... Fifteen trials administered their vaccination post-intervention; k = 32 before or at the first intervention session, k = 57 during the intervention, and k = 2 were not clear in terms of when the vaccination was given in relation to the intervention. Over half of all trials, k = 58/106 (55%) and 50/94 of all RCTs, reported evidence of a statistically significant improvement in the antibody response to vaccination across one or more outcome, but not necessarily all outcomes (see Appendices 2-4) (Ahmed et al., 2009;Akatsu et al., 2013Akatsu et al., , 2016Albert et al., 2003;Bahl et al., 2002;Benn et al., 2002;Bhaskaram et al., 1989;Bhaskaram & Rao, 1997;Boge et al., 2009;Bosch et al., 2012;Chandra & Puri, 1985;Davidson et al., 2011Davidson et al., , 2003de Vrese et al., 2005;Duchateau et al., 1981;Edwards et al., 2006Edwards et al., , 2007Edwards et al., , 2008French & Penny, 2009;Gibson et al., 2012;Girodon et al., 1999;Hawkes et al., 2005;Heine et al., 2011;Hsu et al., 1995;Isolauri et al., 1995;Karlsen et al., 2003;Kohut et al., 2004Kohut et al., , 2005Kukkonen et al., 2006;Langkamp-Henken et al., 2004Link-Amster et al., 1994;Maruyama et al., 2016;Meydani et al., 1997;Negishi et al., 2013;Newton et al., 2007;Olivares et al., 2007;Osendarp et al., 2007;Paineau et al., 2008;Petrie et al., 1995;Rahman et al., 1999;Rizzardini et al., 2012;Roman et al., 2013;Scaglione et al., 1996;Semba & West Jr, 1992;Soh et al., 2010;Stetler et al., 2006;Udani, 2013;Udani et al., 2010;Vedhara et al., 2003;Vidal et al., 2012;Whitham & Blannin, 2003;Woods et al., 2009;Wouters-Wesseling et al., 2002;Yang et al., 2008;Youngster et al., 2011).; k = 43/106 (41%) showed the intervention had no significant effect on the antibody response (Bahl et al., 1999;Benn et al., 1997;Boge et al., 2009;Broome et al., 2004;Brown et al., 1980;Bunout et al., 2002Bunout et al., , 2004Campbell et al., 2010;Cherian et al., 2003;Edwards et al., 2012;Fang et al., 2000;Habib et al., 2015;Harman & White Miller, 1986;Hayney et al., 2014;Huang & Huang, 1999;Ivory et al., 2017;Jespersen et al., 2015;Kelley et al., 1998Kelley et al., , 2000Kriesel & Spruance, 1999;Kutukculer et al., 2000;Link-Amster et al., 1994;Long et al., 2012Long et al., , 2013Namba et al., 2010;Osendarp et al., 2006;Principi et al., 2013;Provinciali et al., 1998;Przemska-Kosicka et al., 2016;Rahman et al., 1998;Ranadive et al., 2014;Remarque et al., 1993;Semba et al., 1997Semba et al., , 1999Soh et al., 2010;Stam et al., 2011;Türk et al., 1998;Van Puyenbroeck et al., 2012;West et al., 2008;Yalçın et al., 2011) and k = 6/106 (6%) showed evidence of a significantly impaired antibody response in the intervention group. In only k = 59/106 trials (56%) was adequate adherence with the intervention reported, or could it be assumed due to the intervention being supervised/administered by the trial team and/or being a single session. ...