Age and psychological influences on immune responses to trivalent inactivated influenza vaccine in the meditation or exercise for preventing acute respiratory infection (MEPARI) trial

Psychosocial and behavioural predictors of immune response to influenza vaccination: a systematic review and meta-analysis

High variability of influenza vaccine efficacy requires the identification of modulators of immunisation that may be targeted as adjuvants in health psychology interventions. Psychosocial and behavioural variables such as psychological stress, greater negative and lower positive affectivity, poor sleep, loneliness, and lack of social support, have been associated with abnormal immune and inflammatory responses and negative health outcomes, yet their effects in modulating vaccine efficacy are yet to be fully understood. We conducted an updated systematic review of longitudinal and experimental studies examining the effects of such variables in predicting immune response to influenza vaccine. PubMed, Medline, PsycINFO, CINAHL and Scopus were searched up to November 2022. Twenty-five studies met the inclusion criteria for qualitative synthesis and 16 provided data for meta-analysis. Low positive and high negative affect were associated with low antibodies and weak cell-mediated immunity following vaccination in qualitative synthesis. Literature on sleep disturbance, loneliness and social support was limited and yielded inconsistent results. Psychological stress was associated with poorer antibody response in meta-analysis. In conclusion, findings from this review suggest a need for further longitudinal and experimental studies on these factors to support their inclusion as target variables in vaccine adjuvant interventions.

Physical activity and sleep relate to antibody maintenance following naturalistic infection and/or vaccination in older adults

Health behaviours such as being physically active and having good quality sleep have been associated with decreased susceptibility to infection and stronger antibody responses to vaccination. Less is known about how such factors might influence the maintenance of immunity following naturalistic infection and/or prior vaccination, particularly among older adults who may have formed initial antibodies some time ago. This analysis explored antibody levels against a range of common infectious diseases in 104 older adults (60 women) aged 65+ years, and whether these relate to self-reported physical activity (PA) and sleep. PA and sleep were measured subjectively through standardized questions. Antibody levels to a range of common pathogens, including pneumococcal (Pn) and meningococcal (Men) serotypes, Haemophilus influenza type b, diphtheria, and tetanus were assayed using Multiplex technology. Higher PA at baseline related to higher antibody levels against three Pn serotypes and MenY, and higher PA at one month with higher levels against six Pn serotypes. Longer time in bed related to higher antibody levels against Pn4, and longer sleep related to higher levels against Pn19f. More difficulty staying awake in the day related to lower antibodies against Pn19a, Pn19f, MenA and MenY, and more frequent daytime napping related to lower levels against three Pn serotypes and MenY. Using clinically protective antibody thresholds as an outcome showed similar results for PA, but effects for sleep became non-significant, with the exception of time in bed. This extends beyond existing literature demonstrating associations between PA and sleep and peak antibody response to vaccination to antibody maintenance. Longitudinal research with objective measures of health behaviours is warranted.

Individual participant data systematic review and meta-analysis of randomised controlled trials assessing adult mindfulness-based programmes for mental health promotion in non-clinical settings

Introduction

Mindfulness-based programmes (MBPs) are widely used to prevent mental ill-health that is becoming the leading global cause of morbidity. Evidence suggests beneficial average effects but wide variability. We aimed to confirm the effect of MBPs on psychological distress, and to understand whether and how baseline distress, gender, age, education, and dispositional mindfulness modify the effect of MBPs on distress among adults in non-clinical settings.

Methods

We conducted a pre-registered systematic review and individual participant data (IPD) meta-analysis (PROSPERO CRD42020200117). Thirteen databases were searched in December 2020 for randomised controlled trials satisfying a quality threshold and comparing in-person, expert-defined MBPs in non-clinical settings with passive control groups. Two researchers independently selected, extracted, and appraised trials using the revised Cochrane Risk-of-Bias Tool (RoB2). Anonymised IPD of eligible trials were sought from collaborating authors. The primary outcome was psychological distress (unpleasant mental or emotional experiences including anxiety and depression) at 1 to 6 months after programme completion. Data were checked and imputed if missing. Pairwise, random-effects, two-stage IPD meta-analyses were conducted. Effect modification analyses followed a within-studies approach. Public and professional stakeholders were involved in the planning, conduct and dissemination of this study.

Results

Fifteen trials were eligible, 13 trialists shared IPD (2,371 participants representing 8 countries, median age 34 years-old, 71% women, moderately distressed on average, 20% missing outcome data). In comparison with passive control groups, MBPs reduced average distress between one- and six-months post-intervention with a small to moderate effect size (standardised mean difference (SMD) -0.32; 95% confidence interval (CI) -0.41 to -0.24; p-value < 0.001; 95% prediction interval (PI) -0.41 to -0.24 (no heterogeneity)). Results were robust to sensitivity analyses, and similar for the other psychological distress time point ranges. Confidence in the primary outcome result is high. We found no clear indication that this effect is modified by baseline psychological distress, gender, age, education level, or dispositional mindfulness.

Conclusions

Group-based teacher-led MBPs generally reduce psychological distress among community adults who volunteer to receive this type of intervention. More research is needed to identify sources of variability in outcomes at an individual level.

Why should I vaccinate? The role of mindfulness and health-protective behaviours during the COVID-19 pandemic

Objective

Health maintenance of the general public through vaccination is a significant component of controlling the COVID-19 pandemic. This study aims to examine the perception of Nigerians toward the COVID-19 vaccine. Methods: Informed by the Extended Parallel Process Model (EPPM), 793 Nigerian participants completed a cross-sectional self-administered online survey to assess: (1) their perception of COVID-19 based on fear-mongering information on social media (2) the potential relationship between threat perception, efficacy, and fear associated with the COVID-19 vaccine, vaccine hesitancy, and attitudes toward the decision to uptake the vaccine using structural equation modeling (SEM) analysis, and (3) we further employed the use of the hierarchical regression analysis to test the moderating effect of mindful critical thinking between vaccine hesitancy and attitudes toward vaccines.

Results

Most participants (65.7%) intend to uptake the COVID-19 vaccine. However, many people did not fear the disease (19.2%). Threat perception and efficacy were associated with a decision to uptake the COVID-19 vaccine via the mediation of attitudes toward vaccines. Previous vaccine hesitancy has no relationship with uptake decisions. The hierarchical regression analysis showed that participants exhibiting high critical thinking mindfulness were more interested in taking the vaccine.

Conclusions

The findings of this study demonstrate that EPPM constructs are effective predictors of the public's decision to uptake the COVID-19 vaccine. This research highlights the theoretical and practical implications.

Yoga, Meditation, Breathing Exercises, and Inflammatory Biomarkers with Possible Implications in COVID-19: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction

COVID-19, a multisystem disease, has implications for various immunity and infection biomarkers. Yoga (Y), meditation (M), and pranayama (P), and their combinations have shown positive changes on those biomarkers among other than COVID-19 patients and healthy people. So, we aimed to document the evidence of possible implication in a systematic way.

Materials and Methods

We screened 84 full texts, published in the last ten years, from three databases, from which only 44 met the eligibility criteria, and then extracted the data related to demographic characteristics, intervention, results, and strengths and limitations in two MS-Excel grids, and then presented them in tables and figures. Furthermore, we carried out meta-analysis including subgroup and sensitivity analysis using a random effects model of 11 RCTs and reported the mean difference, heterogeneity, and p value with 95% CI and presented them with forest and funnel plots and the tables.

Results

Twenty-five biomarkers of 4023 participants (range, 15-413) from 13 countries, healthy and clinical, from both sexes above 18 years, and from mainly clinical settings, were reported. YMP intervention, in solitary or in different possible combinations with varied durations among clinical and pregnant (range, 960-4800 minutes) and healthy (960-8400 minutes, excluding two studies of 20 minutes only) participants, was reported. It was revealed that 25 biomarkers, nine among the apparently healthy, 14 among the patients, and two among the pregnant, changed favourably (p < 0.05). Furthermore, either in meta- or subgroup-analysis, mean differences of IL-6 (-1.44 pg/ml) (95% CI) (-2.33, -0.55), (p = 0.002, I ²  = 82%), Cortisol (-40.75 pg/ml) (95% CI) (-64.13, -17.38), (p = 0.0006, I ²  = 87%), and TNF-α (-3.40 pg/ml) (95% CI) (-4.83, -1.98), (p < 0.0001, I ²  = 79%) showed statistically significant changes. Nonetheless, considerable heterogeneity and publication bias were observed among the studies.

Conclusion

Although more than two dozens of biomarkers in individual studies showed favourable changes, only IL-6, Cortisol, and TNF-α produced significant combined results, even then with much less certainty. Further meta-analysis of biomarkers of COVID-19 patients is highly recommended. Registration: CRD42021283894.

Impact of Diet and Lifestyle on Vaccine Efficacy in Adults Aged 55 and Older: A Review

Context

Age-related declines in immune system function, including vaccine responsiveness, are well established. Dietary and lifestyle factors have been investigated in human clinical trials and observational studies for their effects on vaccine response.

Objective

The review intended to assess dietary and lifestyle factors that can modulate vaccine response in a population aged 55 years or older or in a population with an average age of 55 years or older.

Design

The research team performed a narrative review of studies occurring up until May 2021 by searching electronic PubMed databases.

Results

The review findings suggest that two factors may have clinically relevant effects on vaccine response: regular aerobic exercise and psychological environmental stressors, in particular caregiving stress, which studies have consistently found can have a positive and negative effect or association, respectively. In addition, micronutrients used in combination as well as microbiome-targeted interventions show mostly promising results. Other factors may yet be relevant but very few studies have been done.

Conclusions

Heterogeneity of study design, small sample sizes, and other challenges mean that strong conclusions remain elusive. Further study is needed as well as improvements in study design. However, there are indications that certain dietary and lifestyle factors influence vaccine effectiveness.

Effects of Exercise and Physical Activity Levels on Vaccination Efficacy: A Systematic Review and Meta-Analysis

Objective: We examined whether different intensities of exercise and/or physical activity (PA) levels affected and/or associated with vaccination efficacy. Methods: A systematic review and meta-analysis was conducted and registered with PROSPERO (CRD42021230108). The PubMed, EMBASE, Cochrane Library (trials), SportDiscus, and CINAHL databases were searched up to January 2022. Results: In total, 38 eligible studies were included. Chronic exercise increased influenza antibodies (standardized mean difference (SMD) = 0.49, confidence interval (CI) = 0.25−0.73, Z = 3.95, I2 = 90%, p < 0.01), which was mainly driven by aerobic exercise (SMD = 0.39, CI = 0.19−0.58, Z = 3.96, I2 = 77%, p < 0.01) as opposed to combined (aerobic + resistance; p = 0.07) or other exercise types (i.e., taiji and qigong, unspecified; p > 0.05). PA levels positively affected antibodies in response to influenza vaccination (SMD = 0.18, CI = 0.02−0.34, Z = 2.21, I2 = 76%, p = 0.03), which was mainly driven by high PA levels compared to moderate PA levels (Chi2 = 10.35, I2 = 90.3%, p < 0.01). Physically active individuals developed influenza antibodies in response to vaccination in >4 weeks (SMD = 0.64, CI = 0.30−0.98, Z = 3.72, I2 = 83%, p < 0.01) as opposed to <4 weeks (p > 0.05; Chi2 = 13.40, I2 = 92.5%, p < 0.01) post vaccination. Conclusion: Chronic aerobic exercise or high PA levels increased influenza antibodies in humans more than vaccinated individuals with no participation in exercise/PA. The evidence regarding the effects of exercise/PA levels on antibodies in response to vaccines other than influenza is extremely limited.

Insights Into Sibling Relationships and Longevity From Genetics of Healthy Ageing Nonagenarians: The Importance of Optimisation, Resilience and Social Networks

Understanding how to “Age Longer and Age Well” is a priority for people personally, for populations and for government policy. Approximately ten percent of nonagenarians reach 90 years and beyond in good condition and seem to have a combination of both age-span and health-span. However, the factors which contribute to human longevity remain challenging. Culture is a shared system of learning ideas, feelings, and survival strategies. It has a strong influence on each person’s psychological development, behavior, values and beliefs. Nonagenarians have rich life experiences that can teach us much about aging well; they are rich reservoirs of genetic, lifestyle and psychological information which can help understanding about how to live longer and better. Sibling or trio nonagenarians are important sources of family beliefs and behaviors upon which individual personalities may have been built. Their personal family histories and narratives are powerful tools that help to determine familial traits, beliefs and social behaviors which may help establish factors important in the siblings’ longevity. Using purposefully selected subjects, recruited to the Genetics of Healthy Ageing (GeHA) project in four European countries, this research used the simple life story and qualitative research methods to analyze contrasting and distinctive questions about the interface between the psychological and social worlds as presented in the nonagenarian siblings’ insights about their longevity. Their stories aimed to give better understanding about which psychological aspects of their common life journey and the degree of emotional support in their sibling relationships may have supported their paths to longevity. The most universal finding in each of the four European countries was that nonagenarians demonstrated high positivity, resilience and coping skills and were supported in social networks. Around this theme, nonagenarians reported “being happy,” “always cheerful,” “never melancholy” and having a contentment with a “rich life” and family relationships which fits with accumulating evidence that life satisfaction comes from a perceived self-efficacy and optimism. Most sibling relationships in this study, when analyzed according to the Gold classification, fit the “congenial” or “loyal” relationship type – demonstrating a healthy respect for the others’ opinion without overt dependence, which may help individual coping and survival mechanisms.

Effects of Regular Physical Activity on the Immune System, Vaccination and Risk of Community-Acquired Infectious Disease in the General Population: Systematic Review and Meta-Analysis

Background

Regular physical activity is the prime modality for the prevention of numerous non-communicable diseases and has also been advocated for resilience against COVID-19 and other infectious diseases. However, there is currently no systematic and quantitative evidence synthesis of the association between physical activity and the strength of the immune system.

Objective

To examine the association between habitual physical activity and (1) the risk of community-acquired infectious disease, (2) laboratory‐assessed immune parameters, and (3) immune response to vaccination.

Methods

We conducted a systemic review and meta-analysis according to PRISMA guidelines. We searched seven databases (MEDLINE, Embase, Cochrane CENTRAL, Web of Science, CINAHL, PsycINFO, and SportDiscus) up to April 2020 for randomised controlled trials and prospective observational studies were included if they compared groups of adults with different levels of physical activity and reported immune system cell count, the concentration of antibody, risk of clinically diagnosed infections, risk of hospitalisation and mortality due to infectious disease. Studies involving elite athletes were excluded. The quality of the selected studies was critically examined following the Cochrane guidelines using ROB2 and ROBINS_E. Data were pooled using an inverse variance random-effects model.

Results

Higher level of habitual physical activity is associated with a 31% risk reduction (hazard ratio 0.69, 95% CI 0.61–0.78, 6 studies, N = 557,487 individuals) of community-acquired infectious disease and 37% risk reduction (hazard ratio 0.64, 95% CI 0.59–0.70, 4 studies, N = 422,813 individuals) of infectious disease mortality. Physical activity interventions resulted in increased CD4 cell counts (32 cells/µL, 95% CI 7–56 cells/µL, 24 studies, N = 1112 individuals) and salivary immunoglobulin IgA concentration (standardised mean difference 0.756, 95% CI 0.146–1.365, 7 studies, N = 435 individuals) and decreased neutrophil counts (704 cells/µL, 95% CI 68–1340, 6 studies, N = 704 individuals) compared to controls. Antibody concentration after vaccination is higher with an adjunct physical activity programme (standardised mean difference 0.142, 95% CI 0.021–0.262, 6 studies, N = 497 individuals).

Conclusion

Regular, moderate to vigorous physical activity is associated with reduced risk of community-acquired infectious diseases and infectious disease mortality, enhances the first line of defence of the immune system, and increases the potency of vaccination.

Protocol registration

The original protocol was prospectively registered with PROSPERO (CRD42020178825).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01466-1.

To stress or not to stress: Brain-behavior-immune interaction may weaken or promote the immune response to SARS-CoV-2

The COVID-19 pandemic continues to strongly affect people with health disadvantages, creating a heavy burden on medical systems and societies worldwide. Research is growing rapidly and recently revealed that stress-related factors such as socio-economic status, may also play a pivotal role. However, stress research investigating the underlying psychoneuroimmune interactions is missing. Here we address the question whether stress-associated neuroendocrine-immune mechanisms can possibly contribute to an increase in SARS-CoV-2 infections and influence the course of COVID-19 disease. Additionally, we discuss that not all forms of stress (e.g. acute versus chronic) are detrimental and that some types of stress could attenuate infection-risk and -progression. The overall aim of this review is to motivate future research efforts to clarify whether psychosocial interventions have the potential to optimize neuroendocrine-immune responses against respiratory viral infections during and beyond the COVID-19 pandemic. The current state of research on different types of stress is summarized in a comprehensive narrative review to promote a psychoneuroimmune understanding of how stress and its mediators cortisol, (nor)adrenaline, neuropeptides and neurotrophins can shape the immune defense against viral diseases. Based on this understanding, we describe how people with high psychosocial stress can be identified, which behaviors and psychosocial interventions may contribute to optimal stress management, and how psychoneuroimmune knowledge can be used to improve adequate care for COVID-19 and other patients with viral infections.

[Can Stress Interact with SARS-CoV-2? A Narrative Review with a Focus on Stress-Reducing Interventions that may Improve Defence against COVID-19]

OBJECTIVE

The COVID-19 pandemic is on the rise and causes many concerns and fears in the population as well as among medical care givers. This raises the question as to how psychosocial stress associated with the pandemic can be managed, and also if certain forms of stress can contribute to an increase in infections and critical illnesses.

METHODS

Against the background of the current state of research on stress and the immune response, we provide a narrative review of studies addressing the question as to how stress can influence the immune defence against viral diseases.

RESULTS

Excessive stress can compromise the barrier function of the airways and alter neuroendocrine control of immune function, which can create a virus-permissive immune response.

DISCUSSION

Because certain forms of stress can play a role in the successful immune defence against viral respiratory disease, it is important to identify people with high psychosocial stress and to help them manage their stress. Conclusion Psychosocial measures that contribute to improved stress management may have a positive effect on the immune response against viral respiratory infections.

Mindfulness-based programmes for mental health promotion in adults in nonclinical settings: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

There is an urgent need for mental health promotion in nonclinical settings. Mindfulness-based programmes (MBPs) are being widely implemented to reduce stress, but a comprehensive evidence synthesis is lacking. We reviewed trials to assess whether MBPs promote mental health relative to no intervention or comparator interventions.

METHODS AND FINDINGS

Following a detailed preregistered protocol (PROSPERO CRD42018105213) developed with public and professional stakeholders, 13 databases were searched to August 2020 for randomised controlled trials (RCTs) examining in-person, expert-defined MBPs in nonclinical settings. Two researchers independently selected, extracted, and appraised trials using the Cochrane Risk-of-Bias Tool 2.0. Primary outcomes were psychometrically validated anxiety, depression, psychological distress, and mental well-being questionnaires at 1 to 6 months after programme completion. Multiple testing was performed using p < 0.0125 (Bonferroni) for statistical significance. Secondary outcomes, meta-regression and sensitivity analyses were prespecified. Pairwise random-effects multivariate meta-analyses and prediction intervals (PIs) were calculated. A total of 11,605 participants in 136 trials were included (29 countries, 77% women, age range 18 to 73 years). Compared with no intervention, in most but not all scenarios MBPs improved average anxiety (8 trials; standardised mean difference (SMD) = -0.56; 95% confidence interval (CI) -0.80 to -0.33; p-value < 0.001; 95% PI -1.19 to 0.06), depression (14 trials; SMD = -0.53; 95% CI -0.72 to -0.34; p-value < 0.001; 95% PI -1.14 to 0.07), distress (27 trials; SMD = -0.45; 95% CI -0.58 to -0.31; p-value < 0.001; 95% PI -1.04 to 0.14), and well-being (9 trials; SMD = 0.33; 95% CI 0.11 to 0.54; p-value = 0.003; 95% PI -0.29 to 0.94). Compared with nonspecific active control conditions, in most but not all scenarios MBPs improved average depression (6 trials; SMD = -0.46; 95% CI -0.81 to -0.10; p-value = 0.012, 95% PI -1.57 to 0.66), with no statistically significant evidence for improving anxiety or distress and no reliable data on well-being. Compared with specific active control conditions, there is no statistically significant evidence of MBPs' superiority. Only effects on distress remained when higher-risk trials were excluded. USA-based trials reported smaller effects. MBPs targeted at higher-risk populations had larger effects than universal MBPs. The main limitation of this review is that confidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach is moderate to very low, mainly due to inconsistency and high risk of bias in many trials.

CONCLUSIONS

Compared with taking no action, MBPs of the included studies promote mental health in nonclinical settings, but given the heterogeneity between studies, the findings do not support generalisation of MBP effects across every setting. MBPs may have specific effects on some common mental health symptoms. Other preventative interventions may be equally effective. Implementation of MBPs in nonclinical settings should be partnered with thorough research to confirm findings and learn which settings are most likely to benefit.

The Relevance of Complementary and Integrative Medicine in the COVID-19 Pandemic: A Qualitative Review of the Literature

Background: During the COVID-19 pandemic people are facing risks of adverse health effects due to the restrictions implemented such as quarantine measures, reduced social contact, and self-isolation. In this qualitative review, we collected data on potential preventive and therapeutic health benefits of Complementary and Integrative Medicine (CIM) that might be useful during the COVID-19 pandemic. We have reviewed the scientific literature to summarize CIM practices that could be beneficial for improving physical and mental health and well-being of the population under the current pandemic circumstances. It must be noted that this review is not SARS-CoV-2 specific and we explicitly do not intend to make any SARS-CoV-2 specific health claims in this article. Methods and Findings: A qualitative, non-systematic literature review was conducted in Medline to identify literature describing preventive and therapeutic CIM approaches for strengthening mental and physical health. For a variety of CIM approaches clinical evidence was identified, indicating beneficial effects. CIM approaches include specific dietary measures and selected micronutrients, physical activity, techniques from Mind-Body Medicine, single botanicals or botanical compounds, and spending time in nature among others. The effects of CIM measures on conditions like obesity and hypertension are of special relevance here, as these conditions are considered as risk factors for a severe course of COVID-19. Moreover, a possibly direct effect of CIM approaches on immune functions and clinical parameters in respiratory tract infections, such as influenza, were identified. The findings of this review could be helpful for clinicians, patients, and the general population during the current pandemic when discussing and/or considering CIM options. Conclusions: CIM offers a variety of preventive and therapeutic options for strengthening physical and mental resilience, which could also be useful in the current COVID-19 pandemic. The evidence of CIM approaches with a potential benefit in the COVID-19 pandemic in different areas is worth to be analyzed. While this qualitative review has several obvious limitations, it might serve as useful starting point for further research on this topic.

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

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.

Mindfulness versus Physical Exercise: Effects of Two Recovery Strategies on Mental Health, Stress and Immunoglobulin A during Lunch Breaks. A Randomized Controlled Trial

This research analyses the effects of mindfulness meditation (MM) and physical exercise (PE), practised as daily recovery activities during lunch breaks, on perceived stress, general mental health, and immunoglobin A (IgA). A three-armed randomized controlled trial with 94 employees was conducted for five weeks including two follow-up sessions after one and six months. Daily practice lasted 30 min maximum. Perceived stress and general mental health questionnaires and saliva samples were used. There were significant differences in time factor comparing pre- and post-test of Perceived Stress Questionnaire (PSQ) both for PE [Mdiff = 0.10, SE = 0.03, p = 0.03], and for MM [Mdiff = 0.09, SE = 0.03, p = 0.03]. Moreover, there were significant differences of interaction factor when comparing MM vs. PE in total score at pre-post [F = −2.62 (6, 168.84), p = 0.02, ω² = 0.09], favoring PE with medium and high effect sizes. Regarding General Health Questionnaire (GHQ) variable, practicing MM showed significant effects in time factor compared to pre-Fup2. No significant differences were found for IgA. Thus, practicing both MM and PE as recovery strategies during lunch breaks could reduce perceived stress after five weeks of practice, with better results for PE. Moreover, practicing MM could improve mental health with effects for 6 months.

Benefits of Exercise on Influenza or Pneumonia in Older Adults: A Systematic Review

A coronavirus pandemic has recently become one of the greatest threats the world is facing. Older adults are under a high risk of infection because of weaker immune systems. Therefore, the purpose of this review is to summarize the recent scientific evidence that outlines the effects of exercise on influenza or pneumonia in older adults. An electronic literature search was conducted using the WEB OF SCIENCE, SCIENCEDIRECT and GOOGLE SCHOLAR databases using the following keywords, "Exercise," "Older adult," "Influenza," and "Pneumonia." Any randomized control trials, cross-sectional and observational studies that related to this topic were all included. Twenty studies met the eligibility criteria for this review. Thirteen randomized control trials investigated the effects of exercise on the immune responses to influenza or pneumonia vaccination: seven trials employed moderate aerobic exercise, three employed resistance exercise, and the remaining three used Asian martial arts or special home-based exercises. Five cross-sectional and two observational studies examined the associations between exercise/physical condition and influenza/pneumonia. Most of the current studies suggested that prolonged moderate aerobic exercise may help to reduce the risk of influenza-related infection and improve the immune responses to influenza or pneumonia vaccination in older adults. In addition, training in traditional Asian martial arts was also found to be beneficial. Future research should focus on the different effects of moderate and vigorous exercise on influenza-related diseases.

Effectiveness of Stress-Reducing Interventions on the Response to Challenges to the Immune System: A Meta-Analytic Review

BACKGROUND

There is consistent evidence showing an interplay between psychological processes and immune function in health and disease processes.

OBJECTIVES

The present systematic review and meta-analysis aims to provide a concise overview of the effectiveness of stress-reducing psychological interventions on the activation of immune responses in both healthy subjects and patients.

METHODS

Included are 3 types of challenges: in vivo, in vitro, and psychophysiological. Such challenges are designed to mimic naturally occurring immune-related threats.

RESULTS

A systematic literature search was conducted using PubMed, EMBASE, and PsychInfo, resulting in 75 eligible studies. The risk of bias was assessed with the Cochrane risk-of-bias tool. Across all studies, a small-to-medium effect size was found for the effects of psychological interventions on optimization of the immune function (g = 0.33; 95% CI 0.22-0.43). While the largest effects were found for in vivo immune-related challenges (g = 0.61; 95% CI 0.34-0.88; especially on studies that incorporated skin tests and wound healing), studies incorporating psychophysiological challenges and in vitro immune-related stimulations similarly suggest more optimal immune responses among those receiving stress-reducing interventions (g = 0.28; 95% CI 0.15-0.42).

CONCLUSION

These findings showed substantial heterogeneity depending on the type of challenge, the study populations, and the intervention types. These data demonstrate support for the effectiveness of stress-reducing psychological interventions in improving immunity in studies that tested immune function by means of incorporating an in vivo,in vitro, or psychophysiological challenge. Future research should more consistently incorporate challenges into the study design to gather more insights in the mechanisms underlying the optimized immune function following a psychological intervention. This is also relevant for clinical practice, as psychological interventions can possibly supplement, or at least partially replace, current drug treatments in various somatic conditions to reduce side effects.

Predictors of Mindfulness Meditation and Exercise Practice, from MEPARI-2, a randomized controlled trial

Objectives

Health-supporting behaviors can be challenging to initiate and maintain. Data from the MEPARI-2 randomized trial were used to assess predictors of sustained exercise and meditation practice.

Methods

Adults aged 30 to 69 years not exercising regularly and without prior meditation training were randomized to 8-week trainings in mindfulness meditation, moderate intensity exercise, or observational control, and monitored for 8 months. Exercise participants reported day-to-day minutes of moderate and vigorous activity; mindfulness meditation participants reported minutes of informal and formal practice. Demographic characteristics and psychosocial factors were assessed as predictors of practice. Growth mixture modeling was used to identify higher and lower practice subgroups.

Results

413 participants (75.8% female; mean (SD) age 49.7 (11.6) years) were randomized to exercise (137), mindfulness meditation (138), or control (138), with 390 (95%) completing the study. Seventy-nine percent of exercisers and 62% of meditators reported ≥150 minutes/week practice for at least half of the 37 weeks monitored. Self-reported minutes of mindfulness meditation and/or exercise practice were significantly (p<0.01) predicted by baseline levels of: general mental health, self-efficacy, perceived stress, depressive symptoms, openness, neuroticism, physical activity, smoking status, and number of social contacts. Growth mixture modeling identified subsets of people with moderate (100-200 min/week) and high (300-450 min/week) levels of self-reported practice for both mindfulness meditation (62% moderate; 38% high) and exercise (71% moderate; 29% high).

Conclusions

In this sample, participants randomized to behavioral trainings reported high levels of practice sustained over 37 weeks. Baseline psychosocial measures predicted practice levels in expected directions.

Factors That Influence the Immune Response to Vaccination

There is substantial variation between individuals in the immune response to vaccination. In this review, we provide an overview of the plethora of studies that have investigated factors that influence humoral and cellular vaccine responses in humans. These include intrinsic host factors (such as age, sex, genetics, and comorbidities), perinatal factors (such as gestational age, birth weight, feeding method, and maternal factors), and extrinsic factors (such as preexisting immunity, microbiota, infections, and antibiotics). Further, environmental factors (such as geographic location, season, family size, and toxins), behavioral factors (such as smoking, alcohol consumption, exercise, and sleep), and nutritional factors (such as body mass index, micronutrients, and enteropathy) also influence how individuals respond to vaccines. Moreover, vaccine factors (such as vaccine type, product, adjuvant, and dose) and administration factors (schedule, site, route, time of vaccination, and coadministered vaccines and other drugs) are also important. An understanding of all these factors and their impacts in the design of vaccine studies and decisions on vaccination schedules offers ways to improve vaccine immunogenicity and efficacy.

Measuring Vaccine Responses in the Multiplex Era

Vaccine studies in psychoneuroimmunology (PNI) provide an insight into biopsychosocial interactions and their role in infectious diseases. How to measure vaccine responses is therefore of critical importance for PNI researchers. In this chapter, traditional and modern immunoassays for the assessment of vaccine responses are discussed, highlighting how modern multiplex techniques provide researchers with greater capacity and opportunity for novel research relating to vaccine outcomes.

An online mindfulness-based program is effective in improving affect, over-commitment, optimism and mucosal immunity

Previous studies have demonstrated mindfulness-based programs are effective in reducing workplace stress; however, few have investigated the effectiveness of online mindfulness-based programs. Physiological measures are also underutilised when examining the efficacy of these programs. Therefore, we assessed the efficacy of an online mindfulness-based program on both short-term and more enduring aspects of psychological and physiological measures of stress and ill-health. Participants (N = 22) completed an 8-week online mindfulness-based program. Immediately before and after a mindfulness session, participants completed questionnaires to assess the short-term effects on mood and state anxiety and provided saliva samples to assess salivary alpha amylase (sAA) concentrations. Additionally, pre and post the 8-week intervention, participants completed questionnaires assessing workplace stress, over-commitment, work engagement, dispositional mindfulness and personal resources. Saliva samples were collected to measure the cortisol awakening response, sAA awakening response and secretory immunoglobulin A (sIgA). Our findings demonstrate that online mindfulness-based programs induce short-term improvements in fatigue and anxiety in employees. Additionally, we also report a decrease in over-commitment and increases in optimism and mucosal immunity (sIgA) following the program.

Meditation or exercise for preventing acute respiratory infection (MEPARI-2): A randomized controlled trial

Background

Practice of meditation or exercise may enhance health to protect against acute infectious illness.

Objective

To assess preventive effects of meditation and exercise on acute respiratory infection (ARI) illness.

Design

Randomized controlled prevention trial with three parallel groups.

Setting

Madison, Wisconsin, USA.

Participants

Community-recruited adults who did not regularly exercise or meditate.

Methods

1) 8-week behavioral training in mindfulness-based stress reduction (MBSR); 2) matched 8-week training in moderate intensity sustained exercise (EX); or 3) observational waitlist control. Training classes occurred in September and October, with weekly ARI surveillance through May. Incidence, duration, and area-under-curve ARI global severity were measured using daily reports on the WURSS-24 during ARI illness. Viruses were identified multiplex PCR. Absenteeism, health care utilization, and psychosocial health self-report assessments were also employed.

Results

Of 413 participants randomized, 390 completed the trial. In the MBSR group, 74 experienced 112 ARI episodes with 1045 days of ARI illness. Among exercisers, 84 had 120 episodes totaling 1010 illness days. Eighty-two of the controls had 134 episodes with 1210 days of ARI illness. Mean global severity was 315 for MBSR (95% confidence interval 244, 386), 256 (193, 318) for EX, and 336 (268, 403) for controls. A prespecified multivariate zero-inflated regression model suggested reduced incidence for MBSR (p = 0.036) and lower global severity for EX (p = 0.042), compared to control, not quite attaining the p<0.025 prespecified cut-off for null hypothesis rejection. There were 73 ARI-related missed-work days and 22 ARI-related health care visits in the MBSR group, 82 days and 21 visits for exercisers, and 105 days and 24 visits among controls. Viruses were identified in 63 ARI episodes in the MBSR group, compared to 64 for EX and 72 for control. Statistically significant (p<0.05) improvements in general mental health, self-efficacy, mindful attention, sleep quality, perceived stress, and depressive symptoms were observed in the MBSR and/or EX groups, compared to control.

Conclusions

Training in mindfulness meditation or exercise may help protect against ARI illness.

Limitations

This trial was likely underpowered.

Trial registration

Clinicaltrials.gov NCT01654289

Positive mood on the day of influenza vaccination predicts vaccine effectiveness: A prospective observational cohort study

Influenza vaccination is estimated to only be effective in 17-53% of older adults. Multiple patient behaviors and psychological factors have been shown to act as 'immune modulators' sufficient to influence vaccination outcomes. However, the relative importance of such factors is unknown as they have typically been examined in isolation. The objective of the present study was to explore the effects of multiple behavioral (physical activity, nutrition, sleep) and psychological influences (stress, positive mood, negative mood) on the effectiveness of the immune response to influenza vaccination in the elderly. A prospective, diary-based longitudinal observational cohort study was conducted. One hundred and thirty-eight community-dwelling older adults (65-85years) who received the 2014/15 influenza vaccination completed repeated psycho-behavioral measures over the two weeks prior, and four weeks following influenza vaccination. IgG responses to vaccination were measured via antigen microarray and seroprotection via hemagglutination inhibition assays at 4 and 16weeks post-vaccination. High pre-vaccination seroprotection levels were observed for H3N2 and B viral strains. Positive mood on the day of vaccination was a significant predictor of H1N1 seroprotection at 16weeks post-vaccination and IgG responses to vaccination at 4 and 16weeks post-vaccination, controlling for age and gender. Positive mood across the 6-week observation period was also significantly associated with post-vaccination H1N1 seroprotection and IgG responses to vaccination at 16weeks post-vaccination, but in regression models the proportion of variance explained was lower than for positive mood on the day of vaccination alone. No other factors were found to significantly predict antibody responses to vaccination. Greater positive mood in older adults, particularly on the day of vaccination, is associated with enhanced responses to vaccination.

Mindfulness mediates the physiological markers of stress: Systematic review and meta-analysis

Meditation is a popular form of stress management, argued to mediate stress reactivity. However, many studies in this field commonly fail to include an active control group. Given the frequency with which people are selecting meditation as a form of self-management, it is important to validate if the practice is effective in mediating stress-reactivity using well-controlled studies. Thus, we aimed to conduct a meta-analysis investigating the neurobiological effects of meditation, including focused attention, open monitoring and automatic self-transcending subtypes, compared to an active control, on markers of stress. In the current meta-analysis and systematic review, we included randomised controlled trials comparing meditation interventions compared to an active control on physiological markers of stress. Studied outcomes include cortisol, blood pressure, heart-rate, lipids and peripheral cytokine expression. Forty-five studies were included. All meditation subtypes reduced systolic blood pressure. Focused attention meditations also reduced cortisol and open monitoring meditations also reduced heart rate. When all meditation forms were analysed together, meditation reduced cortisol, C - reactive protein, blood pressure, heart rate, triglycerides and tumour necrosis factor-alpha. Overall, meditation practice leads to decreased physiological markers of stress in a range of populations.

Yoga, mindfulness-based stress reduction and stress-related physiological measures: A meta-analysis

BACKGROUND AND OBJECTIVES

Practices that include yoga asanas and mindfulness-based stress reduction for the management of stress are increasingly popular; however, the neurobiological effects of these practices on stress reactivity are not well understood. Many studies investigating the effects of such practices fail to include an active control group. Given the frequency with which people are selecting such interventions as a form of self-management, it is important to determine their effectiveness. Thus, this review investigates the effects of practices that include yoga asanas, with and without mindfulness-based stress reduction, compared to an active control, on physiological markers of stress.

MATERIALS AND METHODS

A systematic review and meta-analysis of randomised controlled trials published in English compared practices that included yoga asanas, with and without mindfulness-based stress reduction, to an active control, on stress-related physiological measures. The review focused on studies that measured physiological parameters such as blood pressure, heart rate, cortisol and peripheral cytokine expression. MEDLINE, AMED, CINAHL, PsycINFO, SocINDEX, PubMed, and Scopus were searched in May 2016 and updated in December 2016. Randomised controlled trials were included if they assessed at least one of the following outcomes: heart rate, blood pressure, heart rate variability, mean arterial pressure, C-reactive protein, interleukins or cortisol. Risk of bias assessments included sequence generation, allocation concealment, blinding of assessors, incomplete outcome data, selective outcome reporting and other sources of bias. Meta-analysis was undertaken using Comprehensive Meta-Analysis Software Version 3. Sensitivity analyses were performed using 'one-study-removed' analysis. Subgroup analysis was conducted for different yoga and control group types, including mindfulness-based stress reduction versus non-mindfulness-based stress reduction based interventions, different populations, length of intervention, and method of data analysis. A random-effects model was used in all analyses.

RESULTS

Forty two studies were included in the meta-analysis. Interventions that included yoga asanas were associated with reduced evening cortisol, waking cortisol, ambulatory systolic blood pressure, resting heart rate, high frequency heart rate variability, fasting blood glucose, cholesterol and low density lipoprotein, compared to active control. However, the reported interventions were heterogeneous.

CONCLUSIONS

Practices that include yoga asanas appear to be associated with improved regulation of the sympathetic nervous system and hypothalamic-pituitary-adrenal system in various populations.

Effects of mindfulness-based interventions on biomarkers in healthy and cancer populations: a systematic review

Background

Only a small number of articles have investigated the relationship between mindfulness-based interventions (MBIs) and biomarkers. The aim of this systematic review was to study the effect of MBIs on specific biomarkers (cytokines, neuropeptides and C-reactive protein (CRP)) in both healthy subjects and cancer patients.

Methods

A search was conducted using PubMed, EMBASE, PsycINFO and the Cochrane library between 1980 and September 2016.

Results

A total of 13 studies with 1110 participants were included. In the healthy population, MBIs had no effect on cytokines, but were found to increase the levels of the neuropeptide insulin-like growth factor 1 (IGF-1). With respect to neuropeptide Y, despite the absence of post-intervention differences, MBIs may enhance recovery from stress. With regard to CRP, MBIs could be effective in lower Body Mass Index (BMI) individuals. In cancer patients, MBIs seem to have some effect on cytokine levels, although it was not possible to determine which specific cytokines were affected. One possibility is that MBIs might aid recovery of the immune system, increasing the production of interleukin (IL)-4 and decreasing interferon gamma (IFN-γ).

Conclusions

MBIs may be involved in changes from a depressive/carcinogenic profile to a more normalized one. However, given the complexity and different contexts of the immune system, and the fact that this investigation is still in its preliminary stage, additional randomized controlled trials are needed to further establish the impact of MBI programmes on biomarkers in both clinical and non-clinical populations.

Mindfulness Interventions

Mindfulness interventions aim to foster greater attention to and awareness of present moment experience. There has been a dramatic increase in randomized controlled trials (RCTs) of mindfulness interventions over the past two decades. This article evaluates the growing evidence of mindfulness intervention RCTs by reviewing and discussing (a) the effects of mindfulness interventions on health, cognitive, affective, and interpersonal outcomes; (b) evidence-based applications of mindfulness interventions to new settings and populations (e.g., the workplace, military, schools); (c) psychological and neurobiological mechanisms of mindfulness interventions; (d) mindfulness intervention dosing considerations; and (e) potential risks of mindfulness interventions. Methodologically rigorous RCTs have demonstrated that mindfulness interventions improve outcomes in multiple domains (e.g., chronic pain, depression relapse, addiction). Discussion focuses on opportunities and challenges for mindfulness intervention research and on community applications.

Exercise prior to influenza vaccination for limiting influenza incidence and its related complications in adults

BACKGROUND

Influenza is an infectious virus affecting both humans and animals. In humans, symptoms present as fever, cough, sore throat, runny nose, headache, muscle and joint pain, and malaise. The epidemiological profile of influenza is influenced by multiple factors, including transmissibility of the virus and the susceptibility of the population. Annually, influenza is estimated to infect 5% to 10% of adults, with higher rates in winter seasons in countries with seasonal variation. Exercise could be an intervention to enhance immune response and limit influenza incidence and its related complications.

OBJECTIVES

To assess the efficacy and safety of short and long-term exercise prior to influenza vaccination in enhancing influenza prevention in adults.

SEARCH METHODS

We searched CENTRAL (2015, Issue 11), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to 3 November 2015), Embase (1974 to 3 November 2015), CINAHL (1981 to 3 November 2015), LILACS (Latin American and Caribbean Health Sciences, 1982 to 3 November 2015), PEDro (1980 to 3 November 2015), SPORTDiscus (1985 to 3 November 2015), the WHO International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov (November 2015).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of short- and long-term exercise prior to influenza vaccination for the general adult population were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and checked data from the included trials using a standard form. We used the random-effects model due to differences in the type, duration, intensity and frequency of exercise in the analysis.

MAIN RESULTS

We included six trials published between 2007 and 2014 that randomised 599 adult participants. Study size ranged from 46 to 158 participants. Participants were aged between 18 years and 80 years; we could not derive gender proportions, as participants' sex was not reported in all studies. One study was available in abstract form only.We did not find a significant difference in outcomes between people who exercised and those who did not exercise before receiving influenza vaccination.Pre-vaccination exercises included endurance activities such as walking or using a treadmill, and resistance activities included biceps curls and lateral raises. Five of the studies provided one session of exercise between 25 and 50 minutes. In five studies, exercise was undertaken on the same day as the vaccination. One study provided exercise over a period of eight weeks before vaccination, with one 2½ hour supervised session, plus daily home exercise practice of 45 minutes. Exercise intensity ranged from 55% to 85% of maximal heart rate. Control group participants undertook a range of activities, including quiet rest, sitting, reading, meditation or unspecified activity.One study reported numbers of people who contracted influenza; no significant difference was reported between exercise and no-exercise participants. None of the included studies reported complications related to influenza illness. Only one study, which we assessed as providing low-quality evidence, reported numbers of people who experienced adverse events. This study reported no significant difference in outcomes between people who exercised and those who did not. No studies reported numbers of working days or days lost related to influenza illness. Only two studies reported participant-centred outcomes.Overall, study quality was unclear; we assessed five of the six included studies to have at least four unclear 'Risk of bias' domains (allocation concealment, blinding of outcome assessment, selective reporting and other bias). Insufficient reporting in four studies about selective reporting did not provide enough information to enable judgement; only two studies were included in trials registers.

AUTHORS' CONCLUSIONS

From the available evidence, we found that exercising before influenza vaccination is neither beneficial nor harmful. However, study data were limited and of low quality. Small sample sizes, study design limitations, exercise types, and focus on biochemical rather than participant-centred outcomes strongly influenced our findings.

Mindfulness meditation and the immune system: a systematic review of randomized controlled trials

Mindfulness meditation represents a mental training framework for cultivating the state of mindful awareness in daily life. Recently, there has been a surge of interest in how mindfulness meditation improves human health and well-being. Although studies have shown that mindfulness meditation can improve self-reported measures of disease symptomatology, the effect that mindfulness meditation has on biological mechanisms underlying human aging and disease is less clear. To address this issue, we conducted the first comprehensive review of randomized controlled trials examining the effects of mindfulness meditation on immune system parameters, with a specific focus on five outcomes: (1) circulating and stimulated inflammatory proteins, (2) cellular transcription factors and gene expression, (3) immune cell count, (4) immune cell aging, and (5) antibody response. This analysis revealed substantial heterogeneity across studies with respect to patient population, study design, and assay procedures. The findings suggest possible effects of mindfulness meditation on specific markers of inflammation, cell-mediated immunity, and biological aging, but these results are tentative and require further replication. On the basis of this analysis, we describe the limitations of existing work and suggest possible avenues for future research. Mindfulness meditation may be salutogenic for immune system dynamics, but additional work is needed to examine these effects.

Association of interleukin-8 and neutrophils with nasal symptom severity during acute respiratory infection

Using a large data set (n = 811), the relationship between acute respiratory infection illness severity and inflammatory biomarkers was investigated to determine whether certain symptoms are correlated more closely than others with the inflammatory biomarkers, interleukin‐8 (IL‐8) and nasal neutrophils. Participants with community acquired acute respiratory infection underwent nasal lavage for IL‐8 and neutrophil testing, in addition to multiplex polymerase chain reaction (PCR) methods for the detection and identification of respiratory viruses. Information about symptoms was obtained throughout the duration of the illness episode using the well‐validated Wisconsin Upper Respiratory Symptom Survey (WURSS‐21). Global symptom severity was calculated by the area under the curve (AUC) plotting duration versus WURSS total. Of the specimens tested, 56% were positively identified for one or more of nine different respiratory viruses. During acute respiratory infection illness, both IL‐8 and neutrophils positively correlate with AUC (r_s = 0.082, P = 0.022; r_s = 0.080, P = 0.030). IL‐8 and neutrophils correlate with nasal symptom severity: runny nose (r = 0.13, P = < 0.00001; r = 0.18, P = < 0.003), plugged nose (r = 0.045, P = 0.003; r = 0.14, P = 0.058), and sneezing (r = −0.02, P = < 0.0001; r = −0.0055, P = 0.31). Neutrophils correlate with some quality of life measures such as sleeping well (r = 0.15, P = 0.026). Thus, the study demonstrates that IL‐8 and neutrophils are correlated with severity of nasal symptoms during acute respiratory infection. Further research is necessary to determine if the concentration of these or other biomarkers can predict the overall duration and severity of acute respiratory infection illness. J. Med. Virol. 87:330–337, 2015. © 2014 Wiley Periodicals, Inc.

Environmental enrichment alters splenic immune cell composition and enhances secondary influenza vaccine responses in mice

Chronic stress has deleterious effects on immune function, which can lead to adverse health outcomes. However, studies investigating the impact of stress reduction interventions on immunity in clinical research have yielded divergent results, potentially stemming from differences in study design and genetic heterogeneity, among other clinical research challenges. To test the hypothesis that reducing glucocorticoid levels enhances certain immune functions, we administered influenza vaccine once (prime) or twice (boost) to mice housed in either standard control caging or environmental enrichment (EE) caging. We have shown that this approach reduces mouse corticosterone production. Compared with controls, EE mice had significantly lower levels of fecal corticosterone metabolites (FCMs) and increased splenic B and T lymphocyte numbers. Corticosterone levels were negatively associated with the numbers of CD19(+) (r(2) = 0.43, p = 0.0017), CD4(+) (r(2) = 0.28, p = 0.0154) and CD8(+) cells (r(2) = 0.20, p = 0.0503). Vaccinated mice showed nonsignificant differences in immunoglobulin G (IgG) titer between caging groups, although EE mice tended to exhibit larger increases in titer from prime to boost than controls; the interaction between the caging group (control versus EE) and vaccine group (prime versus boost) showed a strong statistical trend (cage-group*vaccine-group, F = 4.27, p = 0.0555), suggesting that there may be distinct effects of EE caging on primary versus secondary IgG vaccine responses. Vaccine-stimulated splenocytes from boosted EE mice had a significantly greater frequency of interleukin 5 (IL-5)-secreting cells than boosted controls (mean difference 7.7, IL-5 spot-forming units/10(6) splenocytes, 95% confidence interval 0.24-135.1, p = 0.0493) and showed a greater increase in the frequency of IL-5-secreting cells from prime to boost. Our results suggest that corticosterone reduction via EE caging was associated with enhanced secondary vaccine responses, but had little effect on primary responses in mice. These findings help identify differences in primary and secondary vaccine responses in relationship to stress mediators that may be relevant in clinical studies.