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

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.

The relationship between mental health, sleep quality and the immunogenicity of COVID-19 vaccinations

Sleep modulates the immune response, and sleep loss can reduce vaccine immunogenicity; vice versa, immune responses impact sleep. We aimed to investigate the influence of mental health and sleep quality on the immunogenicity of COVID-19 vaccinations and, conversely, of COVID-19 vaccinations on sleep quality. The prospective CoVacSer study monitored mental health, sleep quality and Anti-SARS-CoV-2-Spike IgG titres in a cohort of 1082 healthcare workers from 29 September 2021 to 19 December 2022. Questionnaires and blood samples were collected before, 14 days, and 3 months after the third COVID-19 vaccination, as well as in 154 participants before and 14 days after the fourth COVID-19 vaccination. Healthcare workers with psychiatric disorders had slightly lower Anti-SARS-CoV-2-Spike IgG levels before the third COVID-19 vaccination. However, this effect was mediated by higher median age and body mass index in this subgroup. Antibody titres following the third and fourth COVID-19 vaccinations ("booster vaccinations") were not significantly different between subgroups with and without psychiatric disorders. Sleep quality did not affect the humoral immunogenicity of the COVID-19 vaccinations. Moreover, the COVID-19 vaccinations did not impact self-reported sleep quality. Our data suggest that in a working population neither mental health nor sleep quality relevantly impact the immunogenicity of COVID-19 vaccinations, and that COVID-19 vaccinations do not cause a sustained deterioration of sleep, suggesting that they are not a precipitating factor for insomnia. The findings from this large-scale real-life cohort study will inform clinical practice regarding the recommendation of COVID-19 booster vaccinations for individuals with mental health and sleep problems.

The AIMS approach: regulating receptivity in patient-provider vaccine conversations

The World Health Organization named vaccine hesitancy a leading global health threat of modern time. Addressing this public health issue requires a multi-front strategy, one such strategic effort is training health care professionals to respond to reluctant patients/caregivers or those who refuse vaccines. AIMS (Announce, Inquire, Mirror, and Secure) is designed to help HCPs engaged in more productive conversations with patients/caregivers to secure trust, a key behavior leading to higher vaccination rates.

A meta-analysis of the associations between insufficient sleep duration and antibody response to vaccination

Vaccination is a major strategy to control a viral pandemic. Simple behavioral interventions that might boost vaccine responses have yet to be identified. We conducted meta-analyses to summarize the evidence linking the amount of sleep obtained in the days surrounding vaccination to antibody response in healthy adults. Authors of the included studies provided the information needed to accurately estimate the pooled effect size (ES) and 95% confidence intervals (95% CI) and to examine sex differences.^{1,2,3,4,5,6,7} The association between self-reported short sleep (<6 h/night) and reduced vaccine response did not reach our pre-defined statistical significant criteria (total n = 504, ages 18-85; overall ES [95% CI] = 0.29 [-0.04, 0.63]). Objectively assessed short sleep was associated with a robust decrease in antibody response (total n = 304, ages 18-60; overall ES [95% CI] = 0.79 [0.40, 1.18]). In men, the pooled ES was large (overall ES [95% CI] = 0.93 [0.54, 1.33]), whereas it did not reach significance in women (overall ES [95% CI] = 0.42 [-0.49, 1.32]). These results provide evidence that insufficient sleep duration substantially decreases the response to anti-viral vaccination and suggests that achieving adequate amount of sleep during the days surrounding vaccination may enhance and prolong the humoral response. Large-scale well-controlled studies are urgently needed to define (1) the window of time around inoculation when optimizing sleep duration is most beneficial, (2) the causes of the sex disparity in the impact of sleep on the response, and (3) the amount of sleep needed to protect the response.

Psychology Meets Biology in COVID-19: What We Know and Why It Matters for Public Health

Psychosocial factors are related to immune, viral, and vaccination outcomes. Yet, this knowledge has been poorly represented in public health initiatives during the COVID-19 pandemic. This review provides an overview of biopsychosocial links relevant to COVID-19 outcomes by describing seminal evidence about these associations known prepandemic as well as contemporary research conducted during the pandemic. This focuses on the negative impact of the pandemic on psychosocial health and how this in turn has likely consequences for critically relevant viral and vaccination outcomes. We end by looking forward, highlighting the potential of psychosocial interventions that could be leveraged to support all people in navigating a postpandemic world and how a biopsychosocial approach to health could be incorporated into public health responses to future pandemics.

Really just a little prick? A meta-analysis on adverse events in placebo control groups of seasonal influenza vaccination RCTs

BACKGROUND

The Corona pandemic and ongoing mass vaccinations raise the question of the nocebo mechanisms involved. Since immunization is usually administered to healthy people as a preventive health measure, adverse events (AE) following immunization are less accepted and could contribute to vaccine hesitancy. Assuming that vaccinees experience nocebo responses, the aim of this meta-analysis was to investigate the effect sizes of solicited adverse events (or assumed reactogenicity) reported in placebo groups in RCTs on seasonal influenza vaccination.

METHODS

Literature search via PubMed, Web of Science, and CENTRAL was conducted considering gray literature. Only RCTs with placebo groups using pharmacologically inert substances (like saline) were included. Quality was assessed using Cochrane Collaboration's Risk of Bias Tool. Effect sizes were estimated using a random mixed effects model based on k = 31 studies covering 14,326 participants in placebo groups.

RESULTS

Reported solicited AEs in placebo groups showed significant effect sizes of proportions (ES_p). In k = 13 analyzed placebo groups, 35 % of the participants reported at least one solicited systemic AE (p = 0.007). The most common particular solicited systemic AEs were headache (k = 27; 17 %; p = 0.001), malaise (k = 13; 12 %; p = 0.004), and hyperhidrosis (k = 4; 12 %; p < 0.001) within one week after vaccination.

CONCLUSION

The results show significant solicited AEs in placebo groups, indicating substantial nocebo responses after vaccination. Based on the fact that most vaccination programs include similar groups of healthy people, we expect that comparable nocebo effects occur during other campaigns. Health care professionals should be aware of the nocebo response and take action to prevent or decrease the burden of adverse events following immunization. Fear of side effects must be addressed early in order to diminish vaccine hesitancy. Prospero identifier: CRD42020156287, October 2019.

Consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 augments serum antibody titers against seasonal influenza vaccine in healthy adults

Seasonal influenza is a major upper respiratory tract infection occurring in winter. Vaccination is the best method for preventing this infection. We conducted two randomized, double-blind, placebo-controlled trials to examine whether consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1, which has been reported to reduce the risk of catching the common cold, augments serum antibody titers against seasonal influenza vaccines. In the first trial, which included university students, serum antibody titers against influenza A (H3N2) and B viruses were significantly higher in the yogurt group than in the placebo group. According to the guidelines established by the European Medicines Agency (EMA) for the assessment of vaccines, the seroconversion rate and mean geometric increase of influenza A (H3N2) and seroprotection of influenza B met the criteria only in the yogurt group. In the second trial, which included healthy adults, serum antibody titers against influenza A (H1N1) and B viruses were significantly higher in the yogurt group than in the placebo group. The seroconversion rate and mean geometric increase of influenza B met the EMA criteria only in the yogurt group. Furthermore, the cumulative days of ill health, such as throat complaints, upper respiratory inflammation, and cold, were significantly lower in the yogurt group than in the placebo group. Therefore, daily intake of yogurt fermented with L. bulgaricus OLL1073R-1 could reduce the duration of symptoms caused by respiratory infections and act as a mucosal adjuvant enhancing acquired immune responses against vaccines, leading to the improvement of public health.

Sleep and Daily Positive Emotions – Is Heart Rate Variability a Mediator?

Abstract. Sleep quality is considered a basic dimension of emotional health. The psychophysiological mechanisms underlying the associations between sleep quality and positive emotions are still largely unknown, yet autonomic regulation may play a role. This study employed a two-day ecological momentary assessment methodology in a sample of young adults to investigate whether subjective sleep quality reported in the morning was associated with daily positive emotional experience and whether this association was mediated by heart rate variability (HRV), a measure of cardiac vagal tone. Sleep quality was assessed using an electronic sleep diary upon awakening, while resting HRV and positive emotions were inspected at random times throughout the day using photoplethysmography and an electronic diary, respectively. Relevant confounding variables such as smoking, alcohol intake, and physical exercise between each measurement were also assessed. The sample included 121 participants (64.8% females, Mage = 25.97 ± 5.32 years). After controlling for relevant confounders including health behaviors and psychiatric comorbidities, mediation analysis revealed that greater sleep quality positively predicted daily HRV (β = .289, p < .001) which, in turn, had a direct influence on positive emotions (β = .244, p = .006). Also, sleep quality directly predicted positive emotional experience (β = .272, p = .001). Lastly, the model showed an indirect effect between sleep quality and positive emotions via HRV (β = .071, 95% BCI [.011, .146]). Results support the view of HRV as a process variable linking sleep to positive emotions. Experimental data is needed to consolidate the present findings.

Sleep disruption induces activation of inflammation and heightens risk for infectious disease: Role of impairments in thermoregulation and elevated ambient temperature

Thermoregulation and sleep are tightly coordinated, with evidence that impairments in thermoregulation as well as increases in ambient temperature increase the risk of sleep disturbance. As a period of rest and low demand for metabolic resources, sleep functions to support host responses to prior immunological challenges. In addition by priming the innate immune response, sleep prepares the body for injury or infection which might occur the following day. However when sleep is disrupted, this phasic organization between nocturnal sleep and the immune system becomes misaligned, cellular and genomic markers of inflammation are activated, and increases of proinflammatory cytokines shift from the nighttime to the day. Moreover, when sleep disturbance is perpetuated due to thermal factors such as elevated ambient temperature, the beneficial crosstalk between sleep and immune system becomes further imbalanced. Elevations in proinflammatory cytokines have reciprocal effects and induce sleep fragmentation with decreases in sleep efficiency, decreases in deep sleep, and increases in rapid eye movement sleep, further fomenting inflammation and inflammatory disease risk. Under these conditions, sleep disturbance has additional potent effects to decrease adaptive immune response, impair vaccine responses, and increase vulnerability to infectious disease. Behavioral interventions effectively treat insomnia and reverse systemic and cellular inflammation. Further, insomnia treatment redirects the misaligned inflammatory- and adaptive immune transcriptional profiles with the potential to mitigate risk of inflammation-related cardiovascular, neurodegenerative, and mental health diseases, as well as susceptibility to infectious disease.

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.

Immune response to vaccination in adults with mental disorders: A systematic review

BACKGROUND

Mental disorders are associated with immune dysregulation as measured by serum levels of biological markers of immunity. Adults with mental disorders have also been reported to have attenuated post vaccine immune response. The COVID-19 pandemic has invited the need to determine whether individuals with mental disorders exhibit differential immune response following the administration of vaccines for other infections.

METHODS

A systematic search of MEDLINE, Embase, Cochrane, and PsycInfo was conducted from inception to May 2021 investigating vaccine response in persons with mental disorders, as measured by biological markers of immunity (i.e., antibodies, cytokines).

RESULTS

Thirteen articles were identified which evaluated vaccine efficacy in persons with mental disorders. Individuals with major depressive disorder (MDD) or schizophrenia revealed attenuated immune response to vaccination, or no statistical difference compared to control subjects. Individuals with anorexia nervosa or post-traumatic stress disorder (PTSD) displayed no attenuated post-vaccination antibody level. Individuals with insomnia displayed lower levels of antibodies after vaccination, whereas individuals with obstructive sleep apnea (OSA) displayed no difference in vaccine response compared to control subjects.

LIMITATIONS

The limitations of this review include the relatively few articles included (n = 13) and small sample sizes (less than thirty subjects) in the majority of articles.

CONCLUSION

Vaccine response in adults with a mental disorder remains inconclusive. Notwithstanding the heterogeneity and relatively small number of studies, available evidence does suggest attenuated immune response across disparate vaccinations. Future research is required to confirm vaccine efficacy in persons with mental disorders, especially regarding immune responses to COVID-19 vaccination.

Temporal Links Between Self-Reported Sleep and Antibody Responses to the Influenza Vaccine

BACKGROUND

Growing evidence suggests that sleep plays an important role in immunological memory, including antibody responses to vaccination. However, much of the prior research has been carried out in the laboratory limiting the generalizability of the findings. Furthermore, no study has sought to identify sensitive periods prior to or after vaccination where sleep may have a stronger influence on antibody responses.

METHODS

Eighty-three healthy young adults completed 13 days of sleep diaries and received the trivalent influenza vaccine on day 3 of the study. Measures of self-reported sleep duration, sleep efficiency, and subjective sleep quality were assessed on each day. Antibody levels to the influenza viral strains were quantified at baseline and 1 and 4 months following influenza vaccination.

RESULTS

Shorter sleep duration, averaged over the collection period, was associated with fewer antibodies to the A/New Caledonia viral strain 1 and 4 months later, independent of baseline antibodies, age, sex, and cohort year. Analyses focused on nightly sleep on the days preceding and after the vaccination revealed that shorter sleep duration on the two nights before the vaccination predicted fewer antibodies 1 and 4 months later. Measures of self-reported sleep efficiency and subjective quality were unrelated to antibody responses to the influenza vaccination.

CONCLUSION

These findings provide further support for an association between sleep duration and antibody responses to the influenza vaccine and suggest that perhaps sleep on nights prior to vaccination are critical. If replicated, these findings may support sleep as a target for enhancing vaccination efficacy.

Affective Immunology: The Crosstalk Between Microglia and Astrocytes Plays Key Role?

Emerging evidence demonstrates the critical role of the immune response in the mechanisms relating to mood disorders, such as major depression (MDD) and bipolar disorder (BD). This has cast a spotlight on a specialized branch committed to the research of dynamics of the fine interaction between emotion (or affection) and immune response, which has been termed as “affective immunology.” Inflammatory cytokines and gut microbiota are actively involved in affective immunology. Furthermore, abnormalities of the astrocytes and microglia have been observed in mood disorders from both postmortem and molecular imaging studies; however, the underlying mechanisms remain elusive. Notably, the crosstalk between astrocyte and microglia acts as a mutual and pivotal intermediary factor modulating the immune response posed by inflammatory cytokines and gut microbiota. In this study, we propose the “altered astrocyte-microglia crosstalk (AAMC)” hypothesis which suggests that the astrocyte-microglia crosstalk regulates emotional alteration through mediating immune response, and thus, contributing to the development of mood disorders.

Effects of Brief Mood-Improving Interventions on Immunity: A Systematic Review and Meta-Analysis

OBJECTIVE

Positive mood has been associated with enhanced immune function. Interventions that improve mood could therefore provide a mechanism for optimizing immune-related health outcomes. Brief interventions that improve mood, also known as mood inductions, potentially offer a pragmatic approach to enhancing immune function for finite periods where this would be beneficial to health (e.g., in advance of vaccination or surgery). This review sought to systematically examine the evidence regarding the effects of brief, single-session positive mood interventions on immunity.

METHODS

Systematic searches of electronic databases were performed from earliest records to July 25, 2018. We identified 42 interventions suitable for inclusion, 6 of which were tested in multiple subpopulations. Random-effects meta-analyses were performed for pre-post experimental group immune outcomes measured in at least five intervention studies.

RESULTS

Although interventions were heterogeneous, 81% resulted in a statistically significant change in at least one immune parameter after the positive mood intervention for one or more of the subpopulations examined. However, studies were, in general, of low-to-moderate quality with small sample sizes (median n = 32) and did not examine the persistence or clinical relevance of the immune changes observed. Random-effects meta-analyses showed a significant medium-sized effect of interventions on increasing secretory IgA concentration (g = 0.65), a small but statistically significant effect for increased Interleukin-6 production (g = 0.12), and nonsignificant effects on natural killer cell activity (g = 0.15).

CONCLUSIONS

The current literature suggests that improvements in mood resulting from brief interventions can influence some immune parameters in ways indicative of enhanced immune function. However, there is a need for higher-quality research in this area that focuses on clinically relevant immune outcomes and mechanisms.

Acute exercise does not improve immune response to HPV vaccination series in adolescents

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Acute exercise is known to enhance less immunogenic response immunogenic antigens.

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In a 3-dose HPV vaccine series, exercise did not change antibody titers.

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Potential effects of exercise during first dose in series yet to be examined.

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.

Continuity of care with doctors-a matter of life and death? A systematic review of continuity of care and mortality

OBJECTIVE

Continuity of care is a long-standing feature of healthcare, especially of general practice. It is associated with increased patient satisfaction, increased take-up of health promotion, greater adherence to medical advice and decreased use of hospital services. This review aims to examine whether there is a relationship between the receipt of continuity of doctor care and mortality.

DESIGN

Systematic review without meta-analysis.

DATA SOURCES

MEDLINE, Embase and the Web of Science, from 1996 to 2017.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Peer-reviewed primary research articles, published in English which reported measured continuity of care received by patients from any kind of doctor, in any setting, in any country, related to measured mortality of those patients.

RESULTS

Of the 726 articles identified in searches, 22 fulfilled the eligibility criteria. The studies were all cohort or cross-sectional and most adjusted for multiple potential confounding factors. These studies came from nine countries with very different cultures and health systems. We found such heterogeneity of continuity and mortality measurement methods and time frames that it was not possible to combine the results of studies. However, 18 (81.8%) high-quality studies reported statistically significant reductions in mortality, with increased continuity of care. 16 of these were with all-cause mortality. Three others showed no association and one demonstrated mixed results. These significant protective effects occurred with both generalist and specialist doctors.

CONCLUSIONS

This first systematic review reveals that increased continuity of care by doctors is associated with lower mortality rates. Although all the evidence is observational, patients across cultural boundaries appear to benefit from continuity of care with both generalist and specialist doctors. Many of these articles called for continuity to be given a higher priority in healthcare planning. Despite substantial, successive, technical advances in medicine, interpersonal factors remain important.

PROSPERO REGISTRATION NUMBER

CRD42016042091.