Strategies to decrease pertussis transmission to infants

Predictors of maternal pertussis vaccination acceptance among pregnant women in Norway

Maternal vaccination against pertussis is safe and provides effective protection against pertussis for the newborn, but the vaccine coverage rate remains generally low. Norway is currently planning for introduction of routine maternal pertussis vaccination. To assess maternal pertussis vaccination acceptance among pregnant Norwegian women, we surveyed women at 20-40 weeks gestation in 2019. Among the 1,148 pregnant women participating in this cross-sectional study, 73.8% reported they would accept pertussis vaccination during pregnancy if it was recommended, 6.9% would not accept and 19.2% were undecided. Predictors for low likelihood of accepting pertussis vaccination during pregnancy included low confidence in health authorities and in maternal pertussis vaccination safety and effectiveness, low awareness and adherence to influenza vaccination during pregnancy, and low awareness of pertussis vaccination. The major reasons reported for not accepting or being undecided about maternal pertussis vaccination were lack of information on vaccine safety for both mother and child. Most women reported that they would consult their general practitioner or a midwife for information if they were offered maternal pertussis vaccination. General practitioners and midwives were also regarded as the most trustworthy sources of information if the women were in doubt about accepting vaccination. We conclude that information addressing safety concerns and raising awareness about maternal pertussis vaccination could increase acceptance of maternal pertussis vaccination. Our findings highlight the pivotal role of the antenatal and primary health care services in providing such information to pregnant women.

Comparison of Physicians' Attitudes and Practice Regarding Vaccination during Pregnancy in Turkey

This study aimed to investigate the knowledge, attitudes, and behaviors of family physicians (FPs), pediatricians (PPs), and obstetricians and gynecologists (OGs) regarding vaccine administration during pregnancy in Turkey as factors that contribute to decision-making. The survey was distributed among FPs, OGs, and PPs, and participants were asked to rate their knowledge on specific topics using a five-point scale ranging from "Not Effective" to "Effective". The tetanus and diphtheria (Td) vaccine was highly recommended by 94.9% of physicians and considered very effective. Among the physicians surveyed, 80% of PPs and 66.0% of OGs were aware of the disease burden of pertussis. We also found that 74.5% of FPs and 77.2% of PPs believed they needed more information about vaccination during pregnancy. All physicians surveyed agreed or strongly agreed that explaining the disease risks and benefits of vaccination increases the vaccine acceptance rate. The results of this survey study indicate that the knowledge and awareness of physicians need to be improved to increase vaccination rates during pregnancy in Turkey, and it is essential to incorporate influenza and tetanus, diphtheria, and pertussis (TdaP) vaccines into the standard maternal immunization schedule for newborns.

The impact of maternal pertussis vaccination recommendation on infant pertussis incidence and mortality in the USA: an interrupted time series analysis

BACKGROUND

Pertussis is a contagious respiratory disease. Maternal tetanus-diphtheria-acellular pertussis vaccination during pregnancy has been recommended by the United States Centres for Disease Control (US CDC) Advisory Committee on Immunization Practices (ACIP) for unvaccinated pregnant women since October 2011 to prevent infection among infants; in 2012, ACIP extended this recommendation to every pregnancy, regardless of previous vaccination status. The population-level effect of these recommendations on infant pertussis is unknown. This study aimed to examine the impact of the 2011/2012 ACIP pertussis recommendation on pertussis incidence and mortality among US infants.

METHODS

We used monthly data on pertussis deaths among infants aged <1 year between January 2005 and December 2017 in the CDC Death Data and yearly infant pertussis incidence data from the CDC National Notifiable Disease Surveillance System to perform an interrupted time series analysis, accounting for the passage of the Affordable Care Act.

RESULTS

This study included 156 months of data. A potential decline in trend in infant pertussis incidence was noted during the post-recommendations period. No appreciable differences in trend were found in population-level infant pertussis mortality after the guideline changes in both adjusted and unadjusted models. Results were similar for all mortality sensitivity analyses.

CONCLUSIONS

The 2011/2012 ACIP maternal pertussis vaccination recommendations were not associated with a population-level change in the trend in mortality, but were potentially associated with a decrease in incidence in the USA between 2005 and 2017.

Immunomodulation of Antibody Glycosylation through the Placental Transfer

Establishing an immune balance between the mother and fetus during gestation is crucial, with the placenta acting as the epicenter of immune tolerance. The placental transfer of antibodies, mainly immunoglobulin G (IgG), is critical in protecting the developing fetus from infections. This review looks at how immunomodulation of antibody glycosylation occurs during placental transfer and how it affects fetal health. The passage of maternal IgG antibodies through the placental layers, including the syncytiotrophoblast, stroma, and fetal endothelium, is discussed. The effect of IgG subclass, glycosylation, concentration, maternal infections, and antigen specificity on antibody transfer efficiency is investigated. FcRn-mediated IgG transport, influenced by pH-dependent binding, is essential for placental transfer. Additionally, this review delves into the impact of glycosylation patterns on antibody functionality, considering both protective and pathological effects. Factors affecting the transfer of protective antibodies, such as maternal vaccination, are discussed along with reducing harmful antibodies. This in-depth examination of placental antibody transfer and glycosylation provides insights into improving neonatal immunity and mitigating the effects of maternal autoimmune and alloimmune conditions.

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.

Improving Tdap maternal immunization rate in Saudi Arabia

Pertussis is a serious and potentially fatal disease in infants too young for vaccination. Despite a high vaccine coverage in children, pertussis continues to occur in unvaccinated infants in the Kingdom of Saudi Arabia (KSA). Available data supports the use of maternal pertussis immunization for preventing pertussis in young infants. In June 2019, the Saudi Ministry of Health recommended maternal pertussis immunization with combined tetanus-diphtheria-acellular pertussis vaccine (Tdap) during every pregnancy. To understand barriers to maternal immunization and identify strategies to improve maternal immunization, we conducted an online survey in November and December 2020, asking 60 obstetricians/gynecologists about their attitudes to maternal pertussis immunization. Fewer than 50% survey respondents considered maternal immunization as part of their role, and only 47% were aware of the national recommendation. Consequently, the uptake of maternal vaccination in KSA may be sub-optimal. The key barriers that hinder obstetricians/gynecologists from recommending maternal Tdap immunization were the anticipation of patient refusal, and their own need for more information/experience about the disease and the national recommendation. Vaccine availability and supply were important barriers, whereas cost/reimbursement and resource issues were of lesser concern. Disseminating evidence based information to physicians, educating pregnant women and addressing public misconceptions.

Case-Control Study to Estimate the Association Between Tdap Vaccination During Pregnancy and Reduced Risk of Pertussis in Newborn Infants in Peru, 2019-2021

Background

Despite widespread vaccination, pertussis has re-emerged as a serious public health concern worldwide. Since 2017, Peru has experienced an increase in pertussis cases exhibiting a higher risk of severity and death in young infants. Thus, a dose of the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine is recommended for pregnant women in the third trimester. Although evidence suggests the maternal Tdap vaccine is safe and effective, its association with a reduced risk of pertussis in developing countries remains poorly investigated.

Methods

We conducted a case-control study to evaluate the association between Tdap vaccination during pregnancy and reduction in the risk of pertussis among infants aged <2 months in Peru. Pertussis cases and controls treated in healthcare facilities nationwide between 2019 and 2021 and confirmed by real-time polymerase chain reaction were included. The controls were randomly selected from test-negative patients. Odds ratios (ORs) and vaccine effectiveness (VE) were calculated using a multiple logistic regression model and 1 - (OR) × 100%, respectively.

Results

Fifty cases and 150 controls were included in the analysis. The mothers of 4% of cases and 16.7% of controls received Tdap vaccination during pregnancy, resulting in an OR of 0.19 (95% confidence interval [CI], .04-.86) and VE of 81% (95% CI, 14%-96%) for preventing pertussis in infants.

Conclusions

Peruvian infants <2 months old whose mothers received the Tdap vaccine in the third trimester of pregnancy had a significantly lower risk of pertussis. The Tdap vaccination is thus an effective intervention to reduce the burden of pertussis in at-risk populations.

Long-term measles antibody profiles following different vaccine schedules in China, a longitudinal study

Characterizing the long-term kinetics of maternally derived and vaccine-induced measles immunity is critical for informing measles immunization strategies moving forward. Based on two prospective cohorts of children in China, we estimate that maternally derived immunity against measles persists for 2.4 months. Following two-dose series of measles-containing vaccine (MCV) at 8 and 18 months of age, the immune protection against measles is not lifelong, and antibody concentrations are extrapolated to fall below the protective threshold of 200 mIU/ml at 14.3 years. A catch-up MCV dose in addition to the routine doses between 8 months and 5 years reduce the cumulative incidence of seroreversion by 79.3-88.7% by the age of 6 years. Our findings also support a good immune response after the first MCV vaccination at 8 months. These findings, coupled with the effectiveness of a catch-up dose in addition to the routine doses, could be instrumental to relevant stakeholders when planning routine immunization schedules and supplemental immunization activities.

Influenza and Pertussis Vaccine Uptake during Pregnancy: Determinants Found through a Multi-Center Questionnaire Study of Pregnant Women and Healthcare Professionals

The objective of this article is to assess the adherence of pregnant women to the national recommendations for influenza and pertussis vaccination and the reasons behind their non-adherence. This was a retrospective observational study conducted in a well-defined puerperant population of adequate healthcare standards from December 2018 to December 2019. The study was carried out with 1006 puerperants and 66 health care practitioners. Data were collected, including demographic-obstetric features of pregnant women, whether they received antenatal vaccination, the reasons for having been vaccinated or not as well as health professional's opinion regarding antenatal immunization. The uptake of influenza and pertussis vaccine during pregnancy was suboptimal with lack of recommendation of the vaccine by the healthcare providers being the main barrier. Factors positively associated with antenatal vaccination against influenza were higher level of maternal education and advanced maternal age while antenatal vaccination against pertussis was positively associated with higher level of maternal education. This large-scale retrospective study reveals the inadequacy of antenatal vaccination rates against pertussis and influenza in Crete, Greece. Results suggest that obstetricians' confidence in vaccination is of outmost importance for implementing immunization in pregnancy and any doubts on vaccine effectiveness and safety should be resolved. Routine antenatal vaccination counseling and pregnancy immunization campaigns are essential to improve vaccine uptake during pregnancy.

[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.

Post-Marketing Surveillance of Tetravalent Diphtheria-Tetanus-Acellular Pertussis and Inactivated Poliovirus (DTaP-IPV) Vaccine in South Korea, 2009 to 2015

Introduction

TETRAXIM™ (Sanofi), a combined diphtheria, tetanus, acellular pertussis, and inactivated poliovirus (DTaP-IPV) vaccine, has been licensed in South Korea since 2009. In accordance with the Ministry of Food and Drug Safety regulations, this post-marketing surveillance (PMS) study evaluated the safety of the DTaP-IPV vaccine in real-world clinical practice in infants and children who received it as either a part of the three-dose primary series dose at 2, 4, and 6 months or school entry booster between 4 and 6 years of age.

Methods

This multicenter, observational, PMS study was conducted in real-world practice in South Korea for 6 years (2009–2015) in participants aged between 2 months and 6 years. The study outcomes included solicited reactions, unsolicited adverse events (AEs)/adverse drug reactions (ADRs), unexpected AEs/ADRs, and serious AEs (SAEs)/ADRs.

Results

Data from 647 participants was included in the safety analysis. Overall, 268 AEs were reported by 181 (28%) participants: 47 (17.5%) solicited reactions, 220 (82.1%) unsolicited AEs, and 1 (0.4%) unsolicited ADR. A total of 48 AEs (including 47 solicited reactions) were reported to have a causal relationship with the DTaP-IPV vaccine and were reported by 36 (5.6%) participants. A total of 212 unexpected AEs were reported by 152 (23.5%) participants, none of which had a causal relationship with the DTaP-IPV vaccine. Neither immediate AEs nor SAEs were reported during the study. Among the participants who reported AEs, 220 (34%) were on concomitant medications. Most AEs were of mild intensity, and all participants recovered.

Conclusion

No safety concerns related to the DTaP-IPV vaccine in a real-world setting were raised in participants aged 2–6 months for the primary series and 4–6 years for the school-entry booster dose in the Korean population. The DTaP-IPV vaccine was well tolerated and can be continued as part of routine immunization programs in infants and children.

Trial Registration: NCT01437423.

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

Objective

Methods

Results

Conclusions

Efficacy of a Smartphone Application to Promote Maternal Influenza Vaccination: A Randomized Controlled Trial

The maternal vaccine coverage rate has been low in Taiwan. We developed an “Influenza Vaccination Reminder Application” and evaluated its efficacy in improving vaccination intention among pregnant women in Taiwan. A randomized controlled trial was conducted to compare the positive change in vaccination intention between the experimental group and the control group. Pregnant women who were more than 20 years old and at less than 32 weeks of gestation were recruited from four regional hospitals in southern Taiwan during November 2020 to April 2021. Pregnant women were randomly assigned to the experimental group, to whom the “Influenza Vaccination Reminder Application” was provided for at least two months, while pregnant women in the control group received regular maternal education only. The differences in knowledge about influenza and its vaccines, attitudes towards maternal influenza vaccination, and behavior intention of influenza vaccination among pregnant women before and after the experiment intervention were compared between two groups. The results included 126 women in the experimental group and 117 women in the control group and showed that the “Influenza Vaccination Reminder Application” increased pregnant women’s knowledge about influenza and vaccines (percentage increase in the experimental group and control group: 11.64% vs. 7.39%), strengthened their positive attitudes towards maternal influenza vaccination (percentage increase: 5.39% vs. 1.44%), and promoted positive behavioral intention toward influenza vaccination (proportion of participants with positive change in vaccination intention: 17.46% vs. 7.69%). The study supports use of “Influenza Vaccination Reminder Application” to promote the behavior intention of influenza vaccination among pregnant women in Taiwan.

Pertussis in Asia: Recent country-specific data and recommendations

The Global Pertussis Initiative (GPI) Roundtable Meeting held in 2019, which preceded the COVID-19 pandemic, focused on the incidence, surveillance, and immunization practices for pertussis in the Asian region. Participants from China, India, Indonesia, Malaysia, Pakistan, Philippines, South Korea, Taiwan, and Thailand presented country-specific information on pertussis prevalence, diagnosis, surveillance, vaccine administration and schedules, maternal and neonatal disease rates, and policies and practice of vaccination during pregnancy. In recent years, many Asian countries have seen an increase in pertussis cases, although underreporting of the disease is a concern. Currently, most Asian countries have only passive surveillance for pertussis in place. There is a need for improved surveillance to determine the disease burden and justify vaccination policies and recommendations, such as essential vaccination, boosters, and vaccination during pregnancy. Better awareness of the disease in adolescents and adults is necessary, and infant and childhood vaccination schedules need to be improved in many countries. Differences between private versus public sector vaccination schedules and between whole-cell and acellular pertussis vaccines should continue to be examined. It can be anticipated that unmet needs in the prevention and management of pertussis will continue as the COVID-19 pandemic evolves and that key recommendations highlighted in this meeting report will be of ongoing importance.

The need for pertussis vaccination among older adults and high-risk groups: a perspective from advanced economies of the Asia Pacific region

INTRODUCTION

Influenza and pneumococcal vaccines are the most regularly prescribed vaccines amongst adults <65 years of age. Pertussis booster vaccines (available as combined diphtheria-tetanus-acellular pertussis, Tdap) uptake is relatively low in many countries in the Asia-Pacific region. Increasing Tdap vaccination is a strategy that may aid healthy aging.Areas Covered: Epidemiology data, including notification reports from 6 advanced economies in Asia (Australia, Hong Kong, New Zealand, Singapore, South Korea, and Taiwan) were reviewed to assess the pertussis disease burden and identify high-risk groups. Existing Tdap vaccination recommendations were reviewed. Current vaccination practices were discussed to benchmark and identify barriers and success factors for Tdap booster vaccination in older adults.Expert Opinion: The available evidence supports Tdap vaccination at an individual level for the prevention of pertussis, along with tetanus and diphtheria in those aged 65+ years, together with influenza and pneumococcal vaccination. Data gaps need to be filled to support the development of national/supranational recommendations for pertussis booster vaccination. Groups at higher risk of pertussis infection and its complications, including those with chronic obstructive pulmonary disease and asthma, could be considered as priority groups. Increasing disease awareness and establishing adult vaccination registries could improve vaccine coverage and promote healthy aging.

COVID-19 Vaccination in Pregnancy and Lactation: Current Research and Gaps in Understanding

The COVID-19 pandemic has demonstrated the urgent need to develop vaccine strategies optimized for pregnant people and their newborns, as both populations are at risk of developing severe disease. Although not included in COVID-19 vaccine development trials, pregnant people have had access to these vaccines since their initial release in the US and abroad. The rapid development and distribution of novel COVID-19 vaccines to people at risk, including those who are pregnant and lactating, presents an unprecedented opportunity to further our understanding of vaccine-induced immunity in these populations. In this review, we aim to summarize the literature to date on COVID-19 vaccination in pregnancy and lactation and highlight opportunities for investigation that may inform future maternal vaccine development and implementation strategies.

Acceptance of Pertussis Vaccination among Pregnant Women in Taiwan

This cross-sectional study assessed prenatal pertussis vaccination acceptance in Taiwan. A sample of pregnant women from five private clinics in Taiwan was recruited. Demographics, experience of prenatal vaccinations, key considerations, knowledge, and attitude about pertussis and its vaccination were measured. Among 505 participants, the vaccination rate, including planned vaccination, was 29.7%. Factors associated with acceptance included clinic location, primary caregiver of the newborn, newborns with siblings, previous influenza vaccination history, knowledge and attitude toward pertussis and its vaccination. Public health agencies should provide free vaccinations, clarify misinformation, and publicize prevention information, to improve prenatal pertussis vaccination acceptance.

Bordetella pertussis in School-Age Children, Adolescents and Adults: A Systematic Review of Epidemiology and Mortality in Europe

Pertussis (whooping cough) epidemics persist globally despite high vaccine coverage among infants and young children. The resurgence of pertussis in high-income countries is partly due to waning vaccine immunity, resulting in a pool of unprotected adolescents and adults. However, pertussis is generally less severe in adolescents and adults, and this difference in presentation means it can often be unrecognised by healthcare professionals, meaning that it is largely under-diagnosed in older populations. A systematic search of MEDLINE, EMBASE and BIOSIS was undertaken to identify studies published between 1 January 1990 and 17 June 2019, with information on pertussis epidemiology and mortality in school-aged children, adolescents and adults in Europe. A formal statistical comparison (e.g. using meta-analyses) was not possible because of the mix of methodologies reported. There were 69 epidemiological studies and 19 mortality studies identified for review. Over the past decade, the reported incidence of notified pertussis cases varied widely between European countries, which is likely associated with differences in surveillance systems, diagnostic techniques and reporting regulations. However, several studies show that pertussis is circulating among adolescents and adults in Europe, and although pertussis-related morbidity and mortality are highest in infants, there is evidence that adults aged > 50 years are at increased risk. For example, in a hospital-based surveillance study in Portugal, between 2000 and 2015, 94% of hospitalised pertussis cases were infants aged < 1 year, with a case fatality rate (CFR) of 0.8%; however, among hospitalised adult cases of pertussis, the CFRs were 11.5% (aged 18–64 years) and 17.4% (aged > 65 years). Very few European countries currently include pertussis boosters for adults in the national immunisation strategy. In addition to increasing pertussis vaccination coverage in adolescents and adults, mitigation strategies in European countries should include improved diagnosis and treatment in these populations.

Segmentation and shielding of the most vulnerable members of the population as elements of an exit strategy from COVID-19 lockdown

This study demonstrates that an adoption of a segmenting and shielding strategy could increase the scope to partially exit COVID-19 lockdown while limiting the risk of an overwhelming second wave of infection. We illustrate this using a mathematical model that segments the vulnerable population and their closest contacts, the 'shielders'. Effects of extending the duration of lockdown and faster or slower transition to post-lockdown conditions and, most importantly, the trade-off between increased protection of the vulnerable segment and fewer restrictions on the general population are explored. Our study shows that the most important determinants of outcome are: (i) post-lockdown transmission rates within the general and between the general and vulnerable segments; (ii) fractions of the population in the vulnerable and shielder segments; (iii) adherence to protective measures; and (iv) build-up of population immunity. Additionally, we found that effective measures in the shielder segment, e.g. intensive routine screening, allow further relaxations in the general population. We find that the outcome of any future policy is strongly influenced by the contact matrix between segments and the relationships between physical distancing measures and transmission rates. This strategy has potential applications for any infectious disease for which there are defined proportions of the population who cannot be treated or who are at risk of severe outcomes. This article is part of the theme issue 'Modelling that shaped the early COVID-19 pandemic response in the UK'.

Antenatal vaccination for influenza and pertussis: a call to action

Pregnant women should receive influenza and pertussis vaccines according to the National Immunisation Schedule in Greece. The purpose of this study was to assess the knowledge, attitudes and factors associated with antenatal vaccination of women in Greece. A cross-sectional prospective survey was conducted involving 432 pregnant women and women who had recently given birth in Western Greece. Although the majority of women were aware of both diseases (289, 66.9%), they admitted lack of knowledge about antenatal vaccination (317, 73.4%). Overall, there was poor awareness that the vaccination is safe during pregnancy (95, 22%). Only 26 (6%) of women have been offered the vaccines during current pregnancy. Prior vaccination and obstetrician`s recommendation were the stronger predictors of antenatal vaccine uptake. There is substantial room for improvement among antenatal care providers in both patient education and the provision of the vaccines.Impact StatementWhat is already known about the topic? Maternal vaccination has been recognised as an important public health intervention to protect both pregnant women and their offspring from various infectious diseases. Pregnant women should receive influenza and pertussis vaccines according to the National Immunisation Schedules in many countries worldwide. However, scepticism still exists upon vaccine uptake during pregnancy.What do the results of this study add? The purpose of the study was to assess the knowledge, attitudes and factors associated with antenatal vaccination of women in Greece. We found that the knowledge and uptake of influenza and pertussis vaccine among pregnant women in Greece is poor.What the implications are of these findings for clinical practice and/or further research? There is substantial room for improvement among antenatal care providers in both patient education and the provision of the vaccines.

Bordetella pertussis in School-Age Children, Adolescents, and Adults: A Systematic Review of Epidemiology, Burden, and Mortality in Asia

Cyclic epidemics of pertussis (whooping cough) have been observed globally over the past twenty years despite high infant vaccine coverage. The resurgence of pertussis in high-income countries is partly due to waning vaccine immunity in older children and adults, as well as better surveillance and diagnostics. Moreover, in adolescents and adults, pertussis symptoms are mild and similar to common cough syndromes, meaning that it is under-diagnosed in older populations. A systematic search of MEDLINE, EMBASE, and BIOSIS was undertaken to identify studies published between 1 January 1990 and 17 June 2019, with information on pertussis epidemiology, burden of illness, and mortality in school-aged children, adolescents, and adults in Asia. Studies identified for inclusion were reviewed narratively because a statistical comparison was not possible due to the mix of methodologies used. The results showed that in East Asia, including Japan, South Korea, China, and Taiwan, pertussis is circulating in older children and adults. Diphtheria-tetanus-pertussis (DTP4) coverage is high in East Asia, yet outbreaks observed in Japan and South Korea suggest that vaccine-acquired immunity had waned in adolescents and adults. Several school outbreaks in China show that pertussis is circulating in young children, with continued circulation in adolescents and adults. There was a lack of information from Southeast/South Asian countries, although pan-Asian serosurveys showed that recent pertussis infection was common in adolescents and in adults with persistent cough. To conclude, the circulation of pertussis in Asian countries with high DTP4 coverage supports the expansion of routine vaccination to include booster doses for children at school entry and adolescents. However, surveillance is weak or absent in many countries, meaning that the true burden of pertussis, particularly among older populations, is unknown.

Immunogenicity, safety, and reactogenicity of combined reduced-antigen-content diphtheria-tetanus-acellular pertussis vaccine administered as a booster vaccine dose in healthy Russian participants: a phase III, open-label study

As vaccine-induced immunity and protection following natural pertussis infection wane over time, adults and adolescents may develop pertussis and become transmitters to unprotected infants. In Russia, diphtheria and tetanus but not pertussis-containing vaccines are registered for older children, adolescents, or adults. The reduced-antigen-content diphtheria toxoid, tetanus toxoid, and acellular pertussis (dTpa) vaccine (Boostrix, GSK) was developed for booster vaccination of children ≥4 years of age, adolescents, and adults. A phase III, open-label, non-randomized study was performed in eight centers in Russia between January and July 2018. The objective of this study was to assess immunogenicity, reactogenicity and safety of a single dose of dTpa vaccine in healthy Russian participants ≥4 years of age (age categories 4-9 years, 10-17 years, 18-64 years, and ≥65 years). At 1 month post-booster vaccination, across all age groups, >99.0% of participants were seroprotected against diphtheria and tetanus and >96.0% of participants were seropositive for anti-pertussis antibodies. For all antibodies across all age groups, antibody GMCs increased from pre- to 1 month post-booster vaccination and booster responses to diphtheria (in 71.5% of participants), tetanus (85.3%), and pertussis antigens (≥85.6%) were observed. One serious adverse event that was not causally related to the study vaccine was reported. No fatal cases were reported throughout the study period. In conclusion, administration of the dTpa vaccine as a booster dose in healthy Russian participants induced a robust immune response to all vaccine antigens and was generally well tolerated across all age groups.

Impact of Tdap vaccine during pregnancy on the incidence of pertussis in children under one year in Brazil - A time series analysis

Pertussis is a globally distributed infectious disease that is a significant cause of morbidity and mortality, especially in infants who are too young to be immunized. This disease is common in childhood, and when it occurs during the first few months of life, it leads to hospitalization and, sometimes, death. Brazil has adopted the strategy of maternal immunization against pertussis in late 2014. This study aims to analyze public data on the disease to determine whether there was an impact on the disease burden following the introduction of the vaccine Tdap in pregnant women and its magnitude. We performed a time-series analysis of the incidence of pertussis between October 2010 and January 2019. We stratified the population of interest into three groups: infants aged less than two months old, infants aged two to six months, and infants aged six months to one year, according to Brazil's vaccination schedule. We found a protective effect of maternal vaccination in all age groups, more prominent on the first group. Before the intervention, infants under two months had a higher risk of getting pertussis in comparison with infants two to six months old (HR 1.15, CI 95%: 1.11-1.19). After the intervention, age under two months is a protective factor compared with two to six months (HR 0.90, CI 95%: 0.82-0.98). The pertussis incidence reduced in all age groups and all Brazil's Regions.

Effect of educational and financial incentive-based interventions on immunization attitudes, beliefs, intentions and receipt among close contacts of pregnant women

INTRODUCTION

Cocooning, the vaccination of close contacts of a newborn, is a strategy to limit the risk of pertussis and influenza infection among vulnerable infants.

METHODS

Pregnant women in Colorado and Georgia referred close contacts to an app that provided tailored educational videos about vaccines along with a small pharmacy-based financial incentive for vaccine receipt. The primary objective of this study was to determine the feasibility of implementing this app-based cocooning intervention.

RESULTS

Two hundred seventy seven contacts were enrolled in this study. Of those who received the educational videos, 96% found them interesting, 100% found them clear to understand, 97% found them helpful, and 99% trusted them. Completion of the videos led to significant increases in influenza vaccine knowledge (p = 0.025), Tdap vaccine knowledge (p < 0.001), and intention to receive these vaccines (p = 0.046). Of the 136 participants who reported receiving influenza vaccine, 41 (30%) reported receiving it at a pharmacy, and of the 66 who reported receiving Tdap vaccine, 15 (23%) reported receiving it at a pharmacy. Of all participants, 80% reported being comfortable receiving vaccines at a pharmacy instead of a doctor's office. The provision of small pharmacy-based financial incentives combined with individually-tailored educational videos about vaccines led to 6.97 (95%CI: 2.25-21.64) times higher odds of self-reported receipt of influenza vaccine than providing small pharmacy-based financial incentives without these videos. No significant difference was found for Tdap vaccine.

CONCLUSIONS

Tailored vaccine education can positively impact vaccine knowledge and intentions among adults. An app-based referral program providing education and financial incentives for cocooning vaccination at pharmacies is feasible.

Effect of a postpartum prescription for pertussis vaccine: a before-and-after study

BACKGROUND

Among the strategies to encourage pregnant women to be vaccinated against pertussis in the postpartum period, that of giving them a prescription has been evaluated only sparsely.

OBJECTIVE

To measure the effect of giving women who are not immunized against pertussis a prescription for the vaccine at discharge from the maternity unit.

MATERIAL AND METHODS

Single-center before-and-after study (2011: before; 2015: after). All women received both oral and written information about vaccination against pertussis. During the after period, they were also specifically asked their immunization status during pregnancy. Those currently unimmunized received a written prescription for it at discharge.

RESULTS

Among the women unimmunized at delivery, the percentage who were vaccinated postpartum climbed from 17 to 42% between 2011 and 2015 (p < 0.001), while the percentage of their unimmunized partners who were vaccinated remained stable (27 and 29%, p = 0.74). During this time, the percentage of women immunized against pertussis at the beginning of pregnancy rose from 32 to 52% (p < 0.001). Finally, the percentage of all women protected against this disease postpartum climbed from 44 to 72% between these two periods (p < 0.001).

CONCLUSIONS

In the postpartum period, giving a prescription for pertussis vaccine to women unimmunized is accompanied by a significant elevation in their vaccination rate. Nevertheless, this rate remains low and better strategies have to be implemented.

Control of vaccine preventable diseases in Australian infants: reviewing a decade of experience with DTPa-HBV-IPV/Hib vaccine

The combined vaccine against diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis, and Haemophilus influenzae b (DTPa-HBV-IPV/Hib, Infanrix Hexa, GSK) has been used for childhood immunization in Australia according to a two-, four-, six-month schedule since 2009. We reviewed data available in the Australian National Notifiable Diseases Surveillance System, annual vaccination coverage reports, the Database of Adverse Event Notifications, and peer-reviewed literature to assess vaccine coverage rates, incidence of all six vaccine preventable diseases, and the safety profile of DTPa-HBV-IPV/Hib vaccine in Australian infants over a period of ten years of exclusive use. Between 2009 and 2018 vaccine coverage for infants aged 12 months increased from 91.7% to 94.0% and from 84.9% to 92.6% for all and for Indigenous infants, respectively. Over the same time period, there were no reports of poliomyelitis, diphtheria or tetanus in infants <12 months of age. The incidence of hepatitis B among Australian infants <12 months of age remains 10 to 20-fold lower than the national average. Control of Haemophilus influenzae b (Hib) and pertussis disease has continued to be challenging. Timely administration of the primary series, as well as increasing coverage rates, particularly among Indigenous children, has contributed to improvements in Hib and pertussis disease control. The incorporation of additional strategies such as adjustment of the first vaccination encounter to six weeks of age, parental cocooning, and most recently maternal vaccination has further reduced the burden of pertussis, particularly during the first six months of life. The frequency of the ten most common adverse events related to the DTPa-HBV-IPV/Hib vaccine demonstrates an acceptable safety profile. Data collected over ten years of consistent, exclusive use of the DTPa-HBV-IPV/Hib vaccine in Australia highlights combination vaccination as a cornerstone in maintaining infant health.

Vaccination of Term and Preterm Infants

Newborns, especially those born preterm, are at high risk for infection. Preterm birth rates appear to be increasing in most countries, with ∼15 million infants born preterm globally each year, corresponding to ∼11% of all deliveries. Importantly, the vulnerability of preterm infants to infection continues beyond the perinatal period, following them throughout childhood and adolescence, highlighting the long-lasting effects of infection on overall health and well-being. Other than access to clean drinking water and proper sewage systems, immunization is the most effective biomedical intervention to reduce early life infection. Nevertheless, a significant proportion of infants discharged on or after 2 months of age from the NICU remains unimmunized or underimmunized at that time. Despite being safe and effective, protective responses to immunization in early life are different from those in older individuals, in part because of the distinct immune system of newborns and young infants. The paradigms of the Bacille Calmette-Guérin, hepatitis B, and polio vaccines, the only immunizations currently routinely administered in the neonatal period, provide evidence that it is feasible to successfully administer vaccines via different routes of delivery; thus, production of sufficient vaccine-induced immunity leads to disease prevention in the newborn. Strategies such as maternal immunization, adjuvantation systems, leveraging trained immunity, and counseling caregivers can be used to enhance vaccine-induced specific and heterologous protection from infection and boost adherence to the recommended immunization schedule.

[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.

Pertussis in Italy: how to protect the "unprotectable"?

Whooping cough continues to be an important public health issue despite high levels of vaccination coverage with acellular pertussis vaccine. Young unimmunized infants represent the most vulnerable group with the highest rates of complications and death. As infant-specific pertussis epidemiologic data, especially among neonates, in Italy were limited, a retrospective observational study of hospitalizations for whooping cough in Italian infants aged <12 months between 2007 and 2018 was conducted to address this knowledge gap. The temporal trend of rates, also stratified for age classes according to the expected age for the administration of vaccine doses, were analyzed by the slope of the regression line. The mean age at the time of admission was 92 d (±64). A clear seasonal pattern in the occurrence of pertussis hospitalizations with a summer peak was observed. Infants younger than 3 months old had the highest hospitalization rates (169 x 100000 infants on average), with a significant rising trend of 9 x 100000 infants on average per year. Limiting the analysis to Bordetella pertussis-related hospitalizations such trend was even more evident. In the other age classes, hospitalization rates were considerably lower and gradually decreased with increasing age. This study demonstrated that pediatric populations, too young to be protected by vaccination, had a greater risk of contracting pertussis. Thus, it is necessary to promote additional immunization strategies besides one booster dose in adolescents, including vaccination during pregnancy.

Effectiveness of strategies to increase uptake of pertussis vaccination by new parents and family caregivers: A systematic review

OBJECTIVES

Cocoon immunisation strategies involve administration of Bordetella pertussis containing vaccines to parents and family members who are in close contact with newborns. The objective of this systematic review was to evaluate the effectiveness of strategies to increase uptake of vaccination against Bordetella pertussis infection by parents and family caregivers of newborn children (< 3 months of age).

DESIGN

A protocol driven systematic review was conducted between 2005 and February 2020. CINAHL, Medline, and Google Scholar databases were searched.

SETTING

Inpatient maternity care units, ante-natal and post-natal clinics based in acute care or primary/community care contexts.

PARTICIPANTS

(i) mothers, (ii) fathers and (iii) family caregivers or other regular household contacts of infants < 3 months of age.

INTERVENTIONS

Health promotion interventions and immunisation clinics designed to promote "cocoon immunisation" against Bordetella pertussis infections of the newborn.

MEASUREMENTS

Change in uptake of adult vaccination with a pertussis containing vaccine (dTpa or Tdap) by new parents and family caregivers.

FINDINGS

Eight studies were included in this review. Strategies used to promote vaccination included: written and verbal education, promotional videos, provision of vaccine prescriptions and financial incentives, opportunistic vaccination of family members and population-based health promotional messaging. Six of the eight studies reported positive impacts on vaccination uptake. Four studies evaluating providing opportunistic immunisation during the obstetric admission reported statistically significant increases in maternal (+39% to +57%), paternal (+21% to +52%) and household members (+32%) vaccination rates. Targeted public health campaigns were also found to increase vaccination uptake but in isolation were insufficient to achieve vaccination of all household contacts.

CONCLUSION

Promotion of pertussis vaccination to new parents and the provision of opportunistic vaccination during the obstetric admission or post-natal visit, was the most successful strategy to increase uptake of pertussis vaccination by family caregivers.

Relevance of the Materno-Fetal Interface for the Induction of Antigen-Specific Immune Tolerance

In humans, maternal IgGs are transferred to the fetus from the second trimester of pregnancy onwards. The transplacental delivery of maternal IgG is mediated by its binding to the neonatal Fc receptor (FcRn) after endocytosis by the syncytiotrophoblast. IgGs present in the maternal milk are also transferred to the newborn through the digestive epithelium upon binding to the FcRn. Importantly, the binding of IgGs to the FcRn is also responsible for the recycling of circulating IgGs that confers them with a long half-life. Maternally delivered IgG provides passive immunity to the newborn, for instance by conferring protective anti-flu or anti-pertussis toxin IgGs. It may, however, lead to the development of autoimmune manifestations when pathological autoantibodies from the mother cross the placenta and reach the circulation of the fetus. In recent years, strategies that exploit the transplacental delivery of antigen/IgG complexes or of Fc-fused proteins have been validated in mouse models of human diseases to impose antigen-specific tolerance, particularly in the case of Fc-fused factor VIII (FVIII) domains in hemophilia A mice or pre-pro-insulin (PPI) in the case of preclinical models of type 1 diabetes (T1D). The present review summarizes the mechanisms underlying the FcRn-mediated transcytosis of IgGs, the physiopathological relevance of this phenomenon, and the repercussion for drug delivery and shaping of the immune system during its ontogeny.

Pertussis vaccination in mixed markets: Recommendations from the Global Pertussis Initiative

The Global Pertussis Initiative is an expert scientific forum that publishes consensus recommendations concerning pertussis for many regions of the world. Here, we give recommendations for the primary vaccination of infants in those countries where whole-cell pertussis (wP)- and acellular pertussis (aP)-containing combination vaccines are used in parallel. A selective literature review was performed concerning the influence on safety, immunogenicity, and effectiveness of mixing wP- and aP-containing vaccines for primary immunization of infants. In addition, local data were collected from various countries and the results discussed in a face-to-face meeting. Very few data addressing issues of mixing combination vaccines were identified, and no data were available concerning the effectiveness or duration of protection. It was also found that pharmacovigilance data are scarce or lacking in those countries where they would be needed the most. We then identified frequent problems occurring in low- and middle-income countries (LMICs) where both vaccine types are used. Relying on local knowledge, we give practical recommendations for a variety of situations in different settings. Specific needs for additional data addressing these issues were also identified. International bodies, such as the World Health Organization (WHO), as well as vaccine producers should try to find ways to highlight the problems of mixing wP- and aP-containing combination vaccines with robust data. Countries are urged to improve on their pharmacovigilance for vaccines. For practicing physicians, our recommendations offer guidance when wP- and aP-containing vaccines are used in parallel during primary immunization.

Immune interference (blunting) in the context of maternal immunization with Tdap-containing vaccines: is it a class effect?

INTRODUCTION

Maternal immunization with reduced antigen content tetanus-diphtheria-acellular pertussis (Tdap)-containing vaccines has been recommended to prevent infant pertussis. However, maternal antibodies may interfere with infant responses to routine immunization with diphtheria-tetanus-acellular pertussis (DTaP)-containing vaccines, raising concerns of suboptimal protection after infant vaccination. We performed a narrative literature review to assess whether blunting occurs regardless of the manufacturer of maternal and infant vaccines. Because internationally agreed correlates of protection are lacking, the clinical significance of blunting is not yet fully understood. We have reviewed the evidence available to date.

AREAS COVERED

Thirteen studies that evaluated blunting after maternal immunization and infant primary/booster series were identified. Blunting was observed with various combinations of Tdap- and DTaP-containing vaccines for maternal and pediatric immunization. Studies assessing the effectiveness of maternal Tdap immunization beyond the primary infant immunization series in England and in the United States suggested no evidence of a clinically relevant blunting effect so far.

EXPERT COMMENTARY

This review indicates that the phenomenon of blunting does not depend on the manufacturer/brand of the pertussis-containing vaccines used for immunizing mothers or children. Currently, there is no epidemiological evidence that children whose mothers received Tdap are at increased risk of pertussis after pediatric vaccinations, although longer follow-up is required.

Vertically Transferred Immunity in Neonates: Mothers, Mechanisms and Mediators

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

Factors associated with referring close contacts to an app with individually-tailored vaccine information

BACKGROUND

Infants too young to be fully vaccinated are vulnerable to potentially deadly influenza and pertussis infections. The cocooning strategy limits this risk by vaccinating those likely to interact with the infant and mother during this vulnerable time, such as close friends and family members. Distribution of accurate and accessible vaccine information through existing social networks could be an important tool in increasing vaccine confidence and coverage.

METHODS

We surveyed 1095 pregnant women from diverse prenatal care practices in Georgia and Colorado. These women were surveyed through a mobile app to assess vaccine intentions, attitudes, beliefs, norms, and levels of trust, and then presented brief individually-tailored educational videos about maternal and infant vaccines and the cocooning strategy. They were then given the opportunity to refer up to six contacts to enroll in the app and receive similar vaccine education.

RESULTS

Twenty-eight percent of these women referred at least one contact, with an average of 2.67 contacts per referring woman. Most referrals (93%) were partners, parents, siblings, relatives, or close friends. Attitudinal constructs significantly associated with increased likelihood of referring contacts included: intention to receive maternal influenza vaccine, perceived safety of maternal Tdap vaccine, perceived efficacy of maternal influenza vaccine, perceived susceptibility to and severity of influenza during pregnancy, and trust in vaccine information from the Centers for Disease Control and Prevention (CDC) and academic institutions. Uncertainty about infant vaccine intentions was associated with decreased likelihood of referring contacts.

CONCLUSIONS

Pregnant women who valued vaccination and trusted vaccine information from academic institutions were more likely to refer an educational app about vaccines than those who did not. Further research is needed to determine the potential impact of this strategy on vaccine coverage when implemented on a large scale.

TRIAL REGISTRATION

The survey informing this article was part of a randomized controlled trial funded by the National Institutes of Health [clinicaltrials.gov registration number NCT02898688].

Assessing adolescent immunization options for pertussis in Canada: A cost-utility analysis

BACKGROUND

Adolescent tetanus, diphtheria and pertussis (Tdap) immunization helps prevent pertussis infection. Timing of Tdap receipt represents an important facet of successful adolescent pertussis immunization. Potential strategies for timing of vaccine administration are each associated with different benefits - including disease prevention - and costs. The objective of this study was to assess the cost-utility of adolescent pertussis immunization strategies in Canada.

METHODS

A cost-utility analysis was conducted using a pertussis disease history-simulating Markov model, with adolescents (beginning at age 10 years) as the cohort of interest. The model assessed three Tdap vaccination strategies: (1) immunization of 10 year olds, (2) removal of adolescent vaccination, and (3) immunization of 14 year olds (status quo). The analysis was conducted from a healthcare payer perspective and used a lifetime time horizon. Primary outcomes included life years, quality-adjusted life years (QALYs), health system costs, and an incremental cost-effectiveness ratio (ICER). Costs and outcomes were discounted at 1.5 percent annually. Deterministic and probabilistic sensitivity analyses were performed to assess parameter uncertainty.

RESULTS

The current recommended adolescent immunization strategy (at age 14) resulted in an average of 40.4432 expected QALYs and $26.28 per individual. This strategy was dominated by immunization at 10 years and no immunization. Compared to no immunization, immunizing adolescents at age 10 had an ICER of $74,899 per QALY. Results were most sensitive to the incidence of pertussis and the utility of moderate or severe pertussis. At a cost-effectiveness threshold of $50,000/QALY, removal of adolescent vaccination represented the most cost-effective strategy in 78% of simulations.

CONCLUSION

Analysis assumes a policy context where immunization of pregnant women is recommended. Findings suggest that alternate adolescent Tdap vaccine strategies - either immunization of 10 year olds, or removal of the adolescent vaccine - are more cost-effective than the current practice of immunizing 14 year olds.

Trends in Hospital Admissions for Pertussis Infection: A Nationwide Retrospective Observational Study in Italy, 2002-2016

Background: Pertussis is a highly contagious infectious disease which continues to be an important public-health issue despite the high immunization coverage rates achieved. However, evidence of increased circulation of pertussis among adolescents and adults due to waning immunity and atypical clinical manifestations seem to be the main reasons for its resurgence. The aim of this study was the analysis of the epidemiological trend for pertussis-related hospitalizations in Italy, in relation with vaccination coverage and information from laboratory confirmed cases of pertussis. Methods: A retrospective observational study investigating hospitalizations for pertussis from 2002 to 2016 in Italy was conducted. Frequencies and rates of hospitalization were analyzed and hospitalization data were compared with a series of already published laboratory confirmed data. Results: This study highlighted a rising trend for pertussis hospitalizations in Italy since 2008. Infants aged <1 year showed the highest frequencies (63.39%) and average rates (74.60 × 100000 infants) of hospitalization despite an extremely high vaccination coverage (95.89%). An increasing trend of hospitalization frequency emerged for the age group with levels of IgG antibodies to pertussis toxin compatible with pertussis infection within the last year (20–29 years old age group). Conclusions: The rising trend for pertussis hospitalizations and the greater involvement of infants aged <1 year require an integrated approach, including the implementation of booster doses administration in adolescence and adulthood, the vaccination of pregnant women and the cocoon strategy.

The health and economic burden of pertussis in Canada: A microsimulation study

BACKGROUND

Despite excellent vaccine coverage, pertussis persists in Canada, with high incidence during recent outbreaks and non-negligible incidence in non-outbreak years. While Canadian pertussis incidence is well-characterized, the full health and economic impact of pertussis have not been examined in Canada. We estimated age-specific life years (LYs) and quality-adjusted life years (QALYs) lost, and costs due to pertussis in Ontario, Canada, using a model-based approach.

METHODS

We developed a microsimulation model to simulate pertussis natural history. Daily probabilities of pertussis complications, hospitalizations, and disease sequelae as well as utilities and costs for health states were literature-derived. A healthcare payer perspective was used with a lifetime time horizon. Model outcomes were compared to those from a model with no pertussis health states. Probabilistic sensitivity analyses were used to generate distributions for estimates. Economic burden was estimated by multiplying case cost estimates by annual age-specific incidence.

RESULTS

Overall, LYs lost per pertussis case was low, with negligible LYs lost in those aged >4 years. Infants (<6 months) had the greatest mean QALY loss per case (0.58), while adults lost only 0.05 QALYs per case. Infants experienced the greatest mean cost per case of $22,768 (95% CI: 21,144-23,406). Case costs generally declined with age, but increased in seniors (aged 65+) with mean cost of $1920 (95% CI: 1800-2033). Based on historic age-specific incidence, pertussis costs the Ontario healthcare system approximately $7.6-$21.5 M annually. In total economic cost estimates with QALYs valued at 1xGDP (3xGDP) per capita, the net impact of pertussis in Ontario was estimated at $21.7-$66.5 M annually ($50.0-$156.3 M). For all of Canada, total economic costs were estimated at $79.6-$241.3 M ($187.5-$580.5 M) annually.

CONCLUSION

The health and economic consequences of pertussis persistence are substantial and highlight the need for improved control strategies.

Acceptance of pregnant women's vaccination against pertussis among French women and health professionals: PREVACOQ-1 and -2 studies

OBJECTIVES

Protection of French young infants against pertussis only relies on their relatives' vaccination. The alternative is vaccination of pregnant women against pertussis (cocooning strategy), but this strategy is not yet recommended in France. We assessed the acceptance of this strategy among French postpartum women and health professionals.

PATIENTS AND METHODS

We performed a multicenter survey in 2016 among postpartum women and health professionals (family physicians, obstetricians-gynecologists, midwives, and medical students) to determine the acceptance of anti-pertussis vaccination. We evaluated knowledge, perception, and attitude towards vaccination to identify factors associated with acceptance.

RESULTS

Questionnaires were completed by 52% (1208/2337) of women and 40% (694/1754) of health professionals. Seventy-seven per cent of women (95% CI: 74-79) and 93% of health professionals (95% CI: 91-95) were favorable to anti-pertussis vaccination of pregnant women. Thirty-three per cent (227/687) of health professionals believed that pertussis induced life-long immunity and 20% (136/687) of them were not aware of the cocooning strategy. In multivariate analysis, factors associated with acceptance among women were younger age, higher knowledge, having received advice during pregnancy, being vaccinated against influenza, and having never refused any vaccine; among health professionals, factors associated with acceptance were belief that inactivated vaccines are obstetrically safe, regular practice of influenza vaccination in pregnant women, pertussis cocooning strategy, and never prescribing preventive homeopathy for influenza.

CONCLUSION

Vaccination of pregnant women against pertussis should be well-accepted by informed mothers and health professionals. If this strategy were to be implemented in France, efforts should be made towards adequate information.

Paediatric hospitalizations due to whooping cough in Spain (1997-2017)

This epidemiological survey estimates the burden of whooping cough in infants up to 12 months old in Spain during a twenty-one-year period (1997-2017). The survey was conducted by reviewing data from the Spanish Surveillance System for Hospital Data. All hospitalizations due to whooping cough for infants, reported during the 1997-2017 period, were analysed. Codes were selected from the International Classification of Diseases, 9th Revision, Clinical Modification diagnosis codes 033.0-033.9. To explore the latest national outbreak and the implementation of vaccination in pregnant women, analyses were stratified to compare the following periods: 1997-2010, 2011-2015 and 2016-2017. A total of 13,352 hospital discharges for whooping cough in infants up to 12 months old were reported. A total of 6850 discharges in the period 1997-2010, 5271 in the period 2011-2015 and 1231 in 2016-2017 were identified. The annual hospitalization rate prior to 2011 was 131.02 cases per 100,000 infants; in 2011-2015, the rate was significantly higher (250.13 cases per 100,000 infants) and in 2016-2017 it decreased (157.69 cases per 100,000 infants). Most of the cases (n = 11,446) occurred in infants under 4 months of age, with hospitalization rates of 328.80, 670.81 and 385.84 cases per 100,000 infants up to 4 months of age in the periods 1997-2010, 2011-2015 and 2016-17, respectively. Thirty-four deaths occurred in the period 1997-2010, 36 in the period 2011-2015 and 4 in 2016-2017. All of the deaths occurred in infants under 4 months old. The case fatality rate did not vary significantly across the study periods. Whooping cough infections concentrate in infants up to 4 months of age in Spain. Public health measures such as vaccination of pregnant women, caregivers, health care professionals and relatives, especially young parents, could reduce the hospitalization burden during the current outbreak.

Pertussis epidemiological pattern and disease burden in Brazil: an analysis of national public health surveillance data

Objective: We described pertussis epidemiological trends in Brazil between 2010 and 2015. We also assessed tetanus, diphtheria and acellular pertussis (Tdap) vaccine coverage among pregnant women from 2014, the year of the introduction of Tdap maternal immunization recommendation in Brazil, to 2016.Methods: Epidemiological data for incidence, prevalence, hospitalization, mortality, and maternal vaccination coverage were calculated based on the Brazilian public surveillance databases.Results: The epidemiological data analysis results showed that the pertussis average incidence rate (IR) was 2.19/100,000 inhabitants for all ages, with a peak in 2014 (4.03/100,000 inhabitants) and highest incidence in <1-year-old children (IR = 175.20/100,000). 97.6% of pertussis deaths (405/415) were in <1-year-old children. Maternal immunization coverage was 9.2% in 2014, 40.4% in 2015, and 33.8% in 2016.Conclusions: Pertussis incidence and pertussis-related deaths increased in Brazil from 2010 to 2014 and decreased in 2015. In the two years, 2015 and 2016 that followed the NIP recommendation, Tdap vaccination coverage of pregnant women was low and varying from region to region. More efforts and national plans would help increase awareness and maternal immunization coverage.

Pertussis in Latin America: Recent epidemiological data presented at the 2017 Global Pertussis Initiative meeting

The Global Pertussis Initiative (GPI) is an expert scientific forum that publishes consensus recommendations for pertussis monitoring, prevention, and treatment across many regions of the world. Here, we report on the regional 2017 GPI meeting on the Americas, focusing on Latin America. Information on current pertussis epidemiology, surveillance, vaccine strategies, diagnostic capabilities, disease awareness, and major local obstacles was presented by researchers from Argentina, Brazil, Colombia, Costa Rica, El Salvador, Mexico, Peru, Puerto Rico, Uruguay, and Venezuela. Pertussis outbreaks have occurred during the last decade in the majority of participant countries and have been followed by improvements in surveillance. In the countries that introduced maternal immunization during pregnancy, a reduction in the infant case fatality rate has been detected. All countries need to maintain and improve pertussis surveillance to reach primary vaccination coverage >90%. Moreover, countries without maternal immunization programs should strongly consider them.

A rapid and sensitive recombinase aided amplification assay incorporating competitive internal control to detect Bordetella pertussis using the DNA obtained by boiling

OBJECTIVES

Pertussis is a highly transmissible acute respiratory infection caused by the bacterial pathogen Bordetella pertussis. The purpose of this study was to develop a rapid, simple and sensitive diagnostic test for detecting this pathogen.

METHODS

Here we present a recombinase aided amplification (RAA) assay incorporating competitive internal amplification control (IAC) to detect Bordetella pertussis using the DNA obtained by boiling. This assay was performed in a single closed tube at 39°C within 30min. A total of 115 clinical samples suspected of pertussis were collected and tested by the internally controlled RAA assay using both extracted DNA with the commercial kit and the DNA obtained by boiling. For comparison, the real-time PCR (RT-PCR) was also performed with DNA extraction in parallel.

RESULTS

The sensitivity of the internally controlled RAA assay was 10¹ copies or 10CFU/ml per reaction in detecting plasmid DNA or B. pertussis strain. The optimum concentration of the IAC plasmid was determined to be 100 copies, and the introduction of IAC effectively reduced the occurrence of false negatives. Compared to the RT-PCR, RAA results with DNA extraction obtained 100% sensitivity and specificity, and the RAA results with heat-treated DNA showed 85.96% sensitivity and 100% specificity.

CONCLUSION

With the advantages of 45min turn-around time and simple steps of DNA purification, this assay could become a useful diagnostic tool for Bordetella pertussis detection and is potentially suitable for point-of-care identification to guide prompt clinical treatment.

Fc Glycan-Mediated Regulation of Placental Antibody Transfer

Despite the worldwide success of vaccination, newborns remain vulnerable to infections. While neonatal vaccination has been hampered by maternal antibody-mediated dampening of immune responses, enhanced regulatory and tolerogenic mechanisms, and immune system immaturity, maternal pre-natal immunization aims to boost neonatal immunity via antibody transfer to the fetus. However, emerging data suggest that antibodies are not transferred equally across the placenta. To understand this, we used systems serology to define Fc features associated with antibody transfer. The Fc-profile of neonatal and maternal antibodies differed, skewed toward natural killer (NK) cell-activating antibodies. This selective transfer was linked to digalactosylated Fc-glycans that selectively bind FcRn and FCGR3A, resulting in transfer of antibodies able to efficiently leverage innate immune cells present at birth. Given emerging data that vaccination may direct antibody glycosylation, our study provides insights for the development of next-generation maternal vaccines designed to elicit antibodies that will most effectively aid neonates.

Severe Bordetella pertussis infection and vaccine issue in Chongqing, from 2012 to 2018

OBJECTIVE

Pertussis is a highly contagious respiratory illness mainly caused by the Gram-negative bacterium Bordetella pertussis. The infection of B. pertussis has been increasing and the current diagnosis of pertussis in children is challenging; little is known of B. pertussis infection in Chongqing.

METHODS

There were 25,441 children (14,863 male and 10,578 female) with suspected pertussis enrolled in our retrospective study from December 2012 to November 2018. Then 800 children with suspected B. pertussis infection were randomly chosen to be evaluated by simultaneous amplification and testing in this prospective study.

RESULTS

Infants younger than 12 months had the greatest burden of pertussis, and the incidence of pertussis in Chongqing appeared to have a periodic pattern. The problem of vaccine quality in China was more serious than previously reported based on the fluctuation of infection rates from 2012 to 2018. Simultaneous amplification and testing to detect B. pertussis RNA (Area Under Curve: 0.900 and Kappa value: 0.831) had better diagnostic performance than real-time PCR for B. pertussis DNA (Area Under Curve: 0.869 and Kappa value: 0.690).

CONCLUSIONS

We revealed the characteristics of B. pertussis infection and vaccine issues in Chongqing. Simultaneous amplification and testing could be a potential novel assay for measuring B. pertussis infection in the future.

Attributes influencing parental decision-making to receive the Tdap vaccine to reduce the risk of pertussis transmission to their newborn - outcome of a cross-sectional conjoint experiment in Spain and Italy

Pertussis vaccination of parents and household contacts (‘cocooning’) to protect newborn infants is an established strategy in many countries, although uptake may be low. Many aspects may influence such decision-making. We conducted a cross-sectional survey (NCT01890447) of households and other close contacts of newborns aged ≤6 months (or of expectant mothers in their last trimester) in Spain and Italy, using an adaptive discrete-choice experiment questionnaire. Aims were to assess the relative importance of attributes influencing vaccine adoption, and to estimate variation in vaccine adoption rates and the impact of cost on vaccination rates. Six hundred and fifteen participants (Spain, n = 313; Italy, n = 302) completed the survey. Of 144 available questionnaire scenarios, the most frequently selected (14% of respondents in both countries) were infant protection by household vaccination at vaccination center, recommendation by family physician and health authorities, with information available on leaflets and websites. The attribute with highest median relative importance was ‘reduction in source of infection’ in Spain (23.1%) and ‘vaccination location’ in Italy (18.8%). Differences between other attributes were low in both countries, with media attributes showing low importance. Over 80% of respondents indicated a definite or probable response to vaccine adoption (at no-cost) with estimated probability of adoption of 89–98%; applying vaccine costs (25€ per person) would reduce the probability of uptake by 7–20% in definite/probable respondents. Awareness of these determinants is helpful in informing Health Authorities and healthcare practitioners implementing a cocooning strategy for those populations where maternal immunization is not a preferred option.