South Korea | 96 | 18-30 | 3 or 7.5 | 15 | A/H1N1 (A/New Caledonia/20/99), A/H3N2 (A/Wisconsin/67/2005), B Strain (B/Malaysia/2506/2004) | GMT, Sc, Sp | 180 |
| Tsang et al,43 2014 | US | 1912 | ≥65 | 15 or 21 | 15 | A/H1N1 (A/Solomon Islands/3/2006), A/H3N2 (A/Wisconsin/67/2005), B Strain (B/Malaysia/2506/2004) | AEs, GMT, MFI, Sc, Sp | 28 |
| Van Damme et al,44 2010 | France, Belgium | 795 | ≥65 | 15 | 15 | A/H1N1 (A/Solomon Islands/3/2006), A/H3N2 (/Wisconsin/67/2005), B Strain (B/Malaysia/2506/2004) | AEs, GMT, MFI, Sc, Sp | 21 |
| Puig Barbera et al,47 2014a | Spain | 164021 | ≥65 | 15 | 15 | A/H1N1 (A/California/7/2009), A/H3N2 (A/Perth/16/2009), B Strain (B/Brisbane/60/2008) | Influenza | |
Abbreviations: AE, adverse events; GMT, geometric mean titer; ID, intradermal; IM, intramuscular; NR, not reported; MFI, mean fold increase; Sc, seroconversion rate; Sp, seroprotection rate.
a
All other included studies were randomized clinical trials, but Puig Barbera et al47 was a cohort study.