Vitamin A Supplementation during Pregnancy Enhances Pandemic H1N1 Vaccine Response in Mothers, but Enhancement of Transplacental Antibody Transfer May Depend on When Mothers Are Vaccinated during Pregnancy

Association of fat-soluble vitamins (A, D, and E) status with humoral immune response to COVID-19 inactivated vaccination

Background

Fat-soluble vitamins (A, D, and E) are essential for the proper functioning of the immune system and are of central importance for infection risk in humans. Vitamins A, D, and E have been reported to be associated with the immune response following vaccination; however, their effects on the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination remain unknown.

Methods

We measured the neutralizing antibody titers against wild type and omicron within 98 days after the third homologous boosting shot of inactivated SARS-CoV-2 vaccine (BBIBP-CorV or CoronaVac) in 141 healthy adults in a prospective, open-label study. High-performance liquid chromatography-tandem mass spectroscopy was used to determine the concentrations of plasma vitamins A, D, and E.

Results

We found that the anti-wide-type virus and anti-omicron variant antibody levels significantly increased compared with baseline antibody levels (P < 0.001) after the third vaccination. 25(OH)D₃ was significantly negatively associated with the baseline anti-wide-type virus antibody concentrations [beta (95% CI) = -0.331 (-0.659 ~ -0.003)] after adjusting for covariates. A potentially similar association was also observed on day 98 after the third vaccination [beta (95% CI) = -0.317 (-0.641 ~ 0.007)]. After adjusting for covariates, we also found that 25(OH)D₃ was significantly negatively associated with the seropositivity of the anti-omicron variant antibody at day 98 after the third vaccination [OR (95% CI) = 0.940 (0.883 ~ 0.996)]. The association between plasma 25(OH)D₃ with anti-wild-type virus antibody levels and seropositivity of anti-omicron variant antibodies were persistent in subgroup analyses. We observed no association between retinol/α-tocopherol and anti-wide-type virus antibody levels or anti-omicron variant antibody seropositive in our study.

Conclusion

The third inactivated SARS-CoV-2 vaccination significantly improved the ability of anti-SARS-CoV-2 infection in the human body. Higher vitamin D concentrations could significantly decrease the anti-wide-type virus-neutralizing antibody titers and anti-omicron variant antibody seropositive rate after the inactivated SARS-CoV-2 vaccination in people with adequate levels of vitamin D, better immune status, and stronger immune response; further studies comprising large cohorts of patients with different nutritional status are warranted to verify our results.

Influenza vaccination during pregnancy and risk of selected major structural noncardiac birth defects, National Birth Defects Prevention Study 2006-2011

PURPOSE

To assess associations between influenza vaccination during etiologically-relevant windows and selected major structural non-cardiac birth defects.

STUDY DESIGN

We analyzed data from the National Birth Defects Prevention Study, a multisite, population-based case-control study, for 8233 case children diagnosed with a birth defect and 4937 control children without a birth defect with delivery dates during 2006-2011. For all analyses except for neural tube defects (NTDs), we classified mothers who reported influenza vaccination 1 month before through the third pregnancy month as exposed; the exposure window for NTDs was 1 month before through the first pregnancy month. For defects with five or more exposed case children, we used logistic regression to estimate propensity score-adjusted odds ratios (aORs) and 95% confidence intervals (CIs), adjusting for estimated delivery year and season; plurality; maternal age, race/ethnicity, smoking and alcohol use, low folate intake; and, for NTDs, folate antagonist medications.

RESULTS

There were 334 (4.1%) case and 197 (4.0%) control mothers who reported influenza vaccination from 1 month before through the third pregnancy month. Adjusted ORs ranged from 0.53 for omphalocele to 1.74 for duodenal atresia/stenosis. Most aORs (11 of 19) were ≤1 and all adjusted CIs included the null. The unadjusted CIs for two defects, hypospadias and craniosynostosis, excluded the null. These estimates were attenuated upon covariate adjustment (hypospadias aOR: 1.25 (95% CI 0.89, 1.76); craniosynostosis aOR: 1.23 (95% CI: 0.88, 1.74)).

CONCLUSIONS

Results for several non-cardiac major birth defects add to the existing evidence supporting the safety of inactivated influenza vaccination during pregnancy. Under-reporting of vaccination may have biased estimates downward.

Do Micronutrient and Omega-3 Fatty Acid Supplements Affect Human Maternal Immunity during Pregnancy? A Scoping Review

Maternal dietary micronutrients and omega-3 fatty acids support development of the fetal and neonatal immune system. Whether supplementation is similarly beneficial for the mother during gestation has received limited attention. A scoping review of human trials was conducted looking for evidence of biochemical, genomic, and clinical effects of supplementation on the maternal immune system. The authors explored the literature on PubMed, Cochrane Library, and Web of Science databases from 2010 to the present day using PRISMA-ScR methodology. Full-length human trials in English were searched for using general terms and vitamin A, B12, C, D, and E; choline; iodine; iron; selenium; zinc; and docosahexaenoic/eicosapentaenoic acid. Of 1391 unique articles, 36 were eligible for inclusion. Diverse biochemical and epigenomic effects of supplementation were identified that may influence innate and adaptive immunity. Possible clinical benefits were encountered in malaria, HIV infections, anemia, Type 1 diabetes mellitus, and preventing preterm delivery. Only limited publications were identified that directly explored maternal immunity in pregnancy and the effects of micronutrients. None provided a holistic perspective. It is concluded that supplementation may influence biochemical aspects of the maternal immune response and some clinical outcomes, but the evidence from this review is not sufficient to justify changes to current guidelines.

Serological Responses to Influenza Vaccination during Pregnancy

Pregnant women, newborns, and infants under six months old are at the highest risk of developing severe and even fatal influenza. This risk is compounded by the inability to vaccinate infants under six months, highlighting the importance of vertically transferred immunity. This review identifies novel insights that have emerged from recent studies using animal models of pregnancy and vaccination. We also discuss the knowledge obtained using existing clinical trials that have evaluated influenza-specific serological responses in pregnant women and how these responses may impact early life immunity. We delineate the mechanisms involved in transferring specific maternal antibodies and discuss the consequences for early life immunity. Most importantly, we highlight the need for continued research using pregnant animal models and the inclusion of pregnant women, a commonly neglected population, when evaluating novel vaccine platforms to better serve and treat communicable diseases.

Efficacy and safety of influenza vaccination during pregnancy: realizing the potential of maternal influenza immunization

Introduction: Pregnant women are at higher risk of severe complications following influenza infection compared to the general population. Influenza vaccination during pregnancy can offer direct protection to pregnant women and passive immunity to infants up to 6 months of age via maternal antibodies. Pregnant women are a high priority group for influenza immunization.Areas covered: This review provides an overview of the basis for recommending influenza vaccine to pregnant women, current immunization policies, the evidence supporting the safety and effectiveness of maternal vaccination, and future research needed. We conducted a search of PubMed for articles describing the safety or efficacy of influenza vaccines administered during pregnancy. Published articles from inception to 17 November 2020 were reviewed.Expert opinion: Experimental and observational evidence support the efficacy, effectiveness and safety of influenza immunization during pregnancy. These data support the continued provision of inactivated influenza vaccine to pregnant women, as recommended by global immunization policies. To achieve success with maternal influenza immunization programs, further work is needed to inform policy development in low- and middle-income settings and implementation and promotion in high-income settings.

Vitamin A Requirements in Pregnancy and Lactation

Pregnancy and lactation are critical life stages with unique nutritional requirements, including for vitamin A (VA). Current DRIs for VA were published in 2001. The objective of this review was to identify and categorize evidence related to VA requirements in pregnancy and lactation since these DRIs were formulated. We searched MEDLINE and included articles according to an analytic framework of maternal VA exposure on status and health outcomes in the mother-child dyad. Intermediate and indirect evidence supports that maternal VA intakes can impact the mother's VA status, breastmilk, and health outcomes, as well as the child's VA status and select health outcomes. Food-based approaches can lead to more sustained, sufficient VA status in mothers and children. Research needs include further study linking maternal VA intakes on maternal and child VA status, and further associations with outcomes to determine intake requirements to optimize health.

[Relationship of plasma vitamin A levels between neonates and pregnant women in third trimester]

OBJECTIVE

To study the correlation of plasma vitamin A (VitA) levels between neonates and pregnant women in third trimester.

METHODS

A total of 688 pregnant women were recruited in Yuanshi and Laoting counties of Hebei Province, from May to June 2009. Venous blood samples of women before delivery and cord blood samples of newborns were collected and measured for retinol (retinol concentration was used to reflect VitA level) using high performance liquid chromatography assay. According to venous blood plasma retinol concentration, maternal VitA nutritional status was divided into deficiency (<0.70 μmol/L), marginal deficiency (0.70-<1.05 μmol/L), and sufficiency (≥1.05 μmol/L). According to cord blood plasma retinol concentration, neonatal VitA nutritional status was divided into deficiency (<0.35 μmol/L), marginal deficiency (0.35-<0.70 μmol/L), and sufficiency (≥0.70 μmol/L); neonatal VitA relative deficiency was further defined as cord blood plasma retinol concentration lower than the 10th percentile. VitA placental transport ratio was defined as retinol concentration in the neonates divided by that in pregnant women. Multivariable fractional polynomials (MFP) model and Pearson correlation were used to study the dose-response relationship between maternal and neonatal plasma VitA levels, Logistic regression model to estimate the effect of maternal VitA nutritional status on neonatal VitA deficiency, and MFP model and Spearman correlation to describe the relationship between maternal VitA level and VitA placental transport ratio.

RESULTS

The average retinol concentration of the pregnant women was (1.15±0.30) μmol/L, and the prevalence of VitA deficiency and marginal deficiency were 4.5% and 37.8%, respectively. Average retinol concentration of the neonates was (0.78±0.13) μmol/L, and no neonates were VitA deficiency, 28.2% of the neonates were marginal deficiency. After multivariable adjustment, the VitA level of the neonates was positively and linearly related to maternal VitA level (p^m=1, P<0.05), with the corresponding Pearson correlation coefficient of 0.13 (P<0.01). As compared with the women with sufficient VitA, those with VitA deficiency (crude OR=2.20, 95%CI:1.04-4.66) and marginal deficiency (crude OR=1.43, 95%CI:1.01-2.02) had higher risks to deliver neonates with VitA marginal deficiency; while the risks turned to be non-significant after multivariable adjustment. The pregnant women with VitA deficiency had higher risk to deliver neonates with relative VitA deficiency before and after multivariable adjustment (crude OR=3.02, 95%CI:1.21-7.50; adjusted OR=2.76, 95%CI:1.05-7.22). The maternal VitA level was negatively and non-linearly correlated with placental transport ratio (p^m= -0.5, P<0.05), with corresponding adjusted Spearman correlation coefficient of -0.82 (P<0.001).

CONCLUSION

There was a positive linear dose-response relationship between VitA levels of newborns and pregnant women in third trimester, indicating that neonatal VitA storing levels at birth was affected by maternal VitA nutritional status.

Vitamin A and Wound Healing

Vitamin A is a general term for retinoids. Vitamin A deficiency leads to a variety of cutaneous manifestations. It also functions as a hormone through retinoic acid receptors altering the activity of multiple cell lines. Pancreatic vitamin A levels are critical for retinoid signaling and normal pancreatic control of glucose. Vitamin A deficiency is more common during infection, and supplementation reduces severe morbidity and mortality from infectious diseases. Vitamin A modulates activities at the cellular level and, via its interrelationship with hormones such as thyroid, insulin, and corticosteroids, has diffuse metabolic effects on the body. It plays an important role in all stages of wound healing. Vitamin A is known for its ability to stimulate epithelial growth, fibroblasts, granulation tissue, angiogenesis, collagen synthesis, epithelialization, and fibroplasia. Local (topical) and systemic supplementation with vitamin A has been proven to increase dermal collagen deposition. There are numerous animal studies and limited human studies regarding physiologic effect of vitamin A on acute or chronic wounds via systemic or topical administration. The most common use of vitamin A supplementation is to offset steroids' effect. When considering supplementation, the potential benefits must be weighed against the risk of harm. Vitamin A toxicity can be critical and even result in death. The evidence for supplementation with vitamin A is currently limited to expert opinion and is not backed up by rigorous trials. There is an acute need for therapeutic trials with vitamin A supplementations.

Vertically Transferred Immunity in Neonates: Mothers, Mechanisms and Mediators

Over the last years, an increasing number of outbreaks of vaccine-preventable infectious diseases has been reported. Besides elderly and immunocompromised individuals, newborns and small infants are most susceptible to infections, as their immune system is still immature. This vulnerability during infancy can be mitigated by the transplacental transfer of pathogen-specific antibodies and other mediators of immunity from mother to the fetus during pregnancy, followed postnatally by breast milk-derived immunity. Since this largely antibody-mediated passive immunity can prevent the newborn from infections, neonatal immunity depends strongly on the maternal concentration of respective specific antibodies during pregnancy. If titers are low or wane rapidly after birth, the protection transferred to the child may not be sufficient to prevent disease. Moreover, emerging concepts propose that mothers may transfer active immunity to the newborns via vertical transfer of pathogen-specific T cells. Overall, a promising strategy to augment and prolong neonatal immunity is to vaccinate the mother before or during pregnancy in order to boost maternal antibody concentrations or availability of specific T cells. Hence, a large number of pre-and postconceptional vaccine trials have been carried out to test and confirm this concept. We here highlight novel insights arising from recent research endeavors on the influence of prenatal maternal vaccination against pathogens that can pose a threat for newborns, such as measles, pertussis, rubella and influenza A. We delineate pathways involved in the transfer of specific maternal antibodies. We also discuss the consequences for children's health and long-term immunity resulting from an adjustment of prenatal vaccination regimes.

Oral vitamin A supplementation of porcine epidemic diarrhea virus infected gilts enhances IgA and lactogenic immune protection of nursing piglets

Vitamin A (VA) has pleiotropic effects on the immune system and is critical for mucosal immune function and intestinal lymphocyte trafficking. We hypothesized that oral VA supplementation of porcine epidemic diarrhea virus (PEDV)-infected pregnant gilts would enhance the gut-mammary gland-secretory IgA axis to boost lactogenic immunity and passive protection of nursing piglets against PEDV challenge. Gilts received daily oral retinyl acetate (30 000 IU) starting at gestation day 76 throughout lactation. At 3–4 weeks pre-partum, VA-supplemented (PEDV + VA) and non-supplemented (PEDV) gilts were PEDV or mock inoculated (mock + VA and mock, respectively). PEDV + VA gilts had decreased mean PEDV RNA shedding titers and diarrhea scores. To determine if lactogenic immunity correlated with protection, all piglets were PEDV-challenged at 3–5 days post-partum. The survival rate of PEDV + VA litters was 74.2% compared with 55.9% in PEDV litters. Mock and mock + VA litter survival rates were 5.7% and 8.3%, respectively. PEDV + VA gilts had increased PEDV IgA antibody secreting cells and PEDV IgA antibodies in serum pre-partum and IgA⁺β7⁺ (gut homing) cells in milk post piglet challenge compared with PEDV gilts. Our findings suggest that oral VA supplementation may act as an adjuvant during pregnancy, enhancing maternal IgA and lactogenic immune protection in nursing piglets.