Association between obesity and vulnerability and serologic response to influenza vaccination in older adults

Neutralizing Antibodies against SARS-CoV-2: Importance of Comorbidities in Health Personnel against Reinfections

One of the priority lines of action to contain the SARS-CoV-2 pandemic was vaccination programs for healthcare workers. However, with the emergence of highly contagious strains, such as the Omicron variant, it was necessary to know the serological status of health personnel to make decisions for the application of reinforcements. The aim of this work was to determine the seroprevalence against SARS-CoV-2 in healthcare workers in a Mexican hospital after six months of the administration of the Pfizer-BioNTech vaccine (two doses, 4 weeks apart) and to investigate the association between comorbidities, response to the vaccine, and reinfections. Neutralizing antibodies against SARS-CoV-2 were determined using ELISA assays for 262 employees of Hospital Juárez de México with and without a history of COVID-19. A beta regression analysis was performed to study the associated comorbidities and their relationship with the levels of antibodies against SARS-CoV-2. Finally, an epidemiological follow-up was carried out to detect reinfections in this population. A significant difference in SARS-CoV-2 seroprevalence was observed in workers with a history of COVID-19 prior to vaccination compared to those without a history of the disease (MD: 0.961 and SD: 0.049; <0.001). Beta regression showed that workers with a history of COVID-19 have greater protection compared to those without a history of the infection. Neutralizing antibodies were found to be decreased in alcoholic and diabetic subjects (80.1%). Notably, eight cases of Omicron reinfections were identified, and gender and obesity were associated with the presence of reinfections (6.41 OR; 95% BCa CI: 1.15, 105.0). The response to the vaccine was influenced by the history of SARS-CoV-2 infection and associated comorbidities. The above highlights the importance of prioritizing this segment of the population for reinforcements in periods of less than one year to guarantee their effectiveness against new variants.

Impact of Obesity and Diabetes in Pregnant Women on Their Immunity and Vaccination

Pregnant women with obesity and diabetes are at increased risk of developing infections and other complications during pregnancy. Several mechanisms are involved in the immunological mechanisms that contribute to reduced immunity in these populations. Both obesity and diabetes are associated with chronic low-grade inflammation that can lead to an overactive immune response. Pregnant women with obesity and diabetes often have an increase in pro-inflammatory cytokines and adipokines, such as TNF-α, IL-6, IL-1β, leptin, and resistin, which are involved in the inflammatory response. Insulin resistance can also affect the functioning of immune cells. Furthermore, both conditions alter the composition of the gut microbiome, which produces a variety of biomolecules, including short-chain fatty acids, lipopolysaccharides, and other metabolites. These substances may contribute to immune dysfunction. In addition to increasing the risk of infections, obesity and diabetes can also affect the efficacy of vaccinations in pregnant women. Pregnant women with obesity and diabetes are at increased risk of developing severe illness and complications from COVID-19, but COVID-19 vaccination may help protect them and their fetuses from infection and its associated risks. Since both obesity and diabetes classify a pregnancy as high risk, it is important to elucidate the impact of these diseases on immunity and vaccination during pregnancy. Research examining the efficacy of the COVID-19 vaccine in a high-risk pregnant population should be of particular value to obstetricians whose patients are hesitant to vaccinate during pregnancy. Further research is needed to better understand these mechanisms and to develop effective interventions to improve immune function in these populations.

Factors associated with humoral immune response in older adults who received egg-free influenza vaccine

BACKGROUND

Immune responses to influenza vaccination tend to be lower among older, frequently vaccinated adults. Use of egg-free influenza vaccines is increasing, but limited data exist on factors associated with their immunogenicity in older adults.

METHODS

Community-dwelling older adults ≥ 56 years of age were enrolled in a prospective, observational study of immunogenicity of 2018-2019 influenza vaccine. Hemagglutination inhibition (HAI) antibody titers were measured pre-vaccination (Day 0) and four weeks after vaccination (Day 28) to calculate geometric mean titers, seropositivity (HAI titers ≥ 1:40), seroconversion (fourfold rise in HAI titer with post-vaccination titer ≥ 1:40) and geometric mean fold rise (GMFR). Linear regression models assessed the association of predictors of GMFR for each vaccine antigen.

RESULTS

Among 91 participants who received egg-free influenza vaccines, 84 (92.3 %) received quadrivalent recombinant influenza vaccine (RIV4, Flublok, Sanofi Pasteur), and 7 (7.7 %) received quadrivalent cell culture-based influenza vaccine (ccIIV4, Flucelvax, Seqirus). Pre-vaccination seropositivity was 52.8 % for A(H1N1), 94.5 % for A(H3N2), 61.5 % for B/Colorado and 48.4 % for B/Phuket. Seroconversion by antigen ranged from 16.5 % for A(H1N1) and B/Colorado to 37.4 % for A(H3N2); 40 participants failed to seroconvert to any antigen. Factors independently associated with higher GMFR in multivariable models included lower pre-vaccination HAI antibody titer for A(H1N1), B/Colorado and B/Phuket, and younger age for A(H1N1).

CONCLUSION

Overall pre-vaccination seropositivity was high and just over half of the cohort seroconverted to ≥ 1 vaccine antigen. Antibody responses were highest among participants with lower pre-vaccination titers. Among older adults with high pre-existing antibody titers, approaches to improve immune responses are needed.

Immunogenicity of an mRNA-Based COVID-19 Vaccine among Adolescents with Obesity or Liver Transplants

There are limited data regarding the immunogenicity of mRNA-based SARS-CoV-2 vaccine BNT162b2 among immunosuppressed or obese adolescents. We evaluated the humoral immune response in adolescents with obesity and adolescent liver transplant recipients (LTRs) after receiving two BNT162b2 doses. Sixty-eight participants (44 males; mean age 14.9 ± 1.7 years), comprising 12 LTRs, 24 obese, and 32 healthy adolescents, were enrolled. Immunogenicity was evaluated by anti-SARS-CoV-2 spike protein immunoassay and surrogate viral neutralization tests (sVNT) against the Delta and Omicron (BA.1) variants. At 27.1 ± 3.2 days after the second dose, the antibody levels were 1476.6 ± 1185.4, 2999.4 ± 1725.9, and 4960.5 ± 2644.1 IU/mL in the LTRs, obese adolescents, and controls, respectively (p < 0.001). Among obese individuals, liver stiffness <5.5 kPa was associated with higher antibody levels. The %inhibition of sVNT was significantly lower for the Omicron than that for the Delta variant. Injection site pain was the most common local adverse event. Nine participants (three obese and six controls) developed COVID-19 at 49 ± 11 days after the second vaccination; four were treated with favipiravir. All infections were mild, and the patients recovered without any consequences. Our study supports the need for the booster regimen in groups with an inferior immunogenic response, including LTRs and obese individuals.

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 Outcomes in Minority Ethnic Groups: Do Obesity and Metabolic Risk Play a Role?

PURPOSE OF REVIEW

Globally, minority ethnic groups have been at higher risk of COVID-19 mortality and morbidity than majority populations. This review outlines factors that may interact to create these inequalities and explores the hypothesis that differing levels of cardio-metabolic risk, according to ethnic group, play a role.

RECENT FINDINGS

Two UK Biobank studies have reported that the body mass index is more strongly associated with an increased risk of COVID-19 infection and mortality in minority ethnic populations than in White populations. A study of UK patients found that the strongest association between obesity and adverse COVID-19 outcomes was in people of Black ethnicity. Differences in the prevalence of obesity and its metabolic sequelae have been shown to partly mediate ethnic inequalities in COVID-19 outcomes, although not always consistently. It is possible that ethnic differences in the consequences of obesity may explain some of the remaining disparity in COVID-19 risk.

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.

Pandemic Preparedness: Maintaining Adequate Immune Fitness by Attaining a Normal, Healthy Body Weight

In addition to developing effective medicines and vaccines, pandemic preparedness also comprises general health-related, behavioral, and psychological aspects related to being more resistant in the case of future pandemics. In the context of the 2019 coronavirus (COVID-19) pandemic, recent research revealed that reduced perceived immune fitness was the best predictor of reporting more frequent and more severe COVID-19 symptoms. Up until now (June 2022), during the COVID-19 pandemic, the majority of patients who have been hospitalized were characterized as being overweight. It is therefore essential to further evaluate the relationship between body mass index (BMI) and immune fitness. This was performed by analyzing pooled data from previously published studies, conducted among N = 8586 Dutch adults. It was hypothesized that attaining a normal, healthy body weight is associated with optimal perceived immune fitness. The analysis revealed that a deviation from normal weight (i.e., having a BMI outside the range of 18.5 to 24.9 kg/m²) was associated with significantly reduced perceived immune fitness, as assessed with the immune status questionnaire and a single item perceived immune fitness scale. The effects were significant for both underweight and overweight groups and most pronounced for the obese groups. The results suggest that attaining a normal, healthy body weight might significantly contribute to maintaining adequate perceived immune fitness. Therefore, attaining a normal body weight might be an essential component of pandemic preparedness and should be supported by creating awareness and promoting the importance of regular exercise and the consumption of healthy food.

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.

Evaluation of determinants of the serological response to the quadrivalent split-inactivated influenza vaccine

The seasonal influenza vaccine is only effective in half of the vaccinated population. To identify determinants of vaccine efficacy, we used data from > 1,300 vaccination events to predict the response to vaccination measured as seroconversion as well as hemagglutination inhibition (HAI) titer levels one year after. We evaluated the predictive capabilities of age, body mass index (BMI), sex, race, comorbidities, vaccination history, and baseline HAI titers, as well as vaccination month and vaccine dose in multiple linear regression models. The models predicted the categorical response for > 75% of the cases in all subsets with one exception. Prior vaccination, baseline titer level, and age were the major determinants of seroconversion, all of which had negative effects. Further, we identified a gender effect in older participants and an effect of vaccination month. BMI had a surprisingly small effect, likely due to its correlation with age. Comorbidities, vaccine dose, and race had negligible effects. Our models can generate a new seroconversion score that is corrected for the impact of these factors which can facilitate future biomarker identification.

A Prospective Study Investigating the Impact of Obesity on the Immune Response to the Quadrivalent Influenza Vaccine in Children and Adolescents

Obesity can increase the severity of influenza infection. Data are limited regarding immune responses to influenza vaccination in obese children. We aimed to investigate the impact of obesity on quadrivalent influenza vaccine responses in children. Children with obesity (body mass index (BMI) ≥ 95th percentile for age and gender) and children without obesity (BMI < 95th percentile) were enrolled in the study. Blood samples were collected before, 1, and 6 months after influenza vaccination, to measure antibody responses by haemagglutination inhibition (HI) assay. Vaccine immunogenicity outcomes were compared between children with and without obesity. Forty-four children (mean age 13.3 ± 2.1 years, 18 males and 14 with obesity) completed the 6-month study. More than 90% of the participants with and without obesity had seroprotective antibody titres (HI ≥ 40) at both 1 and 6 months following vaccination for each of the four influenza strains (A/H3N2, A/H1N1, B/(Victoria) and B/(Yamagata)). Influenza-specific geometric mean titres at baseline, 1, and 6 months post-vaccination were similar between children with and without obesity for all influenza vaccine strains. Children with and without obesity have robust, sustained antibody responses over 6 months to the quadrivalent influenza vaccine.

Obesity is associated with severe disease and mortality in patients with coronavirus disease 2019 (COVID-19): a meta-analysis

Background

The coronavirus disease 2019 (COVID-19) pandemic has led to global research to predict those who are at greatest risk of developing severe disease and mortality. The aim of this meta-analysis was to determine the associations between obesity and the severity of and mortality due to COVID-19.

Methods

We searched the PubMed, EMBASE, Cochrane Library and Web of Science databases for studies evaluating the associations of obesity with COVID-19.

Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random- or fixed-effects models. Meta-regression analyses were conducted to estimate regression coefficients.

Results

Forty-six studies involving 625,153 patients were included. Compared with nonobese patients, obese patients had a significantly increased risk of infection.

(OR 2.73, 95% CI 1.53–4.87; I² = 96.8%), hospitalization (OR 1.72, 95% CI 1.55–1.92; I² = 47.4%), clinically severe disease (OR 3.81, 95% CI 1.97–7.35; I² = 57.4%), mechanical ventilation (OR 1.66, 95% CI 1.42–1.94; I² = 41.3%), intensive care unit (ICU) admission (OR 2.25, 95% CI 1.55–3.27; I² = 71.5%), and mortality (OR 1.61, 95% CI 1.29–2.01; I² = 83.1%).

Conclusion

Patients with obesity may have a greater risk of infection, hospitalization, clinically severe disease, mechanical ventilation, ICU admission, and mortality due to COVID-19. Therefore, it is important to increase awareness of these associations with obesity in COVID-19 patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11546-6.

Body mass index and vaccine responses following influenza vaccination during pregnancy

BACKGROUND AND AIMS

Influenza vaccination is recommended by the World Health Organisation for pregnant women, offering the dual benefit of protecting pregnant women and their newborn infants against influenza infection. Various factors can influence vaccine immunogenicity, with obesity being one factor implicated in varied responses. This study aimed to investigate the impact of body mass index (BMI) on vaccine responses following influenza vaccination during pregnancy.

METHODS

Pregnant women attending the Women's and Children's Hospital in South Australia during 2014-2016 were invited to participate. Participant's clinical and demographic factors were recorded prior to administration of licensed seasonal influenza vaccination. Blood samples were collected before and one month post-vaccination to measure antibody responses by haemagglutination inhibition (HI) assay. Seroprotection was defined as a post-vaccination HI titre ≥ 1:40. Regression models assessed associations with failure to achieve seroprotective antibodies to H1, H3, and B influenza strains.

RESULTS

A total of 96 women were enrolled in the study at a median gestation of 22 weeks with a BMI range of 18-49 kg/m². Paired sera samples were available for 90/96 (94%). Most pregnant women (72/90, 80%) demonstrated seroprotective antibody titres to all three influenza vaccine antigens (A(H1N1)pdm09, A(H3N2), B/Yamagata) following vaccination. Compared with women with BMI < 30 kg/m², those with high BMI were less likely to fail to achieve seroprotective antibodies, however this was not statistically significant (RR 0.42, 95% CI 0.11-1.68; p = 0.22). A greater proportion of women vaccinated during their second (47/53, 93%) or third trimester (18/25, 72%) demonstrated seroprotection to all three vaccine antigens following vaccination compared with women vaccinated during their first trimester (7/12, 58%).

CONCLUSION

High BMI did not impair seroprotection levels following influenza vaccination in pregnant women. Gestation at vaccination may be an important consideration for optimising vaccine protection for pregnant women and their newborns. Further assessment of first trimester influenza vaccine responses is warranted.

Potential Impact of Diabetes and Obesity on Alveolar Type 2 (AT2)-Lipofibroblast (LIF) Interactions After COVID-19 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new emerging respiratory virus, caused evolving pneumonia outbreak around the world. In SARS-Cov-2 infected patients, diabetes mellitus (DM) and obesity are two metabolic diseases associated with higher severity of SARS-CoV-2 related complications, characterized by acute lung injury requiring assisted ventilation as well as fibrosis development in surviving patients. Different factors are potentially responsible for this exacerbated response to SARS-CoV-2 infection. In patients with DM, base-line increase in inflammation and oxidative stress represent preexisting risk factors for virus-induced damages. Such factors are also likely to be found in obese patients. In addition, it has been proposed that massive injury to the alveolar epithelial type 2 (AT2) cells, which express the SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2), leads to the activation of their stromal niches represented by the Lipofibroblasts (LIF). LIF are instrumental in maintaining the self-renewal of AT2 stem cells. LIF have been proposed to transdifferentiate into Myofibroblast (MYF) following injury to AT2 cells, thereby contributing to fibrosis. We hypothesized that LIF's activity could be impacted by DM or obesity in an age- and gender-dependent manner, rendering them more prone to transition toward the profibrotic MYF status in the context of severe COVID-19 pneumonia. Understanding the cumulative effects of DM and/or obesity in the context of SARS-CoV-2 infection at the cellular level will be crucial for efficient therapeutic solutions.

Obesity and its impact on COVID-19

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic has proven a challenge to healthcare systems since its first appearance in late 2019. The global spread and devastating effects of coronavirus disease 2019 (COVID-19) on patients have resulted in countless studies on risk factors and disease progression. Overweight and obesity emerged as one of the major risk factors for developing severe COVID-19. Here we review the biology of coronavirus infections in relation to obesity. In particular, we review literature about the impact of adiposity-related systemic inflammation on the COVID-19 disease severity, involving cytokine, chemokine, leptin, and growth hormone signaling, and we discuss the involvement of hyperactivation of the renin-angiotensin-aldosterone system (RAAS). Due to the sheer number of publications on COVID-19, we cannot be completed, and therefore, we apologize for all the publications that we do not cite.

Immunogenicity of Split Inactivated Quadrivalent Influenza Vaccine in Adults with Obesity in the 2017/2018 Season

BACKGROUND Obesity is associated with susceptibility to severe influenza infection and several disturbances of the immune response to the influenza vaccine. However, the effect of obesity on the immunogenicity of the influenza vaccine is not fully understood. Our objective here was to assess the immunogenicity of the split, inactivated quadrivalent influenza vaccine (QIV) in Polish adults with obesity. MATERIAL AND METHODS Fifty-three subjects with obesity aged 21-69 years were vaccinated with the QIV in 2017/2018 season. Antibody titers against the 4 vaccine strains were measured using the hemagglutination inhibition (HI) assay. The mean fold antibody increase (MFI), seroprotection rate (protection rate, PR), and seroconversion rate (response rate, RR) were calculated to assess vaccine immunogenicity. RESULTS The vaccine elicited a significant increase in the anti-HI titers against the QIV antigens. The MFI, PR, and RR for the QIV antigens also reached the required age-specific values, indicating the QIV meets current immunogenicity criteria. Individuals with class I and class II/III obesity had similar anti-HI titers, MFI, PR, and RR to each of the vaccine strains. Adults aged <60 years had similar anti-HI titers, MFI, PR, and RR to the QIV strains to those aged ≥60 years. CONCLUSIONS Our results indicate that the split virion, inactivated QIV is immunogenic in adults with obesity regardless of their degree of obesity and age (ie, <60 and ≥60 years).

Ontology-based Precision Vaccinology for Deep Mechanism Understanding and Precision Vaccine Development

Vaccination is one of the most important innovations in human history. It has also become a hot research area in a new application - the development of new vaccines against non-infectious diseases such as cancers. However, effective and safe vaccines still do not exist for many diseases, and where vaccines exist, their protective immune mechanisms are often unclear. Although licensed vaccines are generally safe, various adverse events, and sometimes severe adverse events, still exist for a small population. Precision medicine tailors medical intervention to the personal characteristics of individual patients or sub-populations of individuals with similar immunity-related characteristics. Precision vaccinology is a new strategy that applies precision medicine to the development, administration, and post-administration analysis of vaccines. Several conditions contribute to make this the right time to embark on the development of precision vaccinology. First, the increased level of research in vaccinology has generated voluminous "big data" repositories of vaccinology data. Secondly, new technologies such as multi-omics and immunoinformatics bring new methods for investigating vaccines and immunology. Finally, the advent of AI and machine learning software now makes possible the marriage of Big Data to the development of new vaccines in ways not possible before. However, something is missing in this marriage, and that is a common language that facilitates the correlation, analysis, and reporting nomenclature for the field of vaccinology. Solving this bioinformatics problem is the domain of applied biomedical ontology. Ontology in the informatics field is human- and machine-interpretable representation of entities and the relations among entities in a specific domain. The Vaccine Ontology (VO) and Ontology of Vaccine Adverse Events (OVAE) have been developed to support the standard representation of vaccines, vaccine components, vaccinations, host responses, and vaccine adverse events. Many other biomedical ontologies have also been developed and can be applied in vaccine research. Here, we review the current status of precision vaccinology and how ontological development will enhance this field, and propose an ontology-based precision vaccinology strategy to support precision vaccine research and development.

Obesity and diabetes as high-risk factors for severe coronavirus disease 2019 (Covid-19)

The outbreak of the coronavirus disease 2019 (Covid-19) has become an evolving worldwide health crisis. With the rising prevalence of obesity and diabetes has come an increasing awareness of their impacts on infectious diseases, including increased risk for various infections, post-infection complications and mortality from critical infections. Although epidemiological and clinical characteristics of Covid-19 have been constantly reported, no article has systematically illustrated the role of obesity and diabetes in Covid-19, or how Covid-19 affects obesity and diabetes, or special treatment in these at-risk populations. Here, we present a synthesis of the recent advances in our understanding of the relationships between obesity, diabetes and Covid-19 along with the underlying mechanisms, and provide special treatment guidance for these at-risk populations.

Obesity and immune status in children

PURPOSE OF REVIEW

Childhood obesity, with persistent chronic inflammation, is a worldwide epidemic. Obesity causes dysregulation throughout the immune system, affecting the balance and levels of cytokines, adipokines, and innate and adaptive immune cells. The present review focuses on the impact of obesity on immune function in children: altering the baseline activation state of immune cells and affecting the ability of the host to combat pathogens and malignancy and respond appropriately to vaccination.

RECENT FINDINGS

Obesity causes dysregulation of the immune system. Single-cell RNA-sequencing of adipose tissue and resident immune cells is quantifying the impact of obesity on the frequency of immune cell subsets and their states. The system-wide alterations in immune function in obesity are most evident upon perturbation, including the response to infection (e.g. increased risk of severe COVID-19 in the ongoing pandemic), vaccination, and malignancy. However, mechanistic research in pediatric obesity is limited and this impacts our ability to care for these children.

SUMMARY

We must better understand baseline and perturbed immune health in obese children to determine how to account for altered frequency and function of humoral and cellular immune components in acute infection, during vaccine design and when considering therapeutic options for this complex, medically vulnerable group.

Lifestyle factors in the prevention of COVID-19

Confinement to the home and psychological distress due to the coronavirus disease 2019 (COVID-19) pandemic may lead to harmful health behaviors, such as overeating, sedentary behavior with reduced physical activity, elevated alcohol and tobacco use and increased screen time causing impaired sleep. All of these behaviors are associated with non-communicable diseases and can interfere with immunity. While no foods, single nutrients or dietary supplements are capable of preventing infection with COVID-19, a balanced diet containing sufficient amounts of macronutrients and diverse micronutrients is a prerequisite of an optimally functioning immune system. High-energy "Western" diets and obesity are major risk factors for a more severe course of COVID-19. Alcohol use and tobacco also have detrimental effects on the immune system. Therefore, population-wide body weight control, reduction of smoking rates and limitation of alcohol consumption are important preventive measures. Furthermore, sufficient restorative sleep is needed for adequate immune functioning. Appropriate lifestyle changes in regard to nutrition, exercise, sleep, smoking and alcohol intake may help shift the population distribution of infection risk and aid in preventing severe COVID-19 disease. Large-scale surveys should explore the effects of lifestyle changes, and the provision of reliable lifestyle information and effective interventions to individuals and communities during the pandemic is a pressing need.

Obesity is associated with increased susceptibility to influenza A (H1N1pdm) but not H3N2 infection

BACKGROUND

Obesity has been shown to increase the risk of severe outcomes and death for influenza virus infections. However, we don't understand the influence of obesity on susceptibility to infection or on non-severe influenza outcomes.

METHODS

We performed a case-ascertained, community-based study of influenza transmission within households in Nicaragua. To investigate whether obesity increases the likelihood of influenza infection and symptomatic infection we use logistic regression models.

RESULTS

Between 2015 and 2018, a total of 335 index cases with influenza A and 1,506 of their household contacts were enrolled. Obesity was associated with increased susceptibility to symptomatic H1N1pdm infection among adults (OR: 2.10, 95%CI: 1.08-4.06), but not children, and this association increased with age. Among adults with H1N1pdm infection, obesity was associated with increased likelihood of symptoms (OR: 3.91, 95%CI: 1.55-9.87). For middle aged and older adults with obesity there was also a slight increase in susceptibility to any H1N1pdm infection (OR: 1.20, 95%CI: 0.62-2.34). Body Mass Index (BMI) was also linearly associated with increased susceptibility to symptomatic H1N1pdm infection, primarily among middle aged and older adult women (5-unit BMI increase OR: 1.40, 95%CI: 1.00-1.97). Obesity was not associated with increased H3N2 susceptibility or associated symptoms.

CONCLUSIONS

We found that among adults obesity is associated with susceptibility to H1N1pdm infection and with symptoms associated with H1N1pdm infection, but not with susceptibility to H3N2 infection or associated symptoms. These findings will help target prevention efforts and therapeutics to this high-risk population.

Obesidad: un problema en la atención de Covid-19

Actualmente el mundo atraviesa una de las peores crisis a nivel salud secundario a la infección por un nuevo coronavirus de alta transmisibilidad y mortalidad, que ha impactado múltiples aspectos. Se ha establecido de forma general que la severidad de la infección está asociada con edad avanzada y comorbilidades como hipertensión y diabetes. Por otro lado, la obesidad en este momento representa una de las mayores amenazas del sector salud, por su gran relación con morbimortalidad a nivel cardiometabólico, esto conlleva a un alto costo de la enfermedad. Este artículo busca alertar sobre lo que han llamado algunos expertos el “choque de dos pandemias”, esto dado al aumento de la prevalencia de obesidad a nivel mundial, donde  nuestro país no está exento, que podría relacionarse con un número mayor de personas vulnerables a la infección por COVID-19 y sus complicaciones respiratorias y de esta manera evitar desenlaces catastróficos.

Immunity to influenza: Impact of obesity

Obesity is a health concern that is recognized as a critical factor for vulnerability to influenza A/pdmH1N1 virus infection, with epidemiological and clinical impacts. In humans, obesity induces disturbances in inflammatory and immune responses to the influenza virus and in some cases, this leads to severe complications, with fatal outcomes. Obesity impairs immunity by altering the response of cytokines, resulting in a decrease in the cytotoxic cell response of immunocompetent cells which have a key anti-viral role. Additionally, obesity seems to disturb the balance of endocrine hormones, such as leptin, that affect the interplay between metabolic and immune systems. This contribution focuses on reviewing the current epidemiologic data for the immune response to immunity in obese humans and animal models. In doing so, we aim to provide potential mechanisms to enhance immunity to influenza A/pdmH1N1 virus infection and protective factors in obese people.

Self-reported diabetes and herpes zoster are associated with a weak humoral response to the seasonal influenza A H1N1 vaccine antigen among the elderly

Background

The immune response to seasonal influenza vaccines decreases with advancing age. Therefore, an adjuvanted inactivated trivalent influenza vaccine (Fluad®) exists for elderly individuals. Fluad® is more immunogenic and efficacious than conventional influenza vaccines. However, the immune response varies and may still result in high frequencies of poor responders. Therefore, we aimed to a) examine the prevalence of a weak response to Fluad® and b) identify potential risk factors.

Methods

A prospective population-based study among individuals 65–80 years old was conducted in 2015/2016 in Hannover, Germany (n = 200). Hemagglutination-inhibition titers 21 days after vaccination with Fluad® served as indicator of vaccine responsiveness.

Results

The percentage of vaccinees with an inadequate vaccine response varied depending on the influenza strain: it was lowest for H3N2 (13.5%; 95% CI, 9.4–18.9%), intermediate for B strain (37.0%; 30.6–43.9%), and highest for H1N1 (49.0%; 42.2–55.9%). The risk of a weak response to the influenza A H1N1 strain was independently associated with self-reported diabetes (AOR, 4.64; 95% CI, 1.16–18.54), a history of herpes zoster (2.27; 1.01–5.10) and, to a much lesser extent, increasing age (change per year, 1.08; 0.99–1.16). In addition, herpes zoster was the only risk factor for a weak response to the H3N2 antigen (AOR, 3.12; 1.18–8.23). We found no significant association between sex, Body Mass Index, cancer, hypertension, heart attack and CMV seropositivity and a weak response to these two influenza A antigens. Despite its occurence in over one third of vaccinees, none of the variables examined proved to be risk factors for a weak response to the B antigen.

Conclusions

A considerable proportion of elderly individuals displayed a weak vaccine response to this adjuvanted seasonal influenza vaccine and further efforts are thus needed to improve immune responses to influenza vaccination among the elderly. Diabetes and herpes zoster were identified as potentially modifiable risk factors for a poor vaccine response against influenza A antigens, but the results also reveal the need for broader investigations to identify risk factors for inadequate responses to influenza B antigens.

Trial registration

No. NCT02362919 (ClinicalTrials.gov, date of registration: 09.02.2015).

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4214-x) contains supplementary material, which is available to authorized users.

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.

Underweight, overweight, and obesity as independent risk factors for hospitalization in adults and children from influenza and other respiratory viruses

BACKGROUND

The relationship between obesity and risk of complications described during the 2009 influenza pandemic is poorly defined for seasonal influenza and other viral causes of influenza-like illness (ILI).

METHODS

An observational cohort of hospitalized and outpatient participants with ILI was conducted in six hospitals in Mexico. Nasopharyngeal swabs were tested for influenza and other common respiratory pathogens.

RESULTS

A total of 4778 participants were enrolled in this study and had complete data. A total of 2053 (43.0%) had severe ILI. Seven hundred and seventy-eight (16.3%) were positive for influenza, 2636 (55.2%) were positive for other viral respiratory pathogens, and 1364 (28.5%) had no respiratory virus isolated. Adults with influenza were more likely to be hospitalized if they were underweight (OR: 5.20), obese (OR: 3.18), or morbidly obese (OR: 18.40) compared to normal-weight adults. Obese adults with H1N1 had a sixfold increase in odds of hospitalization over H3N2 and B (obese OR: 8.96 vs 1.35, morbidly obese OR: 35.13 vs 5.58, respectively) compared to normal-weight adults. In adults with coronavirus, metapneumovirus, parainfluenza, and rhinovirus, participants that were underweight (OR: 4.07) and morbidly obese (OR: 2.78) were more likely to be hospitalized as compared to normal-weight adults. All-cause influenza-like illness had a similar but less pronounced association between underweight or morbidly obesity and hospitalization.

CONCLUSIONS

There is an increased risk of being hospitalized in adult participants that are underweight or morbidly obese, regardless of their viral pathogen status. Having influenza, however, significantly increases the odds of hospitalization in those who are underweight or morbidly obese.

Predictors of the immune response to booster immunisation against tetanus in Czech healthy adults

An evaluation of the relationship between predictors and immune response was conducted using data obtained from a clinical trial in 200 Czech healthy adults aged 24-65 years receiving a booster dose of a monovalent tetanus vaccine in 2017. The response was determined from ELISA antibody concentrations of paired sera obtained before and 4 weeks after the immunisation. While all subjects with initial antibody levels 2.2 IU/ml. The immune response was not affected by sex, age, tetanus vaccine type, concomitant medication, related adverse events or post-vaccination period since there were no significant differences in geometric mean concentrations or seroconversion rates. The seroconversion rate of 56% in smokers was significantly lower than that of 73% achieved in non-smokers. Although the seroconversion rates did not differ between individuals with normal or higher body weight, the adjusted odds ratio (1.3; 95% Cl 1.08-1.60) revealed a positive correlation between seroconversion rate and body mass index (BMI). Although the vaccine-induced response was influenced by pre-vaccination antibody levels, smoking or BMI, the booster immunisation against tetanus produced a sufficient response regardless the predictors.

Immune response in highly active young men to the 2014/2015 seasonal influenza vaccine

During the 2009 H1N1 pandemic, individuals with obesity were disproportionately affected by H1N1 with increased levels of mortality and morbidity. This led to questions regarding the potential impact of lifestyle on the effectiveness of immunization. Currently, the research is limited on influenza vaccination and the associated changes in immune response with body composition and physical activity. The purpose of this pilot study was to investigate the potential role of adiposity and physical activity in the immune response elicited by the 2014/2015 seasonal trivalent influenza vaccine. A prospective cohort study examining the 2014/2015 seasonal trivalent influenza vaccine was conducted by collecting baseline and 4-week postvaccination fasting blood samples from 45 male Albertans between the ages of 18 and 35 years. Percent body fat (%BF) was assessed through dual X-ray absorptiometry imagining and physical activity through self-reported survey scores. While no differences in median %BF were associated with seroconversion rates in participants, the median physical activity score was higher among those that did not seroconvert to the vaccine. Significant differences were found for the A/Texas strain (p < 0.01) and a similar trend of lower magnitude observed for the remaining 2 influenza strains. These results suggest that higher physical activity levels may influence immune response to vaccination and that assessing factors beyond those commonly used can be of value when identifying vaccine response in the population.

An Explorative Biomarker Study for Vaccine Responsiveness after a Primary Meningococcal Vaccination in Middle-Aged Adults

Introduction

Prevention of infectious diseases in the elderly is essential to establish healthy aging. Yet, immunological aging impairs successful vaccination of the elderly. Predictive biomarkers for vaccine responsiveness in middle-aged adults may help to identify responders and non-responders before reaching old age. Therefore, we aimed to determine biomarkers associated with low and high responsiveness toward a primary vaccination in middle-aged adults, for which a tetravalent meningococcal vaccine was used as a model.

Methods

Middle-aged adults (50–65 years of age, N = 100), receiving a tetravalent meningococcal vaccination, were divided into low and high responders using the functional antibody titers at 28 days postvaccination. A total of 48 parameters, including absolute numbers of immune cells and serum levels of cytokines and biochemical markers, were determined prevaccination in all participants. Heat maps and multivariate redundancy analysis (RDA) were used to reveal immune phenotype characteristics and associations of the low and high responders.

Results

Several significant differences in prevaccination immune markers were observed between the low and high vaccine responders. Moreover, RDA analysis revealed a significant association between the prevaccination immune phenotype and vaccine responsiveness. In particular, our analysis pointed at high numbers of CD4 T cells, especially naïve CD4 and regulatory T subsets, to be associated with low vaccine responsiveness. In addition, low responders showed lower prevaccination IL-1Ra levels than high responders.

Conclusion

This explorative biomarker study shows associations between the prevaccination immune phenotype and vaccine responsiveness after a primary meningococcal vaccination in middle-aged adults. Consequently, these results provide a basis for predictive biomarker discovery for vaccine responsiveness that will require validation in larger cohort studies.

Phase 4, Post-Marketing Safety Surveillance of the MF59-Adjuvanted Influenza Vaccines FLUAD® and VANTAFLU® in South Korean Subjects Aged ≥65 Years

Backgroud

Influenza vaccination is recommended for adults aged ≥65 years as they are at high risk of significant morbidity and mortality. This open-label, multicenter, post-marketing surveillance study assessed the safety of the MF59-adjuvanted trivalent inactivated subunit influenza vaccine, which is marketed as FLUAD^® and VANTAFLU^®, in South Korean subjects aged ≥65 years.

Materials and Methods

Solicited local and systemic adverse events (AEs) were collected from day 1 to 4 of the study. All unsolicited AEs and serious AEs (SAEs) were recorded from day 1 until study termination (day 29).

Results

Of the 770 subjects enrolled (FLUAD^®, n = 389; VANTAFLU^®, n = 381), 39% overall experienced any solicited AE. Local AEs were reported by 33% of subjects overall; with the most common events being injection-site pain (30%) and tenderness (27%). Systemic AEs were reported by 19% of subjects overall with the most common events being myalgia (11%) and fatigue (8%).

Conclusion

These results show that the MF59-adjuvanted influenza vaccine known as FLUAD^® or VANTAFLU^® had acceptable safety profiles in older adults (aged ≥65 years) in South Korea.

The effect of frailty on HAI response to influenza vaccine among community-dwelling adults ≥ 50 years of age

The immune response to vaccine antigens is less robust in older adults because of changes in the aging immune system. Frailty, the multi-dimensional syndrome marked by losses in function and physiological reserve, is increasingly prevalent with advancing age. Frailty accelerates this immunosenescence but the consequence of frailty on immune response specific to influenza vaccine among older adults, is mixed. An observational, prospective study of 114 adults was conducted in the fall of 2013 to assess the association of physical frailty with immune response to standard dose influenza vaccine in community-dwelling adults ≥ 50 years of age. Participants were stratified by age (<65 years and ≥65 years), and vaccine strain (Influenza A/H1N1, A/H3N2 and B) was analyzed separately adjusting for body mass index (BMI) and baseline log₂ hemagglutination inhibition (HAI) titers. Overall, immune responses were lower among those ≥65 years of age than those <65 years. Among those ≥65 years there were no significant differences between frail and non-frail individuals in seroprotection or seroconversion for any influenza strain. Frail individuals <65 years of age compared with non-frail individuals were more likely to be seroprotected and to seroconvert post vaccination. Linear regression models show the same pattern of significant differences between frail and non-frail for those <65 years but no significant differences between frailty groups for those ≥65 years. Additional research may elucidate the reasons for the differences observed between younger frail and non-frail adults.

Personalized vaccinology: A review

At the current time, the field of vaccinology remains empirical in many respects. Vaccine development, vaccine immunogenicity, and vaccine efficacy have, for the most part, historically been driven by an empiric “isolate-inactivate-inject” paradigm. In turn, a population-level public health paradigm of “the same dose for everyone for every disease” model has been the normative thinking in regard to prevention of vaccine-preventable infectious diseases. In addition, up until recently, no vaccines had been designed specifically to overcome the immunosenescence of aging, consistent with a post-WWII mentality of developing vaccines and vaccine programs for children. It is now recognized that the current lack of knowledge concerning how immune responses to vaccines are generated is a critical barrier to understanding poor vaccine responses in the elderly and in immunoimmaturity, discovery of new correlates of vaccine immunogenicity (vaccine response biomarkers), and a directed approach to new vaccine development.

The new fields of vaccinomics and adversomics provide models that permit global profiling of the innate, humoral, and cellular immune responses integrated at a systems biology level. This has advanced the science beyond that of reductionist scientific approaches by revealing novel interactions between and within the immune system and other biological systems (beyond transcriptional level), which are critical to developing “downstream” adaptive humoral and cellular responses to infectious pathogens and vaccines. Others have applied systems level approaches to the study of antibody responses (a.k.a. “systems serology”), [1] high-dimensional cell subset immunophenotyping through CyTOF, [2,3] and vaccine induced metabolic changes [4]. In turn, this knowledge is being utilized to better understand the following: identifying who is at risk for which infections; the level of risk that exists regarding poor immunogenicity and/or serious adverse events; and the type or dose of vaccine needed to fully protect an individual. In toto, such approaches allow for a personalized approach to the practice of vaccinology, analogous to the substantial inroads that individualized medicine is playing in other fields of human health and medicine. Herein we briefly review the field of vaccinomics, adversomics, and personalized vaccinology.

Factors affecting immune responses to the influenza vaccine

Annual administration of the seasonal influenza vaccine is strongly recommended to reduce the burden of disease, particularly for persons at the highest risk for the viral infection. Even during years when there is a good match between the vaccine and circulating strains, host-related factors such as age, preexisting immunity, genetic polymorphisms, and the presence of chronic underlying conditions may compromise influenza vaccine responsiveness. The application of new methodologies and large-scale profiling technologies are improving the ability to measure vaccine immunogenicity and our understanding of the immune mechanisms by which vaccines induce protective immunity. This review attempts to summarize the general concepts of how host factors can contribute to the heterogeneity of immune responses induced by influenza vaccines.

Increased risk of influenza among vaccinated adults who are obese

Background

Influenza infects 5–15% of the global population each year, and obesity has been shown to be an independent risk factor for increased influenza-related complications including hospitalization and death. However, the risk of developing influenza or ILI in a vaccinated obese adult population has not been addressed.

Objective

This study evaluated whether obesity was associated with increased risk of influenza and influenza-like illness among vaccinated adults.

Subjects and Methods

During the 2013–2014 and 2014–2015 influenza seasons, we recruited 1042 subjects to a prospective observational study of trivalent inactivated influenza vaccine (IIV3) in adults.1022 subjects completed the study. Assessments of relative risk for laboratory confirmed influenza and influenza-like illness were determined based on BMI. Seroconversion and seroprotection rates were determined using pre-vaccination and 26–35 days post-vaccination serum samples. Recruitment criteria for this study were adults 18 years of age and older receiving the seasonal trivalent inactivated influenza vaccine (IIV3) for the years 2013–2014 and 2014–2015. Exclusion criteria were immunosuppressive diseases, use of immunomodulatory or immunosuppressive drugs, acute febrile illness, history of Guillain-Barre syndrome, use of theophylline preparations, or use of warfarin.

Results

Among obese, 9.8% had either confirmed influenza or influenza-like-illness compared with 5.1% of healthy weight participants. Compared with vaccinated healthy weight, obese participants had double the risk of developing influenza or influenza-like illness (relative risk= 2.01, 95% CI 1.12, 3.60, p=0.020). Seroconversion or seroprotection rates were not different between healthy weight and obese adults with influenza or ILI.

Conclusions

Despite robust serological responses, vaccinated obese adults are twice as likely to develop influenza and influenza-like illness compared to healthy weight adults. This finding challenges the current standard for correlates of protection, suggesting use of antibody titers to determine vaccine effectiveness in an obese population may provide misleading information.

Are children's vitamin D levels and BMI associated with antibody titers produced in response to 2014-2015 influenza vaccine?

BACKGROUND

Vitamin D is an immunomodulating hormone, which has been associated with susceptibility to infectious diseases.

METHODS

Serum vitamin D levels in 135 children ages 3-17 y were measured at baseline and hemagglutinin influenza antibody titers were measured pre- and 21 d post influenza vaccination with live attenuated influenza vaccine (LAIV) or inactivated influenza vaccine (IIV). Height and weight were derived from the electronic medical record and were used to calculate body mass index (BMI).

RESULTS

Thirty-nine percent of children were ages 3-8 years; 75% were black, 34% were obese (BMI ≥ 95^th percentile); vitamin D levels were >20 ng/ml in 55%. In linear regression analyses, post vaccination antibody titers for LAIV B lineages (B Brisbane and B Massachusetts) were significantly higher among those with lower vitamin D levels and among younger participants (P < 0.05). No associations between vitamin D levels and responses to LAIV A strains (A/H1N1 and A/H3N2) or to any IIV strains or lineages were found.

CONCLUSION

Low vitamin D levels were associated with higher response to LAIV B lineages in the 2014-2015 LAIV, but not related to LAIV A or any IIV strains.

Barriers to influenza vaccine uptake in obese people in Italy: Changes 2005-2013

BACKGROUND

Obesity is an independent risk factor for developing flu-related complications.

OBJECTIVE

The aim of this study was to analyze influenza vaccine uptake (VU) in the Italian obese, before and after the introduction of obesity among the national recommendations, and to evaluate factors associated to VU.

METHODS

The comparison of two editions of the national survey carried out in 2004-2005, before the inclusion of obese people among the specific high risk categories for flu complications, and in 2013, reaching a sample of 21,857 persons who declared to have a BMI>30. Multilevel logistic regression was used to evaluate potential independent predictors of influenza immunization.

RESULTS

Influenza vaccination coverage was 27.16% in 2013, versus 31.61% in 2005. A significant reduction of VU was registered after the introduction of obesity among the high risk conditions, for which flu VU was recommended. Regression modeling, both in adults and in older people, confirmed that barriers to VU in 2013 were younger age, medium level of education, absence of chronic disease, smoking habit, and reporting no contacts with GPs during the previous 12months. Among those aged 65 or more, the role of regional policies was associated to VU.

CONCLUSIONS

Immunization rates among young obese population are low, especially if not affected by comorbidities. Moreover, a reduction was registered in 2013 with respect to 2005. Flu vaccine uptake among the older population seems to be influenced by regional vaccination strategies. The development of novel strategy is warranted, especially among the young adults.

Prevention and Control of Seasonal Influenza with Vaccines

This report updates the 2015-16 recommendations of the Advisory Committee on Immunization Practices (ACIP) regarding the use of seasonal influenza vaccines (Grohskopf LA, Sokolow LZ, Olsen SJ, Bresee JS, Broder KR, Karron RA. Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices, United States, 2015-16 influenza season. MMWR Morb Mortal Wkly Rep 2015;64:818-25). Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. For the 2016-17 influenza season, inactivated influenza vaccines (IIVs) will be available in both trivalent (IIV3) and quadrivalent (IIV4) formulations. Recombinant influenza vaccine (RIV) will be available in a trivalent formulation (RIV3). In light of concerns regarding low effectiveness against influenza A(H1N1)pdm09 in the United States during the 2013-14 and 2015-16 seasons, for the 2016-17 season, ACIP makes the interim recommendation that live attenuated influenza vaccine (LAIV4) should not be used. Vaccine virus strains included in the 2016-17 U.S. trivalent influenza vaccines will be an A/California/7/2009 (H1N1)-like virus, an A/Hong Kong/4801/2014 (H3N2)-like virus, and a B/Brisbane/60/2008-like virus (Victoria lineage). Quadrivalent vaccines will include an additional influenza B virus strain, a B/Phuket/3073/2013-like virus (Yamagata lineage).Recommendations for use of different vaccine types and specific populations are discussed. A licensed, age-appropriate vaccine should be used. No preferential recommendation is made for one influenza vaccine product over another for persons for whom more than one licensed, recommended product is otherwise appropriate. This information is intended for vaccination providers, immunization program personnel, and public health personnel. Information in this report reflects discussions during public meetings of ACIP held on October 21, 2015; February 24, 2016; and June 22, 2016. These recommendations apply to all licensed influenza vaccines used within Food and Drug Administration-licensed indications, including those licensed after the publication date of this report. Updates and other information are available at CDC's influenza website (http://www.cdc.gov/flu). Vaccination and health care providers should check CDC's influenza website periodically for additional information.

Obesity Outweighs Protection Conferred by Adjuvanted Influenza Vaccination

Obesity is a risk factor for developing severe influenza virus infection, making vaccination of utmost importance for this high-risk population. However, vaccinated obese animals and adults have decreased neutralizing antibody responses. In these studies, we tested the hypothesis that the addition of either alum or a squalene-based adjuvant (AS03) to an influenza vaccine would improve neutralizing antibody responses and protect obese mice from challenge. Our studies demonstrate that adjuvanted vaccine does increase both neutralizing and nonneutralizing antibody levels compared to vaccine alone. Although obese mice mount significantly decreased virus-specific antibody responses, both the breadth and the magnitude of the responses against hemagglutinin (HA) and neuraminidase (NA) are decreased compared to the responses in lean mice. Importantly, even with a greater than fourfold increase in neutralizing antibody levels, obese mice are not protected against influenza virus challenge and viral loads remain elevated in the respiratory tract. Increasing the antigen dose affords no added protection, and a decreasing viral dose did not fully mitigate the increased mortality seen in obese mice. Overall, these studies highlight that, while the use of an adjuvant does improve seroconversion, vaccination does not fully protect obese mice from influenza virus challenge, possibly due to the increased sensitivity of obese animals to infection. Given the continued increase in the global obesity epidemic, our findings have important implications for public health.

Vaccination is the most effective strategy for preventing influenza virus infection and is a key component for pandemic preparedness. However, vaccines may fail to provide optimal protection in high-risk groups, including overweight and obese individuals. Given the worldwide obesity epidemic, it is imperative that we understand and improve vaccine efficacy. No work to date has investigated whether adjuvants increase the protective capacity of influenza vaccines in the obese host. In these studies, we show that adjuvants increased the neutralizing and nonneutralizing antibody responses during vaccination of lean and obese mice to levels considered “protective,” and yet, obese mice still succumbed to infection. This vulnerability is likely due to a combination of factors, including the increased susceptibility of obese animals to develop severe and even lethal disease when infected with very low viral titers. Our studies highlight the critical public health need to translate these findings and better understand vaccination in this increasing population.

Age, serum 25-hydroxyvitamin D and vitamin D receptor (VDR) expression and function in peripheral blood mononuclear cells

The relationship between age, vitamin D status, expression and functionality of the vitamin D receptor (VDR), and key genes in the vitamin D pathway in immune cells is unclear. We enrolled adults 50 to 69 years old (20 subjects) and 70+ (20 subjects) and measured: 1) 25(OH)D levels by liquid chromatography/mass spectrometry; and 2) mRNA expression of VDR, 1α-OHase, 1,25D3-MARRS, TREM-1, cathelicidin, RIG-I, and interferon-β by qRT-PCR. Mean serum 25(OH)D was 30 ± 4 ng/mL and was not associated with age. Baseline expression of VDR, 1α-OHase, 1,25D3-MARRS, TREM-1, and RIG-I also did not differ by age; IFN-β expression, however, was higher in the 70+ year old group. 25(OH)D3- and 1,25(OH)2D3-induced VDR, TREM-1 and cathelicidin expression were similar between age groups, as was LPS-induced expression of VDR and of 1α-OHase. Ligand-induced 1,25D3-MARRS expression was higher in subjects ≥ 70 years. Serum 25(OH)D was inversely associated with LPS-stimulated VDR expression and with baseline or vitamin D-induced TREM-1 expression, adjusting for age, self-rated health, and functional status. In healthy adults ≥ 50 years, the expression and functionality of the VDR, 1α-OHase and key vitamin D pathway genes were not consistently associated with age.

Is immunosenescence influenced by our lifetime "dose" of exercise?

The age-associated decline in immune function, referred to as immunosenescence, is well characterised within the adaptive immune system, and in particular, among T cells. Hallmarks of immunosenescence measured in the T cell pool, include low numbers and proportions of naïve cells, high numbers and proportions of late-stage differentiated effector memory cells, poor proliferative responses to mitogens, and a CD4:CD8 ratio <1.0. These changes are largely driven by infection with Cytomegalovirus, which has been directly linked with increased inflammatory activity, poor responses to vaccination, frailty, accelerated cognitive decline, and early mortality. It has been suggested however, that exercise might exert an anti-immunosenescence effect, perhaps delaying the onset of immunological ageing or even rejuvenating aged immune profiles. This theory has been developed on the basis of evidence that exercise is a powerful stimulus of immune function. For example, in vivo antibody responses to novel antigens can be improved with just minutes of exercise undertaken at the time of vaccination. Further, lymphocyte immune-surveillance, whereby cells search tissues for antigens derived from viruses, bacteria, or malignant transformation, is thought to be facilitated by the transient lymphocytosis and subsequent lymphocytopenia induced by exercise bouts. Moreover, some forms of exercise are anti-inflammatory, and if repeated regularly over the lifespan, there is a lower morbidity and mortality from diseases with an immunological and inflammatory aetiology. The aim of this article is to discuss recent theories for how exercise might influence T cell immunosenescence, exploring themes in the context of hotly debated issues in immunology.

Seasonal influenza vaccination of high-risk adults

INTRODUCTION

Adults at a high risk of severe influenza, because of their age and/or underlying health disorders, should receive seasonal influenza vaccination in order to reduce the incidence of severe illness and premature death. However, because current influenza vaccines are perceived to have suboptimal efficacy, vaccine coverage is below the recommended level in this population. Areas covered: This review examines, for each high-risk group, available data on influenza infection, vaccine efficacy and safety, and vaccine coverage. We conducted a literature search in the PubMed database to identify randomized controlled trials, observational studies and reviews published from 2000 through 2015 on both seasonal and pandemic influenza. Only studies published in English were considered. While the topic of this review is seasonal influenza, data on pandemics are included when relevant. Expert Commentary: Current seasonal influenza vaccines are only moderately protective, and vaccines eliciting broader and more durable immunity are therefore needed. Research on the use of higher doses, adjuvants, and a universal influenza vaccine is ongoing. Influenza vaccine coverage needs to be increased. Vaccination of contacts of high-risk individuals, including healthcare workers, should be encouraged.

Fat and flu: fact or fiction?

Novel risk factors for severe influenza infection were described during the early phases of the influenza pandemic of 2009. Worldwide, the rate of severe influenza in the obese and morbidly obese population was disproportionate to that of the general population. This risk factor has now been recognized presumably due to the increasing prevalence of obesity. The cause behind this trend may extend beyond the known deleterious effects of obesity on respiratory physiology, as emerging evidence in animal models demonstrate A(H1N1)pdm09 itself confers worse outcomes compared with seasonal influenza subtypes. Currently, uncertainty remains regarding the optimal antiviral regimen and vaccination strategies in obese individuals. Therefore, further studies on the effects of obesity on influenza infection need to be prioritized.

Influenza Vaccine is Protective Against Laboratory-confirmed Influenza in Obese Children

BACKGROUND

Obesity emerged as a novel risk factor for severe disease during the 2009 H1N1 influenza pandemic. Murine studies indicate that obesity is associated with ineffective response to influenza vaccine, but few human studies exist. We aimed to determine if influenza vaccine is protective against laboratory-confirmed influenza in obese children.

METHODS

Body mass index, vaccination status, and laboratory-confirmed influenza data were analyzed from a previously conducted prospective study in which active surveillance for influenza-like illness was conducted in 8 elementary schools in Los Angeles County during the 2010-2011 influenza season. Polymerase-chain reaction (PCR) was performed on combined nose/throat swabs collected from children with influenza-like illness at presentation to the school nurse or during absenteeism.

RESULTS

Of 4260 children with height/weight data, 1191 (28.0%) were obese (body mass index ≥95th percentile). Respiratory specimens were obtained from 858 (20.1%) children. Unvaccinated obese compared with vaccinated obese children acquired 3 times more PCR-confirmed influenza (62 vs. 17 per 1000 children, P = 0.003) and missed more school days (4.6 vs. 3.2 per 100 school days, P < 0.001) during influenza season. Obese children with PCR-confirmed influenza were more likely to present with cough (86.2 vs. 72.4%, P = 0.030) and missed more school per episode (2.4 vs.1.9 days, P = 0.023) compared with nonobese children. Among vaccinated children, rates of PCR-confirmed influenza were similar in obese and nonobese children (17 vs. 20 per 1000 children, P = 0.77).

CONCLUSIONS

Obese children with PCR-confirmed influenza suffered from more cough and missed more school days than their nonobese peers. Influenza vaccination protected obese children against PCR-proven influenza illness.

Are plasma mineral levels related to antibody response to influenza vaccination in older adults?

INTRODUCTION

An effective immune response to vaccination may be related to nutritional status. This study examined the association of plasma mineral levels with hemagglutination inhibition (HI) titers produced in response to influenza vaccine in older adults.

METHODS

Prior to (Day 0) and 21 (range = 19-28) days after receiving the 2013-14 influenza vaccine, 109 adults ages 51-81 years, provided blood samples. Serum samples were tested for HI activity against the A/H1N1 and A/H3N2 2013-2014 vaccine virus strains. Plasma minerals were collected in zinc-free tubes and assayed by inductively coupled plasma mass spectrometry. HI titers were reported as seroprotection (≥1:40) and seroconversion (≥ 4-fold rise from Day 0 (minimum HI = 1:10) to Day 21). Both HI titers and mineral values were skewed and thus log2 transformed. Magnesium (Mg), phosphorus (P), zinc (Zn), copper (Cu), iron (Fe), potassium (K) and the Cu to Zn ratio were tested. Logistic regression analyses were used to determine the associations between mineral levels and seroconversion and seroprotection of HI titers for each influenza A strain.

RESULTS

Participants were 61% white, 28% male, 39% diabetic, and 81% overweight/obese with a mean age of 62.6 y. In logistic regression, Day 21 A/H1N1 seroprotection was associated with P and Zn at Day 21(P < 0.05). Seroconversion of A/H1N1 was associated with Day 21 Cu, P, and Mg (P < 0.03). Day 21 A/H3N2 seroprotection and seroconversion were associated with Day 21 P (P < 0.05).

CONCLUSIONS

Phosphorus was associated with seroprotection and seroconversion to influenza A after vaccination; these associations warrant additional studies with larger, more diverse population groups.

Obesity: impact of infections and response to vaccines

Obesity is a common condition that has rapidly increased in both the industrialised and developing world in recent decades. Obese individuals show increased risk factors for severe infections and significant immune system dysregulation that may impair the immune response to vaccines. The main aim of this paper was to review the current knowledge regarding the association between obesity and the risk and outcome of infections as well as immune response to vaccines. The results showed that obesity is a highly complex clinical condition in which the functions of several organ and body systems, including the immune system, are modified. However, only a small minority of the biological mechanisms that lead to reduced host defences have been elucidated. Relevant efforts for future research should focus on obese children, as the available data on this population are scarce compared with the adult population. Even if most vaccines are given in the first months of life when obesity is rare, some vaccines require booster doses at preschool age, and other vaccines, such as the influenza vaccine, are recommended yearly in the obese population, but it is not known whether response to vaccines of obese patients is impaired. The reduced immune response of obese patients to vaccination can be deleterious not only for the patient but also for the community.

Interaction of obesity and infections

There is evidence that certain infections may induce obesity. Obese persons may also have more severe infections and have compromised response to therapies. The objective of this study is to review the available literature identifying infections that potentially contribute to greater body mass index (BMI) and differential responses of overweight and obese persons to infections. A systematic literature review of human studies examining associations between infections and weight gain, differential susceptibility, severity, and response to prevention and treatment of infection according to BMI status (January 1980-July 2014) was conducted. Three hundred and forty-three studies were eligible for inclusion. Evidence indicated that viral infection by human adenovirus Ad36 and antibiotic eradication of Helicobacter pylori were followed by weight gain. People who were overweight or obese had higher susceptibility to developing post-surgical infections, H1N1 influenza and periodontal disease. More severe infections tended to be present in people with a larger BMI. People with a higher BMI had a reduced response to vaccinations and antimicrobial drugs. Higher doses of antibiotics were more effective in obese patients. Infections may influence BMI, and BMI status may influence response to certain infections, as well as to preventive and treatment measures. These observations have potential clinical implications.

Immunogenicity, safety and tolerability of inactivated trivalent influenza vaccine in overweight and obese children

Obesity may be a risk factor for increased hospitalization and deaths from infections due to respiratory pathogens. Additionally, obese patients appear to have impaired immunity after some vaccinations. To evaluate the immunogenicity, safety and tolerability of an inactivated trivalent influenza vaccine (TIV) in overweight and obese children, 28 overweight/obese pediatric patients and 23 healthy normal weight controls aged 3-14 years received a dose of TIV. Four weeks after vaccine administration, significantly higher seroprotection rates against the A/H1N1 strain were observed among overweight/obese children compared with normal weight controls (p<0.05). Four months after vaccination, similar or slightly higher seroconversion and seroprotection rates against the A/H1N1 and A/H3N2 strains were detected in overweight/obese than in normal weight children, whereas significantly higher rates of seroconversion and seroprotection against the B strain were found in overweight/obese patients than in normal weight controls (p<0.05 for seroconversion and seroprotection). Geometric mean titers (GMTs) and fold increase against B strains were significantly higher in overweight/obese patients than in normal weight controls 4 months after vaccine administration (p<0.01 for GMT values and p<0.05 for fold increase). The frequency of local and systemic reactions was similar between the groups, and there were no serious adverse events. The results of this study indicate that in overweight and obese children, antibody response to TIV administration is similar or slightly higher than that evidenced in normal weight subjects of similar age and this situation persists for at least 4 months after vaccine administration in the presence of a favorable safety profile.

Obesity Is Not Associated with Impaired Immune Response to Influenza Vaccination in HIV-Infected Persons

Introduction. HIV-infected individuals demonstrate lower immunogenicity to the influenza vaccine, despite immunologic and virologic control of HIV infection. Obesity has been previously shown to be associated with diminished antibody responses to other vaccines in HIV-uninfected persons. However, no studies have examined if obesity is associated with diminished protective immune response to influenza vaccination among HIV-infected persons on antiretroviral therapy (ART). Methods. We performed a retrospective analysis of immunogenicity data from a clinical trial of inactivated, trivalent influenza vaccine. The primary endpoint was the proportion of participants with seroconversion, defined as >4-fold increase in anti-hemagglutinin antibody titers after vaccination. Secondary endpoints were the proportion of participants with seroprotection (defined as antibody titers of ≥1 : 40) and geometric mean hemagglutination inhibition antibody titers. Results. Overall, 48 (27%) participants were obese (body mass index ≥ 30 kg/m²). Seroconversion rates were comparable between obese and nonobese subjects for all three vaccine strains. Further, postvaccination geometric mean titers did not differ by body mass index category. Conclusion. Obesity was not associated with diminished antibody response to influenza vaccination in a sample of healthy HIV-infected persons.