Effects of non-pharmacological interventions as vaccine adjuvants in humans: a systematic review and network meta-analysis

ABSTRACT

Introduction

Psychological and behavioural may enhance vaccine effectiveness. We conducted a systematic review and network meta-analysis (NMA) to examine the effects of non-pharmacological adjuvants on vaccine effectiveness, as measured by antibody responses to vaccination.

Areas covered

Electronic databases (EMBASE, Medline, PsychINFO, CINAHL) were searched from inception to 6th February 2018. This yielded 100 eligible papers, reporting 106 trials: 79 interventions associated with diet and/or nutrition; 12 physical activity interventions and 9 psychological interventions.Over half (58/106) of trials reported evidence of an enhanced antibody response to vaccination across one or more outcomes. The NMA considered the comparative effects between all intervention types, control and placebo for antibody titres (48 studies), seroconversion (25 studies) and seroprotection (23 studies) separately. The NMA provided weak evidence in support of nutritional formulae and probiotics in increasing antibody titres.

Expert opinion

This review offers a comprehensive summary of the literature on non-pharmacological interventions as vaccine adjuvants. The evidence is characterised by considerable heterogeneity but provides early evidence in support of nutritional formulae and probiotic interventions. Psychological and exercise-based interventions were characterised by limited and unreliable evidence. Large, well-designed studies including consistent core outcomes and measures of intervention adherence and fidelity are required.

KEYWORDS:

• Vaccinations
• antibodies
• diet
• stress
• physical activity
• psychological interventions

Acknowledgements

We would like to acknowledge the support of Ben Jackson, Luke Robles and Lucy Hackshaw who contributed to the initial title and abstract searches conducted for this paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

CMT was supported by a Wellcome Career Re-entry Fellowship (Grant ref: 104077/Z/14/Z) and by the Elizabeth Blackwell Institute for Health Research, University of Bristol, and the Wellcome Trust Institutional Strategic Support Fund. NJW and DMC are members of the NIHR Health Protection Research Unit in Behavioural Science and Evaluation at University of Bristol.