Safety of pertussis vaccination in pregnant women in UK: observational study

Pertussis Epidemiology in Children: The Role of Maternal Immunization

In the last twelve months, a significant global increase in pertussis cases has been observed, particularly among infants under three months of age. This age group is at the highest risk for severe disease, hospitalization, and death. Maternal immunization with the Tdap vaccine during pregnancy has been recommended to protect newborns by transferring maternal antibodies transplacentally. This review examines the current epidemiology of pertussis, the importance of preventing it in young children, and the effectiveness of maternal immunization. Despite the proven benefits of maternal vaccination, which has been found effective in pertussis prevention in up to 90% of cases, coverage remains suboptimal in many countries. Factors contributing to low vaccination rates include vaccine hesitancy due to low trust in health authority assessments, safety concerns, practical barriers to vaccine access, and the impact of the COVID-19 pandemic, which disrupted routine vaccination services. The recent increase in pertussis cases may also be influenced by the natural cyclic nature of the disease, increased Bordetella pertussis (Bp) activity in older children and adults, and the genetic divergence of circulating Bp strains from vaccine antigens. Given the high efficacy of maternal vaccination in preventing pertussis in infants, increasing coverage rates is crucial. Efforts to improve vaccine uptake should address barriers to access and vaccine hesitancy, ensuring consistent immune protection for the youngest and most vulnerable populations. Enhanced maternal vaccination could significantly reduce the incidence of whooping cough in infants, decreasing related hospitalizations and deaths.

Timing of pertussis vaccination during pregnancy: Evidence and implementation - A systematic review

BACKGROUND

Pertussis vaccination in pregnancy has been introduced in an increasing number of countries to better protect infants against the disease in their first weeks of life. The optimal timing of pertussis vaccination in pregnancy is however still under debate.

METHODS

We systematically reviewed published literature on safety, immunogenicity and effectiveness of pertussis vaccination in pregnancy related to timing of vaccination. The search was conducted using PubMed, MEDLINE and Web of Science and yielded 1623 articles, thereof 777 duplicates. Screening resulted in the inclusion of 45 publications reporting on safety (n = 11), immunogenicity (n = 26) and/or effectiveness (n = 9). We also mapped pertussis recommendations in pregnancy by government institutions globally according to the recommended timing of vaccination.

RESULTS

Overall, the selected publications did not indicate increased safety concerns associated with timing of pertussis vaccination in pregnancy. Immunogenicity studies often suggested optimal protection at birth after early third trimester vaccination. Few studies investigated qualitative antibody characteristics, and none investigated antibody titers in breastmilk or cellular-mediated immunity related to timing of vaccination. Effectiveness studies showed decreased vaccine effectiveness of late third trimester pertussis vaccination compared to vaccination earlier in pregnancy. Worldwide, a general recommendation for pertussis vaccination in pregnancy was found for 58 countries, with as many as 22 different recommended timings registered.

CONCLUSION

The timing of pertussis vaccination in pregnancy seems to impact immunogenicity and vaccine effectiveness, with optimal immune responses at birth suggested following early third trimester vaccination and reduced vaccine effectiveness of late third trimester pertussis vaccination suggested compared to vaccination earlier in pregnancy. However, inconsistent and lacking data are reflected in the divergent national recommendations for pertussis vaccination in pregnancy worldwide.

SUMMARY

Pertussis vaccination in pregnancy aims to protect infants in their first weeks of life. Our review suggests that immunogenicity and vaccine effectiveness are impacted by the timing of vaccination in pregnancy. National recommendations for pertussis vaccination in pregnancy vary widely worldwide.

The current state of pertussis vaccination in pregnancy around the world, with recommendations for improved care: Consensus statements from the Global Pertussis Initiative

Bordetella pertussis, which causes a respiratory disease known as pertussis ("whooping cough") remains an important global challenge, with the incidence in pertussis cases increasing in recent years. Newborns and infants are at increased risk for severe morbidity and mortality from this bacterium. Vaccination in pregnancy has become an important strategy to both passively transfer immunity as well as prevent infection in pregnant persons, who are a major source of newborn infection, thus attempting to decrease the impact of this serious disease. It is considered safe for the pregnant person, the developing fetus, and the infant, and during the first 3 months of life it has been shown to be highly effective in preventing pertussis. There are a variety of strategies, recommendations, and adherence rates associated with pertussis vaccination in pregnancy around the world. We summarize the 2021 Global Pertussis Initiative Annual Meeting that reviewed the current global status of pertussis vaccination in pregnancy and remaining medical and scientific questions, with a focus on vaccination challenges and strategies for obstetric and gynecologic healthcare providers.

Prenatal Maternal Immunization for Infant Protection: A Review of the Vaccines Recommended, Infant Immunity and Future Research Directions

Prenatal maternal immunization is an effective tool to protect mothers and infants from poor health outcomes due to infectious diseases. We provide an overview of the rationale for the use of prenatal vaccines, discuss the immunologic environment of the maternal-fetal interface including the impact of maternal vaccines prenatally and subsequently on the infant's immune response, and review vaccines currently recommended in pregnancy and landscape for the future of maternal vaccination. This review aims to provide an understanding of the recent history and progress made in the field and highlight the importance of continued research and development into new vaccines for pregnant populations.

A scoping review of the reasons for and approaches to non-uptake of pertussis and influenza vaccinations in pregnant women in the United Kingdom and Ireland

BACKGROUND

Pertussis and influenza cause significant morbidity and mortality in pregnancy and the neonatal period. Maternal vaccination in pregnancy would reduce harm, but low vaccine uptake is a concern. This scoping review aimed to understand the reasons for, and approaches, to non-uptake of pertussis and influenza vaccinations in pregnant women in the UK and Ireland.

METHODS

The inclusion criteria of this scoping review consist of pregnant women who avail of pertussis and influenza vaccines in the UK and Ireland. MEDLINE, EMBASE, Web of Science and CINAHL databases were searched in June 2021 and updated in October 2022. Searches were limited to English language reports published after 2011. We followed the Joanna Briggs Institute guidance on scoping reviews. Data were extracted and charted.

RESULTS

Five themes emerged from the literature. Acceptability, as well as organisational and awareness issues, were overarching themes regarding reasons for and approaches to non-uptake of the vaccines respectively. Other themes included healthcare professional factors, information interpretation and pregnancy-related factors.

CONCLUSIONS

Women need clear, comprehensible information, ideally provided by their healthcare professionals, in a way that is meaningful and addresses their circumstances and risk perceptions. This research will serve as a base for future work that aims behaviour science interventions at the wider pregnant population as well as the target groups that have been identified in this review.

Maternal vaccination provision in NHS maternity trusts across England

BACKGROUND

Vaccinations for seasonal influenza and pertussis have been recommended for pregnant women in England since 2010 and 2012, respectively. Uptake rates are suboptimal with large regional variations. To improve uptake, from 2016 onwards maternity trusts were commissioned to offer pertussis (and other) vaccinations in addition to these being available in primary care. Since 2021, Covid-19 vaccination has also been recommended for pregnant women. Overall maternal vaccination rates are routinely available, but not the relative provision by maternity trusts. We aimed to describe the national picture of maternity trust provision of maternal vaccinations, including how the maternity trust vaccination programme has progressed.

METHODS

Cross-sectional survey plus comparisons with 2017-18 figures for maternity trust provision of pertussis vaccination, and with UKHSA data for total pertussis vaccination.

RESULTS

Twelve NHS commissioners participated (from 13/06/22 to 31/03/23) providing data for 120 (of a total 124) maternity trusts across England. All 120 (100%) trusts were commissioned to deliver influenza, and 107 (89%) to deliver pertussis vaccinations, though not all actually administered the vaccines; 29% offered Covid-19 vaccinations. For 2021-22 we found a mean of 25% (range 0-81.3%) women were vaccinated for pertussis (a large increase compared with previous estimates for 2017-18); and 11% (range 0-74.2%) for influenza, via their maternity trust. Commissioners reported a negative impact of the pandemic on routine vaccination provision. There was indication of efficiency by vaccinating women attending for other appointments. There are diverse mechanisms for reporting pertussis and influenza vaccinations administered at maternity trusts back to primary care, which may be inefficient for maternity staff workload and accuracy of data transfer (especially for pertussis).

CONCLUSION

A high proportion of maternity trusts provide both pertussis and influenza vaccinations, despite a negative impact of the pandemic. Reasons for large between-trust variation in vaccination rates should be explored to improve uptake and equity.

The Present and Future Aspects of Life-Long Pertussis Prevention: Narrative Review with Regional Perspectives for Türkiye

Pertussis, caused by Bordetella pertussis, remains one of the most widespread, contagious, and vaccine-preventable diseases. It results in notable morbidity and mortality as well as severe medical, social, and economic burden. Despite high global vaccine coverage, pertussis continues to be a significant epidemiologic problem, with outbreak episodes every few years just as in the pre-vaccination era. In Türkiye, there is a lack of comprehensive data on the current burden of pertussis in different age and risk groups, leading to underdiagnosis and underreporting of the disease, especially in adults who are often not considered at risk. Available data from Türkiye also reveal inadequate levels of protective antibodies in preterm newborns, emphasizing the need for additional preventive measures. Authors stated that improving physician awareness of pertussis symptoms in patients with prolonged cough, increasing access to routine pertussis tests, and conducting surveillance studies would aid in accurate diagnosis and reporting in Türkiye. As the Turkish Ministry of Health Antenatal Care Management Guide suggests routine second and third pregnancy check-up visits at weeks 18-24 and 28-32 correspondingly, this period can be considered the ideal vaccination time for Türkiye. Introducing a booster dose of Tdap at around 10 years of age or during national military service would reduce transmission and protect susceptible individuals. Identifying individuals at high risk of severe pertussis and prioritizing them for a booster dose is also crucial in Türkiye. Enhancing surveillance systems, increasing healthcare professionals' awareness through training, and organizing catch-up visits for missed vaccinations during the COVID-19 pandemic are mentioned as additional strategies to improve pertussis prevention in Türkiye. This review focuses on the global and regional burden of pertussis and obstacles to effective prevention and evaluates existing strategies to achieve lifelong pertussis prevention. Literature and current strategies were also discussed from a Turkish national standpoint.

Safety and Clinical Benefits of Adacel® and Adacel®-Polio Vaccination in Pregnancy: A Structured Literature Review

Vaccination in pregnancy using a tetanus toxoid, reduced dose diphtheria toxoid, and reduced dose acellular pertussis (Tdap) vaccine is important for prevention of severe pertussis disease in young infants. The objectives of this systematic literature review were to search for original research studies evaluating the vaccine effectiveness, immunogenicity, and safety of Adacel®/Adacel-Polio® used during pregnancy to prevent pertussis disease in young infants. Medical databases used included EMBASE, BIOSIS Previews, and Chemical Abstracts, with search terms related to pregnancy, vaccines/immunization, safety, pertussis, effectiveness/efficacy, and immune response; other potentially eligible reports were included where applicable. Search results were restricted to literature published from 1 January 1995 to 26 July 2021. A total of 2021 articles and 4 other reports were identified for primary review. A total of 49 publications qualified for inclusion after primary and secondary reviews. Effectiveness studies of Adacel or Adacel-Polio given in pregnancy consistently showed high levels of protection from pertussis disease in the newborn (vaccine effectiveness: 91-93%). In immunogenicity studies, the response in pregnant women was consistent with that of non-pregnant women. Infants of mothers vaccinated with Adacel or Adacel-Polio in pregnancy had higher anti-pertussis antibody levels at birth and at 2 months of age compared to infants born to women vaccinated with comparator vaccines, placebo, or those not vaccinated during pregnancy. There was evidence of a slightly decreased response to primary pertussis vaccination in infants of mothers vaccinated with Adacel or Adacel-Polio, but this was not thought to be clinically significant. In safety studies, Adacel or Adacel-Polio vaccination was well tolerated by pregnant woman and not associated with pregnancy, postpartum, or neonatal complications. In conclusion, Adacel or Adacel-Polio vaccination in pregnancy is highly effective in protecting young infants from pertussis disease, with a favorable safety profile for both pregnant women and their infants.

A phase 2 randomized controlled dose-ranging trial of recombinant pertussis booster vaccines containing genetically inactivated pertussis toxin in pregnant women

INTRODUCTION

Despite a decrease in infections caused by Bordetella pertussis due to COVID-19 pandemic, booster vaccination of pregnant women is still recommended to protect newborns. Highly immunogenic vaccines containing genetically inactivated pertussis toxin (PTgen) and filamentous hemagglutinin (FHA) may generate comparable anti-PT antibody concentrations, even at lower doses, to chemically inactivated acellular pertussis vaccines (Tdapchem) shown effective for maternal immunization.

METHODS

This phase 2 randomized, observer-blind, active-controlled non-inferiority trial was conducted in healthy Thai pregnant women randomly assigned to receive one dose of low-dose recombinant pertussis-only vaccine containing 1 µg PTgen and 1 µg FHA (ap1gen), or tetanus, reduced-dose diphtheria combined with ap1gen (Tdap1gen), or combined with 2 µg PTgen and 5 µg FHA (Tdap2gen), or with 5 µg PTgen and 5 µg FHA (TdaP5gen, Boostagen®) or comparator containing 8 µg of chemically inactivated pertussis toxoid, 8 µg FHA, and 2.5 µg pertactin (Boostrix™, Tdap8chem). Blood was collected at Day 0 and Day 28 post-vaccination. The non-inferiority of the study vaccines was assessed based on anti-PT IgG antibody levels on Day 28 pooled with results from a similarly structured previous trial in non-pregnant women.

RESULTS

400 healthy pregnant women received one dose of vaccine. Combined with data from 250 non-pregnant women, all study vaccines containing PTgen were non-inferior to comparator vaccine (Tdap8chem). Both ap1gen and TdaP5gen vaccines could be considered to have superior immunogenicity to Tdap8chem. Local and systemic solicited reactions were similar among all vaccine groups.

CONCLUSIONS

Vaccine formulations containing PTgen were safe and immunogenic in pregnant women. The ap1gen vaccine, with the lowest cost and reactogenicity, may be suitable for use in pregnant women when diphtheria and tetanus toxoids are not needed. This study is registered in the Thai Clinical Trial Registry (www.

CLINICALTRIALS

in.th), number TCTR20180725004.

Impact of maternal whole-cell or acellular pertussis primary immunization on neonatal immune response

With the introduction of pertussis immunization for pregnant women in many countries, there has been renewed interest in the impact of whole-cell pertussis vaccine (wP) versus acellular vaccine (aP) on disease control, particularly regarding the best approach for priming. To gather evidence on this topic, we analyzed the impact of aP or wP priming on aP vaccination during pregnancy (aPpreg) in mice. Two-mother vaccination schemes were employed (wP-wP-aPpreg and aP-aP-aPpreg), and the immune response in the mothers and their offspring, as well as the protection of the offspring against Bordetella pertussis challenge, were assessed. Pertussis toxin (PTx)-specific IgG responses were detected in mothers after both the second and third doses, with higher titers after the third dose, regardless of the vaccination schedule. However, a significant reduction in PTx-IgG levels was observed after 22 weeks post aPpreg immunization in mothers with the aP-aP-aPpreg scheme but not in the wP-wP-aPpreg immunized mothers. The aP-aP-aPpreg schedule triggered a murine antibody response mainly to a Th2-profile, while wP-wP-aPpreg induced a Th1/Th2 mixed profile. Both immunization schemes administered to the mothers protected the offspring against pertussis, but the wP-wP-aPpreg vaccination conferred offspring protection in all pregnancies at least up to 20 weeks after receiving the aPpreg-dose. In contrast, the immunity induced by aP-aP-aPpreg began to decline in births that occurred 18 weeks after receiving the aPpreg dose. For the aP-aP-aPpreg scheme, pups born from gestations furthest from aPpreg (+22 weeks) had lower PTx-specific IgG levels than those born closer to the application of the dose during pregnancy. In contrast, for pups born to wP-wP-aPpreg vaccinated mothers, the PTx-specific IgG levels were maintained over time, even for those born at the longest time studied (+22 weeks). It is noteworthy that only the pups born from mothers with aP-aP-aPpreg and receiving a neonatal dose of either aP or wP were more susceptible to B. pertussis infection than mice with only maternal immunity, suggesting interference with the induced immunity (p<0.05). However, it should be noted that mice with maternal immunity, whether vaccinated or not with neonatal doses, are better protected against colonization with B. pertussis than mice without maternal immunity but vaccinated with aP or wP.

Safety of COVID-19 vaccines during pregnancy: A systematic review and meta-analysis

BACKGROUND

Assessment of COVID-19 vaccines safety during pregnancy is urgently needed.

METHODS

We conducted a systematic review and meta-analysis to evaluate the safety of COVID-19 vaccines, including their components and technological platforms used in other vaccines during pregnancy and animal studies to complement direct evidence. We searched literature databases from its inception to September 2021 without language restriction, COVID-19 vaccine websites, and reference lists of other systematic reviews and the included studies. Pairs of reviewers independently selected, data extracted, and assessed the risk of bias of the studies. Discrepancies were resolved by consensus. (PROSPERO CRD42021234185).

RESULTS

We retrieved 8,837 records from the literature search; 71 studies were included, involving 17,719,495 pregnant persons and 389 pregnant animals. Most studies (94%) were conducted in high-income countries, were cohort studies (51%), and 15% were classified as high risk of bias. We identified nine COVID-19 vaccine studies, seven involving 309,164 pregnant persons, mostly exposed to mRNA vaccines. Among non-COVID-19 vaccines, the most frequent exposures were AS03 and aluminum-based adjuvants. A meta-analysis of studies that adjusted for potential confounders showed no association with adverse outcomes, regardless of the vaccine or the trimester of vaccination. Neither the reported rates of adverse pregnancy outcomes nor reactogenicity exceeded expected background rates, which was the case for ASO3- or aluminum-adjuvanted non-COVID-19 vaccines in the proportion meta-analyses of uncontrolled studies/arms. The only exception was postpartum hemorrhage after COVID-19 vaccination (10.40%; 95% CI: 6.49-15.10%), reported by two studies; however, the comparison with non-exposed pregnant persons, available for one study, found non-statistically significant differences (adjusted OR 1.09; 95% CI 0.56-2.12). Animal studies showed consistent results with studies in pregnant persons.

CONCLUSION

We found no safety concerns for currently administered COVID-19 vaccines during pregnancy. Additional experimental and real-world evidence could enhance vaccination coverage. Robust safety data for non-mRNA-based COVID-19 vaccines are still needed.

Maternal vaccination against pertussis as part of the national immunization program: a qualitative evaluation among obstetric care providers one year after the implementation in December 2019

BACKGROUND

Immunization of pregnant women with a tetanus-diphtheria-and-acellular-pertussis (Tdap) vaccine is an effective and safe way to protect infants from pertussis before their primary vaccinations. Vaccine uptake among pregnant women is influenced by their care providers' attitudes toward maternal vaccination. This qualitative study aimed to evaluate the implementation of the maternal Tdap vaccination under the National Immunization Program of the Netherlands from the perspective of obstetric care providers.

METHODS

In this qualitative and explorative study, we conducted in-depth interviews by telephone with obstetric care providers who were selected from a pool of respondents (convenience sampling) to a questionnaire in a previous study. The interviews were based on a semi-structured interview guide that covered three aspects of the implementation strategy: providers' overall experience with the implementation of maternal Tdap vaccination in the Netherlands; implementation logistics and counseling, and pregnant women referrals to municipal Youth Healthcare Centers. The interviews were recorded, pseudonymized and transcribed verbatim. Transcripts were analyzed according to the Thematic Analysis approach by two researchers independently in two phases of iterative coding, categorizing, reviewing and redefining until ultimately, emergent themes regarding maternal Tdap vaccination implementation were identified.

RESULTS

Interviews with 11 midwives and 5 OB-GYN physicians yielded 5 major themes regarding the Tdap vaccination implementation strategy: challenges throughout the implementation process, views on maternal Tdap vaccination, general versus tailored counseling, provider responsibilities in vaccine promotion, and impact of materials for information delivery. Participants indicated that to improve provider attitudes toward Tdap vaccination, its implementation requires clear and transparent information about what is entailed, i.e., what is expected from obstetric care providers, how they can obtain information, and when their actions must be initiated. Participants demanded involvement throughout the implementation planning process. They preferred tailored communication with pregnant women over a generalized approach.

CONCLUSION

This study emphasized the importance of involving all relevant healthcare professionals in planning the implementation of maternal Tdap vaccination. Possible barriers perceived by these professionals should be taken into account in order to improve their attitudes toward vaccination, thus to increase uptake among pregnant women.

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.

Diphtheria, tetanus, and pertussis immunity among healthcare professionals and pregnant women in the Moscow region, Russian federation: A preliminary cross-sectional study

Despite more than 50 years of primary immunization against diphtheria, pertussis, and tetanus in Russia, complicated illnesses, including fatal ones, still occur. The goal of this preliminary cross-sectional study is to see how well pregnant women and healthcare workers are protected against diphtheria, pertussis, and tetanus. The required sample size (pregnant women and healthcare professionals, as well as pregnant women of two age categories) for this preliminary cross-sectional study was calculated using a confidence value of 0.95 and a probability of 0.05. The required number of participants in each group calculated sample size must be at least 59 people. In the Moscow region (Solnechnogorsk city, Russia), a cross-sectional study of pregnant patients and healthcare professionals interacting with children regularly as part of their job from numerous medical organizations was conducted in the year 2021 (n = 655). Antibodies to diphtheria, tetanus, and pertussis toxoids and microorganisms were measured using an enzyme-linked immunosorbent assay (ELISA). The STATISTICA and IBM SPSS Statistics 26.0 were used to process the study results statistically. Descriptive statistics methods, the Mann-Whitney U-test, discriminant analysis with the stepwise selection and analysis of ROC-curves were applied. IgG against diphtheria was found in 99.5% of pregnant women, tetanus in 91.5%, and pertussis in only 36.5%. According to the results of the discriminant analysis, the value of IgG to pertussis is linked to the value of IgA to pertussis and the gestational periods. Immunity to diphtheria was discovered in 99.1% of medical personnel, tetanus in 96.9%, and pertussis in 43.9%, no significant variations with age. When comparing the levels of immunity of pregnant women and healthcare professionals, it was shown that healthcare workers have greater levels of immunity against diphtheria and tetanus. The novel contribution of this study is that it will reveal the proportion of those vulnerable to pertussis, diphtheria, and tetanus among health workers and pregnant women in all age groups under the current national immunization program in Russia. Considering the data obtained from the preliminary cross-sectional study, we believe that it is necessary to conduct a full-scale study on a larger sample and, based on that, make certain changes to the national immunization program in Russia.

Vaccination dropout among children in Sub-Saharan Africa: Systematic review and meta-analysis

Immunization is cost-effective preventive strategy for child morbidity and mortality. PubMed, Google Scholar, Scopus, Science Direct, and online institutional repository homes were searched. Data were extracted by Microsoft excel. Begg's rank test, and Egger's regression test was done. A pooled prevalence, Sub-group analysis, sensitivity analysis and meta-regression were conducted. A total of 12 articles were included in this study. The pooled prevalence of vaccination dropout was 26.06% (95% CI: 11.59, 30.53), I2 =91.2%. In sub-group analysis, Nigeria had the highest prevalence of immunization dropouts (33.59%). It was 18.01% and 29.25%, respectively, for published and unpublished research. Community-based studies and institutional-based studies also yield a prevalence of dropout 39.04% and 13.73% respectively. Dropout rate was 22.66% for sample sizes under 500 and 18.01% for sample sizes beyond 500. In Sub-Saharan Africa, the prevalence of vaccination dropout was high. Community education about vaccinations importance should be prioritized.

Evaluation of Whole-Cell and Acellular Pertussis Vaccines in the Context of Long-Term Herd Immunity

After the pertussis vaccine had been introduced in the 1940s and was shown to be very successful in reducing the morbidity and mortality associated with the disease, the possibility of improving both vaccine composition and vaccination schedules has become the subject of continuous interest. As a result, we are witnessing a considerable heterogeneity in pertussis vaccination policies, which remains beyond universal consensus. Many pertussis-related deaths still occur in low- and middle-income countries; however, these deaths are attributable to gaps in vaccination coverage and limited access to healthcare in these countries, rather than to the poor efficacy of the first generation of pertussis vaccine consisting in inactivated and detoxified whole cell pathogen (wP). In many, particularly high-income countries, a switch was made in the 1990s to the use of acellular pertussis (aP) vaccine, to reduce the rate of post-vaccination adverse events and thereby achieve a higher percentage of children vaccinated. However the epidemiological data collected over the past few decades, even in those high-income countries, show an increase in pertussis prevalence and morbidity rates, triggering a wide-ranging debate on the causes of pertussis resurgence and the effectiveness of current pertussis prevention strategies, as well as on the efficacy of available pertussis vaccines and immunization schedules. The current article presents a systematic review of scientific reports on the evaluation of the use of whole-cell and acellular pertussis vaccines, in the context of long-term immunity and vaccines efficacy.

Vaccination in Pregnancy against Pertussis: A Consensus Statement on Behalf of the Global Pertussis Initiative

Infants are at high risk for severe morbidity and mortality from pertussis disease during early infancy. Vaccination against pertussis in pregnancy has emerged as the ideal strategy to protect infants during these early, vulnerable, first months of life. On 30 November and 1 December 2021, the Global Pertussis Initiative held a meeting that aimed to discuss and review the most up-to-date scientific literature supporting vaccination against pertussis in pregnancy and outstanding scientific questions. Herein, we review the current and historically published literature and summarize the findings as consensus statements on vaccination against pertussis in pregnancy on behalf of the Global Pertussis Initiative.

[Preventive activities in women. PAPPS update 2022]

In the 2022 PAPPS update we present those specific preventive activities for women's health, except those related to cancer prevention (which are included in another document) and those aspects related to differential gender morbidity, a cross-cutting aspect for all working groups. Contraception is an essential preventive activity, considering basic the right to decide both the number of children and the time to have them. We must inform about the possible contraceptive methods, guaranteeing the monitoring of their safety, efficacy and effectiveness (tables are included on changing from one method to another to preserve contraceptive protection). We must inform about emergency contraception and propose it in the event of unprotected intercourse. All this will be done through opportunistic screening without requiring screening for thrombophilia or dyslipidemia, but for arterial hypertension. Pregnancy is an important life experience and the family doctor should not remain oblivious. We must be competent both in the preconception consultation (recommending the intake of folic acid, avoiding exposure to occupational and environmental risks, screening for certain pathologies and assessing the intake of drugs not indicated during pregnancy) and in the monitoring of pregnancy. Whether or not we monitor the pregnancy, we must not disregard its control, taking advantage of this period to promote healthy lifestyles and participating in the intercurrent processes that may occur. Menopause in general and osteoporosis in particular exemplify the strategy of medicalization of vital processes that has been followed from different instances and organizations. In our update we address the prevention and treatment of symptoms secondary to estrogen deprivation. We also propose the prevention of osteoporosis, including carrying out densitometry based on the risk of fracture in the next 10 years, and therefore densitometric screening is not recommended in women under 60 years of age. In risk assessment we recommend the use of the frax tool or better, the calibration of the risk of hip fracture with prevalence data from our setting. We linked the indication for treatment with the Z-Score (bone mineral density compared with women of the same age), as it is a condition associated with aging.

Vaccinations in pregnancy

Vaccinations are a cost-effective means of preventing disease. They may be recommended primarily for maternal benefit or for prevention of intrauterine fetal or early neonatal infection. Data from the International Network of Obstetric Survey Systems relating to the COVID-19 pandemic showed that for all countries studied (the UK, the Netherlands, Norway, Denmark, Finland and Italy), at least 80% of pregnant women admitted to critical care were unvaccinated. In the UK this figure was 98%. The MBRRACE-UK 2014 report, covering 2009–2012 during the H1N1 epidemic, demonstrated that one in eleven maternal mortalities were directly from influenza virus: more than half could have been prevented by the flu vaccine in pregnancy. Research is ongoing to develop additional vaccines for infections that cause detrimental effects to pregnant women and their infants. Theoretical concerns regarding adverse effects to the fetus and lack of efficacy have, in general, not been confirmed by clinical evidence. Nevertheless, live attenuated vaccines remain contraindicated due to risk of fetal infection. As with any clinical decision, advice on antenatal vaccination should be based on the balance of risks and benefits to mother and fetus. This article aims to guide such decisions by discussing the issues surrounding commonly used vaccines and presenting current UK guidelines.

[Should French pregnant women be vaccinated against pertussis during pregnancy?]

Many countries with a high perinatal level have started a policy of vaccination of pregnant women against pertussis. To date, France has not chosen this policy. The objective was to review knowledge on pertussis mortality in infants. Compare the strategies available to protect the infant before his first vaccination, scheduled for two months of age. We proceeded to a litterature analysis, from January 1998 to 2021. Search by the following keywords used ; "Whooping cough, vaccination, pregnancy, strategy, cocooning", on the scientific basis of "Pubmed", as well as French and foreign vaccination recommendations. Currently 90% of whooping cough deaths are concerning infants under six months of age and this mortality represents 2% of mortality in the first year of life. Vaccination at birth is not effective. The cocooning strategy, which consists of vaccinating those around the child, is expensive and difficult to implement. A systematic vaccination policy for pregnant women is effective and reasonably expensive when compared to the cocooning strategy. In England, it was recently accompanied by a 78% reduction in confirmed cases of pertussis in infants under six months of age. In conclusion, compared to cocooning strategy, pertussis vaccination of pregnant women appears more effective and cost-effective, and this with each pregnancy.

Flu and pertussis vaccination during pregnancy in Geneva during the COVID-19 pandemic: A multicentric, prospective, survey-based study

Objective

Methods

Results

Conclusions

Epidemiology, prevention and control of pertussis in Spain: New vaccination strategies for lifelong protection

Pertussis is a highly contagious, vaccine-preventable respiratory tract infection, with high morbidity and mortality and a particularly severe effect on newborns and infants under 2 months. The first pertussis vaccines were introduced in the 1940s. Since 1980, however, the incidence of cases has risen despite the extensive vaccination programmes and antibiotic adjuvant treatments available. Transition from the use of whole-cell vaccines to acellular vaccines and the antigenic modifications of Bordetella pertussis have contributed, among other factors, to a reduction in vaccine-acquired immunity and reemergence of the disease. Today, there are still unmet needs not covered by conventional prevention measures and existing antibiotic treatments. This review aims to update the available data, and to discuss which vaccine strategies might contribute to better disease control and prevention.

Evidence of suboptimal maternal vaccination coverage in pregnant New Zealand women and increasing inequity over time: A nationwide retrospective cohort study

Background

Adequate maternal vaccination coverage is critical for the prevention and control of infectious disease outbreaks such as pertussis, influenza, and more recently COVID-19. To guide efforts to increase vaccination coverage this study examined the extent of vaccination coverage in pregnant New Zealand women over time by area-level deprivation and ethnicity.

Methods

A retrospective cohort study was used consisting of all pregnant women who delivered between 01 January 2013 and 31 December 2018, using administrative health datasets. Outcomes were defined as receipt of influenza or pertussis vaccination in any one of the relevant data sources (National Immunisation Register, Proclaims, or Pharmaceutical collection) during their eligible pregnancy. Ethnicity was prioritised as Māori (NZ indigenous), Pacific, Asian, and Other or NZ European and deprivation was defined using New Zealand Index of Multiple Deprivation (IMD).

Results

Between 2013 and 2018, Asian women had the highest maternal vaccination coverage (36%) for pertussis, while Māori and Pacific women had the lowest, 13% and 15% respectively. Coverage of pertussis vaccination during pregnancy in low deprivation Māori women was 24% and 28% in Pacific women. This is in comparison to 30% and 25% in high deprivation Asian and European/Other women, respectively. Similar trends were seen for influenza.

Conclusion

Between 2013 and 2018 maternal vaccination coverage increased for pertussis and influenza. Despite this coverage remains suboptimal, and existing ethnic and deprivation inequities increased. There is an urgent need to focus on equity, to engage and support ethic communities by creating genuinely accessible, culturally appropriate health services.

Improving uptake of vaccines in pregnancy: A service evaluation of an antenatal vaccination clinic at a tertiary hospital in the UK

Background

Vaccination against pertussis and seasonal influenza is recommended for all pregnant women in the UK. More recently COVID-19 vaccination has also been offered to women in pregnancy.

Objectives

To evaluate the uptake of vaccines in pregnant women within a midwife-led immunisation clinic and to assess factors influencing pregnant women's decisions about accepting vaccination.

Methods

Uptake of vaccines amongst pregnant women referred to a single UK centre for antenatal care between 01/01/19 and 02/10/19 was assessed. Interviews with 20 pregnant women explored views of antenatal vaccination and experiences of the vaccination service.

Findings

Amongst 4420 women, uptake was 90.6% for pertussis and 78.8% for influenza vaccines. Factors influencing vaccine-related decision-making amongst 20 interviewed women were: healthcare professional recommendation, perceived susceptibility and risk of infection, and previous experience of vaccination and vaccine-preventable disease.

Conclusions and Implications for Practice

Uptake of pertussis and influenza vaccines within a secondary care immunisation service was higher than the national or regional average. The model of vaccine delivery was associated with high levels of satisfaction. This model of vaccine delivery could be implemented elsewhere to increase vaccine uptake, and should be considered for delivery of COVID-19 vaccines in the future.

Safety and use of tetanus-diphtheria-acellular pertussis-5 (Tdap5) vaccine during pregnancy: findings from 11 years of reporting to a pregnancy registry

The "Adacel (Tdap5) Pregnancy Registry" was used to identify 1182 women who received the tetanus, diphtheria, acellular pertussis [5 components] (Tdap5) vaccine during pregnancy from 2005 to 2016. To evaluate the safety and use of prenatal Tdap5, we calculated the rate of maternal, obstetrical, pregnancy and neonatal outcomes following Tdap5 pregnancy exposure and assessed vaccine uptake by year and trimester of exposure. The most commonly reported maternal adverse events included injection site reactions (2.6%; 95% Confidence Interval 1.8%, 3.7%), nervous system events (1.3%; 0.8%, 2.1%) and musculoskeletal events (1.1%; 0.6%, 1.9%). The most commonly reported complications of pregnancy were hypertension/preeclampsia (5.5%; 3.3%, 8.9%) and gestational diabetes (2.5%; 1.1%, 5.3%), while those for labor and delivery were premature labor (2.9%; 1.4%, 5.7%) and premature membrane rupture (1.5%; 0.4%, 3.8%). These rates were similar to, or lower than those reported for the general population of pregnant women. Among pregnancies with known birth outcomes (N = 275), 90.4% (86.2%, 93.4%) resulted in a live birth, 5.9% (3.6%, 9.5%) in spontaneous abortion, 3.0% (1.4%, 5.8%) in stillbirth, and 0.7% (0.0%, 2.8%) in ectopic pregnancies. Most newborns had normal APGAR scores and birth weights (98.1% and 93.0%, respectively), and only two reported a congenital anomaly (0.7%; 0.0%, 2.8%). An influx of reports in 2012 with third trimester Tdap5 exposure coincided with the 2012 updated Advisory Committee on Immunization Practices recommendations. This analysis did not identify any safety concerns across the continuum of maternal, obstetrical, pregnancy, and neonatal outcomes in women who received Tdap5 vaccination during pregnancy.

Assuring Access to Safe Medicines in Pregnancy and Breastfeeding

Scientists and regulators in Europe and the United States continue to seek methods and strategies to improve knowledge on rational use of medicines for pregnant and breastfeeding populations, an important subset of women's health. Regulatory agencies have made strides toward improvement, but much more is needed. Recognizing the importance of international collaboration, we have begun to consider how to address these important public health issues more globally. The health of the child begins with the health of the mother.

Modification of innate immune responses to Bordetella pertussis in babies from pertussis vaccinated pregnancies

BACKGROUND

Tetanus, diphtheria, acellular pertussis, inactivated polio (Tdap-IPV) vaccines administered during pregnancy protect young infants from Bordetella pertussis (B. pertussis) infection. Whilst the impact of maternal Tdap-IPV vaccination on infants' humoral response to subsequent pertussis immunisation has been investigated, little is known about any impact on innate responses.

METHODS

We investigated the immune response to B. pertussis in mothers and infants from Tdap-IPV-vaccinated and unvaccinated pregnancies, utilising a whole blood assay and flow cytometric phenotyping of neonatal natural killer (NK) cells, monocytes and dendritic cells. Blood was collected from mother and umbilical cord at birth, and from infants at seven weeks (one week pre-primary pertussis immunisation) and five months of age (one month post-primary pertussis immunisation). 21 mothers and 67 infants were studied.

FINDINGS

Vaccinated women had elevated pro-inflammatory cytokine responses to B. pertussis. At birth, babies of vaccinated women had elevated IL-2 and IL-12 responses, elevated classical monocyte proportions, and reduced monocyte and NK cell cytokine responses. The elevated IL-2 response persisted to seven weeks-of-age, when lower IL-10 and IL-13 responses were also seen. One-month post-primary pertussis vaccination, infants from vaccinated pregnancies still had lower IL-10 responses to B. pertussis, as well as lower IL-4.

INTERPRETATION

This study suggests that pertussis vaccination during pregnancy impacts infant cellular immune responses, potentially contributing to the modification of antibody responses already reported following primary immunisation against B. pertussis.

FUNDING

National Institute for Health Research Imperial Biomedical Research Centre and IMmunising PRegnant women and INfants neTwork (funded by the GCRF Networks in Vaccines R&D).

Study protocol of the PIMPI-project, a cohort study on acceptance, tolerability and immunogenicity of second trimester maternal pertussis immunization in relation to term and preterm infants

Background

Maternal immunization confers passive immunity to the fetus by transplacental antibody transfer. Infants may be better protected against pertussis if the mother received a diphtheriae, tetanus and acellular pertussis (Tdap) vaccination in the second trimester of pregnancy compared to the third trimester. This study evaluates IgG antibody concentrations in term and preterm infants at birth and 2 months after birth after maternal Tdap-vaccination between 20⁰ and 24⁰ w of gestation vs third trimester Tdap-vaccination. Further aims are assessing the determinants that underlie acceptance of second trimester maternal Tdap-vaccination as well as the tolerability of vaccination.

Methods

This prospective cohort study consists of two parts. In the acceptance part, pregnant women complete a questionnaire on determinants that underlie acceptance of a second trimester Tdap-vaccination, which is offered subsequently between 20⁰ and 24⁰ w of gestation. Vaccinated women complete an additional questionnaire on vaccination tolerability. Vaccinated women may also participate in the immunogenicity part, in which blood is drawn from mother at delivery and from infant at birth and 2 months after birth. Women are also eligible for the immunogenicity part if they received a Tdap-vaccination between 20⁰ and 24⁰ w of gestation via the national immunization program and get hospitalized for an imminent preterm delivery. Blood sampling continues until 60 term and 60 preterm mother-infant-pairs have been included. Pertussis-specific IgG antibody concentrations are determined in serum using a fluorescent bead-based multiplex immunoassay. For term infants, non-inferiority in IgG antibody concentrations against pertussis toxin (anti-PT) will be assessed referred to a historical control group in which mothers were Tdap-vaccinated between 30⁰ and 32⁰ w of gestation. For preterm infants, non-inferiority of anti-PT IgG concentrations is referred to as 85% of infants having ≥ 20 international units/mL at 2 months after birth.

Discussion

This study investigates acceptance, tolerability and immunogenicity regarding maternal Tdap-immunization between 20⁰ and 24⁰ w of gestation. Its results provide insight into the effects of second trimester Tdap-vaccination on IgG antibody concentrations in term and preterm infants before primary infant vaccinations. Results on acceptance and tolerability guide antenatal care providers in communication with pregnant women and maintain the safety of second trimester Tdap-vaccination.

Trial registration: EU Clinical Trials Register, 2018-002976-41, retrospectively registered 24 July 2019, https://www.clinicaltrialsregister.eu/ctr-search/search?query=2018-002976-41.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06559-w.

Maternal vaccines during the Covid-19 pandemic:A qualitative interview study with UK pregnant women

BACKGROUND

There is suboptimal uptake of recommended maternal vaccines (pertussis and influenza) during pregnancy in the UK. The Covid-19 pandemic has impacted healthcare services, and potentially vaccine coverage, and brought the need for new vaccines to be tested and rolled out.

OBJECTIVES

To explore: i) the impact of the Covid-19 pandemic on pregnant women's access to, and attitudes towards, routine maternal vaccines and; ii) women's attitudes towards testing Covid-19 vaccines on pregnant women and their personal willingness to take part in such a trial.

DESIGN

Qualitative interview study with pregnant women in the Bristol and surrounding area (UK).

METHODS

Semi-structured telephone/videoconference interviews were conducted (following a topic guide), transcribed verbatim and subjected to thematic analysis.

RESULTS

Thirty-one pregnant women (selected for demographic range) were interviewed in April/May 2020. Participants felt the pandemic had elevated the importance of routine maternal vaccines, though women were concerned about safety management around appointment attendance. Women were wary of receiving a new Covid-19 vaccine, with most perceiving it as riskier than Covid-19 itself.

CONCLUSIONS

It is important to maximise the safety and efficiency of maternity appointments to encourage uptake of routine maternal vaccines, and to communicate this well. For pregnant women to gain a new vaccine or participate in a vaccine trial, they need to be convinced that the risk posed by the virus is greater than any risk of receiving a new vaccine.

Tetanus, Diphtheria, Acellular Pertussis Vaccination During Pregnancy and Risk of Pertussis in the Newborn in Publicly and Privately Insured Mother-infant Pairs in the United States

BACKGROUND

In the United States, pertussis circulation persists and primarily infects infants and children, despite routine vaccinations. To minimize infant morbidity and mortality from the disease before the first DTaP dose, the Advisory Committee on Immunization Practices recommends maternal Tdap vaccination in weeks 27-36 of pregnancy.

METHODS

Cohorts of mother-infant pairs in the Medicaid Analytic eXtract (MAX) (2010-2014) and IBM MarketScan (2011-2015) databases were analyzed to estimate the effectiveness of prenatal Tdap vaccination compared with no vaccination to prevent infant pertussis in the first 6 months. Hazard ratios were estimated with Cox proportional hazards models and adjusted for potential confounders via inverse probability weights. The impact of preterm delivery on the risk of pertussis was analyzed. Results from the 2 databases were pooled.

RESULTS

In MarketScan, women received Tdap vaccination before delivery in 114,067 (25.6%) of 445,638 pregnancies and in MAX, 33,286 (4.8%) of 695,262 pregnancies. Among pregnancies with preterm delivery, only 21.2% and 3.8% in MarketScan and MAX had been vaccinated. The risk of pertussis in unvaccinated term infants was 3.5 (MarketScan) and 17 (MAX) per 10,000; and in preterm infants, it was 8.4 (MarketScan) and 19.8 (MAX) per 10,000. The pooled hazard ratio for Tdap vaccination any time before delivery versus no vaccination was 0.64 [95% confidence interval (CI): 0.41-1.00]. The hazard ratio was 0.11 (95% CI: 0.03-0.36) for preterm and 0.78 (95% CI: 0.48-1.29) for term infants vaccinated before 37 weeks. The incidence of pertussis was higher and the protective hazard ratio stronger during pertussis outbreaks.

CONCLUSIONS

Prenatal Tdap vaccination reduces the risk of pertussis infections in the infants' first 6 months by 36%. Vaccination soon after 27 weeks of pregnancy, before when deliveries began, ensures vaccination includes those born preterm, who are at highest risk for pertussis and benefit particularly from this vaccination.

Epidemiology, prevention and control of pertussis in Spain: New vaccination strategies for lifelong protection

Pertussis is a highly contagious, vaccine-preventable respiratory tract infection, with high morbidity and mortality and a particularly severe effect on newborns and infants under 2 months. The first pertussis vaccines were introduced in the 1940s. Since 1980, however, the incidence of cases has risen despite the extensive vaccination programmes and antibiotic adjuvant treatments available. Transition from the use of whole-cell vaccines to acellular vaccines and the antigenic modifications of Bordetella pertussis have contributed, among other factors, to a reduction in vaccine-acquired immunity and reemergence of the disease. Today, there are still unmet needs not covered by conventional prevention measures and existing antibiotic treatments. This review aims to update the available data, and to discuss which vaccine strategies might contribute to better disease control and prevention.

Optimising the Timing of whooping cough Immunisation in MUMs: a randomised controlled trial investigating the timing of pertussis vaccination in pregnancy (OpTIMUM): a protocol paper

Background: Pertussis is a highly infectious respiratory illness caused by the bacteria Bordetella pertussis. A resurgence of pertussis, even in countries with good vaccine coverage, has led to an increase in infant deaths. In response to this, many countries have introduced pertussis vaccination in pregnancy. This strategy is effective at preventing infant disease, but there remains uncertainty about what gestational timing is best to ensure maximal protection of the infant. These uncertainties are the rationale for this randomised controlled trial and a sub-study investigating pertussis-specific antibody in breastmilk.   Protocol: We will recruit 354 pregnant women and will randomise them to receive their pertussis vaccination in one of three gestational age windows: ≤23+6, 24-27+6 and 28-31+6 weeks of gestation.  Vaccination will be with Boostrix-IPV® and participants will be asked to complete a symptom diary for seven days following vaccination. Blood sampling will be performed prior to vaccination, two weeks following vaccination and at the time of delivery. A cord blood sample will be collected at delivery and a blood sample collected from the infant 4-10 weeks after completion of the primary immunisations. Individuals participating in the breastmilk sub-study will provide a sample of colostrum within 48 hours of delivery and samples of breastmilk at two weeks and around five-six months. Blood samples will be analysed using enzyme linked immunosorbent assay (ELISA) techniques for pertussis toxin, filamentous haemagglutinin and pertactin. A subset of serum samples will also be analysed using a functional assay. Colostrum and breastmilk samples will be analysed using functional assays. Discussion: Although pertussis vaccination has been shown to be safe and effective in pregnancy there remains debate about the optimal timing for the administration during pregnancy. This study will investigate antibody responses in serum and breastmilk when vaccination is performed in three different time periods. Clinicaltrials.gov registration: NCT03908164 (09/04/2019)

A phase IV, multi-centre, randomized clinical trial comparing two pertussis-containing vaccines in pregnant women in England and vaccine responses in their infants

BACKGROUND

Pertussis vaccines containing three or five pertussis antigens are recommended in pregnancy in many countries, but no studies have compared the effect on infants' antigen-specific immunoglobulin G (IgG) concentrations. The aim of this study was to compare anti-pertussis IgG responses following primary immunization in infants of mothers vaccinated with TdaP₅-IPV (low dose diphtheria toxoid, tetanus toxoid, acellular pertussis [five antigens] and inactivated polio) or TdaP₃-IPV in pregnancy (three pertussis antigens).

METHODS

This multi-centre phase IV randomized clinical trial was conducted in a tertiary referral centre and primary care sites in England. Women were randomized to receive TdaP₅-IPV (n = 77) or TdaP₃-IPV (n = 77) at 28-32 gestational weeks. A non-randomized control group of 44 women who had not received a pertussis-containing vaccine in pregnancy and their 47 infants were enrolled post-partum.

RESULTS

Following infant primary immunization, there was no difference in the geometric mean concentrations (GMCs) of anti-pertussis toxin, filamentous haemagglutinin or pertactin IgG between infants born to women vaccinated with TdaP₅-IPV (n = 67) or TdaP₃-IPV (n = 63). However, the GMC of anti-pertussis toxin IgG was lower in infants born to TdaP₅-IPV- and TdaP₃-IPV-vaccinated mothers compared to infants born to unvaccinated mothers (n = 45) (geometric mean ratio 0.71 [0.56-0.90] and 0.78 [0.61-0.98], respectively); by 13 months of age, this difference was no longer observed.

CONCLUSION

Blunting of anti-pertussis toxin IgG response following primary immunization occurs in infants born to women vaccinated with TdaP₅-IPV and TdaP₃-IPV, with no difference between maternal vaccines. The blunting effect had resolved by 13 months of age. These results may be helpful for countries considering which pertussis-containing vaccine to recommend for use in pregnancy.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02145624 , registered 23 May 2014.

Is it time to administer acellular pertussis vaccine to childbearing age/pregnant women in all areas using whole-cell pertussis vaccination schedule?

Background:

Whole-cell pertussis (wP) vaccine administration is still advocated for children under 7 years of age in Iran. However, there is no recommendation for the administration of a dose of tetanus, diphtheria, and acellular pertussis (Tdap) vaccine to childbearing age/pregnant women in the Iranian vaccination program and it has increased the risk of infection through waning immunity during women’s childbearing age life. The study aimed to assess the levels of anti-Bordetella pertussis antibodies in childbearing age women of different ages in Iran.

Methods:

A cross-sectional study was conducted on a total number of 360 childbearing age women divided into six age groups, with 5-year intervals from 15 to 45 years old, in 2018–2019. Then, the levels of immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) antibodies against B. pertussis were evaluated using enzyme-linked immunosorbent assay (ELISA). The IBM SPSS Statistics software (version 16.0) (SPSS Inc., Chicago, IL, USA) was used for data analysis.

Results:

The mean age of the participants was 30.01 ± 8.35 years (range 14–45 years). All the cases were IgM negative, but two IgA-positive individuals (in the age groups of 14–19 and 30–34 years) were reported. Overall, 239 (66.4%) cases were IgG positive. The mean age of IgG-positive cases was 30.37 ± 8.37 years. The IgG-positive cases were mostly in the age groups of 30–34 and 35–39 years [43 (71.1%)]. The odds of IgG positivity were 1.97. The highest odds of IgG positivity were seen in 30–34 and 35–39 years groups (2.52) and the lowest odds were seen in the 20–24 and 25–29 years groups (1.60). Using the Jonckheere–Terpstra test, the increasing trend of IgG changes in different age groups was not statistically significant (Tπ=5.78, p = 0.09).

Conclusion:

The infants of women of childbearing age might be prone to pertussis in countries using the wP vaccination schedule. It is suggested to administer a dose of Tdap to women before or during pregnancy to increase the immunity of their infants against this disease during early infancy.

Circulation of pertussis and poor protection against diphtheria among middle-aged adults in 18 European countries

Reported incidence of pertussis in the European Union (EU) and the European Economic Area (EEA) varies and may not reflect the real situation, while vaccine-induced protection against diphtheria and tetanus seems sufficient. We aimed to determine the seroprevalence of DTP antibodies in EU/EEA countries within the age groups of 40-49 and 50-59 years. Eighteen countries collected around 500 samples between 2015 and 2018 (N = 10,302) which were analysed for IgG-DTP specific antibodies. The proportion of sera with pertussis toxin antibody levels ≥100 IU/mL, indicative of recent exposure to pertussis was comparable for 13/18 countries, ranging between 2.7-5.8%. For diphtheria the proportion of sera lacking the protective level (<0.1 IU/mL) varied between 22.8-82.0%. For tetanus the protection was sufficient. Here, we report that the seroprevalence of pertussis in these age groups indicates circulation of B. pertussis across EU/EEA while the lack of vaccine-induced seroprotection against diphtheria is of concern and deserves further attention.

The identification and validity of congenital malformation diagnoses in UK electronic health records: A systematic review

PURPOSE

To describe the methods used to identify and validate congenital malformation diagnoses recorded in UK electronic health records, and the results of validation studies.

METHODS

Medline and Embase were searched for publications between 1987 and 2019 that involved identifying congenital malformations from UK electronic health records using diagnostic codes. The methods and code-lists used to identify congenital malformations, and the methods and results of validations, were examined.

RESULTS

We retrieved 54 eligible studies; 36 identified congenital malformations from primary care data and 18 from secondary care data alone or in combination with birth and/or death records. Identification in secondary care data relied on codes from the 'Q' chapter for congenital malformations in ICD-10. In contrast, studies using primary care data frequently used additional codes outside of the 'P' chapter for congenital malformation diagnoses in Read, although the exact codes used were not always clear. Eight studies validated diagnoses identified in primary care data. The positive predictive value was highest (80%-100%) for congenital malformations overall, major malformations, and heart defects although the validity of the reference standard used was often uncertain. It was lowest for neural tube defects (71%) and developmental hip dysplasia (56%).

CONCLUSIONS

Studies identifying congenital malformations from primary care data provided limited details about the methods used. The few validation studies were limited to diagnoses recorded in primary care. Further assessments of all measures of validity in both data sources and of other malformation subgroups are needed, using robust reference standards and adhering to reporting guidelines.

Antenatal care providers' attitudes and beliefs towards maternal vaccination in Kenya

Background: Maternal immunization is known to be one of the best strategies to protect both mothers and their infants from infectious diseases. Studies have shown that healthcare providers play a critical role in implementation of maternal immunization. However, little is known about providers' attitudes and beliefs towards vaccination that can influence their vaccine recommendations, specifically in low to middle income countries (LMIC). Methods: A self-administrated knowledge, attitude and behavior (KAB) survey was provided to 150 antenatal care providers across four different regions (Nairobi, Mombasa, Marsabit, and Siaya counties) of Kenya. The research staff visited the 150 clinics and hospitals and distributed a quantitative KAB survey. Results: Nearly all of the antenatal care providers (99%) recommended tetanus maternal vaccination. Similarly, 99% of the providers agreed that they would agree to provide additional vaccinations for pregnant women and reported that they always advise their patients to get vaccinated. Between 80 and 90% of the providers reported that religious beliefs, ethnicity, cultural background and political leaders do not affect their attitude or beliefs towards recommending vaccines. Conclusions: Considering the positive responses of healthcare providers towards vaccine acceptance and recommendation, these results highlight an opportunity to work in partnership with these providers to improve coverage of maternal vaccination and to introduce additional vaccines (such as influenza). In order to achieve this, logistical barriers that have affected the coverage of the currently recommended vaccines, should be addressed as part of this partnership.

Uptake of vaccination in pregnancy

Maternal immunisation is a public health strategy that aims to provide protection against certain infections to both mother and her foetus or newborn child. Vaccination of pregnant women induces vaccine-specific antibodies that lead to the subsequent transfer of these antibodies across the placenta or through breastfeeding to the offspring. At present, vaccinations in pregnancy are limited to pertussis, tetanus, diphtheria, polio, and the seasonal Influenza vaccine. Recently, some countries have incorporated routine antenatal vaccinations in their national immunisation programmes. Future vaccines targeted at pregnant women such as respiratory syncytial virus (RSV) and Group B streptococcus (GBS) are under development. The recently approved Covid-19 vaccines have no safety data for use in pregnancy at present, but have been considered in the UK in extremely vulnerable pregnant women or pregnant frontline health and social care workers.

In this article, we review the evidence supporting maternal immunisation and discuss the uptake of vaccines in pregnant women, challenges of recording the data on vaccine coverage, and consider reasons behind the present levels of uptake and strategies for future improvements.

Obstetric and perinatal health outcomes after pertussis vaccination during pregnancy in Ontario, Canada: a retrospective cohort study

BACKGROUND

In February 2018, Canada's National Advisory Committee on Immunization recommended maternal vaccination with tetanus-diphtheria-acellular pertussis (Tdap) vaccine during pregnancy to prevent severe pertussis infection in young infants. This study assessed the relation between maternal Tdap vaccination and obstetric and perinatal outcomes in Ontario.

METHODS

We performed a population-based cohort study of all births from April 2012 to March 2017 using multiple linked health administrative databases. We used Cox regression with a time-dependent exposure variable to estimate adjusted hazard ratios (HRs) for preterm birth (< 37 wk), very preterm birth (< 32 wk) and stillbirth. We assessed remaining outcomes (gestational hypertension, chorioamnionitis, postpartum hemorrhage, severe postpartum hemorrhage, being small for gestational age, neonatal intensive care unit stay > 24 h, composite neonatal morbidity) using log-binomial regression to generate adjusted risk ratios (RRs). We adjusted estimates for potential confounding using propensity score weighting.

RESULTS

Of 615 213 infants (live births and stillbirths), 11 519 were exposed to Tdap vaccination in utero. There was no increased risk for preterm birth (adjusted HR 0.98, 95% confidence interval [CI] 0.91-1.06), very preterm birth (adjusted HR 1.10, 95% CI 0.86-1.41), stillbirth (adjusted HR 1.15, 95% CI 0.82-1.60) or being small for gestational age (adjusted RR 0.96, 95% CI 0.90-1.02). The risks of a neonatal intensive care unit stay exceeding 24 hours (adjusted RR 0.82, 95% CI 0.76-0.88) and neonatal morbidity (adjusted RR 0.81, 95% CI 0.75-0.87) were decreased. There was no association with chorioamnionitis (adjusted RR 1.17, 95% CI 0.99-1.39), postpartum hemorrhage (adjusted RR 1.01, 95% CI 0.91-1.13) or severe postpartum hemorrhage (adjusted RR 0.79, 95% CI 0.55-1.13), but we observed a reduced risk of gestational hypertension (adjusted RR 0.87, 95% CI 0.78-0.96).

INTERPRETATION

Our results complement evidence that maternal Tdap vaccination is not associated with adverse outcomes in mothers or infants. Ongoing evaluation in Canada is needed as maternal Tdap vaccination coverage increases in coming years.

Systematic review and meta-analysis of the effect of pertussis vaccine in pregnancy on the risk of chorioamnionitis, non-pertussis infectious diseases and other adverse pregnancy outcomes

BACKGROUND

Several countries have introduced maternal immunisation with pertussis vaccine to provide protection against pertussis in early infancy. There is increasing interest in non-specific effects of vaccines including that non-live vaccines may enhance susceptibility to non-targeted infections in females. Some studies have shown increased risk of chorioamnionitis among women receiving pertussis vaccine during pregnancy. We aimed to conduct a systematic review and meta-analysis of the effect of maternal pertussis immunisation on the risk of chorioamnionitis, as well as the secondary outcomes of non-pertussis infections in women, non-pertussis infections in infants, spontaneous abortion or stillbirth, maternal death and infant death.

METHODS

We searched PubMed and Embase for articles published until January 14, 2021. We screened articles for eligibility and extracted data using Covidence. Quality was assessed using Cochrane RoB tool and Newcastle-Ottawa Scale. Data were imported into RevMan for pooling and conduction of a meta-analysis stratified by study type. Outcomes are presented as risk ratios.

RESULTS

We identified 13 observational studies and six randomized controlled trials eligible for inclusion. We pooled data on chorioamnionitis from six observational studies and found maternal pertussis vaccine (mostly compared with other maternal immunizations with non-live vaccines) to be associated with an increased risk among the pertussis vaccinated women, RR = 1.27 [CI 95%: 1.14-1.42]. We found no difference in the analysis of our secondary outcomes of non-pertussis infections, spontaneous abortion or stillbirth and death.

CONCLUSION

We found an increased risk of chorioamnionitis among women who received pertussis vaccine in pregnancy. The large number of women receiving pertussis vaccine during pregnancy, as well as the growing evidence of non-live vaccines causing increased susceptibility to infections, indicates a need for further randomised trials to assess potential adverse effects of maternal immunisation with pertussis-containing vaccines.

Impact of maternal diphtheria-tetanus-acellular pertussis vaccination on pertussis booster immune responses in toddlers: Follow-up of a randomized trial

BACKGROUND

Transplacentally transferred antibodies induced by maternal pertussis vaccination interfere with infant immune responses to pertussis primary vaccination. We evaluated whether this interference remains in toddlers after booster vaccination.

METHODS

In a prior phase IV, observer-blind, placebo-controlled, randomized study (NCT02377349), pregnant women in Australia, Canada and Europe received intramuscular tetanus-reduced-antigen-content diphtheria-three-component acellular pertussis vaccine (Tdap group) or placebo (control group) at 27^0/7-36^6/7 weeks' gestation, with crossover immunization postpartum. Their infants were primed (study NCT02422264) and boosted (at 11-18 months; current study NCT02853929) with diphtheria-tetanus-three-component acellular pertussis-hepatitis B virus-inactivated poliovirus/Haemophilus influenzae type b vaccine (DTaP-HepB-IPV/Hib) and 13-valent pneumococcal conjugate vaccine. Immunogenicity before and after booster vaccination, and reactogenicity and safety of the booster were evaluated descriptively.

RESULTS

263 (Tdap group) and 277 (control group) toddlers received a DTaP-HepB-IPV/Hib booster. Pre-booster vaccination, observed geometric mean concentrations (GMCs) for the three pertussis antigens and diphtheria were 1.4-1.5-fold higher in controls than in the Tdap group. No differences were observed for the other DTaP-HepB-IPV/Hib antigens. One month post-booster vaccination, booster response rates for pertussis antigens were ≥ 92.1% and seroprotection rates for the other DTaP-HepB-IPV/Hib antigens were ≥ 99.2% in both groups (primary objective). Higher post-booster GMCs were observed in controls versus the Tdap group for anti-filamentous hemagglutinin (1.2-fold), anti-pertussis toxoid (1.5-fold) and anti-diphtheria (1.4-fold). GMCs for the other DTaP-HepB-IPV/Hib antigens were similar between groups. Serious adverse events were reported for three toddlers (controls, not vaccination-related). One death occurred pre-booster (Tdap group, not vaccination-related).

CONCLUSIONS

As a consequence of interference of maternal pertussis antibodies with infant immune responses to pertussis primary vaccination, pertussis antibody concentrations were still lower in toddlers from Tdap-vaccinated mothers before DTaP-HepB-IPV/Hib booster vaccination. After the booster, antibody concentrations were lower for filamentous hemagglutinin and pertussis toxoid but not for pertactin. The clinical significance of this interference requires further evaluation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT02853929.

Evaluating the Association of Stillbirths After Maternal Vaccination in the Vaccine Safety Datalink

OBJECTIVE

To evaluate whether the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices recommended influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccinations in pregnancy are associated with increased risk of stillbirth.

METHODS

We performed a case-control study in the Vaccine Safety Datalink that was matched 1:4 on site, month, and year of last menstrual period, comparing the odds of vaccination in pregnancies that ended in stillbirth (defined as fetal loss at or after 20 weeks of gestation) compared with those that ended in live birth from January 1, 2012, to September 30, 2015. We included patients with singleton pregnancies that ended in stillbirth or live birth who had at least one prenatal care visit, pregnancy dating information, and continuous health plan enrollment for the duration of pregnancy. Medical records for all stillbirths were reviewed. We were statistically powered to detect an odds ratio (OR) of 1.37 when evaluating the association between influenza or Tdap vaccination and stillbirth. We also examined stillbirth rates in pregnant patients aged 14-49 years in the Vaccine Safety Datalink between 2007 and 2015.

RESULTS

In our matched analysis of 795 confirmed stillbirths in the case group and 3,180 live births in the control group, there was no significant association between influenza vaccination during pregnancy and stillbirth (343/795 [43.1%] stillbirths in the case group vs 1,407/3,180 [44.3%] live births in the control group, OR 0.94, adjusted OR 0.95, 95% CI 0.79-1.14, P=.54) and no significant association between Tdap vaccination during pregnancy and stillbirth (184/795 [23.1%] stillbirths in the case group vs 746/3,180 [23.5%] live births in the control group, OR 0.97, aOR 0.96, 95% CI 0.76-1.28, P=.91). From 2007 to 2015, the stillbirth rate in the Vaccine Safety Datalink was 5.2 per 1,000 live births and stillbirths.

CONCLUSION

No association was found between vaccination during pregnancy and the odds of stillbirth. These findings support the safety of ACIP recommendations for vaccination during pregnancy.

The Fifth International Neonatal and Maternal Immunization Symposium (INMIS 2019): Securing Protection for the Next Generation

Despite significant progress in reaching some milestones of the United Nations Sustainable Development Goals, neonatal and early infant morbidity and mortality remain high, and maternal health remains suboptimal in many countries. Novel and improved preventative strategies with the potential to benefit pregnant women and their infants are needed, with maternal and neonatal immunization representing effective approaches. Experts from immunology, vaccinology, infectious diseases, clinicians, industry, public health, and vaccine-related social sciences convened at the 5th International Neonatal and Maternal Immunization Symposium (INMIS) in Vancouver, Canada, from 15 to 17 September 2019. We critically evaluated the lessons learned from recent clinical studies, presented cutting-edge scientific progress in maternal and neonatal immunology and vaccine development, and discussed maternal and neonatal immunization in the broader context of infectious disease epidemiology and public health. Focusing on practical aspects of research and implementation, we also discussed the safety, awareness, and perception of maternal immunization as an existing strategy to address the need to improve maternal and neonatal health worldwide. The symposium provided a comprehensive scientific and practical primer as well as an update for all those with an interest in maternal and neonatal infection, immunity, and vaccination. The summary presented here provides an update of the current status of progress in maternal and neonatal immunization.

Evaluation of a midwife-led, hospital based vaccination service for pregnant women

Background: Vaccines against whooping cough (pertussis) and seasonal-influenza are recommended for pregnant women in England. Uptake however varies regionally and by ethnicity. Pregnant women are traditionally vaccinated in primary care, though some hospitals now offer vaccines through antenatal clinics. This mixed-methods evaluation describes the demographic characteristics of women seen in a hospital midwife-led antenatal vaccine clinic and explores vaccine decision making. Methods: Descriptive statistics of women seen in a London hospital's midwife-led vaccine clinic were generated from electronic routine maternity records, including data on ethnicity, parity, age and deprivation indices. Reasons for vaccine decline given by women to midwives were categorized by themes. Qualitative interviews of women seen in the clinic were also undertaken. Results: Between 1st April 2017 and 31st March 2018 the vaccine clinic saw 1501 pregnant women. Of these, 83% received pertussis vaccine and (during flu season) 51% received influenza vaccine, from the clinic. Fewer Black Afro-Caribbean women seen by the clinic were vaccinated, compared to other ethnicities with only 68% receiving pertussis and 34% flu vaccines respectively (p < .05). Among all women delivering at the hospital over the year, 42%, (1334/3147) were vaccinated by the clinic. Qualitative interviews found that reassurance from healthcare professionals, particularly midwives, was the most important factor influencing maternal vaccine decisions. Conclusions: Midwife-led hospital clinics can offer an effective alternative to primary care provision for vaccines in pregnancy. Consistent with previous work, vaccine uptake varied by ethnicity. Midwives play a key role in the provision of vaccine services and influence women's vaccine decisions.

Background incidence rates of adverse pregnancy outcomes in the Netherlands: Data of 2006-2018

OBJECTIVE

Maternal vaccination is an effective and safe intervention to protect newborns against infectious diseases shortly after birth. We assessed background rates of adverse pregnancy outcomes before the implementation of a maternal pertussis immunisation programme in the Netherlands, to put into perspective the safety concerns about such outcomes following immunisation.

STUDY DESIGN

In this retrospective cross-sectional study, annual numbers of pregnancy outcomes derived from the Dutch Perinatal Registry were used to calculate incidence rates per 10,000 in the 2006-2018 period. Births of ≥500 g birth weight and ≥24 + 0 w gestational age were included. Trends with moving-average-lines over the past 3 years were plotted, with 95 % confidence interval.

RESULTS

From 2006 through 2018, yearly numbers of pregnancies ranged between 158,868-175,710. Numbers of newborns ranged between 161,307-178,874, of whom 160,838-178,177 were live-born. Most outcomes were stable over time. Between 2006-2011, occurrence of labour induction increased by 68 %, and postpartum hemorrhage increased by 25 %. Both stabilised from 2011 onwards. Perinatal mortality up to day 7 or 28 postpartum decreased by 38 % and 37 %, respectively. Occurrence of low Apgar score among preterm infants born before 37 + 0 w gestational age and among term infants increased by 19 % and 27 %, respectively.

CONCLUSION

Our study on background incidences showed notable increases over time in occurrence of labour induction, postpartum hemorrhage and low Apgar score, while showing a considerable decrease in overall perinatal mortality. These findings should be considered when interpreting data on adverse events occurring since the maternal pertussis immunisation programme was implemented.

Risk factors associated with death in infants <120 days old with severe pertussis: a case-control study

Background and purpose

Pertussis is a serious infectious disease in young infants, and severe cases frequently cause death. Our study explored risk factors for death from severe pertussis.

Method

A case-control study of infants with severe pertussis admitted to the paediatric intensive care unit (PICU) in the Children’s Hospital of Chongqing Medical University, China, from January 1, 2013, to June 30, 2019, was conducted. Pertussis was confirmed by clinical features and laboratory examinations. Severe pertussis was defined as patients with pertussis resulting in PICU admission or death. To understand the risk factors for death, we compared fatal and nonfatal cases of severe pertussis in infants aged < 120 days by collecting clinical and laboratory data.

Results

The participants included 63 infants < 120 days of age with severe pertussis. Fifteen fatal cases were confirmed and compared with 44 nonfatal severe pertussis cases, Four patients with termination of treatment were excluded. In the univariate analysis, the risk factors associated with death included apnoea (P = 0.001), leukocytosis (white blood cell (WBC) count≥30 × 10⁹/L (P = 0.001) or ≥ 50 × 10⁹/L (P = 0)), highest lymphocyte count (P = 0), pulmonary hypertension (P = 0.001), and length of PICU stay (P = 0.003). The multivariate analysis revealed that apnoea (OR 23.722, 95%CI 2.796–201.26, P = 0.004), leukocytosis (OR 63.708, 95%CI 3.574–1135.674, P = 0.005) and pulmonary hypertension (OR 26.109, 95%CI 1.800–378.809, P = 0.017) were significantly associated with death.

Conclusion

Leukocytosis and pulmonary hypertension exhibited the greatest associations with death in infants with severe pertussis admitted to the PICU. Vaccination is still the most effective protection method against pertussis.

[Preventive activities in women's care]

A review is presented of the scientific evidence on preventive activities in women's care in relation to pregnancy follow-up, preventive activities in the planning and follow-up of contraceptive methods, preventive activities in menopause, and the prevention of osteoporotic fractures.

The historical aspects of vaccination in pregnancy

As we live through the history-making pandemic of coronavirus disease 2019 (COVID-19), it is timely to consider the lessons that history has taught us about vaccine-preventable disease in pregnancy. Vaccinations have earned an established place in pregnancy care to prevent communicable disease in the mother, fetus and newborn. The improvements in maternal and perinatal outcome have been achieved through the evolution and application of new knowledge in many areas. These include recognition of the unique pathogenic consequences of diseases in pregnancy; improved understanding of the maternal immune system and its interplay with the fetus; optimizing safe vaccine development; ensuring pregnant women are included in appropriately designed trials of efficacy, and public health engagement to optimize uptake. As the world eagerly awaits an effective vaccine for COVID 19, these lessons of history help signpost the way, to ensure the potential of vaccinations to reduce morbidity for pregnant women and their newborns is fully realized.

Pertussis and influenza immunisation coverage of pregnant women in New Zealand

BACKGROUND

Immunisation is an important public health policy and measuring coverage is imperative to identify gaps and monitor trends. New Zealand (NZ), like many countries, does not routinely publish coverage of immunisations given during pregnancy. Therefore, this study examined pregnancy immunisation coverage of all pregnant NZ women between 2013 and 2018, and what factors affected uptake.

METHODS

A retrospective cohort study of pregnant women who delivered between 2013 and 2018 was undertaken using administrative datasets. Maternity and immunisation data were linked to determine coverage of pertussis and influenza vaccinations in pregnancy. Generalised estimating equations were used to estimate the odds of receiving a vaccination during pregnancy.

RESULTS

From 2013 to 2018 data were available for 323,622 pregnant women, of whom 21.7% received maternal influenza immunisations and 25.7% maternal pertussis immunisations. Coverage for both vaccines increased over time, pertussis increased from 10.2% to 43.6% and influenza from 11.2% to 30.8%. The odds of being vaccinated, with either vaccine, during pregnancy increased with increasing age and decreasing deprivation. Compared to NZ European or Other women, Māori and Pacific women had lower odds of receiving a maternal pertussis (OR:0.55, 95% CI: 0.54, 0.57; OR:0.60, 95% CI: 0.58, 0.62, respectively) and influenza (OR: 0.69, 95% CI: 0.67, 0.71; OR:0.90, 95% CI: 0.87, 0.94, respectively) immunisations during pregnancy. Women were also more likely to be vaccinated against pertussis if they received antenatal care from a General Practitioner or Obstetrician compared to a Midwife. A similar pattern was seen for influenza vaccination.

CONCLUSION

Gaps in maternal coverage for pertussis and influenza exist and work is needed to reduce immunisation inequities.

Kinetics of maternal pertussis-specific antibodies in infants of mothers vaccinated with tetanus, diphtheria and acellular pertussis (Tdap) during pregnancy

BACKGROUND

Kinetics of Tdap-induced maternally-derived antibodies in infants are poorly understood. Pre-Tdap era data suggest that maternal pertussis antibodies in infants have a half-life of approximately 5-6 weeks.

METHODS

34 mother-infant pairs had blood collected before maternal Tdap vaccination, 4 weeks later, at delivery (maternal and cord), and at infant ages 3 and 6 weeks from June 2014-March 2015. Immunoglobulin G (IgG) to pertussis toxin (PT), filamentous hemagglutinin (FHA), fimbrial proteins (FIM) and pertactin (PRN) was quantified by multiplex luminex assay (IU/ml). Geometric mean concentrations (GMCs) with 95% confidence intervals (C.I.) and half-life of pertussis antibodies were calculated.

RESULTS

Tdap was administered to 34 women (mean age 31.1 years) at mean gestation 30.7 weeks (28-32.7). Mean neonatal gestation was 39.1 weeks (36-41.1) and mean birthweight was 3379 g (2580-4584). Four weeks post-Tdap vaccination, maternal pertussis-specific IgG GMCs increased ≥4-fold in 59%, 41%, 29% and 44% of women for PT, FHA, FIM and PRN, respectively, and then waned. The transplacental transport ratio of pertussis antibodies was 1.35 for PT, 1.41 for FHA, 1.31 for FIM and 1.36 for PRN. Between birth and age 6 weeks, infant serum GMC for PT-specific IgG decreased from 55.1 IU/mL (38.6-78.6) to 21.1 IU/ml (14.7-30.2), and the proportion of infants with PT levels ≥10 IU/ml fell from 97% to 67%. Half-life of pertussis-specific IgG in infants in days was 29.4 (95% CI 27.3-31.7) for PT, 29.8 (95% CI 27.7-32.2) for FHA, 31.2 (95% CI 28.9-33.7) for PRN, and 35.8 (95% CI 30.1-44.3) for FIM.

CONCLUSION

The half-life of pertussis-specific antibodies in infants induced by maternal Tdap vaccination (29-36 days) is shorter than previously reported. Understanding how the durability of passively-acquired antibodies impacts infant susceptibility to pertussis and response to primary vaccination is critical to refine prevention strategies.