Differences in the immune response to hepatitis B and Haemophilus influenzae type b vaccines in Guatemalan infants by ethnic group and nutritional status

The Impact of Smoking on Long-Term Protection Following Hepatitis B Vaccination: A 24-Year Cohort Study

The hepatitis B vaccination-induced immune response has been demonstrated to be associated with a number of factors, including age, sex, BMI, and the presence of comorbidities. Additionally, modifiable determinants such as smoking have been identified as influencing the response to vaccination. However, despite the evidence that smokers are at an increased risk of not responding to vaccination, the long-term effects of smoking on antibody persistence remain poorly understood. This study aims to assess the impact of smoking habits on long-term immunity following the primary vaccination cycle. Participants were required to have received a standard three-dose vaccine schedule in childhood, without subsequent doses, and to be between 18 and 24 years of age. Data on age, sex, BMI, age of administration of the first vaccine dose, and time between doses were collected. An antibody concentration < 10 IU/L was considered as non-protective. A total of 2133 individuals were included, 14.2% of whom were smokers. The mean age was 20.28 ± 0.92 years. The probability of having a non-protective antibody concentration was significantly higher in smokers than in non-smokers (AOR: 1.287; 95% CI: 1.002-1.652). The detrimental effects of smoking extend beyond the immediate effects on the vaccine response, also impairing the long-term immune response in individuals who received vaccinations during childhood.

Sustained S-IgG and S-IgA antibodies to Moderna's mRNA-1273 vaccine in a Sub-Saharan African cohort suggests need for booster timing reconsiderations

Introduction

This study sought to elucidate the long-term antibody responses to the Moderna mRNA-1273 COVID-19 vaccine within a Ugandan cohort, aiming to contribute to the sparse data on m-RNA vaccine immunogenicity in Sub-Saharan Africa.

Methods

We tracked the development and persistence of the elicited antibodies in 19 participants aged 18 to 67, who received two doses of the mRNA-1273 vaccine. A validated enzyme-linked immunosorbent assay (ELISA) was used to quantify SARS-CoV-2-specific IgG, IgM, and IgA antibodies against the spike (S) and nucleoproteins (N). The study's temporal scope extended from the baseline to one year, capturing immediate and long-term immune responses. Statistical analyses were performed using the Wilcoxon test to evaluate changes in antibody levels across predetermined intervals with the Hochberg correction for multiple comparisons.

Results

Our results showed a significant initial rise in spike-directed IgG (S-IgG) and spike-directed IgA (S-IgA) levels, which remained elevated for the duration of the study. The S-IgG concentrations peaked 14 days afterboosting, while spike-directed IgM (S-IgM) levels were transient, aligning with their early response role. Notably, post-booster antibody concentrations did not significantly change. Prior S-IgG status influenced the post-priming S-IgA dynamics, with baseline S-IgG positive individuals maintaining higher S-IgA responses, a difference that did not reach statistical difference post-boost. Three instances of breakthrough infections: two among participants who exhibited baseline seropositivity for S-IgG, and one in a participant initially seronegative for S-IgG.

Discussion

In conclusion, the mRNA-1273 vaccine elicited robust and persistent S-IgG and S-IgA antibody responses, particularly after the first dose, indicating potential for long-term immunity. Prior viral exposure enhances post-vaccination S-IgA responses compared to naive individuals, which aligned with the prior-naïve, post-boost. The stable antibody levels observed post-booster dose, remaining high over an extended period, with no significant secondary rise, and no difference by baseline exposure, suggest that initial vaccination may sufficiently prime the immune system for prolonged protection in this population, allowing for potential to delay booster schedules as antibody responses remained high at the time of boosting. This finding calls for a reassessment of the booster dose scheduling in this demographic.

Vaccine and malnutrition: A narrative review

Nearly 45% of under 5 mortality is directly or indirectly linked to malnutrition. Infection adds to the increased mortality and morbidity in these groups. Vaccination is very important in these undernourished children protecting against life-threatening infections. The goal of vaccination is to produce long-term protection by generating memory cells and the generation of antibodies. Since malnutrition is a state of immunodeficiency, the immune response to vaccines in these children is a matter of concern. We did an exhaustive search to gather more recent studies and corroborated previous findings. Oral Polio Vaccine (OPV), Pneumococcal Polysaccharide Vaccine, Haemophilus influenza vaccine, rabies, and cholera vaccine showed normal response to immunization. Measles and rotavirus vaccines were found to elicit lower seroprotection and lower efficacy in undernourished children. Data regarding response to vaccination against BCG, DPwT, Hepatitis B, pneumococcal conjugate vaccine, and meningococcal vaccine was inconclusive. Although most of the studies show a normal immune response to different vaccines, excluding other confounding factors and effect modifiers had not been easy to interpret. However, with the advances in the understanding of vaccine physiology with newer immunological techniques, good-quality studies might explore the gray areas that remain untouched.

[Hepatitis B in indigenous people in Latin America: a literature reviewHepatite B em indígenas na América Latina: revisão da literatura]

Objetivo.

Identificar publicaciones realizadas entre los años 2000 y 2020 sobre hepatitis B en indígenas de América Latina, con el fin de conocer avances y vacíos en el tema durante los últimos 20 años.

Métodos.

Revisión exploratoria y síntesis rápida de la evidencia. El proceso de organización documental se realizó con los programas Excel^® y Rayyan^®.

Resultados.

Se seleccionaron 30 de 107 artículos encontrados, 17 corresponden a estudios epidemiológicos, 10 a revisiones documentales, dos estudios clínicos y una carta al editor. Brasil fue el país con más publicaciones (50%), la mayoría con enfoque epidemiológico. La temática más abordada fue la medición de prevalencia de la infección por hepatitis B con 22 publicaciones, le siguieron 11 estudios que informan resultados de estudios moleculares del virus, siete estudios sobre vacunación, cinco estudios sobre factores de riesgo y cuatro publicaciones con temas como la transmisión vertical y estudios sociales.

Conclusión.

En comparación con revisiones previas realizadas por otros autores, se observa una mayor diversidad en los temas y métodos de investigación utilizados; sin embargo, aún prevalecen los enfoques epidemiológicos convencionales centrados en la medición de la prevalencia de marcadores serológicos. Esto hace necesario encarar otro tipo de investigaciones centradas en los determinantes socioculturales.

Ethnicity and response to primary three-dose hepatitis B vaccination in employees in the Netherlands, 1983 through 2017

BACKGROUND AND AIMS

Hepatitis B virus (HBV) vaccination is recommended to all employees who have an occupational risk in the Netherlands. This study assessed the determinants of the immune response to primary standard three-dose HBV vaccination (0, 1, 6 months), with the main focus on ethnicity.

METHODS

Out of 76 239 individuals who received HBV vaccination between April 1983 and December 2017, 11 567 persons with a known country of birth and complete vaccination schedule were included in this study. Weighted multiple logistic regression with Firth's bias adjustment was used to assess the determinants of nonresponse (anti-HBs < 10 mIU/mL) and low response (anti-HBs 10-99 mIU/mL).

RESULTS

Baseline characteristics of the study population (n = 11 567) were as follows: mean age 27.5 years (95% confidence interval [CI], 27.23-27.72), 99.4% born in the Netherlands and 93.5% of Western European origin. Of all identified subjects, 180 (1.6%) were HBV vaccine nonresponders and 549 (4.8%) were low responders. When compared with individuals aged <40 years, the rate of nonresponse (4.3% vs 0.8%; P < .001) and low response (11.9% vs 2.9%; P < .001) was higher in those aged 40 years or older. The height of anti-HBs levels were lower in those subjects aged >40 years in comparison with those younger than 40 years, P < .001. All nonresponders were born in the Netherlands. Although no significant association was found between nonresponse and individuals of Western European origin (adjusted odds ratio [aOR] = 1.20; 95% CI, 0.66-2.44; P = .163), low response to HBV vaccination was significantly associated with Western European origin (aOR = 2.21; 95% CI, 1.41-3.86; P = .001). Significant determinants for nonresponse were older age at vaccination (aOR = 1.06; 95% CI, 1.06-1.07; P < .001) and male gender (aOR = 2.51; 95% CI, 1.97-3.22; P < .001).

CONCLUSIONS

The nonresponse rate was low in our study population. Our findings suggest that the vaccines being used for the primary vaccination are probably less immunogenic for older individuals, males, and persons of Western European origin.

A biocultural approach to psychiatric illnesses

RATIONALE

As a species, humans are vulnerable to numerous mental disorders, including depression and schizophrenia. This susceptibility may be due to the evolution of our large, complex brains, or perhaps because these illnesses counterintuitively confer some adaptive advantage. Additionally, cultural and biological factors may contribute to susceptibility and variation in mental illness experience and expression. Taking a holistic perspective could strengthen our understanding of these illnesses in diverse cultural contexts.

OBJECTIVES

This paper reviews some of these potential factors and contextualizes mental disorders within a biocultural framework.

RESULTS

There is growing evidence that suggests cultural norms may influence inflammation, neurotransmitters, and neurobiology, as well as the illness experience. Specific examples include variation in schizophrenia delusions between countries, differences in links between inflammation and emotion between the United States and Japan, and differences in brain activity between Caucasian and Asian participants indicating that cultural values may moderate cognitive processes related to social cognition and interoception.

CONCLUSIONS

Research agendas that are grounded in an appreciation of biocultural diversity as it relates to psychiatric illness represent key areas for truly interdisciplinary research that can result in culturally sensitive treatments and highlight possible biological variation affecting medical treatment.

Serologic testing of randomly selected children after hepatitis B vaccination: a cross-sectional population-based study in Lao People's Democratic Republic

BACKGROUND

Population immunity against hepatitis B virus (HBV) in Lao People's Demographic Republic (PDR) has not been examined since the national HBV vaccination program was started in 2002. Vaccine has been observed to be frozen at times during cold-chain transport in vaccination programs in Lao PDR and other developing countries, which will inactivate the vaccine. Therefore, this study used post-vaccination serologic testing to evaluate the effects of HBV immunization in Lao PDR.

METHODS

A cross-sectional serologic study was conducted among children (age range, 5-9 years) and mothers (15-45 years) who were randomly selected using probability-proportional-to-size sampling from central Lao PDR. Blood samples were collected as dried blood spots (DBS) and analyzed using chemiluminescent microparticle immunoassay to detect anti-hepatitis B surface (HBs) titers. We also evaluated the correlation between anti-HBs levels measured in DBS and serum among healthy healthcare workers in Vientiane.

RESULTS

Anti-HBs titers from DBS were strongly correlated with serum levels (correlation coefficient = 0.999) in all 12 healthcare workers evaluated. A linear regression model showed that 10 mIU/mL of serum anti-HBs was equivalent to 3.45 mIU/mL (95% CI: 3.06-3.85) of DBS. Among 911 mother-child pairs tested, 171 children had documentation of vaccination. Of the 147 children who had received ≥3 doses of the hepatitis B vaccine, 1 (0.7%) was positive for anti-HBs. The remaining 24 children received the hepatitis B vaccine only twice, once or no dose.

CONCLUSIONS

The results showed extremely low positivity for anti-HBs among vaccinated children in central Lao PDR. Therefore, post-vaccination serologic testing is important to evaluate population immunity against HBV infection. DBS testing is a potential low-cost tool to evaluating the effectiveness of HBV vaccination programs.

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.

Stunting correlates with high salivary and serum antibody levels after 13-valent pneumococcal conjugate vaccination of Venezuelan Amerindian children

OBJECTIVE

To determine the impact of pre-vaccination nutritional status on vaccine responses in Venezuelan Warao Amerindian children vaccinated with the 13-valent pneumococcal conjugate vaccine (PCV13) and to investigate whether saliva can be used as read-out for these vaccine responses.

METHODS

A cross-sectional cohort of 504 Venezuelan Warao children aged 6 weeks - 59 months residing in nine geographically isolated Warao communities were vaccinated with a primary series of PCV13 according to Centers for Disease Control and Prevention (CDC)-recommended age-related schedules. Post-vaccination antibody concentrations in serum and saliva of 411 children were measured by multiplex immunoassay. The influence of malnutrition present upon vaccination on post-vaccination antibody levels was assessed by univariate and multivariable generalized estimating equations linear regression analysis.

RESULTS

In both stunted (38%) and non-stunted (62%) children, salivary antibody concentrations correlated well with serum levels for all serotypes with coefficients varying from 0.61 for serotype 3-0.80 for serotypes 5, 6A and 23F (all p < 0.01). Surprisingly, higher serum and salivary antibody levels were observed with increasing levels of stunting in children for all serotypes. This was statistically significant for 5/13 and 11/13 serotype-specific serum and saliva IgG concentrations respectively.

CONCLUSION

Stunted Amerindian children showed generally higher antibody concentrations than well-nourished children following PCV13 vaccination, indicating that chronic malnutrition influences vaccine response. Saliva samples might be useful to monitor serotype-specific antibody levels induced by PCV vaccination. This would greatly facilitate studies of vaccine efficacy in rural settings, since participant resistance generally hampers blood drawing.

Malnutrition and vaccination in developing countries

Malnutrition contributes to an estimated 45% of deaths among children under 5 years of age in developing countries, predominantly due to infections. Malnourished children therefore stand to benefit hugely from vaccination, but malnutrition has been described as the most common immunodeficiency globally, suggesting that they may not be able to respond effectively to vaccines. The immunology of malnutrition remains poorly characterized, but is associated with impairments in mucosal barrier integrity, and innate and adaptive immune dysfunction. Despite this, the majority of malnourished children can mount a protective immune response following vaccination, although the timing, quality and duration of responses may be impaired. This paper reviews the evidence for vaccine immunogenicity in malnourished children, discusses the importance of vaccination in prevention of malnutrition and highlights evidence gaps in our current knowledge.

Impaired haemophilus influenzae type b transplacental antibody transmission and declining antibody avidity through the first year of life represent potential vulnerabilities for HIV-exposed but -uninfected infants

To determine whether immune function is impaired among HIV-exposed but -uninfected (HEU) infants born to HIV-infected mothers and to identify potential vulnerabilities to vaccine-preventable infection, we characterized the mother-to-infant placental transfer of Haemophilus influenzae type b-specific IgG (Hib-IgG) and its levels and avidity after vaccination in Ugandan HEU infants and in HIV-unexposed U.S. infants. Hib-IgG was measured by enzyme-linked immunosorbent assay in 57 Ugandan HIV-infected mothers prenatally and in their vaccinated HEU infants and 14 HIV-unexposed U.S. infants at birth and 12, 24, and 48 weeks of age. Antibody avidity at birth and 48 weeks of age was determined with 1 M ammonium thiocyanate. A median of 43% of maternal Hib-IgG was transferred to HEU infants. Although its level was lower in HEU infants than in U.S. infants at birth (P < 0.001), Hib-IgG was present at protective levels (>1.0 μg/ml) at birth in 90% of HEU infants and all U.S. infants. HEU infants had robust Hib-IgG responses to a primary vaccination. Although Hib-IgG levels declined from 24 to 48 weeks of age in HEU infants, they were higher than those in U.S. infants (P = 0.002). Antibody avidity, comparable at birth, declined by 48 weeks of age in both populations. Early vaccination of HEU infants may limit an initial vulnerability to Hib disease resulting from impaired transplacental antibody transfer. While initial Hib vaccine responses appeared adequate, the confluence of lower antibody avidity and declining Hib-IgG levels in HEU infants by 12 months support Hib booster vaccination at 1 year. Potential immunologic impairments of HEU infants should be considered in the development of vaccine platforms for populations with high maternal HIV prevalence.

The immune system in children with malnutrition--a systematic review

BACKGROUND

Malnourished children have increased risk of dying, with most deaths caused by infectious diseases. One mechanism behind this may be impaired immune function. However, this immune deficiency of malnutrition has not previously been systematically reviewed.

OBJECTIVES

To review the scientific literature about immune function in children with malnutrition.

METHODS

A systematic literature search was done in PubMed, and additional articles identified in reference lists and by correspondence with experts in the field. The inclusion criteria were studies investigating immune parameters in children aged 1-60 months, in relation to malnutrition, defined as wasting, underweight, stunting, or oedematous malnutrition.

RESULTS

The literature search yielded 3402 articles, of which 245 met the inclusion criteria. Most were published between 1970 and 1990, and only 33 after 2003. Malnutrition is associated with impaired gut-barrier function, reduced exocrine secretion of protective substances, and low levels of plasma complement. Lymphatic tissue, particularly the thymus, undergoes atrophy, and delayed-type hypersensitivity responses are reduced. Levels of antibodies produced after vaccination are reduced in severely malnourished children, but intact in moderate malnutrition. Cytokine patterns are skewed towards a Th2-response. Other immune parameters seem intact or elevated: leukocyte and lymphocyte counts are unaffected, and levels of immunoglobulins, particularly immunoglobulin A, are high. The acute phase response appears intact, and sometimes present in the absence of clinical infection. Limitations to the studies include their observational and often cross-sectional design and frequent confounding by infections in the children studied.

CONCLUSION

The immunological alterations associated with malnutrition in children may contribute to increased mortality. However, the underlying mechanisms are still inadequately understood, as well as why different types of malnutrition are associated with different immunological alterations. Better designed prospective studies are needed, based on current understanding of immunology and with state-of-the-art methods.

Comparing Haemophilus influenzae type b conjugate vaccine schedules: a systematic review and meta-analysis of vaccine trials

BACKGROUND

The optimal schedule and the need for a booster dose are unclear for Haemophilus influenzae type b (Hib) conjugate vaccines. We systematically reviewed relative effects of Hib vaccine schedules.

METHODS

We searched 21 databases to May 2010 or June 2012 and selected randomized controlled trials or quasi-randomized controlled trials that compared different Hib schedules (3 primary doses with no booster dose [3p+0], 3p+1 and 2p+1) or different intervals in primary schedules and between primary and booster schedules. Outcomes were clinical efficacy, nasopharyngeal carriage and immunological response. Results were combined in random-effects meta-analysis.

RESULTS

Twenty trials from 15 countries were included; 16 used vaccines conjugated to tetanus toxoid (polyribosylribitol phosphate conjugated to tetanus toxoid). No trials assessed clinical or carriage outcomes. Twenty trials examined immunological outcomes and found few relevant differences. Comparing polyribosylribitol phosphate conjugated to tetanus toxoid 3p+0 with 2p+0, there was no difference in seropositivity at the 1.0 μg/mL threshold by 6 months after the last primary dose (combined risk difference -0.02; 95% confidence interval: -0.10, 0.06). Only small differences were seen between schedules starting at different ages, with different intervals between primary doses, or with different intervals between primary and booster doses. Individuals receiving a booster were more likely to be seropositive than those at the same age who did not.

CONCLUSIONS

There is no clear evidence from trials that any 2p+1, 3p+0 or 3p+1 schedule of Hib conjugate vaccine is likely to provide better protection against Hib disease than other schedules. Until more data become available, scheduling is likely to be determined by epidemiological and programmatic considerations in individual settings.

Variation between Populations in the Innate Immune Response to Vaccine Adjuvants

The success of the World Health Organization recommended “Expanded Program of Immunization” (EPI) and similar regional or national programs has been astounding. However, infectious threats currently not covered by these programs continue to infect millions of infants around the world. Furthermore, many infants do not receive existing vaccines either on time or for the required number of doses to provide optimal protection. Nor do all infants around the world develop the same protective immune response to the same vaccine. As a result approximately three million infants die every year from vaccine preventable infections. To tackle these issues, new vaccines need to be developed as well as existing ones made easier to administer. This requires identification of age-optimized vaccine schedules and formulations. In order to be most effective this approach will need to take population-based differences in response to vaccines and adjuvants into account. This review summarizes what is currently known about differences between populations around the world in the innate immune response to existing as well as new and promising vaccine adjuvants.