Immunogenicity at delivery after Tdap vaccination in successive pregnancies

Background

Tetanus, diphtheria, acellular pertussis (Tdap) vaccination is recommended to be administered in every pregnancy. Although the safety of this strategy has been confirmed, the immunogenicity of Tdap vaccination in two successive pregnancies has not yet been described. This study investigated Tdap-specific immunity levels and transplacental transfer in two successive pregnancies after repeated Tdap-vaccination.

Methods

Women enrolled in prior studies on Tdap vaccination during pregnancy were invited to participate in a follow-up study if they became pregnant again. Women who received a Tdap vaccine in both pregnancies were considered for this analysis. Tdap-specific total IgG and IgG subclasses were measured with a multiplex immunoassay.

Results

In total, 27 participants with a mean interval between deliveries of 2.4 years were included in the analysis. In maternal serum, Tdap-specific total IgG levels were comparable at both deliveries whereas in cord serum, all Tdap-specific total IgG antibody levels were reduced at the second compared to the first delivery. This was largely reflected in the IgG1 levels in maternal and cord serum. Transplacental transfer ratios of total IgG and IgG1 were also mostly reduced in the second compared to the first pregnancy.

Conclusion

This study reports for the first time Tdap-specific total IgG and IgG subclass levels and transfer ratios after repeated Tdap vaccination in successive pregnancies. We found reduced transfer of most Tdap-specific IgG and IgG1 antibodies in the successive pregnancy. As pertussis-specific antibodies wane quickly, Tdap vaccination in each pregnancy remains beneficial. However, more research is needed to understand the impact of closely spaced booster doses during pregnancy on early infant protection against pertussis.

Half-life Estimation of Pertussis-Specific Maternal Antibodies in (Pre)Term Infants After In-Pregnancy Tetanus, Diphtheria, Acellular Pertussis Vaccination

BACKGROUND

To reduce the risk of pertussis-related morbidity and mortality in early life, an increasing number of countries recommend maternal pertussis vaccination. However, there is limited knowledge about half-lives of vaccine-induced pertussis-specific maternal antibodies, especially in preterm infants, and factors potentially influencing them.

METHODS

We compared 2 different approaches to provide estimates of the half-lives of pertussis-specific maternal antibodies in infants and explored potential effects on the half-life in 2 studies. In the first approach, we estimated the half-lives per child and used these estimates as responses in linear models. In the second approach, we used linear mixed effect models on a log2 transformed scale of the longitudinal data to use the inverse of the time parameter as an estimate for the half-lives.

RESULTS

Both approaches provided similar results. The identified covariates partly explain differences in half-life estimates. The strongest evidence we observed was a difference between term and preterm infants, with the preterm infants showing a longer half-life. Among others, a longer interval between vaccination and delivery increases the half-life.

CONCLUSIONS

Several variables influence the decay speed of maternal antibodies. Both approaches have advantages and disadvantages, while the choice is secondary when assessing the half-life of pertussis-specific antibodies.

CLINICAL TRIALS REGISTRATION

NCT02408926 and NCT02511327.

Influence of the COVID-19 pandemic and social media on the behaviour of pregnant and lactating women towards vaccination: a scoping review

BACKGROUND

Pregnant women, foetuses and infants are at risk of infectious disease-related complications. Maternal vaccination is a strategy developed to better protect pregnant women and their offspring against infectious disease-related morbidity and mortality. Vaccines against influenza, pertussis and recently also COVID-19 are widely recommended for pregnant women. Yet, there is still a significant amount of hesitation towards maternal vaccination policies. Furthermore, contradictory messages circulating social media impact vaccine confidence.

OBJECTIVES

This scoping review aims to reveal how COVID-19 and COVID-19 vaccination impacted vaccine confidence in pregnant and lactating women. Additionally, this review studied the role social media plays in creating opinions towards vaccination in these target groups.

ELIGIBILITY CRITERIA

Articles published between 23 November 2018 and 18 July 2022 that are linked to the objectives of this review were included. Reviews, articles not focusing on the target group, abstracts, articles describing outcomes of COVID-19 infection/COVID-19 vaccination were excluded.

SOURCES OF EVIDENCE

The PubMed database was searched to select articles. Search terms used were linked to pregnancy, lactation, vaccination, vaccine hesitancy, COVID-19 and social media.

CHARTING METHODS

Included articles were abstracted and synthesised by one reviewer. Verification was done by a second reviewer. Disagreements were addressed through discussion between reviewers and other researchers.

RESULTS

Pregnant and lactating women are generally less likely to accept a COVID-19 vaccine compared with non-pregnant and non-nursing women. The main reason to refuse maternal vaccination is safety concerns. A positive link was detected between COVID-19 vaccine willingness and acceptance of other vaccines during pregnancy. The internet and social media are identified as important information sources for maternal vaccination.

DISCUSSION AND CONCLUSION

Vaccine hesitancy in pregnant and lactating women remains an important issue, expressing the need for effective interventions to increase vaccine confidence and coverage. The role social media plays in vaccine uptake remains unclear.

Immunogenicity of a liquid hexavalent DTaP-IPV-HB-PRP∼T vaccine after primary and booster vaccination of term and preterm infants born to women vaccinated with Tdap during pregnancy

BACKGROUND

Vaccination during pregnancy with tetanus, diphtheria, acellular pertussis (aP) (Tdap) antigens is important for early protection of newborn infants against pertussis, particularly for preterm infants. This study evaluated the effect of Tdap vaccination during pregnancy on the immunogenicity of a diphtheria (D), tetanus (T), aP, inactivated poliovirus (IPV), hepatitis B (HB), and Haemophilus influenzae type b (PRP ∼ T) vaccine in term and preterm populations.

METHODS

A prospective, observational study (NCT02511327) recruited women and their infants based on delivery (term or preterm) and vaccination status (vaccinated with a Tdap vaccine [Boostrix™, GlaxoSmithKline] during pregnancy or not vaccinated in the last 5 years). All infants received licensed DTaP-IPV-HB-PRP ∼ T (Hexyon™, Sanofi) (8, 12, 16 week primary series and booster at 13 months of age [preterm infants] or 15 months of age [term infants]). Immunogenicity was evaluated using validated assays. Data were pooled into term (N = 127) and preterm infants (N = 105), and infants of women who received a Tdap vaccine during pregnancy (N = 199) or not (N = 33).

RESULTS

Before primary vaccination, antibody levels were higher for term than preterm infants for anti-D, anti-polio 1, 2, 3, anti-PT, anti-FHA, and anti-PRP, and similar for anti-HBs and anti-T. At this time, infants of Tdap-vaccinated women had higher anti-D, anti-T, anti-PT, anti-FHA, and anti-PRP antibody levels than infants of Tdap-unvaccinated women; anti-HBs and anti-polio antibody levels were similar in both groups. Post-primary, pre-booster, and post-booster, there were only small differences in seroprotection rates (anti-D, anti-T, anti-polio 1, 2, 3, anti-HBs, anti-PRP) and seroconversion rates (anti-PT, anti-FHA), except for anti-HBs ≥ 10 mIU/mL and anti-PRP ≥ 0.15 µg/mL post-primary vaccination (higher for term [98.31 % and 90.91 %, respectively] versus preterm infants [89.80 % and 79.41 %, respectively]).

CONCLUSIONS

These data support the use of DTaP-IPV-HB-PRP ∼ T vaccine for primary and booster vaccination in term and preterm born infants and in infants born to Tdap-vaccinated or Tdap-unvaccinated women.

Haemophilus influenzae carriage and antibiotic resistance profile in Belgian infants over a three-year period (2016-2018)

Background

Non-typeable Haemophilus influenzae has become increasingly important as a causative agent of invasive diseases following vaccination against H. influenzae type b. The emergence of antibiotic resistance underscores the necessity to investigate typeable non-b carriage and non-typeable H. influenzae (NTHi) in children.

Methods

Nasopharyngeal swab samples were taken over a three-year period (2016-2018) from 336 children (6-30 months of age) attending daycare centers (DCCs) in Belgium, and from 218 children with acute otitis media (AOM). Biotype, serotype, and antibiotic resistance of H. influenzae strains were determined phenotypically. Mutations in the ftsI gene were explored in 129 strains that were resistant or had reduced susceptibility to beta-lactam antibiotics. Results were compared with data obtained during overlapping time periods from 94 children experiencing invasive disease.

Results

Overall, NTHi was most frequently present in both carriage (DCC, AOM) and invasive group. This was followed by serotype "f" (2.2%) and "e" (1.4%) in carriage, and "b" (16.0%), "f" (11.7%), and "a" (4.3%) in invasive strains. Biotype II was most prevalent in all studied groups, followed by biotype III in carriage and I in invasive strains. Strains from both groups showed highest resistance to ampicillin (26.7% in carriage vs. 18.1% in invasive group). A higher frequency of ftsI mutations were found in the AOM group than the DCC group (21.6 vs. 14.9% - p = 0.056). Even more so, the proportion of biotype III strains that carried a ftsI mutation was higher in AOM compared to DCC (50.0 vs. 26.3% - p < 0.01) and invasive group.

Conclusion

In both groups, NTHi was most frequently circulating, while specific encapsulated serotypes for carriage and invasive group were found. Biotypes I, II and III were more frequently present in the carriage and invasive group. The carriage group had a higher resistance-frequency to the analyzed antibiotics than the invasive group. Interestingly, a higher degree of ftsI mutations was found in children with AOM compared to DCC and invasive group. This data helps understanding the H. influenzae carriage in Belgian children, as such information is scarce.

The Impact of Timing of Pertussis Vaccination During Pregnancy on Infant Antibody Levels at Birth: A Multi-Country Analysis

Background

Pertussis vaccination during pregnancy is an effective strategy at reducing pertussis-related morbidity and mortality in infancy and is recommended across several countries. However, the optimal timepoint for vaccination in pregnancy to afford maximal protection to newborns is yet to be elucidated. This multi-country analysis aimed to model the impact of timing of vaccination during pregnancy on infant antibody titers at birth.

Methods

A multi-country analysis on a cohort of mother-infant pairs (n=698) vaccinated between 19.6-37.1 weeks gestation was conducted. Data taken from four parent studies on pertussis vaccination during pregnancy were modelled using natural cubic splines and linear mixed models to study the association of both gestational age at vaccination and the interval between vaccination and delivery with pertussis-specific cord blood antibody levels after pertussis vaccination during pregnancy.

Results

Term born infants on average achieve the highest antibody levels at birth if women are vaccinated before 31 weeks’ gestation. When considering both term and preterm deliveries, an interval of at least 7.5 weeks between vaccination and delivery is required to achieve the highest cord blood antibody levels. The models show that vaccinating earlier than these timeframes will also provide the infant with equally high antibody levels at birth.

Conclusions

Vaccinating in the second and early third trimester results in the highest antibody levels at birth. Vaccinating earlier within this window is needed to provide equal benefits to both term and preterm born infants.

The Effects of COVID-19 Vaccination on Lactating Women: A Systematic Review of the Literature

Objectives

The availability of new vaccines against COVID-19 urges for guidance about vaccination during lactation. We aimed to review the literature to get an insight into the effects of COVID-19 vaccination on lactating women.

Design

Systematic review.

Data Sources

We searched Ovid Embase Classic+Embase, PubMed and BioMed Central for articles published between December 1st 2020 and December 31st 2021.

Review Methods

The search strategy contained terms and combinations related to COVID-19 vaccination during lactation, including the MeSH terms "COVID-19", "COVID-19 Vaccines", "SARS-CoV-2", "Lactation", "Breast Feeding", "Pregnancy" and "Postpartum period". The database search was completed with a manual search of the reference lists of included articles. Data concerning country, study period, number of participants, type of applied vaccine, time points of sampling and outcome measures were collected from the selected manuscripts. The data are summarized and synthesized in a descriptive way.

Results

30 manuscripts were included in this review. Data on safety of COVID-19 vaccination during lactation indicate no severe vaccine-related local and systemic reactions, both after first and second dose, neither in the mother nor the nursing child. No significant amount of vaccine components seems to appear in breast milk. Milk supply data after vaccination are inconclusive as there are no quantitative data available. Some women however observe a temporary increase or reduction in milk supply, without long-term effects. All prospective cohort studies demonstrated the presence of SARS-CoV-2-specific antibodies in breast milk of nursing mothers vaccinated against SARS-CoV-2. Nearly all studies were conducted with mRNA vaccines.

Conclusion

There is evidence that the administration of a COVID-19 vaccine is safe and poses no additional risk to the breastfeeding woman or the breastfed baby. After vaccination of the mother during the lactation period, antibodies appear in the milk, which could protect the infant against COVID-19. Professional associations and government health authorities should therefore recommend offering COVID-19 vaccines to breastfeeding women, as the potential benefits of maternal vaccination while breastfeeding outweigh the risks.

Global Perspectives on Immunization Against SARS-CoV-2 During Pregnancy and Priorities for Future Research: An International Consensus Paper From the World Association of Infectious Diseases and Immunological Disorders

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pregnancy is associated with a higher risk for severe morbidity and mortality when compared with infection in non-pregnant women of childbearing age. An increasing number of countries recommend immunization against SARS-CoV-2 in pregnant women. Recent studies provide preliminary and supportive evidence on safety, immunogenicity and effectiveness of coronavirus disease 2019 (COVID-19) vaccines in pregnant women; however, important knowledge gaps remain which warrant further studies. This collaborative consensus paper provides a review of the current literature on COVID-19 vaccines in pregnant women, identifies knowledge gaps and outlines priorities for future research to optimize protection against SARS-CoV-2 in the pregnant women and their infants.

The half-life of maternal transplacental antibodies against diphtheria, tetanus, and pertussis in infants: an individual participant data meta-analysis

AIM

There are few reliable estimates of the half-lives of maternal antibodies to the antigens found in the primary series vaccines. We aimed to calculate the half-lives of passively acquired diphtheria, tetanus and pertussis (DTP) antibodies in infants. We aimed to determine whether decay rates varied according to country, maternal age, gestational age, birthweight, World Bank income classifications, or vaccine received by the mother during pregnancy.

METHODS

De-identified data from infants born to women taking part in 10 studies, in 9 countries (UK, Belgium, Thailand, Vietnam, Canada, Pakistan, USA, Guatemala and the Netherlands) were combined in an individual participant data meta-analysis. Blood samples were taken at two timepoints before any DTP-containing vaccines were received by the infant: at birth and at 2-months of age. Decay rates for each antigen were log₂-transformed and a mixed effects model was applied. Half-lives were calculated by taking the reciprocal of the absolute value of the mean decay rates.

RESULTS

Data from 1426 mother-infant pairs were included in the analysis. The half-lives of the 6 antigen-specific maternal antibodies of interest were similar, with point estimates ranging from 28.7 (95% CI: 24.4 - 35) days for tetanus toxoid antibodies to 35.1 (95% CI: 30.7 - 41.1) days for pertactin antibodies. The decay of maternal antibodies did not significantly differ by maternal age, gestational age, birthweight, maternal vaccination status or type of vaccine administered.

CONCLUSION

Maternal antibodies decay at different rates for the different antigens; however, the magnitude of the difference is small. Decay rates are not modified by key demographic or vaccine characteristics.

Impact of maternal pertussis antibodies on the infants' cellular immune responses

INTRODUCTION

Maternal antibody interference of the infant's humoral immune responses raises some concern to the strategy of maternal Tdap (tetanus, diphtheria, acellular pertussis [aP]) vaccination. This study assessed the impact of maternal Tdap antibodies on the infant's pertussis-specific T lymphocyte responses following infant vaccination with an aP containing vaccine, in a term and preterm born cohort.

METHODS

Heparin samples (±0.5mL) were conveniently drawn from infants of a Belgian prospective cohort study (N=79, NCT02511327), including Tdap vaccinated (Boostrix®) and non-vaccinated women (no Tdap vaccine in the last 5 years) that delivered at term or prematurely. Sampling was performed before and one month after primary (8-12-16 weeks) and booster vaccination (13 or 15 months) with DTaP-IPV-HB-PRP~T vaccine (Hexyon®). Pertussis toxin (PT)-specific CD3 +, CD3 +CD4 + and CD3 +CD8 + lymphoblasts and their cytokine secretions were measured using a flow cytometric assay on whole blood (FASCIA) and multiplex technology (Meso Scale Discovery), respectively.

RESULTS

57% of all infants were considered PT-specific CD3 +CD4 + lymphoblasts responders after primary and booster vaccination, whereas 17% were CD3 +CD8 + lymphoblast responders. IFN-γ, IL-13, IL-17A and IL-5 cytokine secretions after primary and booster vaccination were indicative of a mixed T helper (Th) 1/Th2/Th17 cell profile. Lymphoblast and cytokine levels were comparable between term and preterm infants. Non-responders for IL-13 after booster vaccination had higher maternal PT IgG levels at birth when compared to responders.

CONCLUSIONS

Term and preterm born infants are capable of inducing Th1, Th2 and Th17 responses after aP vaccination, yet maternal vaccination modulate these responses. Evaluation of this effect in larger trials is needed.

Factors affecting antibody responses to immunizations in infants born to women immunized against pertussis in pregnancy and unimmunized women: Individual-Participant Data Meta-analysis

BACKGROUND

Exploring factors that affect immune responses to immunizations in infants born to women immunized with tetanus-diphtheria-acellular-pertussis (Tdap) in pregnancy compared with unimmunized women is important in designing immunization programs.

METHODS

Individual-participant data meta-analysis of 8 studies reporting post-immunization immunoglobulin G (IgG) levels to vaccine antigens in infants born to either women immunized with Tdap in pregnancy or unimmunized women, using mixed-effects models.

RESULTS

In infants of Tdap-immunized women, two-fold higher levels of anti-pertussis toxin (PT) and anti-diphtheria-toxoid (DT) IgG pre-primary immunization were associated with 9% and 10% lower post-primary immunization levels, (geometric mean ratio [GMR], PT: 0.91; 95% CI, 0.88-0.95,n = 494, DT: 0.9; 0.87-0.93,n = 519). Timing of immunization in pregnancy did not affect post-primary immunization anti-Bordetella pertussis, anti-tetanus-toxoid (TT) and anti-DT IgG levels. Spacing of infant immunization did not affect post-primary immunization anti-B. pertussis and anti-DT levels. In infants of Tdap-immunized women, two-fold higher levels of anti-PT and anti-filamentous haemagglutinin (FHA) IgG pre-primary immunization were associated with lower post-booster immunization levels, (GMR, PT: 0.91; 0.85-0.97,n = 224, FHA: 0.92; 0.85-0.99,n = 232). Timing of immunization in pregnancy did not affect post-booster immunization anti-Bordetella pertussis, anti-tetanus-toxoid (TT) and anti-DT IgG levels. Spacing of infant immunization did not affect post-booster immunization anti-PT, anti-pertactin (PRN), anti-TT and anti-DT IgG levels. In infants of unimmunized women, two-fold higher IgG levels of some vaccine antigens pre-primary immunization were associated with 8-17% lower post-primary immunization levels (GMR, PT 0.92, 95% CI:0.88-0.97, n = 373; FHA:0.88, 95% CI:0.85-0.92,n = 378; PRN:0.84, 95% CI:0.81-0.88, n = 367; TT:0.88, 95% CI:0.83-0.93, n = 241; DT: 0.83, 95% CI:0.79-0.87,n = 278). Two-fold higher levels of anti-FHA IgG pre-primary immunization were associated with 8% lower post-booster immunization levels (GMR, 0.92; 95% CI: 0.86-0.99,n = 138).

DISCUSSION

Increased IgG levels pre-primary immunization is associated with reduced post-primary and post-booster immunization levels for some antigens in infants of women immunized or unimmunized in pregnancy, but their clinical significance is uncertain.

The Effect of Tetanus-Diphtheria-Acellular-Pertussis Immunization During Pregnancy on Infant Antibody Responses: Individual-Participant Data Meta-Analysis

Background

Immunization with tetanus-diphtheria-acellular pertussis (Tdap) vaccine in pregnancy is increasingly recommended. We determined the effect of Tdap immunization in pregnancy on infants' vaccine responses.

Methods

Individual-participant data meta-analysis of ten studies (n=1884) investigating infants' antibody response to routine immunizations following Tdap immunization in pregnancy was performed. Geometric mean ratios (GMRs) of antigen-specific immunoglobulin G (IgG) levels were calculated using mixed-effects models. Seroprotection rates were compared using chi-squared tests.

Results

Infants of Tdap-immunized women had significantly lower IgG against pertussis toxin (GMR 0.65; 95%CI 0.57-0.74), filamentous haemagglutinin (FHA) (0.68; 0.53-0.87), pertactin (0.65; 0.58-0.72) and fimbria 2/3 (FIM2/3) (0.41; 0.32-0.52) after primary immunization, compared with infants of unimmunized women. These lower levels persisted after booster immunization for FHA (0.72; 0.61-0.84) and FIM2/3 (0.53; 0.29-0.96). After primary immunization, infants of Tdap-immunized women had lower seroprotection rates against diphtheria (90% [843/973] vs 98% [566/579]; p<0.001) and invasive pneumococcal disease (IPD) caused by 5 Streptococcus pneumoniae (SPN) serotypes (SPN5, SPN6B, SPN9V, SPN19A, SPN23F), and higher seroprotection rates against Haemophilus influenzae type b (short-term and long-term seroprotection rates, 86%[471/547] vs 76%[188/247] and 62%[337/547] vs 49%(121/247), respectively, all p=0.001). After booster immunization, seroprotection rates against diphtheria and tetanus were 99% (286/288) and (618/619) in infants of Tdap-immunized women, respectively.

Conclusions

Infants of Tdap-immunized women in pregnancy had lower IgG levels against pertussis, diphtheria and some SPN serotypes after their immunization compared with infants of unimmunized women. Enhanced surveillance of pertussis, diphtheria and IPD in infants is needed to determine the clinical significance of these findings.

Systematic Review Registration

CRD42017079171.

Pertussis immunization during pregnancy: assessment of the role of maternal antibodies on immune responses in term and preterm born infants

BACKGROUND

Limited data exist on the impact of maternal Tetanus, Diphtheria, acellular Pertussis (aP) (Tdap) vaccination for preterm born infants. We report its effect at birth and on antibody-mediated immune responses to a DTaP-IPV-HB-PRP~T vaccine in preterm compared to term infants.

METHODS

Women delivering at term or prematurely were either vaccinated with a Tdap vaccine (Boostrix®, GSK) during pregnancy or not vaccinated in the last 5 years. Cord and maternal blood were collected at delivery. Infants were vaccinated with DTaP-IPV-HB-PRP~T vaccine (Hexyon®, Sanofi Pasteur) and bled before and one month after primary (8-12-16 weeks) and before and one month after booster vaccination (13 or 15 months for preterm and term respectively). Immunoglobulin G antibodies against all antigens included in DTaP-IPV-HB-PRP~T vaccine were measured (NCT02511327).

RESULTS

Cord blood Geometric Mean Concentrations (GMCs) in preterm infants from Tdap-vaccinated women were significantly higher than in term and preterm infants from unvaccinated women. A longer time interval between maternal vaccination and delivery resulted in higher cord blood GMCs in preterm infants. Equal GMCs in term and preterm infants from Tdap-vaccinated women were observed after primary vaccination. After boosting, significantly lower GMCs were seen for PT, FHA and TT in preterm compared to term infants from Tdap-vaccinated women, yet still comparable to GMCs in both term and preterm infants from unvaccinated women.

CONCLUSION

Preterm infants profit from maternal Tdap vaccination. Prematurity did not influence primary immune responses in the presence of maternal antibodies, but was associated with a lower booster immune response.

Measuring association among censored antibody titer data

Censoring due to a limit of detection or limit of quantification happens quite often in many medical studies. Conventional approaches to deal with censoring when analyzing these data include, for example, the substitution method and the complete case (CC) analysis. More recently, maximum likelihood estimation (MLE) has been increasingly used. While the CC analysis and the substitution method usually lead to biased estimates, the MLE approach appears to perform well in many situations. This article proposes an MLE approach to estimate the association between two measurements in the presence of censoring in one or both quantities. The central idea is to use a copula function to join the marginal distributions of the two measurements. In various simulation studies, we show that our approach outperforms existing conventional methods (CC and substitution analyses). In addition, rank‐based measures of global association such as Kendall's tau or Spearman's rho can be studied, hence, attention is not only confined to Pearson's product‐moment correlation coefficient capturing solely linear association. We have shown in our simulations that our approach is robust to misspecification of the copula function or marginal distributions given a small association. Furthermore, we propose a straightforward MLE method to fit a (multiple) linear regression model in the presence of censoring in a covariate or both the covariate and the response. Given the marginal distribution of the censored covariate, our method outperforms conventional approaches. We also compare and discuss the performance of our method with multiple imputation and missing indicator model approaches.

Breast milk antibody levels in Tdap vaccinated women after preterm delivery

INTRODUCTION/BACKGROUND & AIMS

Enrichment of breast milk (BM) with immunoglobin (Ig)A and IgG, through maternal vaccination, could help young infants combat targeted pathogens. However, evidence on this effect after preterm delivery is lacking. This study investigated the total and anti-pertussis toxin (anti-PT) specific IgA and IgG production in BM after term or preterm delivery in the presence of maternal Tdap (tetanus, diphtheria, acellular pertussis) vaccination.

METHODS

Serum and BM samples of lactating women, who delivered at term or prematurely and did or did not receive Tdap vaccine (Boostrix®, GSK Biologicals) during pregnancy, were collected as part of a clinical study (N=234, NCT02511327). Anti-PT IgA/IgG (IBL®; MSD®) and Total IgA/IgG (Thermofisher®, on BM samples only) immunosorbent assays were performed on all samples collected at 72 hours, 4, 8, and 12 weeks postpartum.

RESULTS

BM after preterm delivery contained anti-PT IgA and IgG geometric mean concentrations (GMCs) comparable to those after term delivery (e.g. colostrum anti-PT IgA: 5.39 International Units per milliliter (IU/mL) vs 6.69 IU/mL, respectively). Maternal Tdap vaccination induced significantly higher anti-PT IgG GMC's in colostrum of vaccinated compared to unvaccinated women delivering at term (0.110 IU/mL vs 0.027 IU/mL, p=0.009). Compliance with postpartum vaccination led to no differences in BM after 4 weeks postpartum. Anti-PT antibodies persisted up to 12 weeks postpartum.

CONCLUSIONS

This study provides evidence that maternal Tdap vaccination induces high Ig levels in BM after both term and preterm delivery and that these antibodies remain abundantly present throughout lactation, possibly offering additional mucosal protection during the most vulnerable period in early life.

Quantity and Quality of Antibodies After Acellular Versus Whole-cell Pertussis Vaccines in Infants Born to Mothers Who Received Tetanus, Diphtheria, and Acellular Pertussis Vaccine During Pregnancy: A Randomized Trial

BACKGROUND

The blunting effect of pertussis immunization during pregnancy on infant antibody responses induced by whole-cell pertussis (wP) vaccination is not well-defined.

METHODS

This randomized controlled trial (NCT02408926) followed term infants born to mothers vaccinated with tetanus, diphtheria, and acellular pertussis (Tdap) vaccine during pregnancy in Thailand. Infants received either acellular pertussis (aP)- or wP-containing vaccine at 2, 4, 6, and 18 months of age. A comparison group comprised wP-vaccinated children born to mothers not vaccinated during pregnancy. Antibodies against pertussis toxin (PT), filamentous hemagglutinin (FHA), and pertactin (PRN) were evaluated using commercial enzyme-linked immunosorbent assays. Functionality of antibodies against Bordetella pertussis was measured using Bordetella pertussis growth inhibition assay.

RESULTS

After maternal Tdap vaccination, 158 infants vaccinated with aP-containing vaccines possessed higher antibody levels (P < .001) against all tested B. pertussis antigens postpriming compared to 157 infants receiving wP-containing vaccines. At 1 month postbooster, only anti-FHA and anti-PRN antibodies were still significantly higher (P < .001) in the aP group. Significantly higher anti-PT and anti-FHA (P < .001), but not anti-PRN immunoglobulin G, were observed among 69 wP-vaccinated infants born to control mothers compared with wP-vaccinated infants of Tdap-vaccinated mothers after primary and booster vaccination. The antibody functionality was higher in all wP-vaccinated infants at all times.

CONCLUSIONS

Maternal Tdap vaccination inhibited more pertussis-specific responses in wP-vaccinated infants compared to aP-vaccinated infants, and the control group of unvaccinated women had highest PT-specific responses, persisting until after the booster dose. Antibody functionality was better in the wP groups.

CLINICAL TRIALS REGISTRATION

NCT02408926.Infant whole-cell pertussis (wP) vaccine responses are blunted after maternal Tdap vaccination. Pertussis antibody titers are higher in acellular pertussis (aP)- than wP-vaccinated infants of immunized mothers, yet quality of antibodies, measured as serum-mediated bacterial growth inhibition, is better after wP than aP vaccination.

Protection of the Newborn Through Vaccination in Pregnancy

Newborns and infants are at risk for severe infections with some pathogens (eg, Bordetella pertussis, influenza, respiratory syncytial virus, group B Streptococcus) during early life. To decrease this window of high susceptibility to some infections during early life and protect young infants, vaccination in pregnancy against some vaccine-preventable diseases (eg, influenza, pertussis, tetanus) has been recommended in an increasing number of countries with notable success. In addition, recent advances have been made in developing vaccines for pregnant women with the aim of reducing the respiratory syncytial virus and group B Streptococcus burden in infancy. In this article, we review the vaccines currently recommended during pregnancy and their benefits to newborns and infants. We also discuss progress made in the development of other vaccines that are expected to be evaluated in pregnant women in the near future.

Coronavirus Disease-19: An Interim Evidence Synthesis of the World Association for Infectious Diseases and Immunological Disorders (Waidid)

Coronavirus disease 2019 (COVID-19) is a rapidly evolving, highly transmissible, and potentially lethal pandemic caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As of June 11 2020, more than 7,000,000 COVID-19 cases have been reported worldwide, and more than 400,000 patients have died, affecting at least 188 countries. While literature on the disease is rapidly accumulating, an integrated, multinational perspective on clinical manifestations, immunological effects, diagnosis, prevention, and treatment of COVID-19 can be of global benefit. We aimed to synthesize the most relevant literature and experiences in different parts of the world through our global consortium of experts to provide a consensus-based document at this early stage of the pandemic.

Levels of antibodies specific to diphtheria toxoid, tetanus toxoid, and Haemophilus influenzae type b in healthy children born to Tdap-vaccinated mothers

INTRODUCTION

Vaccination of pregnant women protects both women and their newborns against some infectious diseases. Thailand implemented tetanus toxoid (TT) vaccination of pregnant women in 1977, which was replaced by tetanus-diphtheria toxoid (dT) vaccination in 2005. The tetanus-diphtheria-acellular pertussis (Tdap) vaccine has been recommended for pregnant women at 27-36 weeks of gestation since 2012 in several countries. Data on antibody responses to diphtheria toxoid (DT), TT, and Hemophilus influenzae type b (Hib) induced by combined vaccines in children born to TT-vaccinated and/or Tdap-vaccinated mothers are limited.

MATERIAL AND METHODS

We investigated anti-DT, anti-TT, and anti-Hib IgG responses in a cohort of Thai children (ClinicalTrial.gov NCT02408926) born to mothers who received a TT-containing and/or the Tdap vaccine during pregnancy. Children born to Tdap-vaccinated mothers were randomized to receive either a hexavalent (Infanrix-hexa) or pentavalent (Quinvaxem) vaccine, whereas children born to TT-vaccinated mothers received only Quinvaxem vaccine at 2, 4, 6, and 18 months of age. IgG levels were evaluated at birth (cord blood), 2 (pre-primary), 7 (post-primary), 18 (pre-booster), and 19 months of age (post-booster) using a commercially available enzyme-linked immunoassay.

RESULTS

Seroprotective concentrations of anti-DT, anti-TT, and anti-Hib IgG were achieved in >90% and >99% of children following primary and booster vaccination, respectively. Among children born to Tdap-vaccinated mothers, the pentavalent vaccine induced higher levels of anti-Hib IgG than the hexavalent vaccine after primary and booster vaccination. Significantly higher anti-Hib IgG levels were observed among children receiving the pentavalent vaccine and who were born to TT-vaccinated mothers than among children receiving the pentavalent vaccine and born to Tdap-vaccinated mothers after primary and booster vaccination.

CONCLUSIONS

Vaccination with a TT-containing and/or the Tdap vaccine during pregnancy did not compromise the seroprotection rate achieved following primary and booster immunization in individuals receiving either the pentavalent or hexavalent vaccine.

Global Perspectives on Immunization During Pregnancy and Priorities for Future Research and Development: An International Consensus Statement

Immunization during pregnancy has been recommended in an increasing number of countries. The aim of this strategy is to protect pregnant women and infants from severe infectious disease, morbidity and mortality and is currently limited to tetanus, inactivated influenza, and pertussis-containing vaccines. There have been recent advancements in the development of vaccines designed primarily for use in pregnant women (respiratory syncytial virus and group B Streptococcus vaccines). Although there is increasing evidence to support vaccination in pregnancy, important gaps in knowledge still exist and need to be addressed by future studies. This collaborative consensus paper provides a review of the current literature on immunization during pregnancy and highlights the gaps in knowledge and a consensus of priorities for future research initiatives, in order to optimize protection for both the mother and the infant.

Vaccination during pregnancy: current and possible future recommendations

Immunizing pregnant women to protect the mother, fetus and infant from infection has increasingly been used over the last decade. Protection against infectious diseases in neonates is mainly provided by maternal antibodies transferred from mother to infant during pregnancy through transplacental transport or after delivery via breastfeeding. Both the transplacental- and breast milk-derived maternal antibodies function as the primary source of protection against infectious diseases in neonates during the first vulnerable weeks of life. During recent infectious disease outbreaks (influenza, pertussis, Zika…) and for other infectious diseases (CMV, GBS…), pregnant women are increasingly identified as an important target for vaccination. For some of these diseases, vaccines are already on the market, and recommended during pregnancy. For others, vaccines are currently under development; furthermore, some are even specifically designed to be administered during pregnancy.Conclusion: This review article provides an overview on the rationale and main mechanism of the maternal vaccination strategy and gives a summary about the current and possible future recommendations for maternal vaccination.What is Known:• Maternal vaccination has a far-reaching potential in the protection of both women and offspring.• Currently, tetanus, pertussis and influenza vaccination during pregnancy is recommended in some countries. Several new vaccines specifically designed for use in pregnancy are currently under development.What is New:• Review providing a timely overview of the rationale and main mechanisms of the maternal vaccination strategy• Up-to-date summary of the current and possible future recommendations for maternal vaccination.

Assessing the reactogenicity of Tdap vaccine administered during pregnancy and antibodies to Bordetella pertussis antigens in maternal and cord sera of Thai women

INTRODUCTION

Pregnant Thai women have low antibody titers against B. pertussis antigens, which coincide with an increasing incidence of pertussis among Thai infants. Thus, there exists a potential benefit of a booster dose of tetanus- diphtheria-acellular pertussis (Tdap) vaccine administered during pregnancy. Here, we report the vaccine reactogenicity profile and birth outcomes in Tdap-vaccinated pregnant women who have or have not had prior immunization with tetanus vaccine, and the IgG levels to B. pertussis antigens in maternal and cord sera at delivery.

MATERIALS AND METHODS

Pregnant women (N = 370) aged 18-40 years were administered the Tdap vaccine (Boostrix®, GlaxoSmithKline, Rixensart, Belgium) at 26-36 weeks gestation. Adverse events following vaccination were identified by follow-up telephone call and medical record review. IgG against pertussis toxin (anti-PT), filamentous hemagglutinin (anti-FHA) and pertactin (anti-PRN) in both maternal and umbilical cord blood obtained at delivery were quantitatively evaluated using enzyme-linked immunosorbent assay (EUROIMMUN®, Lübeck, Germany).

RESULTS

There was no reported increase in the severity or duration of adverse events associated with the administration of an extra tetanus-containing vaccine within the previous five years (N = 181) or multiple doses of tetanus-containing vaccines during the current pregnancy (N = 98). Vaccination at least eight weeks prior to delivery resulted in high antibody titers to all B. pertussis antigens studied.

CONCLUSIONS

The reactogenicity of Tdap vaccine administered during pregnancy was not affected by prior tetanus toxoid immunization. High transplacental antibody against B. pertussis antigens in the cord blood provides evidence of antibody transfer and should thus help to protect newborns from pertussis during early life.

Assessment of the timely administration of the hepatitis B and BCG birth dose and the primary infant vaccination schedule in 2015-2016 in the Mekong Delta, Viet Nam

INTRODUCTION

Vietnam is implementing hepatitis B (HBV) birth dose (BD) vaccination since 2003 but coverage remains low, especially in the Mekong River Delta. This study aimed to determine the coverage of the HBV BD vaccination, to identify socio-demographic factors influencing HBV BD, and to assess reasons for non-immunization of neonates.

METHODS

A cross-sectional survey was conducted in 2015-2016. Mothers from 526 children aged 6-11 months living in 3 provinces in the Mekong River Delta - representing respectively urban, rural and remote area - were interviewed at home and infant vaccination documents were checked. The three-stage sampling method was adapted from WHO 30-cluster sampling. Predictors of HBV BD administration were identified with multiple regression analysis.

RESULTS

The overall HBV BD coverage (within 24 h) was 46.6% (compared to 44.5% for BCG) and was significantly higher in remote or rural than in urban area (OR 1.87 and 3.36, respectively), and in children whose father had a higher educational level (OR 2.76; 2.29 and 1.86, respectively, for master degree, bachelor and secondary school) as compared to a lower level. Main reasons for not having received HBV BD mentioned by parents were vaccines not offered by health care workers (53.0%), and illness of the infant (27.2%).

CONCLUSION

Although Vietnam started HBV BD vaccination more than 10 years ago, the coverage and timeliness need to improve to reach WHO targets (95% within 24 h after birth). Better training and information of health care workers, and better protocols ensuring timely HBV BD could address these vaccine administration thresholds.

Coverage of recommended vaccines during pregnancy in Flanders, Belgium. Fairly good but can we do better?

BACKGROUND

In Flanders, Belgium, pertussis vaccination is recommended since 2013 and available free-of-charge in every pregnancy between 24 and 32 weeks of gestation. Influenza vaccination is recommended for more than 10 years with a co-payment system in the second or third trimester of pregnancy, when pregnancy coincides with the influenza season. This study aims to estimate the coverage of pertussis and influenza vaccination during pregnancy in 2016 and to determine predictors for missing vaccination.

METHODS

Postpartum women were visited at home for a vaccination coverage survey using an Expanded Program on Immunization (EPI)-based two-stage cluster sampling design. Predictors for missed vaccination were identified using a multiple logistic regression model.

RESULTS

Among 481 participating women, 69.3% were vaccinated against pertussis and 47.2% were vaccinated against influenza. Moreover, 65.3% of pertussis vaccine recipients and 96.9% of influenza vaccine recipients were vaccinated within the recommended gestational window. Surprisingly, among women who were completely informed (i.e. on disease-associated risks, maternal vaccination costs and recommendations), still 12.4% were unvaccinated against pertussis and 23.9% against influenza. In the final models, the only common predictor of missing maternal pertussis and influenza vaccination was multiparity. Significant predictors of maternal pertussis vaccination were family income (less likely if unknown or low (< €3000) than if moderate (€3001-€4000)) and hospital of delivery (less likely if >800 annual deliveries than <800). Significant predictors of maternal influenza vaccination, though with less straight-forward associations, were maternal ethnicity and educational level, involvement of a gynaecologist in pregnancy follow-up, and characteristics of the hospital of delivery.

CONCLUSION

In Flanders, more than two-third of pregnant women receives pertussis vaccination but less than half of them receives the influenza vaccine. Further improvement for both maternal vaccination programs can be achieved by targeting the underserved populations and diminishing vaccination hurdles.

The Effect of Maternal Pertussis Immunization on Infant Vaccine Responses to a Booster Pertussis-Containing Vaccine in Vietnam

Background. Maternal vaccination with an acellular pertussis (aP)–containing vaccine is a recommended strategy in a growing number of industrialized countries, to protect young infants from disease. Little is known on the effect of this strategy in low- and middle-income countries. Following a previous report on the effect of adding a pertussis and diphtheria component to the tetanus vaccination program in pregnant women in Vietnam, we report on infant immune responses to a booster aP vaccine dose in this randomized controlled clinical trial.

Methods. Thirty infants of Tdap (tetanus, diphtheria, and acellular pertussis)–vaccinated pregnant women and 37 infants of women vaccinated with a tetanus-only vaccine received a fourth aP-containing vaccine dose in the second year of life. Blood was taken 1 month after the fourth infant dose. Immunoglobulin G (IgG) antibodies against pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (Prn), tetanus toxoid (TT), and diphtheria toxoid (DT) were measured using commercially available enzyme-linked immunosorbent assays (ELISA).

Results. One month after the booster dose, significantly lower antibody titers were measured in the Tdap group for anti-TT IgG (P < .001) only. Anti-DT IgG, anti-PT IgG, anti-Prn IgG, and anti-FHA IgG antibody titers were comparable for both groups. A rise in antibody concentrations was elicited for all (except DT) antigens after boosting.

Conclusions. The present results indicate that the blunting of infant pertussis responses induced by maternal immunization, measured after a primary series of aP vaccines, was resolved with the booster aP vaccine dose. These results add to the evidence for national and international decision makers on maternal immunization as a vaccination strategy for protection of young infants against infectious diseases.

Effect of Prepregnancy Pertussis Vaccination in Young Infants

Background

Maternal antibodies to pertussis can hamper infant immune responses to pertussis vaccines. The effect a maternal tetanus, diphtheria, acellular pertussis (Tdap) vaccine booster between 2 consecutive pregnancies is investigated.

Methods

A prospective study was conducted in Belgium during 2008-2014 on the kinetics of maternal pertussis antibodies in unvaccinated women and their infants (group A; 86 mother-infant pairs) and in siblings born after the women received Tdap vaccine (group B; 58 mother-infant pairs). Levels of antibody to pertussis toxin, antibody to filamentous hemagglutinin, and antibody to pertactin were measured in maternal blood before and after vaccination and at both deliveries, in cord blood from both siblings, and in infants before and after they received a priming series of acellular pertussis containing vaccines.

Results

Levels of pertussis antibodies in all group B siblings at birth were significantly higher than those in their siblings at birth, even as the interval since maternal vaccination increased. Blunting of the infant pertussis vaccine response was detected in group B siblings. We estimated the maximum interval between repeat Tdap vaccine doses in adult women that would yield a beneficial effect for the consecutive infant.

Conclusions

Prepregnancy Tdap vaccination significantly increases maternal antibody concentrations in consecutive infants. However, similar to the effect of Tdap vaccination during pregnancy, immune responses of later-born infants born to mothers who received a prepregnancy immunization, are blunted.

Influence of maternal vaccination against diphtheria, tetanus, and pertussis on the avidity of infant antibody responses to a pertussis containing vaccine in Belgium

Maternal antibodies induced by vaccination during pregnancy cross the placental barrier and can close the susceptibility gap to pertussis in young infants up to the start of primary immunization. As not only the quantity but also the quality of circulating antibodies is important for protection, we assessed whether maternal immunization affects the avidity of infant vaccine-induced IgG antibodies, in the frame of a prospective clinical trial on pregnancy vaccination in Belgium. Infants born from Tdap (Boostrix®) vaccinated (N = 55) and unvaccinated (N = 26) mothers were immunized with a hexavalent pertussis containing vaccine (Infanrix Hexa®) at 8, 12 and 16 weeks, followed by a fourth dose at 15 months of age. Right before and one month after this fourth vaccine dose, the avidity of IgG antibodies against diphtheria toxin (DT), tetanus toxin (TT), pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (Prn) was determined using 1.5 M ammonium thiocyanate as dissociating agent. In both groups, antibody avidity was moderate for TT, PT, FHA and Prn and low for DT after priming. After a fourth dose, antibody avidity increased significantly to high avidity for TT and PT, whereas it remained moderate for FHA and Prn and low for DT. The avidity correlated positively with antibody level in both study groups, yet not significantly for PT. When comparing both study groups, only PT-specific antibodies showed significantly lower avidity in infants born from vaccinated than from unvaccinated mothers after the fourth vaccine dose. The clinical significance of lower avidity of vaccine induced infant antibodies after maternal vaccination, if any, needs further investigation.

Pertussis vaccination during pregnancy in Belgium: Results of a prospective controlled cohort study

Vaccination during pregnancy has been recommended in some countries as a means to protect young infants from severe infection. Nevertheless, many aspects are still unknown and possible blunting of the infant's immune responses by maternal antibodies, is one of the concerns with maternal vaccination. We report the first prospective controlled cohort study in women and infants on the effects of using Boostrix(®), a combined tetanus, diphtheria and acellular pertussis vaccine, during pregnancy. The primary aim was to measure the influence of this booster dose on the titer and duration of the presence of maternal antibodies in the infants and assess possible interference with infant immune responses. In a controlled cohort study, 57 pregnant women were vaccinated with Tdap vaccine (Tetanus Diphtheria acellular Pertussis, Boostrix, GSK Biologicals), at a mean gestational age of 28.6 weeks. A control group of pregnant women (N=42) received no vaccine. Antibody geometric mean concentrations (GMCs) against tetanus (TT), diphtheria (DT), pertussis toxin (PT), filamentous haemagglutinin (FHA) and pertactin (Prn) were measured with commercial ELISA tests in samples taken preceding maternal vaccination and one month afterwards, at delivery and from the cord blood, and in infants before and 1 month after the primary series of 3 pertussis containing hexavalent vaccines. Infants born to vaccinated women had significantly higher GMC at birth and during the first 2 months of life for all vaccine antigens compared to the offspring of unvaccinated women, thereby closing the susceptibility gap for pertussis in infants. However, blunting was noticed for infant diphtheria and pertussis toxin vaccine responses (p<0.001) in the infants from vaccinated women after the primary vaccination schedule (weeks 8,12 and 16). Since pertussis vaccination has been recommended during pregnancy already, the results of this study support that recommendation and provide additional scientific evidence to document possible interference by maternal antibodies.

Pertussis vaccination during pregnancy in Vietnam: Results of a randomized controlled trial Pertussis vaccination during pregnancy

A pertussis vaccination during pregnancy has recently been adopted in several countries to indirectly protect young infants. This study assessed the effect of adding a pertussis component to the tetanus vaccination, in the pregnancy immunization program in Vietnam. A randomized controlled trial was performed. Pregnant women received either a Tdap (tetanus, diphtheria acellular pertussis) vaccine or a tetanus only vaccine between 19 and 35 weeks' gestational age. Immunoglobulin G (IgG) against tetanus (TT), diphtheria (DT), pertussis toxin (PT), filamentous hemaglutinin (FHA) and pertactin (Prn) were measured using commercial ELISA tests, at baseline, 1 month after maternal vaccination, at delivery, and in infants from cord blood and before and after the primary series (EPI: month 2-3-4) of a pertussis containing vaccine. Significantly higher geometric mean concentrations (GMC) were observed for all 3 measured pertussis antigens in the offspring of the Tdap group, up to 2 months of age. One month after completion of the primary infant vaccination schedule, anti-Prn GMC, but not anti-PT and anti-FHA GMCs, was significantly (p=0.006) higher in the control group. Maternal antibodies induced by vaccination during pregnancy close the susceptibility gap for pertussis in young infants. Limited interference with the infant vaccine responses was observed. Whether this interference effect disappears with the administration of a fourth vaccine dose is further studied.

Susceptibility to measles, mumps, and rubella in 5-year-old children in Flanders, Belgium

The second dose of an MMR vaccine is a catch up for persons who did not receive the first dose or for primary vaccine failures. Catch up doses can be scheduled according to convenience into the program of the country. The second MMR dose is often administered at the age of 5 years, before school entry. Some countries chose to implement the second dose at the age of 10-13 years, as is the case for Belgium. The here presented long-term follow-up of a cohort of children, set up originally to analyze maternal antibodies against vaccine preventable diseases, offers a unique opportunity to evaluate ad interim the current long-interval MMR vaccination schedule in Belgium. After 1 MMR dose at 12 months of age, rubella immunity is almost intact at 5 years of age (94.5 % is seropositive), measles seropositivity scores 86.8 %, and mumps 32 %, measured with ELISA. A seroneutralization (SN) test for mumps antibodies reveals much higher seropositivity rates (88 %). Using a regression model on the log (IgG) titer for all antigens, no influence was found from any of the studied variables, except for girls who had a significantly higher rubella IgG titer (p=0.002) compared to boys.

CONCLUSION

The data show considerable susceptibility to mumps and measles in 5-year-old children, confirming a previously conducted seroprevalence study (2006). Both advantages and disadvantages of shortening or enlarging the vaccine schedule are discussed.

Interrater and intrarater reliability of the Semmes Weinstein aesthesiometer to assess touch pressure threshold in burn scars

Burn scars are frequently accompanied with sensory deficits often remaining present months or even years after injury. Clinimetric properties of assessment tools remain understudied within burn literature. Tactile sense of touch can be examined with the touch pressure threshold (TPT) method using the Semmes Weinstein monofilament test (SWMT). There is in recent research no consensus on the exact measurement procedure when using the SWMT. The aim of this paper was to determine the interrater and intrarater reliability of TPT within burn scars and healthy controls using the 'ascending descending' measurement procedure. We used the newly developed guidelines for reporting reliability and agreement studies (GRRAS) as a basis to report this reliability study. In total 36 individuals were tested; a healthy control group and a scar group. The interrater reliability was excellent in the scar group (ICC=0.908/SEM=0.21) and fair to good in the control group (ICC=0.731/SEM=0.12). In the scar group intrarater ICC value was excellent (ICC=0.822/SEM=0.33). Within the control group also an excellent intrarater reliability (ICC=0.807/SEM=0.27) was found. In conclusion this study shows that the SWMT with the 'ascending descending' measurement procedure is a feasible and reliable objective measure to evaluate TPT in (older) upper extremities burn scars as well as in healthy skin.

Classification of quality of life subscales within the ICF framework in burn research: identifying overlaps and gaps

OBJECTIVE

Quality of life (QOL) is one of the leading outcomes in burn care research. This study classifies subscales of common QOL measures within the International Classification of Functioning disability and health (ICF) framework to determine to which extent the measures are complementary or overlapping and to investigate whether the instruments are able to describe the full spectrum of patients' functioning.

METHODS

A literature search was performed to determine the most frequently used questionnaires in burn research. The subscales of the three mostly used questionnaires were classified within the ICF framework.

RESULTS

Two generic measures, the Short Form-36 items (SF-36) and the European Quality of Life 5 Dimensions (EQ-5D), and a disease specific measure, the Burn Specific Health Scale-Brief (BSHS-B), were analyzed. The BSHS-B covered most domains and was the only scale that included personal factors. The SF-36 included only one domain in the activity limitations and similar to the EQ-5D no contextual factors were included. Environmental factors were not addressed in the questionnaires, even though these may have an impact on the quality of life in patients with burns.

CONCLUSION

To capture the full spectrum of dysfunctioning a combination of the BSHS-B with a generic questionnaire seems obligatory. However still some domains of functioning remain uncovered.

Breastfeeding after maternal immunisation during pregnancy: providing immunological protection to the newborn: a review

Vaccination during pregnancy results in an augmentation of disease specific maternal antibodies. Immunoglobulin G (IgG) is mainly transferred through the placenta during the third trimester of pregnancy, while secretory Immunoglobulin A (sIgA) is passed through breast milk. At birth, newborns are partially protected against infectious diseases by these antibodies. This review aims to provide an overview of the effect of vaccination during pregnancy on the immunological protection of the newborn by the presence of disease specific sIgA antibodies in breast milk and their possible protective function against disease. Our search produced 11 relevant papers; 1 on pertussis, 7 on pneumococcus, 2 on influenza and 1 on meningococcus. All of the studies in this review that measured disease specific antibodies in breast milk (n=8 papers), stressed the beneficial effect of maternal vaccination during pregnancy on the amount of disease specific sIgA in breast milk. Only a few studies demonstrated a potential protective effect, particularly with influenza vaccines. In an era where maternal vaccination is increasingly considered as a valuable strategy to protect both the mother and infant, further research is needed to assess the effect on breast milk sIgA and to understand the potentially beneficial effects to the infant.

[Mobile biosensor-based gait analysis: a diagnostic and therapeutic tool in Parkinson's disease]

Parkinson's disease (PD) is characterized by progressive motor and non-motor symptoms, leading to distinct diagnostic and therapeutic challenges in all stages of the disease. This study investigated a mobile biosensor-based gait analysis system for patients in early and intermediate stages of PD compared to controls. Subjects wearing a motion sensor-equipped shoe performed a standardized gait exercise. Accelerometer- and gyroscope-based signals were analysed using a complex set of pattern recognition algorithms. The analysis was able (1) to distinguish between PD patients and controls, (2) to identify patients at an early stage of the disease and (3) to distinguish between early and intermediate stage patients. Thus, using this mobile biosensor-based analysis system we were able to obtain objective classifications of gait characteristics in PD. Future studies will show that mobile biosensor-based movement detection technology will support identification of early PD stages and allow objective characterization of motor fluctuations in advanced stages of the disease. This will provide an important and supportive tool for patients, caregivers and therapists.

The voice handicap index as a tool for assessment of the biopsychosocial impact of voice problems

BACKGROUND

Objective measurements do not evaluate the biopsychosocial impact of a voice disorder. The Voice Handicap Index (VHI) measures the influence of voice problems on a patient's quality of life.

OBJECTIVE

To investigate if the VHI can monitor biopsychosocial impact of voice disorders and to provide a frame of reference for use of the VHI in general ENT practice.

METHODS

VHI scores and subscores were analysed in 272 controls, 237 patients with initial voice complaints ("new patients") and 92 patients before and after microsurgery ("operated patients").

RESULTS

The VHI scores of the controls were not normally distributed (Kolmogorov-Smirnov test: < .001). The total VHI scores for the 5th, 10th, 25th, 50th, 75th, 90th and 95th percentiles were, respectively, 0.0, 0.0, 2.0, 6.0, 12.0, 23.0 and 32.8. In the controls, there was not a significant effect of gender on either VHI totals or subscores (p = 0.060-0.858). In the "new patients" group, males scored significantly higher on the functional subscore (p = 0.004). There was a very weak negative correlation between age and VHI totals and subscores in controls (correlation coefficient: -0.092 to -0.187). There was a significant difference in VHI totals and subscores between subjects with and without voice complaints (p < 0.001). In the patient group, VHI scores of professional voice users (PVUs) were not significantly different from those of non-PVUs (p = 0.112-0.753). In controls, a significantly higher score was found for PVUs in the P domain of the VHI (p = 0.017). After microsurgical treatment, 82.0% of patients had a lower total VHI score, and 93.3% reported an improvement in voice. In the patient group, the median postoperative VHI score was almost halved.

CONCLUSION

Gender and profession did not have a significant influence on the total VHI score. There was a weak tendency for VHI to decrease with age. The VHI is a useful instrument for quantifying the biopsychosocial impact of a voice disorder, and is able to monitor changes in self-perception of voice handicap after treatment.

Changes of the eye caused by the climate in Rwanda, Africa

Rwanda is a small but densely populated country, situated at the watershed between East and West Africa, close to the equator. The mean elevation is around 1500 m. We studied 114 males (mean age 28.42 years) and 111 females (mean age 29.84 years) at the ophthalmological outpatient department of the Centre Hospitalier in Kigali. Changes to the eye caused by the climate were fewer than expected. Only 10 patients (5 males, 5 females) with pterygium (mean age 33.0 years), and four males and two females with climatic droplet keratopathy (mean age 47.5 years) were observed. However, the size of the pinguecula was marked. Corneal thickness, measured with Haag-Streit's device, averaged 0.524 mm in 38 males and 0.521 mm in 38 females. The Rwandans showed a normal chamber depth, a mean of 2.98 mm being noted in 107 males and a mean of 2.80 mm in 106 females.

Ocular ulcerative herpes following measles in Kinshasa, Zaire

Eight cases of ocular ulcerative herpes following measles are reported. The clinical features are characterized by dendritic corneal ulcer (6 cases) and ulcero-erosive blepharitis associated with corneal ulcer (2 cases). Bacteriologic examination disclosed Pseudomonas aeruginosas in 2 cases. The serum level of retinol, RBP, prealbumin and albumin were generally diminished in cases of dendritic corneal ulcer. These data are discussed in relation to the onset and severity of ocular ulcerative herpes associated with measles.

The onchocerciasis focus at Kinsuka/Kinshasa (Republic of Zaire) in 1985. II. Parasitological and clinical aspects

Since the antivectorial control in 1948, the parasitological and clinical aspects of the onchocerciasis focus at Kinsuka/Kinshasa have not been studied further until now. The population examined was selected for its daily contact with the vector. It constituted 143 adults, including fishermen, stonebreakers and women cultivators, and 26 children aged from 10 to 16 years. People were subjected to an ophthalmological examination as well as to an investigation for Onchocerca volvulus microfilariae. Adults were examined for the presence of nodules as well as for dermal and lymphatic manifestations of onchocerciasis. The microfilaria carrier rate (MfCR) was 59.2%. The mean microfilaria density (MfD) was 9.7 mf mg-1. Only 20% of the adults presented with small onchocercal nodules. Cutaneous lesions were mild. Lymphatic complications such as adenolymphocele, hydrocele and elephantiasis of the lower limbs were observed in 18% of the adults. No one was blind from onchocerciasis, although nine patients of 60 years or over had lost the use of one eye. Punctate keratitis occurred commonly in young people. Ocular lesions, except for punctate keratitis, developed progressively after 55 years and they became worse with the degree of infection, age and length of stay. Hyperendemic and insufferable in 1940, onchocerciasis has become, in 1985, hypoendemic and no longer a public health problem. One could deduce that a situation similar to that in Kinsuka may occur within 30 years in other foci which are today hyperendemic and where prophylaxis has been started.

Onchocerciasis in Zaïre

The first mention in Africa of ocular lesions and of blindness due to onchocerciasis was made by Hissette in Zaïre in 1931, although the disease had already been known there since 1903. On a map of Zaïre were indicated all the known data of the geographical distribution of onchocerciasis: data from the literature, from field work and from the patients seen in Kinshasa. An estimation of the relative incidence of the disease was made by comparing the number of patients with the number of the latest population census for each administrative zone. The environmental and developmental factors determining the epidemiological aspects are discussed. The clinical aspects of the typical eye symptoms are reviewed. Their correlation with age, with immunology and with some specialized eye examinations are discussed.

Epidemic spastic paraparesis in Bandundu (Zaire)

Epidemiological findings of twenty sporadic cases of epidemic spastic paraparesis (buka-buka) in three areas of Bandundu (Zaire) are reported. These findings suggest the involvement of an infectious agent and do not support the hypothesis of a dietary cyanide intoxication, which has been advanced to explain the outbreak of a very similar disease (Mantakassa) in Mozambique.