Influenza and pertussis vaccine coverage in pregnancy in Australia, 2016-2021.

Vaccination in pregnancy is the best strategy to reduce complications from influenza or pertussis infection in infants who are too young to be protected directly from vaccination. Pregnant women are also at risk of influenza complications preventable through antenatal vaccination. Both vaccines are funded under the National Immunisation Program for pregnant women in Australia, but coverage is not routinely reported nationally. We reviewed all reported Australian maternal influenza and pertussis vaccine coverage data for the period 2016-2021, to identify gaps and information needs. Maternal influenza vaccine coverage was suboptimal at < 58% for 2016-2018, with higher coverage of 62-75% reported in two states (Victoria and Western Australia) for 2019-2021. Maternal pertussis vaccine coverage from 2016 was generally higher than for influenza at > 70%, with the highest jurisdictional coverage of 89% reported in Western Australia in 2020. Vaccination rates were often suboptimal among First Nations pregnant women and up to 20% lower than among non-First Nations Australian women; while data were limited, coverage was low among culturally and linguistically diverse women and among women of lower socio-economic status. Jurisdictional perinatal data collections were the best source of information on antenatal vaccine coverage but were only available for a minority of the population; a nationally consistent systematic approach is lacking. Timely and comprehensive data are needed to provide feedback to improve maternal vaccination coverage, particularly among groups with higher risk and/or low uptake, and as new vaccines are recommended, including COVID-19 vaccination.

Acceptance of vaccination against pertussis, COVID-19 and influenza during pregnancy: a cross-sectional study.

BACKGROUND: This study aims to assess the uptake of maternal pertussis and COVID-19 vaccination and the intention towards accepting the maternal influenza vaccination. Insights into different socio-demographic factors related to maternal vaccination coverage might help to address vaccine acceptance and improve maternal vaccine uptake in the future. METHODS: We conducted a cross-sectional survey among pregnant women and recent mothers, up to 6 months post-partum. The primary outcome measures of this study were behaviour for maternal pertussis and COVID-19 vaccination, and maternal influenza vaccination intention. Associations between socio-demographic factors and maternal pertussis vaccination and maternal COVID-19 vaccination behaviour; and socio-demographic factors and maternal influenza vaccination intention were assessed using binary logistic regression analyses. RESULTS: In total 1361 respondents filled out the questionnaire. Almost all women (95%) were vaccinated against pertussis during pregnancy, while almost two-third were vaccinated against COVID-19 during pregnancy (58%) and almost one-third (28%) had a positive intention towards receiving the maternal influenza vaccination. Results show that young maternal age and low education level were associated with lower maternal vaccination acceptance. CONCLUSION: Vaccination campaigns focusing on the severity of diseases that are prevented, are needed to increase maternal vaccine acceptance in younger and low-educated pregnant women. We expect that differences in vaccination coverage between the three maternal vaccinations might partly be explained by existing recommendations, campaigns and whether the vaccination is part of the national immunisation program.

Assessing the relationship between operationally defined zero-dose communities and access to selected primary healthcare services for children and pregnant women in emergency settings.

In this study the authors examine the relationship between "zero-dose" communities and access to healthcare services. This was done by first ensuring the first dose of the Diphtheria Tetanus and Pertussis vaccine was a better measure of zero-dose communities than the measles-containing vaccine. Once ensured, it was used to examine the association with access to primary healthcare services for children and pregnant women in the Democratic Republic of Congo, Afghanistan, and Bangladesh. These services were divided into: a) unscheduled healthcare services such as birth assistance as well as seeking care and treatment for diarrheal diseases and cough/fever episodes and b) other scheduled health services such as antenatal care visits and vitamin A supplementation. Using recent Demographic Health Survey data (2014: Democratic Republic of Congo, 2015: Afghanistan, 2018: Bangladesh), data was analyzed via Chi Squared analysis or Fischer's Exact Test. If significant, a linear regression analysis was performed to examine if the association was linear. While the linear relationship observed between children who had received the first dose of the Diphtheria Tetanus and Pertussis vaccine (the reverse to zero-dose communities) and coverage of other vaccines was expected, the results of the regression analysis depicted an unexpected split in behavior. For scheduled and birth assistance health services, a linear relationship was generally observed. For unscheduled services associated with illness treatments, this was not the case. While it does not appear that the first dose of the Diphtheria Tetanus and Pertussis vaccine can be used to predict (at least in a linear manner) access to some primary (particularly illness treatment) healthcare services in emergency/ humanitarian settings, it can serve as an indirect measure of health services not associated with the treatment of childhood infections such as antenatal care, skilled birth assistance, and to a lesser degree even vitamin A supplementation.

Knowledge and decisions about maternal immunisation by pregnant women in Aotearoa New Zealand.

BACKGROUND: Maternal vaccinations for influenza and pertussis are recommended in New Zealand to protect mothers and their infant from infection. However, maternal immunisation coverage in New Zealand is suboptimal. Furthermore, there is unacceptable inequitable maternal immunisation rates across the country with Maori and Pacific women having significantly lower maternal immunisation rates than those of other New Zealanders. METHODS: This research set out to explore what pregnant/recently pregnant Maori and Pacific women knew about immunisation during pregnancy and what factors influenced their decision to be vaccinated. A semi-structured interview guide was developed with questions focusing on knowledge of pertussis and influenza vaccination during pregnancy and decision-making. Maori and Pacific women aged over 16 years were purposively sampled and interviewed in Dunedin and Gisborne, New Zealand between May and August 2021. Interviews were analysed following a directed qualitative content approach. Data were arranged into coding nodes based on the study aims (deductive analysis) informed by previous literature and within these participant experiences were inductively coded into themes and subthemes. RESULTS: Not all women were aware of maternal vaccine recommendations or they diseases they protected against. Many underestimated how dangerous influenza and pertussis could be and some were more concerned about potential harms of the vaccine. Furthermore, understanding potential harms of infection and protection provided by vaccination did not necessarily mean women would choose to be vaccinated. Those who decided to vaccinate felt well-informed, had vaccination recommended by their healthcare provider, and did so to protect their and their infant's health. Those who decided against vaccination were concerned about safety of the vaccines, lacked the information they needed, were not offered the vaccine, or did not consider vaccination a priority. CONCLUSIONS: There is a lack of understanding about vaccine benefits and risks of vaccine-preventable diseases which can result in the reinforcement of negative influences such as the fear of side effects. Furthermore, if vaccine benefits are not understood, inaccessibility of vaccines and the precedence of other life priorities may prevent uptake. Being well-informed and supported to make positive decisions to vaccinate in pregnancy is likely to improve vaccine coverage in Maori and Pacific Island New Zealanders.

The decline in immunity and circulation of pertussis among Chinese population during the COVID-19 pandemic: A cross-sectional sero-epidemiological study.

BACKGROUND: In recent years, the resurgence of pertussis has posed a public health challenge in many countries. This study aimed to evaluate the immunity levels against pertussis among populations of different ages in China. METHODS: We conducted a cross-sectional serological survey in Zhejiang Province, China in 2020. Serum IgG antibodies against pertussis toxin (anti-PT), filamentous hemagglutinin (anti-FHA), and pertactin (anti-PRN) were quantitatively measured. The geometric mean concentration (GMC) of three antibodies was calculated. An anti-PT level < 5 IU/mL was considered undetectable, ≥20 IU/mL as seropositive and ≥80 IU/mL as an indicator of recent infection. Mathematical models were fitted for anti-PT concentrations over time in children after four doses of the pertussis vaccination. RESULTS: A total of 4459 participants aged 0-59 years were included in the analyses. The overall positivity rate of anti-PT was 29.80% with the highest (81.44%) rate in the 1-2 years old and the lowest (4.72%) in 10-14 years old. The GMCs of anti-PT, anti-FHA and anti-PRN for the whole participants were 9.67 (95%CI: 9.25-10.10),18.93 (18.24-19.67), and 8.99 (8.61-9.38) IU/mL, respectively. Over 50% of subjects aged ≥ 7 years had undetectable anti-PT IgG antibodies (<5IU/mL). The proportions of the populations with anti-PT IgG ≥ 80 IU/mL were approximately 0.9%, 0.3% and 1.1% among the 10-14, 15-29, and 40-59 years old groups, respectively. The power regression equation of the attenuation model after last dose of pertussis vaccine was y = 41.088x-1.238 (R2 = 0.935, p < 0.001). The fitted anti-PT concentrations was only 5.60 IU/mL at 5 years following the last vaccination dose. CONCLUSION: The prevalence of pertussis decreased during the study period in the COVID-19 pandemic; however, there was still a certain proportion of adolescents and adults with evidence of recent infection. The decline in antibody levels after pertussis vaccination was observed, and booster doses are in urgent need in China.

Lessons from a mature acellular pertussis vaccination program and strategies to overcome suboptimal vaccine effectiveness.

INTRODUCTION: Despite high vaccination coverage among children and adolescents, pertussis remains a public health problem, with large outbreaks occurring periodically in the US and other developed countries. AREAS COVERED: We examine lessons learned more than 20 years after implementation of programs which use only acellular pertussis vaccines and propose avenues for possible effective use of acellular pertussis vaccine to prevent large outbreaks. EXPERT OPINION: Acellular pertussis vaccines were introduced more than 20 years ago, yet the incidence of pertussis has been increasing over the past decade, with periodic large outbreaks marked by notable shifts in disease burden from infants and young children toward fully vaccinated adolescents and young adults. This age shift is mainly driven by the waning of vaccine immunity. To better protect adolescents against pertussis, modification of the current acellular pertussis vaccination schedule or adoption of new vaccination strategies should be considered. For infants not yet eligible to be vaccinated, maternal vaccination against pertussis during pregnancy is an effective way to protect infants from infection, severe disease and death. Implementation of maternal vaccination programs should be encouraged in countries without one or efforts to improve coverage should be supported in countries with existing program.

Barriers and facilitators to vaccination for COVID-19, pertussis, and influenza during pregnancy: Protocol for an umbrella review.

Pregnant women are particularly vulnerable to infection. Furthermore, infection from pertussis, influenza and COVID-19 increases the likelihood of adverse consequences to the mother and developing baby such as stillbirth, ICU admission, and pre-term caesarean birth. Increased rates of transmission and risk of adverse consequences from infection justifies the provision of national maternal vaccination programmes. Additionally, maternal vaccination helps protect the infant until they are able to receive their own vaccinations; a time when they are most at risk of mortality from influenza and pertussis. Vaccination during pregnancy has been repeatedly demonstrated as safe and effective in reducing harm, although rates of uptake remain low compared to the general population. The current protocol describes the methodology for an umbrella review aiming to explore the barriers and facilitators of vaccination during pregnancy for pertussis, influenza, and COVID-19. Systematic reviews that investigate the barriers and facilitators of at least one of either pertussis, influenza, or COVID-19 will be included in this review. Multiple databases will be searched, and included reviews assessed for quality (using the Joanna Briggs Institute (JBI) quality assessment for systematic reviews) and degree of overlap of included primary studies. Included reviews will be analysed according to the WHO SAGE model of determinants of vaccine hesitancy and separated by whether these explore influenza and pertussis, or COVID-19. The outcomes of this review will help inform the development of interventions to increase uptake of vaccination during pregnancy, and on whether interventions need to be tailored depending on the infectious disease. The key findings will identify the specific barriers and facilitators of vaccination hesitancy by considering contextual influences (e.g. sociodemographic variables), individual/social group influences (e.g. trust in the institutions), and vaccine-specific issues (e.g. safety and recommendations).

Women's views and experiences of accessing pertussis vaccination in pregnancy and infant vaccinations during the COVID-19 pandemic: A multi-methods study in the UK.

BACKGROUND: COVID-19 changed access to healthcare, including vaccinations, in the United Kingdom (UK). This study explored UK women's experiences of accessing pertussis vaccination during pregnancy and infant vaccinations during COVID-19. METHODS: An online cross-sectional survey was completed, between 3rd August-11th October 2020, by 1404 women aged 16+ years who were pregnant at some point after the first UK lockdown from March 23rd, 2020. Ten follow-up semi-structured interviews were conducted. RESULTS: Most women surveyed were pregnant (65.7%) and a third postnatal (34.3%). Almost all women (95.6%) were aware that pertussis vaccination is recommended in pregnancy. Most pregnant (72.1%) and postnatal women (84.0%) had received pertussis vaccination; however, access issues were reported. Over a third (39.6%) of women had a pregnancy vaccination appointment changed. COVID-19 made it physically difficult to access pregnancy vaccinations for one fifth (21.5%) of women and physically difficult to access infant vaccinations for almost half of women (45.8%). Nearly half of women (45.2%) reported feeling less safe attending pregnancy vaccinations and over three quarters (76.3%) less safe attending infant vaccinations due to COVID-19. The majority (94.2%) felt it was important to get their baby vaccinated during COVID-19. Pregnant women from ethnic-minorities and lower-income households were less likely to have been vaccinated. Minority-ethnicity women were more likely to report access problems and feeling less safe attending vaccinations for both themselves and their babies. Qualitative analysis found women experienced difficulties accessing antenatal care and relied on knowledge from previous pregnancies to access vaccines in pregnancy. CONCLUSION: During the ongoing and future pandemics, healthcare services should prioritise equitable access to routine vaccinations, including tailoring services for ethnic-minority families who experience greater barriers to vaccination.

Pertussis in Poland in 2018-2019.

INTRODUCTION: Pertussis is an endemic, highly contagious disease that can be prevented through vaccination. In Poland, since the second half of the nineties, changes in the epidemiology of pertussis have been observed - an increase in the number of cases, despite the high level of vaccination of the population. The highest percentage of registered cases of pertussis concerned people aged 15 and over. The causes of the increased incidence of pertussis are a complex problem. Immunity after pertussis vaccination is unstable, disappears within 4-12 years, and the risk of the disease increases with time after the last dose of the vaccine. Due to the loss of protection against pertussis in adults, it is important to repeat immunization with dTpa every 10 years. OBJECTIVE: The aim of the study was to assess the epidemiological situation of pertussis in Poland in 2018-2019 compared to the situation in previous years, with particular emphasis on the assessment of the vaccination status of children against pertussis. MATERIAL AND METHODS: The assessment of the epidemiological situation of pertussis in Poland was performed on the basis of the results of the analysis of unit reports of pertussis registered in the NIPH-NIH through the SRWE system and data from the bulletins "Infectious diseases and poisonings in Poland" for 2018 and 2019 and the bulletins "Vaccinations in Poland" for 2018 and 2019. RESULTS: In 2018, 1 548 were registered, and in 2019 - 1 629 cases of pertussis. The incidence was respectively: 4.0 and 4.2 per 100 000 population and was lower compared to the incidence in 2017 (8.0). The highest incidence of pertussis was in the age group 0-4 years (20.6 and 23.6 respectively), and high in children and adolescents aged 5-9 (10.9 and 11.5 respectively) and 10-14 years (respectively: 12.2 and 11.2 - per 100 000 population). About half of the cases concerned people over 15 years of age. In general, a higher incidence among women was observed than in men, as well as a higher incidence in cities than in rural areas. In 2018, among people with pertussis, 434 people (i.e. 28%) and in 2019 - 482 people (i.e. 29.6%) were hospitalized. In 2019, one fatal case of the disease was reported to the epidemiological surveillance system. SUMMARY AND CONCLUSIONS: In Poland, in the years 2018-2019, there was a decrease in the number of cases of pertussis, the most common were children under the age of four (the highest incidence). A worrying trend is the decreasing number of vaccinations in children aged 2 years against pertussis covered by compulsory primary vaccinations in individual provinces. In the current epidemiological situation, the best way to prevent new cases of pertussis is to use vaccination according to the current regimen and to recommend to adults a single dose of dTpa vaccination, which should be repeated every 10 years.

Effect of pertussis vaccine in pregnancy and COVID-19 pandemic in the cases of wooping cough.

BACKGROUND: Whooping cough has had an increased incidence and severity specially in infants and maternal immunization has been implemented as a prevention strategy. COVID-19 pandemic seems to decrease the incidence of other respiratory diseases. METHODS: Retrospective study from 2012 to 2021 to assess the influence of pertussis maternal immunizations and the first year of COVID-19 pandemic in the cases of whooping cough. RESULTS: 960 suspected cases from primary care and hospital, with 130 cases (104 children and 26 adults) being diagnosed of whooping cough. In the post-vaccination period, a reduction in the cases and severity in infants up to 6 months old was observed as well as in the pertussis diagnosis in adult women. There were no whooping cough cases during the COVID-19 period. CONCLUSIONS: Both the pertussis vaccination in pregnancy and the first year of the COVID-19 pandemic have decreased the number of pertussis cases.

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

OBJECTIVE: To determine pertussis and influenza vaccination coverage during pregnancy among women delivering in all the maternities of Geneva (Switzerland), during the COVID-19 pandemic. METHODS: All women delivering in all the maternity centres of the canton of Geneva from 1st November 2020 to 30th November 2020 (beginning of the flu vaccination season) and from 8th March 2021 to 7th April 2021 (end of the flu vaccination season) had their records checked upon admission to the labour ward regarding pertussis and influenza vaccination during pregnancy. Reasons for non-vaccination were recorded. Univariate and multivariate analyses were done to identify predictors of vaccine uptake. RESULTS: 951 women delivered in Geneva during the two study periods, of which 950 were included in the study. 86.2% were vaccinated against pertussis, with no significant difference between the study periods (87.5% vs 85% at the beginning and end of the flu vaccination season respectively). 49.8% were vaccinated against influenza, with no significant difference between the study periods (48.8% vs 50.7% beginning and end of the flu vaccination season respectively). The influenza vaccine was 5 times more likely not to be proposed (8.9% vs. 1.7%) and 3 times more likely to be refused (26.6% vs. 8%) than the pertussis vaccine. Main reason for refusal was a lack of maternal desire for both vaccines, but not vaccine fear. Maternal parity ≥ 1 was significantly associated with pertussis vaccine uptake at univariate analysis. Women were significantly more likely to accept the influenza vaccine if they had a university degree or if they did not deliver in a midwife-only run delivery unit in both univariate and multivariate analysis. CONCLUSIONS: In Geneva, most gynaecologists offer pertussis immunization during antenatal care and uptake is high, but more efforts must be done to increase influenza vaccination coverage. Education level impacts maternal flu vaccination uptake, but other social disparities did not.

Impact of the COVID-19 pandemic on Bordetella pertussis infections in England.

BACKGROUND: In March 2020, England went into its first lockdown in response to the COVID-19 pandemic. Restrictions eased temporarily, followed by second and third waves in October 2020 and January 2021. Recent data showed that the COVID-19 pandemic resulted in reduced transmission of some invasive diseases. We assess the impact of the COVID-19 pandemic on pertussis incidence and on the immunisation programme in England. METHODS: We assessed trends in pertussis cases from 2012 to 2020 by age group and month. Incidence from the time that England eased its initial lockdown measures in July 2020 through to summer 2021 was calculated and the incidence rate ratios of pertussis cases from five years prior to the pandemic (July 2014 - June 2019) compared to the same time period during the pandemic (July 2020 - June 2021). Vaccine coverage estimates for pertussis containing vaccines were reviewed for the maternal and childhood programmes. RESULTS: A substantial decline in pertussis cases was observed from April 2020 onwards, marking the lowest number of cases in the last decade. Pertussis incidence dropped in all age groups, particularly among infants less than one year old (0.50 / 100,000 during July 2020 to June 2021 compared to 24.49/ 100,000 from July 2014 to June 2019). The incidence rate ratio was 0.02 (95% CI 0.01 to 0.02) for July 2014 to June 2019 (pre-pandemic) compared to the pandemic period of July 2020 to June 2021. None of the cases had a co-infection with SARS-CoV-2. Vaccine coverage for infants born between January to March 2020 with three doses of pertussis vaccine by 12 months of age decreased by 1.1% points compared to infants born between January to March 2019 (91.6% and 92.7%, respectively). Prenatal pertussis coverage for the 2020 to 2021 financial year was 2.7% points lower than the year prior to the pandemic (70.5% and 76.8%, respectively). CONCLUSIONS: Lockdown measures due to the COVID-19 pandemic have had a significant impact on pertussis transmission. With the easing of restrictions it is important to continue monitoring pertussis cases in England alongside coverage of the maternal and childhood immunisation programmes.

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.

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.

Diphtheria And Tetanus Vaccination History Is Associated With Lower Odds of COVID-19 Hospitalization.

Background: COVID-19 is characterized by strikingly large, mostly unexplained, interindividual variation in symptom severity: while some individuals remain nearly asymptomatic, others suffer from severe respiratory failure. Previous vaccinations for other pathogens, in particular tetanus, may partly explain this variation, possibly by readying the immune system. Methods: We made use of data on COVID-19 testing from 103,049 participants of the UK Biobank (mean age 71.5 years, 54.2% female), coupled to immunization records of the last ten years. Using logistic regression, covarying for age, sex, respiratory disease diagnosis, and socioeconomic status, we tested whether individuals vaccinated for tetanus, diphtheria or pertussis, differed from individuals that had only received other vaccinations on 1) undergoing a COVID-19 test, 2) being diagnosed with COVID-19, and 3) whether they developed severe COVID-19 symptoms. Results: We found that individuals with registered diphtheria or tetanus vaccinations are less likely to develop severe COVID-19 than people who had only received other vaccinations (diphtheria odds ratio (OR)=0.47, p-value=5.3*10-5; tetanus OR=0.52, p-value=1.2*10-4). Discussion: These results indicate that a history of diphtheria or tetanus vaccinations is associated with less severe manifestations of COVID-19. These vaccinations may protect against severe COVID-19 symptoms by stimulating the immune system. We note the correlational nature of these results, yet the possibility that these vaccinations may influence the severity of COVID-19 warrants follow-up investigations.

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.

Barriers and Facilitators Associated With Vaccine Acceptance and Uptake Among Pregnant Women in High Income Countries: A Mini-Review.

Vaccination during pregnancy is a safe and effective intervention to protect women from potentially severe consequences of influenza and reduce risk of influenza and pertussis in their infants. However, coverage remains variable. In this mini-review we update findings from a 2015 systematic review to describe results from recent studies in high income countries on the uptake of influenza and pertussis vaccination in pregnancy, reasons for vaccine hesitancy and barriers to increasing uptake, from maternal and healthcare provider (HCP) perspectives. Studies reported highly variable uptake (from 0% to 78%). A main facilitator for uptake among pregnant women was receiving a recommendation from their HCP. However, studies showed that HCP awareness of guidelines did not consistently translate into them recommending vaccines to pregnant women. Safety concerns are a well-established barrier to uptake/coverage of maternal immunization; 7%-52% of unvaccinated women gave safety concerns as a reason but these were also present in vaccinated women. Knowledge/awareness gaps among pregnant women and lack of confidence among HCPs to discuss vaccination were both important barriers. Several studies indicated that midwives were more likely to express safety concerns than other HCPs, and less likely to recommend vaccination to pregnant women. Women who perceived the risk of infection to be low were less likely to accept vaccination in several studies, along with women with prior vaccine refusal. Findings highlight the importance of further research to explore context-specific barriers to vaccination in pregnancy, which may include lack of vaccine confidence among pregnant woman and HCPs, and policy and structural factors.