The weight of obesity on the human immune response to vaccination

An in-depth understanding of the role and mechanisms of T cells in immune organ aging and age-related diseases

T cells play a critical and irreplaceable role in maintaining overall health. However, their functions undergo alterations as individuals age. It is of utmost importance to comprehend the specific characteristics of T-cell aging, as this knowledge is crucial for gaining deeper insights into the pathogenesis of aging-related diseases and developing effective therapeutic strategies. In this review, we have thoroughly examined the existing studies on the characteristics of immune organ aging. Furthermore, we elucidated the changes and potential mechanisms that occur in T cells during the aging process. Additionally, we have discussed the latest research advancements pertaining to T-cell aging-related diseases. These findings provide a fresh perspective for the study of T cells in the context of aging.

Post-COVID syndrome prevalence: a systematic review and meta-analysis

BACKGROUND

Since the Coronavirus disease 2019 (COVID-19) pandemic began, the number of individuals recovering from COVID-19 infection have increased. Post-COVID Syndrome, or PCS, which is defined as signs and symptoms that develop during or after infection in line with COVID-19, continue beyond 12 weeks, and are not explained by an alternative diagnosis, has also gained attention. We systematically reviewed and determined the pooled prevalence estimate of PCS worldwide based on published literature.

METHODS

Relevant articles from the Web of Science, Scopus, PubMed, Cochrane Library, and Ovid MEDLINE databases were screened using a Preferred Reporting Items for Systematic Reviews and Meta-Analyses-guided systematic search process. The included studies were in English, published from January 2020 to April 2024, had overall PCS prevalence as one of the outcomes studied, involved a human population with confirmed COVID-19 diagnosis and undergone assessment at 12 weeks post-COVID infection or beyond. As the primary outcome measured, the pooled prevalence of PCS was estimated from a meta-analysis of the PCS prevalence data extracted from individual studies, which was conducted via the random-effects model. This study has been registered on PROSPERO (CRD42023435280).

RESULTS

Forty eight studies met the eligibility criteria and were included in this review. 16 were accepted for meta-analysis to estimate the pooled prevalence for PCS worldwide, which was 41.79% (95% confidence interval [CI] 39.70-43.88%, I2 = 51%, p = 0.03). Based on different assessment or follow-up timepoints after acute COVID-19 infection, PCS prevalence estimated at ≥ 3rd, ≥ 6th, and ≥ 12th months timepoints were each 45.06% (95% CI: 41.25-48.87%), 41.30% (95% CI: 34.37-48.24%), and 41.32% (95% CI: 39.27-43.37%), respectively. Sex-stratified PCS prevalence was estimated at 47.23% (95% CI: 44.03-50.42%) in male and 52.77% (95% CI: 49.58-55.97%) in female. Based on continental regions, pooled PCS prevalence was estimated at 46.28% (95% CI: 39.53%-53.03%) in Europe, 46.29% (95% CI: 35.82%-56.77%) in America, 49.79% (95% CI: 30.05%-69.54%) in Asia, and 42.41% (95% CI: 0.00%-90.06%) in Australia.

CONCLUSION

The prevalence estimates in this meta-analysis could be used in further comprehensive studies on PCS, which might enable the development of better PCS management plans to reduce the effect of PCS on population health and the related economic burden.

Impact of nutritional status on vaccine-induced immunity in children living in South Africa: Investigating the B-cell repertoire and metabolic hormones

OBJECTIVES

We explored the role of metabolic hormones and the B-cell repertoire in the association between nutritional status and vaccine responses.

METHODS

In this prospective cohort study, nested within a larger randomized open-label trial, 211 South African children received two doses of measles vaccine and two or three doses of pneumococcal conjugate vaccine (PCV). Metabolic markers (leptin, ghrelin and adiponectin) and distribution of B-cell subsets (n = 106) were assessed at 18 months of age.

RESULTS

Children with a weight-for-height z-score (WHZ) ≤ -1 standard deviation (SD) at booster vaccination had a decreased mean serotype-specific PCV IgG response compared with those with WHZ > -1 and <+1 SD or WHZ ≥ +1 SD at 9 months post-booster (18 months of age). (Naive) pre-germinal center B-cells were associated with pneumococcal antibody decay between one to nine months post-booster. Predictive performance of elastic net models for the combined effect of B-cell subsets, metabolic hormones and nutritional status (in addition to age, sex, and randomization group) on measles and PCV vaccine response had an average area under the receiver operating curve of 0.9 and 0.7, respectively.

CONCLUSIONS

The combined effect of B-cell subsets, metabolic hormones and nutritional status correlated well with the vaccination response for measles and most PCV serotypes.

CLINICALTRIALS

gov registration of parent studies: NCT02943902 and NCT03330171.

Plant stanol consumption increases anti-COVID-19 antibody responses, independent of changes in serum cholesterol concentrations: a randomized controlled trial

BACKGROUND

People with overweight/obesity generally have impaired immune responses, resulting among others in increased risk of severe complaints and hospitalization after infections with severe acute respiratory syndrome coronavirus 2 (COVID-19), as well as decreased antibody production after vaccinations. Plant stanol ester previously increased the combined IgM/IgG antibody titers toward a hepatitis A vaccination in patients with allergic asthma, but the underlying mechanism is unknown.

OBJECTIVES

We evaluated whether plant stanol ester consumption improved the immune response in subjects with overweight/obesity after a COVID-19 vaccination.

METHODS

A double-blind, randomized, placebo-controlled trial was performed. Thirty-two subjects with overweight/obesity consumed products with added plant stanols (4 g/d; provided as plant stanol ester) or control ≥2 wk before receiving their COVID-19 vaccination until 4 wk after vaccination. Antibody titers were analyzed weekly and statistically analyzed using mixed models. Serum metabolic markers and cytokine profiles were also analyzed.

RESULTS

IgM concentrations against the COVID-19 Spike protein were increased in the plant stanol ester group compared with the control group, with the largest difference observed 2 wk after vaccination [31.2 (0.43, 62.1) BAU/mL, or +139%; Group × Time: P = 0.031]. Subjects that produced very low IgM antibodies produced, as expected, hardly any IgG antibodies. In those with IgG seroconversion, IgG Spike concentrations were also increased in the plant stanol ester group compared with the control group [71.3 (2.51, 140.1) BAU/mL; Group P = 0.043]. Stimulated cytokine concentrations decreased in the plant stanol ester group compared with the control group in all 3 cytokine domains (that is, proinflammatory, T helper [Th1]/Th17, and Th2/regulatory T cells). Between-group differences in serum LDL cholesterol or other metabolic markers were not observed.

CONCLUSIONS

Consuming plant stanols (4 g/d) affects immune responses to COVID-19 vaccinations, translating into increased serum anti-COVID-19 IgM concentrations in subjects with overweight/obesity. Only in IgG seroconverted subjects, serum anti-COVID-19 IgG concentrations also increase. These effects are independent of reductions in LDL cholesterol. These results suggest that this high-risk group for COVID-19 complications could benefit from plant stanol consumption. This trial was registered at clinicaltrials.gov as NCT04844346.

Immune Cells, Gut Microbiota, and Vaccines: A Gender Perspective

The development of preventive and therapeutic vaccines has played a crucial role in preventing infections and treating chronic and non-communicable diseases, respectively. For a long time, the influence of sex differences on modifying health and disease has not been addressed in clinical and preclinical studies. The interaction of genetic, epigenetic, and hormonal factors plays a role in the sex-related differences in the epidemiology of diseases, clinical manifestations, and the response to treatment. Moreover, sex is one of the leading factors influencing the gut microbiota composition, which could further explain the different predisposition to diseases in men and women. In the same way, differences between sexes occur also in the immune response to vaccines. This narrative review aims to highlight these differences, focusing on the immune response to vaccines. Comparative data about immune responses, vaccine effectiveness, and side effects are reviewed. Hence, the intricate interplay between sex, immunity, and the gut microbiota will be discussed for its potential role in the response to vaccination. Embracing a sex-oriented perspective in research may improve the efficacy of the immune response and allow the design of tailored vaccine schedules.

Gene expression profiling of host lipid metabolism in SARS-CoV-2 infected patients: a systematic review and integrated bioinformatics analysis

BACKGROUND

The Coronavirus disease 2019 (COVID-19) pandemic occurred due to the dispersion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Severe symptoms can be observed in COVID-19 patients with lipid-related comorbidities such as obesity and diabetes. Yet, the extensive molecular mechanisms of how SARS-CoV-2 causes dysregulation of lipid metabolism remain unknown.

METHODS

Here, an advanced search of articles was conducted using PubMed, Scopus, EBSCOhost, and Web of Science databases using terms from Medical Subject Heading (MeSH) like SARS-CoV-2, lipid metabolism and transcriptomic as the keywords. From 428 retrieved studies, only clinical studies using next-generation sequencing as a gene expression method in COVID-19 patients were accepted. Study design, study population, sample type, the method for gene expression and differentially expressed genes (DEGs) were extracted from the five included studies. The DEGs obtained from the studies were pooled and analyzed using the bioinformatics software package, DAVID, to determine the enriched pathways. The DEGs involved in lipid metabolic pathways were selected and further analyzed using STRING and Cytoscape through visualization by protein-protein interaction (PPI) network complex.

RESULTS

The analysis identified nine remarkable clusters from the PPI complex, where cluster 1 showed the highest molecular interaction score. Three potential candidate genes (PPARG, IFITM3 and APOBEC3G) were pointed out from the integrated bioinformatics analysis in this systematic review and were chosen due to their significant role in regulating lipid metabolism. These candidate genes were significantly involved in enriched lipid metabolic pathways, mainly in regulating lipid homeostasis affecting the pathogenicity of SARS-CoV-2, specifically in mechanisms of viral entry and viral replication in COVID-19 patients.

CONCLUSIONS

Taken together, our findings in this systematic review highlight the affected lipid-metabolic pathways along with the affected genes upon SARS-CoV-2 invasion, which could be a potential target for new therapeutic strategies study in the future.

Systemic immunometabolism and responses to vaccines: insights from T and B cell perspectives

Vaccination stands as the cornerstone in the battle against infectious diseases, and its efficacy hinges on several host-related factors like genetics, age, and metabolic status. Vulnerable populations, such as malnourished individuals, the obese, and the elderly, commonly exhibit diminished vaccine responses and efficacy. While the specific factors contributing to this impairment may vary, these individuals typically display a degree of metabolic dysregulation, thereby underscoring its potential significance as a fundamental determinant of suboptimal vaccine responses. The emerging field of immunometabolism aims to unravel the intricate interplay between immune regulation and metabolic pathways, and recent research has revealed diverse metabolic signatures linked to various vaccine responses and outcomes. In this review, we summarize the major metabolic pathways utilized by B and T cells during vaccine responses, their complex and varied metabolic requirements, and the impact of micronutrients and metabolic hormones on vaccine outcomes. Furthermore, we examine how systemic metabolism influences vaccine responses and the evidence suggesting that metabolic dysregulation in vulnerable populations can lead to impaired vaccine responses. Lastly, we reflect on the challenge of proving causality with respect to the contribution of metabolic dysregulation to poor vaccine outcomes, and highlight the need for a systems biology approach that combines multimodal profiling and mathematical modelling to reveal the underlying mechanisms of such complex interactions.

Genome-wide association studies of response and side effects to the BNT162b2 vaccine in Italian healthcare workers: Increased antibody levels and side effects in carriers of the HLA-A*03:01 allele

The remarkable variability of response to vaccines against SARS-CoV-2 is apparent. The present study aims to estimate the extent to which the host genetic background contributes to this variability in terms of immune response and side effects following the administration of the BNT162b2 vaccine. We carried out a genome wide association study (GWAS) by genotyping 873 Italian healthcare workers who underwent anti-SARS-CoV-2 vaccination with the BNT162b2 vaccine and for whom information about anti-SARS-CoV-2 spike antibodies titers and vaccine side effects were available. The GWAS revealed a significant association between the HLA locus and the anti-SARS-CoV-2 Spike antibodies level at 2 months following the first dose of vaccine (SNP: rs1737060; p = 9.80 × 10-11 ). In particular, we observed a positive association between the antibody levels and the presence of the HLA-A*03:01 allele. The same allele was found associated with a 2-2.4-fold increased risk of experiencing specific side effects such as fever, chills and myalgia and a 1.5-1.8-fold increased risk of joint pain, nausea, fatigue, headache and asthenia, independently of age and sex. This study confirms that the heterogeneity in the immune response to the BNT162b2 vaccine and in its side effects are at least partially influenced by genetic variants. This information, integrated with individual biological and lifestyle-related correlates, could be of use in the definition of algorithms aimed at the identification of subjects in which the administration of additional vaccine doses would be particularly beneficial to maintain immunity against the virus.

Diet-induced obesity and diabetes enhance mortality and reduce vaccine efficacy for SARS-CoV-2

IMPORTANCE

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a wide spectrum of diseases in the human population, from asymptomatic infections to death. It is important to study the host differences that may alter the pathogenesis of this virus. One clinical finding in coronavirus disease 2019 (COVID-19) patients is that people with obesity or diabetes are at increased risk of severe illness from SARS-CoV-2 infection. We used a high-fat diet model in mice to study the effects of obesity and type 2 diabetes on SARS-CoV-2 infection as well as how these comorbidities alter the response to vaccination. We find that diabetic/obese mice have increased disease after SARS-CoV-2 infection and they have slower clearance of the virus. We find that the lungs of these mice have increased neutrophils and that removing these neutrophils protects diabetic/obese mice from disease. This demonstrates why these diseases have increased risk of severe disease and suggests specific interventions upon infection.

Dose Intervals and Time since Final Dose on Changes in Metabolic Indices after COVID-19 Vaccination

The rapid development and implementation of COVID-19 vaccines merit understanding its effects on metabolic indices. This retrospective longitudinal study investigated the influence of first-to-second-dose intervals and time since the final dose on the metabolic indices of individuals receiving COVID-19 vaccinations. A total of 318 Saudi subjects (59.7% females) aged 12-60 years received COVID-19 vaccines via the national vaccination program. We collected the anthropometric data and fasting blood samples at specific time points before vaccination and after the final vaccination dose, and biochemical metabolic indices, including glucose and lipid profile, were measured. We also collected the dates of vaccination and COVID-19 history during the study period. The participants were stratified into groups based on first-to-second-dose intervals and time since the final dose to compare pre-and post-vaccination changes in metabolic indices between the groups. Logistic regression analysis revealed no differences in pre- to post-vaccination metabolic status between groups based on first-to-second-dose intervals in either adolescents or adults. However, shorter intervals (≤6 months) between the final dose and follow-up were associated with a decrease in total cardiometabolic components, especially triglyceride levels (OR = 0.39, 95% CI: (0.22-0.68), p < 0.001) than longer intervals (>6 months) in adults. In conclusion, time duration since final dose was associated with pre- to post-vaccination changes in metabolic indices, especially triglyceride levels, indicating that post-vaccination improvements wane over time. Further research is needed to validate the observed relationship, as it may contribute to optimizing vaccine effectiveness and safety in the future.

Prior cycles of anti-CD20 antibodies affect antibody responses after repeated SARS-CoV-2 mRNA vaccination

BACKGROUNDWhile B cell depletion is associated with attenuated antibody responses to SARS-CoV-2 mRNA vaccination, responses vary among individuals. Thus, elucidating the factors that affect immune responses after repeated vaccination is an important clinical need.METHODSWe evaluated the quality and magnitude of the T cell, B cell, antibody, and cytokine responses to a third dose of BNT162b2 or mRNA-1273 mRNA vaccine in patients with B cell depletion.RESULTSIn contrast with control individuals (n = 10), most patients on anti-CD20 therapy (n = 48) did not demonstrate an increase in spike-specific B cells or antibodies after a third dose of vaccine. A third vaccine elicited significantly increased frequencies of spike-specific non-naive T cells. A small subset of B cell-depleted individuals effectively produced spike-specific antibodies, and logistic regression models identified time since last anti-CD20 treatment and lower cumulative exposure to anti-CD20 mAbs as predictors of those having a serologic response. B cell-depleted patients who mounted an antibody response to 3 vaccine doses had persistent humoral immunity 6 months later.CONCLUSIONThese results demonstrate that serial vaccination strategies can be effective for a subset of B cell-depleted patients.FUNDINGThe NIH (R25 NS079193, P01 AI073748, U24 AI11867, R01 AI22220, UM 1HG009390, P01 AI039671, P50 CA121974, R01 CA227473, U01CA260507, 75N93019C00065, K24 AG042489), NIH HIPC Consortium (U19 AI089992), the National Multiple Sclerosis Society (CA 1061-A-18, RG-1802-30153), the Nancy Taylor Foundation for Chronic Diseases, Erase MS, and the Claude D. Pepper Older Americans Independence Center at Yale (P30 AG21342).

Considering skin-to-muscle depth for successful intramuscular injections in an increasingly obese population

BACKGROUND

Intramuscular (IM) injection practice is an essential nursing skill. Current practice relies on clinical judgement to determine needle length (unless specified in the medicine's product licence). Obesity is increasing in the global population, but guidelines have largely ignored how to select needle length to meet individual patient need.

AIM

The aim of this review was to systematically review the skin-to-muscle depth required to achieve injection into muscle in adults. The objectives were to identify any implications of obesity status when selecting an appropriate needle length and site in clinical practice. Search and review methodology: Studies of subjects above the age of 18 years using observational or experimental designs where the distance from the skin to muscle had been measured at any IM injection site, and obesity status was reported, were included in the search strategy. The primary outcome of interest was the distance from skin surface to muscle penetration.

FINDINGS

14 studies were identified that investigated the dorsogluteal, ventrogluteal, deltoid and vastus lateralis sites, all used cross-sectional observational designs. Ten used ultrasound, three used computed tomography (CT) and one used magnetic resonance imaging. Obesity status was reported as BMI or hip-to-waist ratio. In all studies there was a correlation between obesity status and the distance from skin surface to muscle. In females this exceeded 37 mm at both gluteal sites, independent of obesity status.

CONCLUSIONS

There should be an assessment of obesity status before selecting needle length for IM injections in both genders. Needles longer than the standard 37 mm are recommended for all females, whatever their obesity status, for any gluteal site. Injections into gluteal sites should be avoided in females who are obese. Deltoid injections are more likely to achieve muscle penetration in both genders, and in patients who are overweight or obese. Further research is required.

Assessment of the Immune Response in Patients with Insulin Resistance, Obesity, and Diabetes to COVID-19 Vaccination

The SARS-CoV-19 pandemic overwhelmed multiple healthcare systems across the world. Patients with underlying medical conditions such as obesity or diabetes were particularly vulnerable, had more severe symptoms, and were more frequently hospitalized. To date, there have been many studies on the severity of SARS-CoV-2 in patients with metabolic disorders, but data on the efficiency of vaccines against COVID-19 are still limited. This paper aims to provide a comprehensive overview of the effectiveness of COVID-19 vaccines in individuals with diabetes, insulin resistance, and obesity. A comparison is made between the immune response after vaccination in patients with and without metabolic comorbidities. Additionally, an attempt is made to highlight the mechanisms of immune stimulation affected by SARS-CoV-2 vaccines and how metabolic comorbidities modulate these mechanisms. The focus is on the most common COVID-19 vaccines, which include mRNA vaccines such as Pfizer-BioNTech and Moderna, as well as viral vector vaccines such as AstraZeneca and Johnson & Johnson. Furthermore, an effort is made to clarify how the functional differences between these vaccines may impact the response in individuals with metabolic disorders, drawing from available experimental data. This review summarizes the current knowledge regarding the post-vaccination response to COVID-19 in the context of metabolic comorbidities such as diabetes, insulin resistance, and obesity.

Concurrent stunting and overweight or obesity among under-five children in sub-Saharan Africa: a multilevel analysis

BACKGROUND

Globally, the co-occurrence of stunting and overweight or obesity (CSO) in the same individual is becoming an emerging layer of malnutrition and there is a paucity of information in low- and middle-income countries, particularly in sub-Saharan Africa. Hence, this study aimed to determine the pooled prevalence and determinants of concurrent stunting and overweight or obesity among under-five children in SSA.

METHODS

Secondary data analysis was conducted from a recent nationally representative Demographic and Health Survey dataset of 35 SSA countries. A total weighted sample of 210,565 under-five children was included in the study. A multivariable multilevel mixed effect model was employed to identify the determinant of the prevalence of under-5 CSO. The Intra-class Correlation Coefficient (ICC) and Likelihood Ratio (LR) test were used to assess the presence of the clustering effect. A p-value of p < 0.05 was used to declare statistical significance.

RESULT

The pooled prevalence of concurrent stunting and overweight/obesity among under-five children was 1.82% (95% CI: 1.76, 1.87) in SSA. Across the SSA regions, the highest prevalence of CSO was reported in Southern Africa (2.64%, 95% CI: 2.17, 3.17) followed by the Central Africa region (2.21%, 95% CI: 2.06, 2.37). Under five children aged 12-23 months (AOR = 0.45, 95% CI: 0.34, 0.59), 24-35 months (AOR = 0.41, 95% CI: 0.32, 0.52), 36-59 months (AOR = 055, 95% CI: 0.43, 0.70), ever had no vaccination (AOR = 1.25, 95% CI: 1.09, 1.54), under-five children born from 25 to 34 years mother (AOR = 0.75, 95% CI: 0.61, 0.91), under-five children born from overweight/obese mothers (AOR = 1.63, 95% CI: 1.14, 2.34), and under-five children living in West Africa (AOR = 0.77, 95% CI: 0.61, 0.96) were significant determinants for under-five CSO.

CONCLUSION

Concurrent stunting and overweight or obesity is becoming an emerging layer of malnutrition. Under five children born in the SSA region had almost a 2% overall risk of developing CSO. Age of the children, vaccination status, maternal age, maternal obesity, and region of SSA were significantly associated with under-five CSO. Therefore, nutrition policies and programs should base on the identified factors and promote a quality and nutritious diet to limit the risk of developing CSO in early life.

Development of an Effective Neutralizing Antibody Assay for SARS-CoV-2 Diagnosis

Introduction

Neutralizing antibodies (NAbs) are essential for preventing reinfection with SARS-CoV-2 and the recurrence of COVID-19; nonetheless, the formation of NAbs following vaccination and infection remains enigmatic due to the lack of a practical and effective NAb assay in routine laboratory settings. In this study, we developed a convenient lateral flow assay for the rapid and precise measurement of serum NAb levels within 20 minutes.

Methods

Receptor-binding domain-fragment crystallizable (RBD-Fc) and angiotensin-converting enzyme 2-histidine tag (ACE2-His) were expressed by the eukaryotic expression systems of Spodoptera frugiperda clone 9 and human embryonic kidney 293T, respectively. Then, colloidal gold was synthesized and conjugated with ACE2. After optimizing various operating parameters, an NAb lateral flow assay was constructed. Subsequently, its detection limit, specificity, and stability were systematically evaluated, and clinical samples were analyzed to validate its clinical feasibility.

Results

RBD-Fc and ACE2-His were obtained with 94.01% and 90.05% purity, respectively. The synthesized colloidal gold had a uniform distribution with an average diameter of 24.15 ± 2.56 nm. With a detection limit of 2 μg/mL, the proposed assay demonstrated a sensitivity of 97.80% and a specificity of 100% in 684 uninfected clinical samples. By evaluating 356 specimens from infected individuals, we observed that the overall concordance rate between the proposed assay and conventional enzyme-linked immunosorbent assay was 95.22%, and we noticed that 16.57% (59/356) of individuals still did not produce NAbs after infection (both by ELISA and the proposed assay). All the above tests by this assay can obtain results within 20 minutes by the naked eye without any additional instruments or equipment.

Conclusion

The proposed assay can expediently and reliably detect anti-SARS-CoV-2 NAbs after infection, and the results provide valuable data to facilitate effective prevention and control of SARS-CoV-2.

Clinical trial registration

Serum and blood samples were used under approval from the Biomedical Research Ethics Subcommittee of Henan University, and the clinical trial registration number was HUSOM-2022-052. We confirm that this study complies with the Declaration of Helsinki.

Human immunodeficiency virus and antiretroviral therapy-mediated immune cell metabolic dysregulation in children born to HIV-infected women: potential clinical implications

Commencing lifelong antiretroviral therapy (ART) immediately following HIV diagnosis (Option B+) has dramatically improved the health of HIV-infected women and their children, with the majority being of HIV-exposed children born uninfected (HEU). This success has led to an increasing population of HIV-infected women receiving ART during pregnancy and children exposed to ART in utero. Nonetheless, a small proportion of children are still infected with HIV (HEI) each year. HEI children suffer from reduced immunocompetence and host-defence, due to CD4+ T lymphocyte depletion, but also dysregulation of other immune cells including CD8+ T lymphocytes, natural killer (NK) cells, macrophages including B lymphocytes. Furthermore, although HEU children are uninfected, altered immune responses are observed and associated with increased vulnerability to infections. The mechanisms underlying immune dysregulation in HEU children remain poorly described. Building on early studies, emerging data suggests that HIV/ART exposure early in life affects cell metabolic function of HEU children. Prenatal HIV/ART exposure has been associated with dysregulation of mitochondria, including impaired DNA polymerase activity. Furthermore, dysregulation of oxidative phosphorylation (OXPHOS) causes a decreased generation of adenosine triphosphate (ATP) and increased production of reactive oxygen species (ROS), resulting in oxidative stress. These altered metabolic processes can affect immune cell viability and immune responses. Recent studies have indicated that immune-metabolic dysregulation may contribute to HIV-associated pathogenesis and clinical observations associated with HIV and ART exposure in HEU/HEI children. Given the critical role metabolic processes in immune cell functioning, immune-metabolic dysregulation in HEU and HEI children may have implications in effective host-defence responses against pathogens, as well as efficacy of standard ART regimens and future novel HIV cure approaches in HEI children. At the same time, targeting metabolic pathways of immune cells may provide safer and novel approaches for HIV cure strategies. Here, we review the current literature investigating immune-metabolic dysregulation in paediatric HIV pathogenesis.

Antibody Response to Inactive SARS-CoV-2 Vaccination in a Cohort of Elderly Patients Living with Obesity

INTRODUCTION

Obesity and aging negatively affect the immune system and host defense mechanisms, increasing vulnerability to and worsening prognosis of infectious diseases, leading to vaccine failure. Our aim was to investigate the antibody response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike antigens and the risk factors affecting antibody levels in elderly patients living with obesity (PwO) after inactive SARS-CoV-2 vaccine (CoronaVac) administration.

METHODS

One hundred twenty-three consecutive elderly patients with obesity (age ≥65 years, body mass index [BMI] ≥30 kg/m2) and 47 adults with obesity (age 18-64 years, BMI ≥30 kg/m2) admitted between August and November 2021 were enrolled. Seventy-five nonobese elderly people (age ≥65 years, BMI 18.5-29.9 kg/m2) and 105 nonobese adults (age 18-64 years, BMI 18.5-29.9 kg/m2) were recruited from subjects who visited the Vaccination Unit. SARS-CoV-2 spike protein antibody titers were measured in patients with obesity and nonobese controls who received two doses of CoronaVac.

RESULTS

SARS-CoV-2 levels of patients with obesity were found to be significantly lower than those of nonobese elderly individuals who had non-prior infection. There was no difference in SARS-CoV-2 levels between patients with obesity and nonobese individuals with prior infection. Age and SARS-CoV-2 level were found to be highly correlated in the correlation analysis in the group of elderly individuals (r: -0.184). In multivariate regression analysis, when SARS-CoV-2 immunoglobulin class G (IgG) was regressed on age, sex, BMI, type 2 diabetes mellitus, and hypertension (HT), HT was found to be an independent factor of the SARS-CoV-2 level (β: -2,730).

CONCLUSION

In the non-prior infection group, elderly patients with obesity generated significantly reduced antibody titers against SARS-CoV-2 spike antigen after CoronaVac vaccine compared to nonobese people. It is anticipated that the results obtained will provide invaluable information about SARS-CoV-2 vaccination strategies in this vulnerable population. Antibody titers may be measured, and booster doses should be delivered accordingly in elderly PwO for optimal protection.

Implications of obesity and adiposopathy on respiratory infections; focus on emerging challenges

Obesity is characterized by excessive adipose tissue accumulation, which impacts physiological, metabolic, and immune functions. Several respiratory infections, including bacterial pneumonia, influenza, and coronavirus disease 2019, appear to be linked to unfavorable results in individuals with obesity. These may be attributed to the direct mechanical/physiological effects of excess body fat on the lungs’ function. Notably, adipose tissue dysfunction is associated with a low-grade chronic inflammatory status and hyperleptinemia, among other characteristics. These have all been linked to immune system dysfunction and weakened immune responses to these infections. A better understanding and clinical awareness of these risk factors are necessary for better disease outcomes.

Diet Induced Obesity and Diabetes Enhance Mortality and Reduces Vaccine Efficacy for SARS-CoV-2

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), the causative agent of Coronavirus disease 2019 (COVID-19), emerged in Wuhan, China, in December 2019. As of October 2022, there have been over 625 million confirmed cases of COVID-19, including over 6.5 million deaths. Epidemiological studies have indicated that comorbidities of obesity and diabetes mellitus are associated with increased morbidity and mortality following SARS-CoV-2 infection. We determined how the comorbidities of obesity and diabetes affect morbidity and mortality following SARS-CoV-2 infection in unvaccinated and adjuvanted spike nanoparticle (NVX-CoV2373) vaccinated mice. We find that obese/diabetic mice infected with SARS-CoV-2 have increased morbidity and mortality compared to age matched normal mice. Mice fed a high-fat diet (HFD) then vaccinated with NVX-CoV2373 produce equivalent neutralizing antibody titers to those fed a normal diet (ND). However, the HFD mice have reduced viral clearance early in infection. Analysis of the inflammatory immune response in HFD mice demonstrates a recruitment of neutrophils that was correlated with increased mortality and reduced clearance of the virus. Depletion of neutrophils in diabetic/obese vaccinated mice reduced disease severity and protected mice from lethality. This model recapitulates the increased disease severity associated with obesity and diabetes in humans with COVID-19 and is an important comorbidity to study with increasing obesity and diabetes across the world.

Accelerated waning of the humoral response to COVID-19 vaccines in obesity

Obesity is associated with an increased risk of severe Coronavirus Disease 2019 (COVID-19) infection and mortality. COVID-19 vaccines reduce the risk of serious COVID-19 outcomes; however, their effectiveness in people with obesity is incompletely understood. We studied the relationship among body mass index (BMI), hospitalization and mortality due to COVID-19 among 3.6 million people in Scotland using the Early Pandemic Evaluation and Enhanced Surveillance of COVID-19 (EAVE II) surveillance platform. We found that vaccinated individuals with severe obesity (BMI > 40 kg/m2) were 76% more likely to experience hospitalization or death from COVID-19 (adjusted rate ratio of 1.76 (95% confidence interval (CI), 1.60-1.94). We also conducted a prospective longitudinal study of a cohort of 28 individuals with severe obesity compared to 41 control individuals with normal BMI (BMI 18.5-24.9 kg/m2). We found that 55% of individuals with severe obesity had unquantifiable titers of neutralizing antibody against authentic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus compared to 12% of individuals with normal BMI (P = 0.0003) 6 months after their second vaccine dose. Furthermore, we observed that, for individuals with severe obesity, at any given anti-spike and anti-receptor-binding domain (RBD) antibody level, neutralizing capacity was lower than that of individuals with a normal BMI. Neutralizing capacity was restored by a third dose of vaccine but again declined more rapidly in people with severe obesity. We demonstrate that waning of COVID-19 vaccine-induced humoral immunity is accelerated in individuals with severe obesity. As obesity is associated with increased hospitalization and mortality from breakthrough infections, our findings have implications for vaccine prioritization policies.

The relationship between triglyceride, cholesterol and lipoprotein levels, and immune responses to hepatitis B vaccine

Cholesterol homeostasis disorder and hypertriglyceridemia, as common metabolic conditions, have rarely been reported to affect the immune responses to the hepatitis B vaccine. Our study found that higher high-density lipoprotein (HDL) level showed a significant relationship with positive anti-HBs results (cOR = 1.479, 95% CI: 1.150, 1.901, p = 0.002; aOR = 1.304, 95% CI: 1.006, 1.691, p = 0.045), especially in individuals aged 18- to 40-year-old, female, smoking more than 100 cigarettes in life, and drinking more than 12 times every year. Lower low-density lipoprotein (LDL) level was associated with a negative anti-HBs result among participants aged 18- to 40-year-old, and participants who were obese. Higher level of HDL and lower level of LDL may be protective factors of better immune effect of hepatitis B vaccine. More research should be conducted to investigate the influence of the cholesterol level on the immune responses to the hepatitis B vaccine, and more in-depth research should be performed to uncover the mechanism.

Elicitation of potent neutralizing antibodies in obese mice by ISA 51-adjuvanted SARS-CoV-2 spike RBD-Fc vaccine

Vaccination is considered to be the most effective countermeasure to prevent and combat the global health threats of COVID-19. People with obesity are at a greater risk of hospitalization, life-threatening illness, and adverse outcomes after having COVID-19. Therefore, a safe and effective COVID-19 vaccine for obese individuals is urgently needed. In the study, the vaccine composed of the ISA 51 adjuvant and the SARS-CoV-2 spike (S) receptor-binding domain (RBD) in conjugation with the human IgG1 Fc fragment (named as ISA 51-adjuvanted RBD-Fc vaccine) was developed and inoculated in the regular chow diet (RCD) lean mice and the high-fat diet (HFD)-induced obese mice. The S protein-specific IgG titers were largely induced in an increasing manner along with three doses of ISA 51-adjuvanted RBD-Fc vaccine without causing any harmful side effect. In the HFD mice, the S protein-specific IgG titers can be quickly observed 2 weeks post the first inoculation. The antisera elicited by the ISA 51-adjuvanted RBD-Fc vaccine in the RCD and HFD mice exhibited potent SARS-CoV-2 neutralizing activities in the plaque reduction neutralization test (PRNT) assays and showed similar specificity for recognizing the key residues in the RBD which were involved in interacting with angiotensin-converting enzyme 2 (ACE2) receptor. The immune efficacy of the ISA 51-adjuvanted RBD-Fc vaccine in the HFD mice can be sustainably maintained with the PRNT50 values of 1.80-1.91×10^-3 for at least 8 weeks post the third inoculation. Collectively, the RBD-Fc-based immunogen and the ISA 51-adjuvanted formulation can be developed as an effective COVID-19 vaccine for obese individuals. KEY POINTS: • The ISA 51-adjuvanted RBD-Fc vaccine can induce potent SARS-CoV-2 neutralizing antibodies in the obese mouse • The antibodies elicited by the ISA 51-adjuvanted RBD-Fc vaccine can bind to the key RBD residues involved in interacting with ACE2 • The immune efficacy of the ISA 51-adjuvanted RBD-Fc vaccine can be sustainably maintained for at least 8 weeks post the third inoculation.

Intramuscular vaccine administrations including the adoption of “Zeta-track technique” & “without aspiration slow injection technique” (ZTT & WASiT): a prospective review

Objective

To review the current literature on the practice of intramuscular injections (IMIs), focusing on immunizations.

Methods

The present study comprises 2 reviews, characterized by high-quality evidence, pertaining to the deployment of the slow injection technique without aspiration (referred to in this paper as the without-aspiration slow injection technique [WASiT]) and combined with the Zeta-track technique (ZTT). The literature review is oriented toward the analysis of 2 features associated with IMIs techniques: safety and pain, integrating new evidence on vaccinee positioning for each muscle site and general relaxation techniques in the multi-parametric analysis.

Results

The rigorous and in-depth reviews in the current study reveal the usefulness of including, among the international guidelines for via intramuscular immunizations, the adoption of WASiT only for compliant vaccinees, and in combination with all validated techniques for IMIs, and the use of ZTT limitedly if specific well-developed muscles are indicated. All the technique’s limitations are exposed.

Conclusions

Future research directions are presented by including the author’s study designs to provide indirect evidence for the validity of the rationale of the slow injection technique using scientific methods, and for the conduction of future randomized controlled trials (RCTs) focused on revisiting the adoption of ZTT in a dynamic and integrated immunizations protocol in anterolateral thigh (ALT), ventrogluteal (VG), and also in the deltoid muscle, in the specific cases analyzed.

Impaired antibody responses were observed in patients with type 2 diabetes mellitus after receiving the inactivated COVID-19 vaccines

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) have been reported to be more susceptible to 2019 novel coronavirus (2019-nCoV) and more likely to develop severe pneumonia. However, the safety and immunological responses of T2DM patients after receiving the inactivated vaccines are not quite definite. Therefore, we aimed to explore the safety, antibody responses, and B-cell immunity of T2DM patients who were vaccinated with inactivated coronavirus disease 2019 (COVID-19) vaccines.

METHODS

Eighty-nine patients with T2DM and 100 healthy controls (HCs) were enrolled, all of whom had received two doses of full-course inactivated vaccines. At 21-105 days after full-course vaccines: first, the safety of the vaccines was assessed by questionnaires; second, the titers of anti-receptor binding domain IgG (anti-RBD-IgG) and neutralizing antibodies (NAbs) were measured; third, we detected the frequency of RBD-specific memory B cells (RBD-specific MBCs) to explore the cellular immunity of T2DM patients.

RESULTS

The overall incidence of adverse events was similar between T2DM patients and HCs, and no serious adverse events were recorded in either group. Compared with HCs, significantly lower titers of anti-RBD-IgG (p = 0.004) and NAbs (p = 0.013) were observed in T2DM patients. Moreover, the frequency of RBD-specific MBCs was lower in T2DM patients than in HCs (p = 0.027). Among the 89 T2DM patients, individuals with lower body mass index (BMI) had higher antibody titers (anti-RBD-IgG: p = 0.009; NAbs: p = 0.084). Furthermore, we found that sex, BMI, and days after vaccination were correlated with antibody titers.

CONCLUSIONS

Inactivated COVID-19 vaccines were safe in patients with T2DM, but the antibody responses and memory B-cell responses were significantly decreased compared to HCs.

TRIAL REGISTRATION NUMBER AND DATE

NCT05043246. September 14, 2021. (Clinical Trials.gov).

Diverse effects of obesity on antitumor immunity and immunotherapy

Currently, obesity is one of the biggest health burdens facing society because it causes several comorbidities, such as type 2 diabetes, atherosclerosis, and heart disease. Obesity is also linked to multiple types of cancer. Obesity is the second most common preventable cause of cancer after smoking; the rates of obesity are increasing worldwide, as are the rates of obesity-associated cancer. Multiple factors link obesity to cancer, such as increased levels of growth hormones and adipokines, gut dysbiosis, altered tumor metabolism, and chronic low-grade inflammation. More recently, obesity has been shown to also affect the immune response against cancer. In this review we discuss the interplay between obesity, the immune system, and cancer.

Immune Response to Vaccination against COVID-19 at Different Second-Dose Intervals and Their Associations with Metabolic Parameters

Obesity and diabetes are associated with severe outcomes of coronavirus disease (COVID-19). Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been proven protective against infection and severe COVID-19. However, the immune response of metabolically burdened individuals to the vaccines remains unclear. Thus, we aimed to assess whether the metabolic status of individuals affects their humoral immune responses to the vaccination. Moreover, we evaluated whether the interval between the first two doses influenced antibody concentration. Sixty-seven individuals (21 males, 46 females) were vaccinated with the BNT162b2 mRNA COVID-19 vaccine. Fifty-four individuals were vaccinated with the second dose after 3 weeks and 13 after 5 weeks. We measured the antibody titers in all participants during the 19-week follow-up period. Patients diagnosed with COVID-19 were excluded. In the 5-week interval group, a significantly higher level of maximal antibody titers was observed. However, there were no differences in antibody concentrations after 19 weeks and no significant correlation between cardiometabolic factors and humoral response. The elongation of second-dose timing to 5 weeks leads to a higher acute antibody response but does not change long-term levels of antibody titers. Moreover, dysregulation of metabolic parameters does not lead to a diminished immune response to vaccination.

Impact of clinico-biochemical and inflammatory biomarkers on the immunogenicity and efficacy of SARS-CoV-2 adenoviral vaccine: a longitudinal study

Purpose

Due to a lack of effective antiviral treatment, several vaccines have been put forth to curb SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection and to reduce the mortality and morbidity rate by eliciting a protective immune response, primarily through virus-neutralizing antibodies specific for SARS-CoV-2 spike protein. This longitudinal study was designed to evaluate the vaccine effectiveness and immune response following the administration of adenoviral vaccine, COVISHIELD, in Indian population who were previously uninfected with SARS-CoV-2 and to reveal the effect of various sociodemographic, inflammatory and biochemical factors on antibody response.

Methods

Briefly, the total immunoglobulin G (IgG) against SARS-CoV-2 spike and nucleocapsid protein along with the immunological markers were estimated by chemiluminescent microparticle immunoassay (CMIA) technology. Biochemical parameters were estimated by spectrometry.

Results

A total of 348 subjects received two doses of COVISHIELD (224 males, 124 females). The mean age of the study subjects was 42.03 ± 13.54 years. Although both the doses of COVISHIELD against SARS-CoV-2 spike protein induced a robust immune response that lasted for months in all the subjects, the total IgG titer against SARS-CoV-2 spike protein was found significantly higher in subjects ≥50 years of age, and those with obesity, elevated triglycerides and elevated lactate dehydrogenase levels.

Conclusions

There is a definite effect of age and biochemical factors on the immunogenicity of COVISHIELD. An understanding of these factors could not only impact the design of vaccines and help improve vaccine immunogenicity and efficacy but also assist in decisions on vaccination schedules, in order to combat this deadly pandemic.

B cell contribution to immunometabolic dysfunction and impaired immune responses in obesity

Obesity increases the risk of type 2 diabetes mellitus, cardiovascular disease, fatty liver disease, and cancer. It is also linked with more severe complications from infections, including COVID-19, and poor vaccine responses. Chronic, low-grade inflammation and associated immune perturbations play an important role in determining morbidity in people living with obesity. The contribution of B cells to immune dysregulation and meta-inflammation associated with obesity has been documented by studies over the past decade. With a focus on human studies, here we consolidate the observations demonstrating that there is altered B cell subset composition, differentiation, and function both systemically and in the adipose tissue of individuals living with obesity. Finally, we discuss the potential factors that drive B cell dysfunction in obesity and propose a model by which altered B cell subset composition in obesity underlies dysfunctional B cell responses to novel pathogens.

The Influence of Sex, Body Mass Index, and Age on Cellular and Humoral Immune Responses Against Measles After a Third Dose of Measles-Mumps-Rubella Vaccine

BACKGROUND

A third dose of measles-mumps-rubella vaccine (MMR3) is recommended in mumps outbreak scenarios, but the immune response and the need for widespread use of MMR3 remain uncertain. Herein, we characterized measles-specific immune responses to MMR3 in a cohort of 232 healthy subjects.

METHODS

Serum and peripheral blood mononuclear cells (PBMCs) were sampled at day 0 and day 28 after MMR3. Measles-specific binding and neutralizing antibodies were quantified in sera by enzyme-linked immunosorbent assay and a microneutralization assay, respectively. PBMCs were stimulated with inactivated measles virus, and the release of cytokines/chemokines was assessed by a multiplex assay. Demographic variables of subjects were examined for potential correlations with immune outcomes.

RESULTS

Of the study participants, 95.69% and 100% were seropositive at day 0 and day 28, respectively. Antibody avidity significantly increased from 38.08% at day 0 to 42.8% at day 28 (P = .00026). Neutralizing antibodies were significantly enhanced, from 928.7 at day 0 to 1289.64 mIU/mL at day 28 (P = .0001). Meanwhile, cytokine/chemokine responses remained largely unchanged. Body mass index was significantly correlated with the levels of inflammatory cytokines/chemokines.

CONCLUSIONS

Measles-specific humoral immune responses, but not cellular responses, were enhanced after MMR3 receipt, extending current understanding of immune responses to MMR3 and supporting MMR3 administration to seronegative or high-risk individuals.

Evaluation and comparison of post-vaccination adverse effects among Janssen and Oxford-AstraZeneca vaccinated adult individuals in Debre Tabor Town: A cross- sectional survey in Northwest Ethiopia

COVID 19 vaccination has recently been launched globally to halt the pandemic. But COVID 19 vaccines have some adverse effects that raise concerns in the global community. This study aimed to evaluate and compare the adverse effects of Janssen and Oxford-AstraZeneca vaccinated adults. A community-based cross-sectional study was conducted from March 15 to 30, 2022 among 421 (211 Janssen and 210 Astra Zeneca vaccinated) adults recruited by a convenience sampling technique in Debre Tabor Town, Northwest Ethiopia. Data were collected via face-to-face interviews and by reviewing the immunization card. Chi-square test, independent t-test, and Mann-Whitney test were used to compare the adverse symptoms and related parameters between the two vaccines. A linear regression model was also used to identify predictors of the number of post-vaccination symptoms. The majority (75.8%) of participants reported at least one side effect after vaccination. Adverse symptoms had a significantly greater occurrence (p < .05) among recipients of the AstraZeneca vaccine (84.8%) than receivers of the Janssen vaccine (66.8%). The main adverse symptoms were injection site pain, fever, fatigue, arthralgia, and myalgia in both vaccines. Significant variations (p < .05) between the receipts of the two vaccines were shown in injection site pain, fever, and arthralgia. The total number of symptoms was significantly higher (p < .05) in participants with female sex, younger age, BMI <25 kg/m2, no prior COVID 19, and those who had received AstraZeneca vaccine. Thus, the authors advise that they should receive vaccines with no hesitation, while continuous tracking of vaccine safety is kept in place.

Distinct immunological and molecular signatures underpinning influenza vaccine responsiveness in the elderly

Seasonal influenza outbreaks, especially in high-risk groups such as the elderly, represent an important public health problem. Prevailing inadequate efficacy of seasonal vaccines is a crucial bottleneck. Understanding the immunological and molecular mechanisms underpinning differential influenza vaccine responsiveness is essential to improve vaccination strategies. Here we show comprehensive characterization of the immune response of randomly selected elderly participants (≥ 65 years), immunized with the adjuvanted influenza vaccine Fluad. In-depth analyses by serology, multi-parametric flow cytometry, multiplex and transcriptome analysis, coupled to bioinformatics and mathematical modelling, reveal distinguishing immunological and molecular features between responders and non-responders defined by vaccine-induced seroconversion. Non-responders are specifically characterized by multiple suppressive immune mechanisms. The generated comprehensive high dimensional dataset enables the identification of putative mechanisms and nodes responsible for vaccine non-responsiveness independently of confounding age-related effects, with the potential to facilitate development of tailored vaccination strategies for the elderly.

Body fat percentage is independently and inversely associated with serum antibody responses to SARS-CoV-2 mRNA vaccines

Vaccination is widely considered the most effective preventative strategy to protect against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. An individual's exercise habits, and physical fitness have been shown to impact the immune response following vaccination using traditional vaccine platforms, but their effects are not well characterized following administration of newer vaccination technology (mRNA vaccines). We investigated these effects on the magnitude of antibody responses following SARS-CoV-2 mRNA vaccination while accounting for known covariates (age, sex, time since vaccination, and the type of vaccine administered). Adults of varying fitness levels (18-65 years; N = 50) who had received either the Moderna or Pfizer SARS-CoV-2 mRNA vaccine between 2 weeks and 6 months prior, completed health history and physical activity questionnaires, had their blood drawn, body composition, cardiorespiratory fitness, and strength assessed. Multiple linear regressions assessed the effect of percent body fat, hand grip strength, cardiorespiratory fitness, and physical activity levels on the magnitude of receptor binding domain protein (RBD) and spike protein subunit 1 (S1) and 2 (S2) while accounting for known covariates. Body fat percentage was inversely associated with the magnitude of S1 (p = 0.006, β = - 366.56), RBD (p = 0.003, β = - 249.30), and S2 (p = 0.106, β = - 190.08) antibodies present in the serum following SARS-CoV-2 mRNA vaccination. Given the increasing number of infections, variants, and the known waning effects of vaccination, future mRNA vaccinations such as boosters are encouraged to sustain immunity; reducing excess body fat may improve the efficacy of these vaccinations.

SARS-CoV-2 and Influenza Vaccines in People with Excessive Body Mass-A Narrative Review

In the face of a growing number of overweight people and two widely known viral diseases, SARS-CoV-2 and influenza, it is crucial to be aware of the impact of excess body weight on immunisation against these diseases. The aim of this review is to show the effectiveness of SARS-CoV-2 and influenza vaccines in overweight and obese patients. Excessive adipose tissue releases cytokines and maintains local hypoxia, which causes persistent low-grade inflammation. These factors make excess body mass patients' immune systems weaker. Under such conditions, the humoral response becomes less efficient, leading to a weakened ability to fight against infection and an increased risk of developing lower antibody titres. Vaccines help to reduce morbidity both in normal-weight and excess body mass people, although most studies show that patients with higher BMI tend to lose the antibodies produced more quickly. It is shown that the most effective vaccines (in terms of preventing the infection and potential post-illness complications) are the BNT162b2 vaccine against SARS-CoV-2 and the inactivated influenza vaccine against influenza among both obese and non-obese subjects.

COVID-19, obesity, and immune response 2 years after the pandemic: A timeline of scientific advances

In the 2 years since the COVID-19 pandemic was officially declared, science has made considerable strides in understanding the disease's pathophysiology, pharmacological treatments, immune response, and vaccination, but there is still much room for further advances, especially in comprehending its relationship with obesity. Science has not yet described the mechanisms that explain how obesity is directly associated with a poor prognosis. This paper gathers all published studies over the past 2 years that have described immune response, obesity, and COVID-19, a historical and chronological record for researchers and the general public alike. In summary, these studies describe how the cytokine/adipokine levels and inflammatory markers, such as the C-reactive protein, are associated with a higher body mass index in COVID-19-positive patients, suggesting that the inflammatory background and immune dysregulation in individuals with obesity may be expressed in the results and that adiposity may influence the immune response. The timeline presented here is a compilation of the results of 2 years of scientific inquiry, describing how the science has progressed, the principal findings, and the challenges ahead regarding SARS-CoV-2, COVID-19, and emerging variants, especially in patients with obesity.

Myeloid-derived suppressor cells and vaccination against pathogens

It is widely accepted that the immune system includes molecular and cellular components that play a role in regulating and suppressing the effector immune response in almost any process in which the immune system is involved. Myeloid-derived suppressor cells (MDSCs) are described as a heterogeneous population of myeloid origin, immature state, with a strong capacity to suppress T cells and other immune populations. Although the initial characterization of these cells was strongly associated with pathological conditions such as cancer and then with chronic and acute infections, extensive evidence supports that MDSCs are also involved in physiological/non-pathological settings, including pregnancy, neonatal period, aging, and vaccination. Vaccination is one of the greatest public health achievements and has reduced mortality and morbidity caused by many pathogens. The primary goal of prophylactic vaccination is to induce protection against a potential pathogen by mimicking, at least in a part, the events that take place during its natural interaction with the host. This strategy allows the immune system to prepare humoral and cellular effector components to cope with the real infection. This approach has been successful in developing vaccines against many pathogens. However, when the infectious agents can evade and subvert the host immune system, inducing cells with regulatory/suppressive capacity, the development of vaccines may not be straightforward. Notably, there is a long list of complex pathogens that can expand MDSCs, for which a vaccine is still not available. Moreover, vaccination against numerous bacteria, viruses, parasites, and fungi has also been shown to cause MDSC expansion. Increases are not due to a particular adjuvant or immunization route; indeed, numerous adjuvants and immunization routes have been reported to cause an accumulation of this immunosuppressive population. Most of the reports describe that, according to their suppressive nature, MDSCs may limit vaccine efficacy. Taking into account the accumulated evidence supporting the involvement of MDSCs in vaccination, this review aims to compile the studies that highlight the role of MDSCs during the assessment of vaccines against pathogens.

An Immune Response to Heterologous ChAdOx1/BNT162b2 Vaccination against COVID-19: Evaluation of the anti-RBD Specific IgG Antibodies Titers and Interferon Gamma Release Assay (IGRA) Test Results

This study aimed to assess the magnitude of anti-SARS-CoV-2 immunoglobulin G (IgG) titers and Interferon-Gamma Release Assay (IGRA) test results following administration of booster BNT162b2 in 48 ChAd-primed participants (vaccination schedule: ChAd/ChAd/BNT). Whole blood samples were collected: first, before and second, 21 days after the booster dose. The IgG level was measured using chemiluminescent immunoassay; the intensity of the T-cell response—IFNγ concentration—was assessed using IGRA test. At 21 days after the booster, all subjects achieved reactive/positive anti-SARS-CoV-2 IgG, and IGRA test results showed a significant increase compared to the results before booster administration. We compared the results before and after the booster between participants with and without prior history of COVID-19. The IFNγ concentrations in both cohorts were higher in convalescents (both before booster and 21 days after). The IgG titers were subtly lower in COVID-19 convalescents than in naïve but without statistical significance. Data on cell-mediated immunity are scarce, especially with regard to the general population. A better understanding of the complexity of the immune response to SARS-CoV-2 could contribute to developing more effective vaccination strategies.

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.

Factors Influencing Longevity of Humoral Response to SARS-CoV-2 Vaccination in Patients with End Stage Kidney Disease Receiving Renal Replacement Therapy

COVID-19 has severely affected the population of patients with end stage renal disease. Current data have proved a two-dose vaccination schedule against SARS-CoV-2 to be effective among dialyzed patients. There are limited data on the longevity and modulating factors of humoral response after vaccination. We performed a prospective longitudinal cohort study to determine longevity of the humoral response after SARS-CoV-2 vaccine. The study included 191 adult patients on hemodialysis and peritoneal dialysis. All participants had been vaccinated with three doses, either with BNT162b2 (Pfizer-BioNTech) (n = 109) or mRNA-1273 (Moderna) (n = 82). Anti-spike protein receptor-binding domain antibodies (anti-S IgG) were assessed using SARS-CoV-2 (RBD) IgG ELISA EIA-6150 IVD assay at baseline, on the 21st day and 43rd day, before a booster dose and two weeks thereafter. We found that before vaccination, 37.7% of the cohort had anti-S IgG titres concordant with seroconversion. After two-dose vaccination, seroconversion occurred in 97% of patients. The booster dose evoked a ~12-fold increase in antibody level. Obesity increased more than two-fold the odds for a decrease in anti-S IgG. Previous COVID-19 infection enhanced longevity of the humoral response following vaccination. In patients with previous COVID-19 infection, the BNT162b2 vaccine was associated with a higher odds of anti-S IgG waning compared to the mRNA-1273 vaccine. In conclusion, we report that obesity predisposes patients to protective antibody waning, hybrid immunity enhances odds for higher anti-S IgG concentrations and vaccine efficacy may be influenced by previous SARS-CoV-2 infection. The results might provide a rationale for vaccination protocol design.

Inactivated vaccine injection and immunoglobulin G levels related to severe coronavirus disease 2019 (Delta) pneumonia in Xi’an, China: A single-centered, retrospective, observational study

The World Health Organization declared a public health emergency of international concern in January 2020. The Delta variant became the main epidemic strain on 11 May 2021. Vaccines were proven highly effective in controlling hospitalization and deaths associated with severe acute respiratory syndrome coronavirus 2 infections. Real data on vaccine efficacy against B.1.617.2 infection in the Chinese population were currently limited. This study aimed to evaluate the protective effect of inactivated vaccine injection and immunoglobulin (Ig) G levels in coronavirus disease 2019 (COVID-19) severity. This retrospective study included patients with COVID-19 in Xi’an Chest Hospital from December 2021 to January 2022. The protective effect of inactivated vaccine injection and IgG levels on COVID-19 severity was analyzed using multiple logistic regressions. A total of 580 patients were included in the study, of whom 158 (27.24%) were mild, 412 (71.03%) were moderate, 5 (0.9%) were severe, and 5 (0.86%) were critical. Severe case (including severe and critical) rates were 1.72% (10/580). Compared with the unvaccinated group, the vac+IgG− group had a 0.21 (0.02–2.05)-fold risk of suffering from severe cases, and the vac+IgG+ group had a 0.05 (0–0.63)-fold risk of suffering from severe cases. Of the 10 severe cases, 8 were older than 60 years, 8 were men, 8 had underlying diseases, 6 were in the unvaccinated group, and 2 were in the vac+IgG− group. Vaccination and sufficient IgG antibody production can protect patients with COVID-19 from severe cases. Booster vaccine injection can produce a stronger immune response and protection.

Obesity Dysregulates the Immune Response to Influenza Infection and Vaccination Through Metabolic and Inflammatory Mechanisms

The COVID-19 pandemic demonstrates that obesity alone, independent of comorbidities, is a significant risk factor for severe outcomes from infection. This susceptibility mirrors a similar pattern with influenza infection; that is, obesity is a unique risk factor for increased morbidity and mortality. Therefore, it is critical to understand how obesity contributes to a reduced ability to respond to respiratory viral infections. Herein, we discuss human and animal studies with influenza infection and vaccination that show obesity impairs immunity. We cover several key mechanisms for the dysfunction. These mechanisms include systemic and cellular level changes that dysregulate immune cell metabolism and function in addition to how obesity promotes deficiencies in metabolites that control the resolution of inflammation and infection. Finally, we discuss major gaps in knowledge, particularly as they pertain to diet and mechanisms, which will drive future efforts to improve outcomes in response to respiratory viral infections in an increasingly obese population.

Insights into induction of the immune response by the hepatitis B vaccine

After more than four decades of hepatitis B virus (HBV) vaccine implementation, its safety and efficacy in preventing HBV infection have been proven and several milestones have been achieved. Most countries have included HBV immunization schedules in their health policies and progress has been made regarding universalization of the first HBV vaccine dose at birth. All of these actions have significantly contributed to reducing both the incidence of HBV infection and its related complications. However, there are still many drawbacks to overcome. The main concerns are the deficient coverage rate of the dose at birth and the large adult population that has not been reached timely by universal immunization. Additionally, the current most widely used second-generation vaccines do not induce protective immunity in 5% to 10% of the population, particularly in people over 40-years-old, obese (body mass index > 25 kg/m²), heavy smokers, and patients undergoing dialysis or infection with human immunodeficiency virus. Recently developed and approved novel vaccine formulations using more potent adjuvants or multiple antigens have shown better performance, particularly in difficult settings. These advances re-launch the expectations of achieving the World Health Organization’s objective of completing hepatitis control by 2030.

Associations of BMI with COVID-19 vaccine uptake, vaccine effectiveness, and risk of severe COVID-19 outcomes after vaccination in England: a population-based cohort study

BACKGROUND

A high BMI has been associated with a reduced immune response to vaccination against influenza. We aimed to investigate the association between BMI and COVID-19 vaccine uptake, vaccine effectiveness, and risk of severe COVID-19 outcomes after vaccination by using a large, representative population-based cohort from England.

METHODS

In this population-based cohort study, we used the QResearch database of general practice records and included patients aged 18 years or older who were registered at a practice that was part of the database in England between Dec 8, 2020 (date of the first vaccination in the UK), to Nov 17, 2021, with available data on BMI. Uptake was calculated as the proportion of people with zero, one, two, or three doses of the vaccine across BMI categories. Effectiveness was assessed through a nested matched case-control design to estimate odds ratios (OR) for severe COVID-19 outcomes (ie, admission to hospital or death) in people who had been vaccinated versus those who had not, considering vaccine dose and time periods since vaccination. Vaccine effectiveness against infection with SARS-CoV-2 was also investigated. Multivariable Cox proportional hazard models estimated the risk of severe COVID-19 outcomes associated with BMI (reference BMI 23 kg/m2) after vaccination.

FINDINGS

Among 9 171 524 participants (mean age 52 [SD 19] years; BMI 26·7 [5·6] kg/m2), 566 461 tested positive for SARS-CoV-2 during follow-up, of whom 32 808 were admitted to hospital and 14 389 died. Of the total study sample, 19·2% (1 758 689) were unvaccinated, 3·1% (287 246) had one vaccine dose, 52·6% (4 828 327) had two doses, and 25·0% (2 297 262) had three doses. In people aged 40 years and older, uptake of two or three vaccine doses was more than 80% among people with overweight or obesity, which was slightly lower in people with underweight (70-83%). Although significant heterogeneity was found across BMI groups, protection against severe COVID-19 disease (comparing people who were vaccinated vs those who were not) was high after 14 days or more from the second dose for hospital admission (underweight: OR 0·51 [95% CI 0·41-0·63]; healthy weight: 0·34 [0·32-0·36]; overweight: 0·32 [0·30-0·34]; and obesity: 0·32 [0·30-0·34]) and death (underweight: 0·60 [0·36-0·98]; healthy weight: 0·39 [0·33-0·47]; overweight: 0·30 [0·25-0·35]; and obesity: 0·26 [0·22-0·30]). In the vaccinated cohort, there were significant linear associations between BMI and COVID-19 hospitalisation and death after the first dose, and J-shaped associations after the second dose.

INTERPRETATION

Using BMI categories, there is evidence of protection against severe COVID-19 in people with overweight or obesity who have been vaccinated, which was of a similar magnitude to that of people of healthy weight. Vaccine effectiveness was slightly lower in people with underweight, in whom vaccine uptake was also the lowest for all ages. In the vaccinated cohort, there were increased risks of severe COVID-19 outcomes for people with underweight or obesity compared with the vaccinated population with a healthy weight. These results suggest the need for targeted efforts to increase uptake in people with low BMI (<18·5 kg/m2), in whom uptake is lower and vaccine effectiveness seems to be reduced. Strategies to achieve and maintain a healthy weight should be prioritised at the population level, which could help reduce the burden of COVID-19 disease.

FUNDING

UK Research and Innovation and National Institute for Health Research Oxford Biomedical Research Centre.

Body Mass Index and Antibody Persistence after Measles, Mumps, Rubella and Hepatitis B Vaccinations

Overweight and obesity may cause a reduced response to vaccination. The purpose of the present research was to study the relationship between current body mass index (BMI) and antibody persistence after vaccination against measles, mumps, and rubella (MMR) and hepatitis B virus (HBV) given during childhood, as per the current vaccination schedule. The study was conducted on 2185 students at the School of Medicine, University of Padua, Italy. The mean age of the participants was 20.3 years. After adjusting for sex, age at first dose of vaccine administered, age at last dose, and age at study enrollment, no significant association was found between lack of serologic protection and BMI for either the HBV vaccine or each component of the MMR vaccine. For the first time, the absence of this relationship was demonstrated for the MMR vaccine. Given the evidence currently available, further research on BMI and vaccines in general remains desirable.

Association between Recent Usage of Antibiotics and Immunogenicity within Six Months after COVID-19 Vaccination

Background: Gut microbiota can be associated with COVID-19 vaccine immunogenicity. We investigated whether recent antibiotic use influences BNT162b2 vaccine immunogenicity. Methods: BNT162b2 recipients from three centers were prospectively recruited. Outcomes of interest were seroconversion of neutralising antibody (NAb) at day 21, 56 and 180 after first dose. We calculated the adjusted odds ratio (aOR) of seroconversion with antibiotic usage (defined as ever use of any antibiotics within six months before first dose of vaccine) by adjusting for covariates including age, sex, smoking, alcohol, and comorbidities. Results: Of 316 BNT162b2 recipients (100 [31.6%] male; median age: 50.1 [IQR: 40.0–57.0] years) recruited, 29 (9.2%) were antibiotic users. There was a trend of lower seroconversion rates in antibiotic users than non-users at day 21 (82.8% vs. 91.3%; p = 0.14) and day 56 (96.6% vs. 99.3%; p = 0.15), but not at day 180 (93.3% vs. 94.1%). A multivariate analysis showed that recent antibiotic usage was associated with a lower seroconversion rate at day 21 (aOR 0.26;95% CI: 0.08–0.96). Other factors associated with a lower seroconversion rate after first dose of the BNT162b2 vaccine included age ≥ 60 years (aOR: 0.34;95% CI: 0.13–0.95) and male sex (aOR: 0.14, 95% CI: 0.05–0.34). There were no significant factors associated with seroconversion after two doses of BNT16b2, including antibiotic use (aOR: 0.03;95% CI: 0.001–1.15). Conclusions: Recent antibiotic use may be associated with a lower seroconversion rate at day 21 (but not day 56 or 180) among BNT162b2 recipients. Further long-term follow-up data with a larger sample size is needed to reach a definite conclusion on how antibiotics influence immunogenicity and the durability of the vaccine response.

Changes in the Blood Viscosity in Patients With SARS-CoV-2 Infection

Coronavirus disease 2019 (COVID-19) is caused by a novel virus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2-induced hyperinflammation together with alteration of plasma proteins, erythrocyte deformability, and platelet activation, may affect blood viscosity. Thus, this review aimed to study the link between SARS-CoV-2 infection and alteration of blood viscosity in COVID-19 patients. In order to review findings related to hyperviscosity in COVID-19, we suggested a protocol for narrative review of related published COVID-19 articles. Hyperviscosity syndrome is developed in different hematological disorders including multiple myeloma, sickle cell anemia, Waldenstorm macroglobulinemia, polycythemia, and leukemia. In COVID-19, SARS-CoV-2 may affect erythrocyte morphology via binding of membrane cluster of differentiation 147 (CD147) receptors, and B and 3 proteins on the erythrocyte membrane. Variations in erythrocyte fragility and deformability with endothelial dysfunction and oxidative stress in SARS-CoV-2 infection may cause hyperviscosity syndrome in COVID-19. Of interest, hyperviscosity syndrome in COVID-19 may cause poor tissue perfusion, peripheral vascular resistance, and thrombosis. Most of the COVID-19 patients with a blood viscosity more than 3.5 cp may develop coagulation disorders. Of interest, hyperviscosity syndrome is more commonly developed in vaccine recipients who had formerly received the COVID-19 vaccine due to higher underlying immunoglobulin concentrations, and only infrequently in those who have not received the COVID-19 vaccine. Taken together, these observations are untimely too early to give a final connotation between COVID-19 vaccination and the risk for development of hyperviscosity syndrome, consequently prospective and retrospective studies are necessary in this regard.

N6-Acetyl-L-Lysine and p-Cresol as Key Metabolites in the Pathogenesis of COVID-19 in Obese Patients

Despite the growing number of the vaccinated population, COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global health burden. Obesity, a metabolic syndrome affecting one-third of the population, has proven to be a major risk factor for COVID-19 severe complications. Several studies have identified metabolic signatures and disrupted metabolic pathways associated with COVID-19, however there are no reports evaluating the role of obesity in the COVID-19 metabolic regulation. In this study we highlight the involvement of obesity metabolically in affecting SARS-CoV-2 infection and the consequent health complications, mainly cardiovascular disease. We measured one hundred and forty-four (144) metabolites using ultra high-performance liquid chromatography-quadrupole time of flight mass spectrometry (UHPLC-QTOF-MS) to identify metabolic changes in response to SARS-CoV-2 infection, in lean and obese COVID-19 positive (n=82) and COVID-19 negative (n=24) patients. The identified metabolites are found to be mainly correlating with glucose, energy and steroid metabolisms. Further data analysis indicated twelve (12) significantly yet differentially abundant metabolites associated with viral infection and health complications, in COVID-19 obese patients. Two of the detected metabolites, n6-acetyl-l-lysine and p-cresol, are detected only among the COVID-19 cohort, exhibiting significantly higher levels in COVID-19 obese patients when compared to COVID-19 lean patients. These metabolites have important roles in viral entry and could explain the increased susceptibility of obese patients. On the same note, a set of six metabolites associated with antiviral and anti-inflammatory functions displayed significantly lower abundance in COVID-19 obese patients. In conclusion, this report highlights the plasma metabolome of COVID-19 obese patients as a metabolic feature and signature to help improve clinical outcomes. We propose n6-acetyl-l-lysine and p-cresol as potential metabolic markers which warrant further investigations to better understand their involvement in different metabolic pathways in COVID-19.

Obesity: A comorbidity-acquired immunodeficiency syndrome (CAIDS)

Accumulating data emphasize a strong link between obesity and the severity of coronavirus disease-2019 (COVID-19), including mortality. Obesity interferes with several components of the immune system including lymphoid tissue's integrity, leukocytes' development and function, complement system's activation, and the coordination of innate and adaptive immune responses. Overall, obesity results in a less efficient immune response to infectious agents. Severe acute respiratory syndrome coronavirus 2 exploits this weakened immune system in people with obesity to precipitate COVID-19, and in some cases death. It is therefore the author's recommendation that obesity should be viewed as another form of acquired immunodeficiency syndrome and be treated with the appropriate seriousness. Unlike the previously described acquired immunodeficiency syndrome (AIDS) that is caused by the Human Immunodeficiency Virus (HIV), obesity is a comorbidity-acquired immunodeficiency syndrome. People with AIDS do not die from HIV, but may die from opportunistic pathogens such as Mycobacterium tuberculosis. However, AIDS is ascribed its due importance in the course of deterioration of the patient. Similarly, obesity should be acknowledged further as a risk factor for mortality from COVID-19. Obesity is a modifiable condition and even in people with a strong genetic predisposition, lifestyle modifications can reverse obesity, and even moderate weight loss can improve the inflammatory milieu. Strong public health actions are warranted to promote lifestyle measures to reduce the burden from overweight and obesity that currently affect more than one-third of the global population, with projections alarming this may reach 55-80% within the next thirty years.

Oxidative stress and endogenous DNA damage in blood mononuclear cells may predict anti-SARS-CoV-2 antibody titers after vaccination in older adults

Immune senescence in the elderly has been associated with chronic oxidative stress and DNA damage accumulation. Herein we tested the hypothesis that increased endogenous DNA damage and oxidative stress in peripheral blood mononuclear cells of older adults associate with diminished humoral immune response to SARS-CoV-2 vaccination. Increased oxidative stress and DNA double-strand breaks (DSBs) were detected in 9 non-immunocompromised individuals aged 80-96 years compared to 11 adults aged 27-44 years, before, as well as on days 1 and 14 after the first dose, and on day 14 after the second dose of the BNT162B2-mRNA vaccine (all p < 0.05). SARS-CoV-2 vaccination induced a resolvable increase in oxidative stress and DNA damage, but individual DSB-repair efficiency was unaffected by vaccination irrespective of age, confirming vaccination safety. Individual titers of anti-Spike-Receptor Binding Domain (S-RBD)-IgG antibodies, and the neutralizing capacity of circulating anti-SARS-CoV-2 antibodies, measured on day 14 after the second dose in all participants, correlated inversely with the corresponding pre-vaccination endogenous oxidative stress and DSB levels (all p < 0.05). In particular, a strong inverse correlation of individual pre-vaccination DSB levels with both the respective anti-S-RBD-IgG antibodies titers (r = -0.867) and neutralizing capacity of circulating anti-SARS-CoV-2 antibodies (r = -0.983) among the 9 older adults was evident. These findings suggest that humoral responses to SARS-CoV-2 vaccination may be weaker when immune cells are under oxidative and/or genomic stress. Whether such measurements may serve as biomarkers of vaccine efficacy in older adults warrants further studies.

Hyperviscosity syndrome in COVID-19 and related vaccines: exploring of uncertainties

Hyperviscosity syndrome (HVS) recently emerged as a complication of coronavirus disease 2019 (COVID-19) and COVID-19 vaccines. Therefore, the objectives of this critical review are to establish the association between COVID-19 and COVID-19 vaccines with the development of HVS. HVS may develop in various viral infections due to impairment of humoral and cellular immunity with elevation of immunoglobulins. COVID-19 can increase blood viscosity (BV) through modulation of fibrinogen, albumin, lipoproteins, and red blood cell (RBC) indices. HVS can cause cardiovascular and neurological complications in COVID-19 like myocardial infarction (MI) and stroke. HVS with or without abnormal RBCs function in COVID-19 participates in the reduction of tissue oxygenation with the development of cardio-metabolic complications and long COVID-19. Besides, HVS may develop in vaccine recipients with previous COVID-19 due to higher underlying Ig concentrations and rarely without previous COVID-19. Similarly, patients with metabolic syndrome are at the highest risk for propagation of HVS after COVID-19 vaccination. In conclusion, COVID-19 and related vaccines are linked with the development of HVS, mainly in patients with previous COVID-19 and underlying metabolic derangements. The possible mechanism of HVS in COVID-19 and related vaccines is increasing levels of fibrinogen and immunoglobulins. However, dehydration, oxidative stress, and inflammatory reactions are regarded as additional contributing factors in the pathogenesis of HVS in COVID-19. However, this critical review cannot determine the final causal relationship between COVID-19 and related vaccines and the development of HVS. Prospective and retrospective studies are warranted in this field.

Factors associated with anti-SARS-CoV-2 antibody titres 3 months post-vaccination with the second dose of BNT162b2 vaccine: a longitudinal observational cohort study in western Greece

OBJECTIVES

Vaccination against SARS-CoV-2 has been extensively deployed during COVID-19 pandemic. One efficient method to evaluate response to vaccination is the assessment of humoral immunity by measuring SARS-CoV-2 antibody titres. We investigated the association between anthropometric parameters (age, body mass index), smoking, diabetes, statin use, hypertension, levels of 25(OH)D and dehydroepiandrosterone sulfate (DHEAS), and SARS-CoV-2 antibody titres after vaccination.

DESIGN

In this longitudinal observational cohort study, 712 subjects were tested for SARS-CoV-2 antibodies 3 months after the second dose of BNT162b2 vaccine. Multiple linear regression analysis was performed to identify which factors are associated with the antibody titres.

SETTING

Healthcare units of western Greece (University Hospital of Patras and "St Andrews" State General Hospital of Patras).

PARTICIPANTS

All adults receiving their second dose of BNT162b2 vaccine at the participating healthcare units were eligible to participate in the study. Exclusion criteria were SARS-CoV-2 infection or positive SARS-CoV-2 antibody titre at baseline. Patients who did not provide all necessary information were excluded from our analyses.

RESULTS

We found age to be negatively associated with antibody titre (-0.005; 95% CI -0.009 to -0.001, p=0.0073), as was male gender (-0.11; 95% CI -0.1738 to -0.04617, p=0.0008). The interaction of age and gender was significant (-0.01090; 95% CI -0.01631 to -0.005490, p<0.0001), highlighting that the rate of decline in antibody titre with increasing age tends to be higher in men rather than in women. No linear trend was found between DHEAS levels and antibody titres when the lower quartile of DHEAS levels was used as reference. Tobacco use was associated with low antibody titre (-0.1097; 95% CI -0.174 to -0.046, p=0.0008) but overweight, obese or underweight subjects had similar antibody responses to normal-weight individuals. Although subjects with diabetes and hypertension had numerically lower antibody titres, this association was not statistically significant. Vitamin D levels showed no clear relationships with antibody titres.

CONCLUSIONS

Age, male gender and tobacco use are negatively associated with antibody titres after COVID-19 vaccination, but our data showed no clear correlation with vitamin D levels.

TRIAL REGISTRATION NUMBER

NCT04954651; Results.