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

Abstract

Introduction: Psychological and behavioural factors influence the effectiveness of vaccines. This has led to interest in the potential for non-pharmacological treatments, which modify these factors, to 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 6 th 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. We observed that over half (58/106, 55%) of the trials reported evidence of non-pharmacological interventions enhancing the antibody response to vaccination across one or more outcomes. The NMA considered the evidence for 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 only weak evidence in support of nutritional formulae and probiotics in increasing antibody titres. Expert opinion: This review offers a comprehensive summary of the available literature on nonpharmacological interventions as vaccine adjuvants. The evidence is characterised by considerable heterogeneity but provides early evidence of nutritional formulae and probiotic interventions being associated with enhanced antibody responses to vaccination. The absence of evidence for other treatments may be the consequence of limited and unreliable evidence on these treatments. Large, well-designed studies which include consistent core outcomes and measures of intervention adherence and fidelity are required.

Psychological Predictors of Self-reported COVID-19 Outcomes: Results From a Prospective Cohort Study

“…This in turn raises questions about whether comparable effects may be observed for COVID-19 vaccines that is, might the effectiveness of these vaccines in protecting against disease also be influenced by psychological well-being? [ 29 ] As the success of COVID-19 vaccines will play a critical role in the route out of this pandemic, understanding the role of psychological factors in vaccine effectiveness, and the potential for psychological interventions to enhance effectiveness, could be important areas for future research [ 30 , 31 ].…”

The effect of stress on the antibody response after vaccination in children aged 0–18 years: A systematic review

“…1 As mentioned, the effect of stress might be more significant for T-cell-dependent vaccines, 11 meaning the vaccine requires helper T-cells to activate an antibody response from B-cells. 2 A difference between live-attenuated and inactivated vaccine responses have also been reported, where live-attenuated vaccines typically generate longer protection. 1 Because of the heterogeneity of the studies, the evidence regarding the effect of vaccine type on the results is insufficient.…”

“…However, the immune response after vaccination is heterogeneous, and knowledge about factors influencing the vaccine response may contribute to more effective immunization. [1][2][3] Neuroimmunology and psychoneuroimmunology have gained increased attention during the last decades, and it is now recognized that the brain and mind are not separated from the rest of the bodily systems and functions, but constant crosstalk exists between these entities. Prolonged exposure to stressors may dysregulate the immune response by disturbing the sensitive interplay among these systems.…”

“…Often a pre-defined increase in the antibody titre after vaccination, such as a four-fold rise, is considered an adequate response, requiring earlier exposure and antibody production. 2 Vaccine-specific cut-off levels are also used, for example, the cut-off for seroprotection for meningococcal infection defined as 2 μg/mL IgG. 47 The different types of measures have their advantages and limitations, however, they do not necessarily correlate with one another.…”

“…In modern medicine, vaccines are the most effective medical way of preventing diseases, resulting in many lives saved annually. However, the immune response after vaccination is heterogeneous, and knowledge about factors influencing the vaccine response may contribute to more effective immunization 1–3 …”