Antibodies to tetanus toxoid in women of childbearing age in Dar es Salaam and Bagamoyo, Tanzania

Effect of Plasmodium Infection during Pregnancy on Passive Neonatal Immunity against Tetanus Toxoid and Rotavirus

Passive immunity acquired through transplacental IgG transport is essential to protect infants against pathogens as childhood vaccination programs begins. Diarrhea caused by rotavirus and neonatal tetanus are common and potentially fatal childhood infections that can be prevented by transplacental IgG. However, it is not known whether maternal infections in pregnancy can reduce the transfer of these antibodies to the fetus. This study evaluated the effect of submicroscopic Plasmodium infection during pregnancy on the transfer of maternal IgG antibodies against rotavirus (anti-RV) and tetanus toxoid (anti-TT) to newborns of pregnant women residing in Puerto Libertador and Tierralta, Colombia. Expression of different immune mediators and levels of IgG against rotavirus and tetanus toxoid were quantified in pregnant women with and without Plasmodium infection during pregnancy. Submicroscopic infection at the time of delivery was associated with a cord-to-maternal ratio (CMR) > 1 for anti-RV and < 1 for anti-TT IgG, as well as with an increase in the expression of immune mediators of inflammation (IFN-γ), anti-inflammation (IL-10, TGF-β), and regulation (FoxP3, CTLA-4). When compared by species, these findings (CMR > 1 for anti-RV and < 1 for anti-TT IgG) were conserved in submicroscopic Plasmodium vivax infections at delivery. The impact of Plasmodium infections on neonatal susceptibility to other infections warrants further exploration.

Long-Term Immunogenicity upon Pertussis Booster Vaccination in Young Adults and Children in Relation to Priming Vaccinations in Infancy

Booster vaccinations for pertussis are advised in many countries during childhood or adulthood. In a phase IV longitudinal interventional study, we assessed long-term immunity following an extra pertussis booster vaccination in children and adults. Children (9 years of age) were primed in infancy with either the Dutch whole cell pertussis (wP) vaccine (n = 49) or acellular pertussis (aP) vaccines (n = 59), and all children received a preschool aP booster. Adults (25–29 years, n = 86) were wP-primed in infancy and did not receive a preschool booster. All were followed-up for approximately 6 years. After the additional booster, antibody responses to pertussis were more heterogeneous but generally higher in adults compared with children, and additional modelling showed that antibody concentrations remained higher for at least a decade. Serologic parameters indicative of recent pertussis infection were more often found in aP-primed children (12%) compared with wP-primed individuals (2%) (p = 0.052). This suggests that the aP booster vaccination in aP-primed children offers less long-term protection against pertussis infection and consequently against transmission. Together, these data show that aP priming in combination with aP boosting may not be sufficient to prevent circulation and transmission, while wP-primed adults may benefit from enhanced long-lasting immunity.

Short-term Persistence of Protective Maternally Acquired Immunity in Neonates Delivered by Primiparous Women in Ibadan, Nigeria

Background

Unresolved questions remain concerning the protective effect and duration of immunity acquired from mothers. This study investigated persistence of immunity against tetanus in the first two weeks of life among neonates in Nigeria.

Methods

In a longitudinal study, 244 primiparous mothers and their newborns were consecutively recruited at 16 selected Primary Healthcare Centres in Ibadan, Nigeria. All the newborns were tested for protection against tetanus using a validated rapid diagnostic, “Tetanos Quick Sticks” (TQS) on days 1, 7 and 14. Persistent immunity was defined as positive TQS result on day-14. Data were analysed using descriptive statistics, Chi-square and logistic regression at p = 0.05.

Results

There were 137(56.1%) male neonates; 87.7% were delivered at ≥37weeks of gestation. The prevalence of protective immunity against tetanus (PIaT) among neonates on day-1 was 63.5%; 119 out of 153 neonates remained positive to TQS test by day-14, giving a persistence rate of 77.8%. Independent predictors of persistent PIaT were residence in urban area (OR = 9.66; 95% CI = 2.42–38.45), maternal age (OR = 2.06; 95% CI = 1.49–2.85) and gestational age (OR = 1.84; 95% CI = 1.23–2.74).

Conclusion

Protective immunity against tetanus waned in some neonates over the first two weeks of life, and this decline was inversely related to maternal and gestational ages.

Maternal immunisation to improve the health of HIV-exposed infants

HIV-exposed but uninfected (HEU) infants are at an increased risk of many infectious diseases that can contribute to the high mortality seen among HEU children. Maternal immunisation could be a promising strategy to reduce infections in HEU infants. However, very little research has explored the effect of HIV on the immunogenicity and effectiveness of vaccines given during pregnancy. We review the available evidence on maternal immunisation among women living with HIV (WLWH) for all vaccines recommended, considered, or being investigated for routine or risk-based use during pregnancy. Of the 11 vaccines included, only three have been investigated in WLWH. Available evidence suggests that maternal HIV infection limits the immunogenicity of several vaccines, leaving HEU infants more susceptible to infection during their first few months of life. Whether maternal immunisation reduces the infectious morbidity and mortality associated with infectious diseases in HEU children remains unknown. We conclude the Review by identifying future research priorities.

Non-protective immunity against tetanus in primiparous women and newborns at birth in rural and urban settings in Ibadan, Nigeria

INTRODUCTION

Nigeria remains among the few countries that are yet to achieve eradication of neonatal tetanus in the world despite the availability of an effective vaccine. This study investigated immunity against tetanus in primiparous mothers and neonates at birth, and identified associated factors.

METHODS

This cross-sectional study involved consecutive selection of 244 primiparous mother-neonate pairs (119 from rural areas, 125 from urban areas, 137 male neonates and 107 female neonates) delivered at primary healthcare facilities in Ibadan, Nigeria. Socio-demographic characteristics, obstetric history, immunisation and birthweight were obtained from mothers by interview. A validated immunochromatographic rapid diagnostic test kit was used to test for immunity against tetanus. Positive and negative results were interpreted as protective immunity against tetanus (PIaT) and non-protective immunity against tetanus (NPIaT), respectively. Data were analysed using descriptive statistics, Chi-square and logistic regression at p = 0.05.

RESULTS

The mean age of mothers was 27.9±3.4 years (range: 20-33) and median birthweight was 2700g (range: 1760-3300). Of the 244 mothers, 198 (81.1%) received at least two doses of tetanus toxoid injection during pregnancy and prevalence of NPIaT and PIaT was 28.7% and 71.3%, respectively. The prevalence of PIaT was significantly higher among mothers in urban areas (n= 96; 80.7%) than rural (n=78; 62.4%), p<0.001.The prevalence of NPIaT among neonates was 36.5% (n= 89). Predictors of NPIaT among neonates were residence in rural LGA (OR = 2.22; 95% CI = 1.23-3.99) and maternal tetanus immunisation <2 doses (OR = 11.68; 95% CI = 4.05-21.75).

CONCLUSION

Lack of protective immunity against tetanus among neonates of primiparous women in Ibadan is prevalent and a more conscientious enforcement of routine tetanus prevention practices is needed.

Tetanus Immunity Gaps in Children 5-14 Years and Men ≥ 15 Years of Age Revealed by Integrated Disease Serosurveillance in Kenya, Tanzania, and Mozambique

Recent tetanus cases associated with male circumcision in Eastern and Southern Africa (ESA) prompted an examination of tetanus immunity by age and sex using multiplex serologic data from community surveys in three ESA countries during 2012-2013. Tetanus seroprotection was lower among children 5-14 years versus 1-4 years of age in Kenya (66% versus 90%) and Tanzania (66% versus 89%), but not in Mozambique (91% versus 88%), where children receive two booster doses in school. Among males ≥ 15 years of age, tetanus seroprotection was lower than females in Kenya (45% versus 96%), Tanzania (28% versus 94%), and Mozambique (64% versus 90%). Tetanus immunity from infant vaccination doses wanes over time, and only women of reproductive age routinely receive booster doses. To prevent immunity gaps in older children, adolescents, and adult men, a life-course vaccination strategy is needed to provide the three recommended tetanus booster doses.

Tetanus and diphtheria immunity among term and preterm infant-mother pairs in Turkey, a country where maternal and neonatal tetanus have recently been eliminated

The aim of our study was to investigate the anti-tetanus and anti-diphtheria antibody titres and the placental transfer of these antibodies in a group of vaccinated and unvaccinated mothers and their term or preterm offsprings. Anti-tetanus and anti-diphtheria toxoid IgG antibodies were measured quantitatively by ELISA in 91 infant-mother pairs. Protective concentrations of anti-tetanus and anti-diphtheria were found in 58.3 and 50% of mothers in the unvaccinated group and 94.5 and 85.5% of the mothers in the vaccinated group. Protective concentrations were found in 63.9 and 50% of cord samples, respectively, in the unvaccinated group and in 96.4 and 85.5% of cord samples, respectively, in the vaccinated group (p = 0.0001). There were no differences in the maternal and cord geometric mean concentrations (GMCs) of anti-toxoid antibodies between those who received two doses or one dose of Td. The GMCs of maternal and cord anti-tetanus and anti-diphtheria were statistically similar between preterm and term groups. Placental transfer ratios (TR) for anti-tetanus and anti-diphtheria were 175 and 150%, respectively, in the preterm group and 213 and 178%, respectively, in the term group. There was a strong correlation between maternal and cord anti-toxoid antibody levels. Maternal vaccination was the only predictor of having protective concentrations of anti-toxoid antibodies in cord blood.

CONCLUSIONS

Vaccinating pregnant women with at least one dose of Td would confer protection for both the term and preterm infant-mother pairs. Therefore, health personnel caring for pregnant women have the responsibility to emphasize the importance of Td vaccination to avoid missed immunization opportunities.

A microassay for measurement of Fc function of human immunoglobulin preparations by using tetanus toxoid as antigen

In order to minimize possible adverse reactions, the functional integrity of proteins in products derived from human plasma has to be unaffected by methods of preparation and storage conditions. Numerous biologically relevant functions of IgG, a major component of immunoglobulin for intravenous use preparations (IVIG), rely on the integrity of Fc fragments. Manufacturers are obliged to prove that Fc-mediated functions are maintained in IVIG preparations. The European Pharmacopoeia's monograph proposes a Rubella antigen-based test for Fc function of immunoglobulins. We present a modification of the proposed method achieved by using more convenient and readily available tetanus toxoid as an alternative antigen target and by adapting the procedure for the use on microtitre plates, thus greatly enhancing its feasibility and sample throughput. The test conditions were optimized so that batch-to-batch variability in tetanus antibody content did not influence the result. The precision of the test was within +/- 5%. By using this test, we compared Fc functionality of 9 commercial IVIG-7S preparations, which were prepared by using different virus inactivation/removal approaches. No significant differences between them have been found.

Does infection with Human Immunodeficiency Virus affect the antibody responses to Plasmodium falciparum antigenic determinants in asymptomatic pregnant women?

OBJECTIVES

HIV-seropositive pregnant women are more susceptible to malaria than HIV-seronegative women. We assessed whether HIV infection alters maternal and cord plasma malarial antibody responses and the mother-to-infant transfer of malaria antibodies.

METHODS

We determined plasma levels of maternal and cord antibodies [Immunoglobulin (IgG)] to recombinant malarial proteins [merozoite surface protein 1 (MSP-1(19kD)), the erythrocyte binding antigen (EBA-175)], the synthetic peptides [MSP-2, MSP-3, rhoptry associated protein 1 (RAP-1), and the pre-erythrocytic stage, circumsporozoite protein (NANP)(5)] antigenic determinants of Plasmodium falciparum; and tetanus toxoid (TT) by ELISA among samples of 99 HIV-seropositive mothers, 69 of their infants, 102 HIV-seronegative mothers and 62 of their infants.

RESULTS

The prevalence of maternal antibodies to the malarial antigenic determinants ranged from 18% on MSP3 to 91% on EBA-175; in cord plasma it ranged from 13% to 91%, respectively. More than 97% of maternal and cord samples had antibodies to TT. In multivariate analysis, HIV infection was only associated with reduced antibodies to (NANP)(5) in maternal (P=0.001) and cord plasma (P=0.001); and reduced mother-to-infant antibody transfer to (NANP)(5) (P=0.012). This effect of HIV was independent of maternal age, gravidity and placental malaria. No consistent HIV-associated differences were observed for other antigenic determinants.

CONCLUSION

An effect of HIV infection was only observed on one malarial antigenic determinant, suggesting that the increased susceptibility to malaria among HIV-infected pregnant women may not be explained on the basis of their reduced antibody response to malaria antigens.

Evaluation of a botulinum fragment C-based ELISA for measuring the humoral immune response in primates

An enzyme-linked immunosorbent assay (ELISA) using botulinum neurotoxin serotype B recombinant fragment C (rBoNTB(HC)) was developed to measure specific humoral immune responses of monkeys vaccinated with a vaccine consisting of rBoNTB(HC). Several fundamental parameters for a bioassay were evaluated. The evaluation results demonstrated that using BoNTB(HC) as the capture antigen led to a specific and sensitive ELISA for botulinum type B antibody with excellent precision, accuracy, and linearity. There was a good correlation (r=0.91) between ELISA titers and neutralization bioassay titers. Experimental results suggested that the ELISA could be useful for detecting botulinum type B antibody levels and may supplement mouse neutralization bioassays during planned clinical manufacturing and clinical trials of rBoNTB(HC) vaccine.