Antibodies against vaccine-preventable diseases in pregnant women and their offspring in the eastern part of Germany

One single-center serological survey on measles, rubella and mumps antibody levels of people in Youyang, China

Although measles, rubella and mumps elimination had achieved great progress in recent years, outbreaks were still reported worldwide. Serological surveillance on the remaining susceptibility in the population is essential to evaluate the preventive policy, estimate the current risk of infection, and predict evolutions in the future. In this study, we aimed to investigate the prevalence of seropositivity of antibodies against measles, rubella and mumps in a population of all ages in Youyang, southwest China. A cross-sectional hospital-based study was conducted among 657 cases who attended to Youyang Hospital from Sep 2018 to Aug 2019. Sero IgG antibodies were measured by ELISA. No difference in the seropositivity of antibodies against measles, rubella and mumps was found between neither urban vs. rural, nor male vs. female. The overall seropositivity of anti-measles, rubella, mumps IgG antibodies was 81.1% (95% CI: 78.0-83.9), 65.9% (95% CI: 62.2-69.4) and 63.2% (95% CI: 59.4-66.8), respectively. The IgG seropositivity varied with age significantly. In this study, the seropositivity of antibodies against measles, rubella and mumps among the participants was insufficient in the population, especially among infants, teenagers and productive women, who were suggested to booster the immunity. To better control and eliminate measles, mumps and rubella-related diseases, nation-wide active laboratory-supported surveillance, outbreak investigation and revaccination for vulnerable population are needed.

Measles in pregnant women: A systematic review of clinical outcomes and a meta-analysis of antibodies seroprevalence

OBJECTIVES

Pregnant women represent a category at high risk of severe measles infection, that negatively affects the fetus as well. A systematic review of clinical outcomes of measles infection in gravid subjects and a meta-analysis of antibodies prevalence among pregnant women was conducted.

METHODS

MEDLINE and EMBASE databases were searched up to 18 June 2018. The screening focused on: (i) articles describing the outcome of measles in pregnancy, synthesized in a descriptive fashion; (ii) articles addressing the measles seroprevalence in cohorts of gravid women, analysed quantitatively.

RESULTS

Twenty-nine articles met inclusion criteria. A total of 420 cases of measles in gravid subjects were described, from 1941 to 2012. Among women, 18 deaths (4.3%) occurred, and the most frequent complication was pneumonia (75/420, 17.9%). Prematurity was the most important complication concerning fetal outcomes (55 out of 410 cases with available data, 13.4%). The random-effects pooled seroprevalence of measles in 20,546 gravid women worldwide was 89.3% (95% CI: 87.3-91.1%), that decreased, although not in a statistically significant way, over time (p = 0.54).

CONCLUSIONS

Measles infection in pregnancy is dangerous both for the mother and the foetus. Antibody seroprevalence among gravid women on a global scale is lower than the herd immunity threshold.

Seroprevalence of Maternal and Cord Antibodies Specific for Diphtheria, Tetanus, Pertussis, Measles, Mumps and Rubella in Shunyi, Beijing

Maternal antibodies contribute to the protection of young infants from infectious diseases during the early life. However, vaccinations for women of child-bearing age are not routine in China. Therefore, we investigated the level of protective immunity against vaccine preventable diseases in pregnant women and newborns in China. A total of 194 paired maternal and cord blood samples were collected in Beijing from 2016 to 2017. Antibodies specific for the antigens covered by diphtheria-tetanus-pertussis (DTP) and measles-mumps-rubella (MMR) vaccine were determined by ELISA (Euroimmun, Lübeck, Germany). The cut off value of ≥0.1 IU/ml (anti-diphtheria), >0.1 IU/ml (anti-tetanus), >40 IU/ml (anti-pertussis toxin), ≥200 IU/l (anti-measles), ≥45 RU/ml (anti-mumps) and ≥10 IU/ml (anti-rubella) were used to assess the percentage of newborns with protective IgG concentrations, respectively. The results revealed that 61.3%, 73.2%, 97.4%, 30.4%, 65.5% and 17.0% of newborns had no protection against diphtheria, tetanus, pertussis, measles, mumps and rubella. Only 1.0% and 23.7% of newborns had protection against all three components of DTP or MMR, respectively. The finding suggested that most of newborns were susceptible to diphtheria, tetanus, pertussis and mumps, almost one-third of this population had no immune protection against measles, and about one-sixth of them were under threat of rubella infection. These data supported the immunization program for DTP and MMR vaccine in women at child-bearing age.

Systematic Review of Measles and Rubella Serology Studies

Serological tests provide information about individual immunity from historical infection or immunization. Cross-sectional serological studies provide data about the age- and sex-specific immunity levels for individuals in the studied population, and these data can provide a point of comparison for the results of transmission models. In the context of developing an integrated model for measles and rubella transmission, we reviewed the existing measles and rubella literature to identify the results of national serological studies that provided cross-sectional estimates of population immunity at the time of data collection. We systematically searched PubMed, the Science Citation Index, and references we identified from relevant articles published in English. We extracted serological data for comparison to transmission model outputs. For rubella, serological studies of women of child-bearing age provide information about the potential risks of infants born with congenital rubella syndrome. Serological studies also document the loss of maternal antibodies, which occurs at different rates for the different viruses and according to the nature of the induced immunity (i.e., infection or vaccine). The serological evidence remains limited for some areas, with studies from developed countries representing a disproportionate part of the evidence. The collection and review of serological evidence can help program managers identify immunity gaps in the population, which may help them better understand the characteristics of individuals within their populations who may participate in transmission and manage risks.

Is EU/EEA population protected from polio?

The WHO European Region has been declared polio-free since 2002. By 2010, inactivated polio vaccine (IPV) was the only polio vaccine in use in the EU/EEA for the primary vaccination of children. A systematic review of the literature on polio seroprevalence studies, complemented by the analysis of available vaccine coverage data, has been carried out with the aim of assessing the level of protection against polio in the European population. A total of 52 studies, with data from 14 out of the 31 EU/EEA countries, were included in the analysis. This systematic review shows that, overall, seroprevalence for PV1 and PV3 is high in most countries, although seroimmunity gaps have been detected in several birth cohorts. In particular, relatively low immunity status was found in some countries for individuals born in the 60's and 70's. Discrepancies between reported vaccination coverage and immunity levels have been also highlighted. Countries should make sure that their population is being vaccinated for polio to reduce the risk of local poliovirus transmission in case of importation. Moreover, assessing immunity status should be priority for those traveling to areas where wild polioviruses are still circulating.

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.

Development of serum antibodies during early infancy in rhesus macaques: implications for humoral immune responses to vaccination at birth

BACKGROUND

A better understanding of immune responses in human infants could lead to more effective immunization and vaccination strategies in early life.

METHODS

Since antibodies are key components of protective vaccine responses, we examined developmental changes in serum levels of immunoglobulins (IgG, IgA, IgM) in infant rhesus macaques from birth through 6 months of age.

RESULTS

As in human infants, macaques are born with high levels of IgG in sera, with rapid increases in serum IgM, yet very slow increases in levels of IgA from birth. We also examined levels of anti-tetanus antibodies in infants born to vaccinated dams to distinguish and track maternal and infant antibodies. These data suggest essentially all serum IgG in newborn infants is derived from the dams, which gradually wanes over a few weeks. In contrast, levels of IgM and IgA appear to all be infant-derived, as evidenced by their low to undetectable levels at birth. In addition, abnormally high levels of serum IgM and IgA were detected in a few infants, which correlated with specific, yet clinically silent disease processes.

CONCLUSIONS

Our data indicate that newborn macaques have competent immune systems, and are able to produce their own antibodies in response to exposure to environmental antigens immediately upon birth.

Waning of maternal antibodies against measles, mumps, rubella, and varicella in communities with contrasting vaccination coverage

BACKGROUND

The combined measles, mumps, and rubella (MMR) vaccine has been successfully administered for >20 years. Because of this, protection by maternal antibodies in infants born to vaccinated mothers might be negatively affected.

METHODS

 A large cross-sectional serologic survey was conducted in the Netherlands during 2006-2007. We compared the kinetics of antibody concentrations in children and women of childbearing age in the highly vaccinated general population with those in orthodox Protestant communities that were exposed to outbreaks.

RESULTS

 The estimated duration of protection by maternal antibodies among infants in the general population, most of whom were born to vaccinated mothers, was short: 3.3 months for measles, 2.7 months for mumps, 3.9 months for rubella, and 3.4 months for varicella. The duration of protection against measles was 2 months longer for infants born in the orthodox communities, most of whom had unvaccinated mothers. For rubella, mothers in the orthodox communities had higher concentrations of antibodies as compared to the general population.

CONCLUSION

 Children of mothers vaccinated against measles and, possibly, rubella have lower concentrations of maternal antibodies and lose protection by maternal antibodies at an earlier age than children of mothers in communities that oppose vaccination. This increases the risk of disease transmission in highly vaccinated populations.

Maternal mumps antibodies in a cohort of children up to the age of 1 year

The duration of the presence of maternal mumps antibodies in a prospective cohort study is presented. Immunoglobulin G against mumps was portioned with a commercial ELISA test (Euroimmun® anti-mumps Virus AT ELISA, Germany) on samples from 213 mother-child pairs at seven time points between pregnancy and 12 months of age. Non-linear mixed models were used to model maternal antibody decay in infants. The model-based median time to loss of antibodies was 3.6 months. The median child-specific time to loss of antibodies in children of naturally immune women (3.8 months) and children of vaccinated women (2.4 months) differed significantly (p = 0.025). The log antibody level of the mother and the log birth weight were correlated with the duration of maternal antibodies in infants (p < 0.0001).

CONCLUSION

Children of vaccinated women loose maternal mumps antibodies significantly earlier in life compared to children of naturally infected women. If early administration (<12 months) of the combined measles, mumps, and rubella vaccine is needed, maternal mumps antibodies are not expected to interfere with infant humoral vaccine responses.

Prevalence of influenza A and B antibodies in pregnant women and their offspring

BACKGROUND

Influenza is associated with substantial morbidity and mortality in pregnant women and neonates, but few countries offer annual influenza vaccination with the inactivated vaccine to all women who are, or intend to become, pregnant.

OBJECTIVES

To provide seroepidemiological information on influenza A and B antibodies in pregnant women and their offspring in Germany.

STUDY DESIGN

Anti-influenza antibodies were determined using commercially available enzyme-linked immunosorbent assays (ELISA) on serum obtained from 209 women and their newborns at delivery.

RESULTS

The prevalence of antibodies against influenza A virus was 93.8% [89.6-96.6%] in the mothers and 96.7% [93.2-98.6%] in the newborns. The prevalence of antibodies against influenza B virus was 42.1% [35.3-49.1%] in the mothers and 78.5% [72.3-83.8%] in their newborns, which was a significant difference. The antibody concentrations against both influenza A and influenza B viruses were significantly lower in mother than in their newborns.

CONCLUSIONS

Because of active placental transport of IgG antibodies, neonates have higher prevalence and/or concentrations of influenza A and B virus-specific antibodies induced by natural infections than their mothers. Considering these serological findings, especially the lower prevalence of maternal antibody against influenza B virus, annual influenza vaccination may improve the protection of pregnant women and their offspring against influenza.

Passive transmission and persistence of naturally acquired or vaccine-induced maternal antibodies against measles in newborns

This paper reviews literature on passively transferred maternal antibodies against measles in infants. The amount and decay of these antibodies can be a result of changing patterns in society: increasing cohorts of women are vaccinated against measles instead of having naturally acquired immunity, the age of first childbirth is increasing and young adults are less exposed to natural boosters. The concentration and persistence of maternal antibodies differ in infants of women vaccinated against measles versus infants of naturally immune women. The date for commencing universal measles vaccination should take into account the presence of these antibodies since they can hamper the immunological response to vaccination. Each country should therefore consider adapting the timing of vaccination in relation to its measles sero-epidemiological situation. The possibility of priming the immune system with an early vaccine dose and boosting later on offers opportunities for vaccination at very young age.

The seroepidemiology of tetanus in Catalonia, Spain

Titres of anti-tetanus toxin antibodies > or = 0.1 IU/ml were determined using an enzyme linked immunosorbent assay in representative samples of the juvenile and adult population of Catalonia. The prevalence obtained in 1,316 juveniles and 1,296 adults was 99.4 and 68.3%, respectively. In adults, the prevalence in males (76.5%) was higher (P < 0.001) than in females (61.7%), fell with increasing age and was higher in subjects born in Catalonia (72.5%) than in those born outside Catalonia (57.9%) (P < 0.001). These results show that routine vaccination of children is successful. In adults aged > or = 45 years, the prevalence is inadequate and efforts should be made to increase vaccination.

Seroprevalence of rubella among Jordanian women of childbearing age

This study was conducted to assess immunity (seroprevalence) to rubella among Jordanian women of childbearing age. A multistage cluster sampling was used to recruit 1125 women of childbearing age (15-49 year) from the 12 Governorates of Jordan. Anti-rubella antibody titers were measured using enzyme-linked immunoassays. The overall immunity rate to rubella among women in childbearing age was 90.9% (CI: 88.8-92.9). However, the immunity rate was significantly lower in younger women aged 15-19 years (83%) compared to the whole cohort (P</=0.001) which means potential increased risk for congenital rubella syndrome (CRS). Immunity rates did not differ between regions and between urban and rural areas. Since the main priority is to decrease CRS among relatively susceptible cohorts, we recommend modifying the existing Expanded Program on Immunization with inclusion of a second dose of rubella vaccine at school entry (6 years of age) to decrease circulation of the virus among susceptible young females. We also recommend yearly catch-up school vaccination of young females entering the 10th grade for the next 10 years. Strengthening of rubella and CRS surveillance programs is also recommended in parallel with pre-marriage counseling regarding rubella and CRS for young females.

Sero epidemiology of Bordetella pertussis immune responses in a healthy population in northern Greece

A seroepidemiological study was conducted on a representative sample of the northern Greek population (healthy individuals, age range=1 day to 80 years) to assess the prevalence of antibodies to pertussis toxin (PT) and filamentous hemagglutinin (FHA). Antibody concentrations were significantly elevated with age (analysis of variance (ANOVA), P<0.001). In addition, a significant increase in antibody levels was detected in subjects >50 years old compared to children aged 5-10 years (post-hoc Scheffe analysis, P=0.007). These data suggest that pertussis occurs frequently in Greek adults, and that sometimes a fifth booster vaccine dose is not given after the second year of life. Routine revaccination with the acellular vaccine for children >4 years of age, adolescents, and adults should be considered in order to ensure effective protection of the whole population.

Placental boost to varicella-zoster antibodies in the newborn

IgG antibodies to varicella-zoster (VZV) were analyzed in cord and the corresponding maternal blood samples using the indirect fluorescence antibody test and the fluorescent antibody to membrane antigen test. The investigations revealed protective antibody levels in 96.7% of both newborns and mothers. In the cord blood samples, significantly higher titers were detected being indicative of an active placental transfer of VZV-specific IgG.