Psychosocial determinants of pertussis and influenza vaccine uptake in pregnant women: A prospective study

Influenza vaccination hesitancy and related factors among pregnant and breastfeeding women: A cross-sectional study

Achieving safe influenza vaccination coverage among pregnant and breastfeeding women is a global health goal due to the potential risks of serious influenza for both mother and child. However, vaccine hesitancy remains a significant barrier to vaccination uptake. Since anxiety represents a determinant in vaccine decision-making, this study aimed to assess influenza vaccination hesitancy and anxiety levels in this population and to explore the association between women's characteristics, their reluctance, and anxiety levels. A multicentre, cross-sectional study was conducted between February and June 2022 using structured phone interviews to assess: (1) socio-demographics and clinical history; (2) anti-flu vaccination status, previous anti-flu vaccination, and Sars-CoV-2 infection history; (3) insights into influenza vaccination during pregnancy; (4) attitudes toward anti-flu vaccination, using the Vaccination Attitudes Examination (VAX) Scale; (5) anxiety levels, measured by the Self-Rating Anxiety Scale (SAS). Among the 387 participants, 22.8% were already vaccinated or expressed willingness to be vaccinated against influenza, and 54% had an anxiety disorder. While anxiety was not significantly associated with vaccine hesitancy, ongoing pregnancy emerged as an independent predictor of anxiety. Higher educational levels, ongoing pregnancy, already being vaccinated or willingness to get vaccinated, and being employed were associated with reduced vaccine hesitancy, while prior SARS-CoV-2 infection with increased hesitancy. Fear of unpredictable events and lack of healthcare professionals' recommendations emerged as reasons for vaccine reluctance. Given the low coverage rates, these findings highlight the need for health services to enhance vaccination efforts and provide clear recommendations to counter misinformation and ensure accurate vaccine safety information.

Influenza and COVID-19 Vaccine Uptake Among Individuals With Versus Without Diagnosed Psychiatric Disorders

OBJECTIVE

The authors sought to examine influenza and COVID-19 vaccine uptake among individuals diagnosed as having psychiatric disorders compared with those without such diagnoses and to examine variations in vaccine uptake by sociodemographic and clinical characteristics.

METHODS

The study was conducted in the Kaiser Permanente Georgia, Washington, and Southern California health care systems. Individuals with psychiatric conditions had at least one diagnosis of any psychiatric disorder during a 12-month study period; individuals in the control group had no psychiatric disorder diagnoses during this period, and the two groups were matched on age and sex. Bivariate analyses were conducted with Pearson chi-square tests; multivariate analyses were used to calculate the odds of receiving an influenza vaccine (N=1,307,202 individuals) or COVID-19 vaccine (N=1,380,894 individuals) and were controlled for selected covariates.

RESULTS

After controlling for relevant confounders, the authors found that having a diagnosis of any psychiatric illness was associated with significantly increased odds of receiving an influenza vaccine (OR=1.18; 95% CI=1.17-1.19, p<0.001), compared with no diagnosis of a psychiatric disorder. Having any psychiatric illness was associated with decreased odds of receiving a COVID-19 vaccine (OR=0.97; 95% CI=0.96-0.98, p<0.001), after the analysis was controlled for the same covariates.

CONCLUSIONS

The findings provide evidence that people with mental health conditions were more likely to receive an influenza vaccine but were less likely to receive a COVID-19 vaccine, compared with individuals without such conditions. However, the vaccination rates observed for individuals with and without diagnosed psychiatric conditions were below national benchmarks, suggesting room for improving vaccine uptake in both patient populations.

Analyzing Changes in Attitudes and Behaviors towards Seasonal Influenza Vaccination in Spain's Adult Population over Three Seasons

Background/Objectives: The experience of the COVID-19 pandemic has turned the spotlight on the importance of public health measures and disease prevention. Despite this, the acceptance of influenza vaccination has remained low in most countries (and far from the 75% target set by the World Health Organization). The objective of this study has been to investigate how attitudes and behaviors regarding influenza vaccination in the Spanish adult population have changed over the last three years (from 2021 to 2024) in order to analyze trends in influenza vaccination. Methods: To this end, a cross-sectional study was conducted through 2206 telephone interviews, and the results were compared with those obtained in previous campaigns. Results: The findings indicate a significant decline in overall vaccination intent. Healthcare professionals remain the most influential factor in encouraging vaccination, yet there is a notable increase in the lack of vaccine recommendations, contributing to the decision not to vaccinate. This study also reveals low awareness of the influenza vaccine campaign, emphasizing the need for improved public health communication. Conclusions: To counteract these trends, this study recommends intensifying awareness campaigns, strengthening the role of healthcare providers in vaccine advocacy, and tailoring communication strategies. These efforts are crucial to enhancing vaccination coverage and protecting vulnerable populations against influenza.

Predictors of Intention to Vaccinate or Continue to Vaccinate Children Against SARS-CoV-2 During the Fifth Wave of the COVID-19 Pandemic in the USA

The Centre for Disease Control recommends vaccination of children against SARS-CoV-2 to reduce the severity of COVID-19 disease and reduce the likelihood of associated complications. Vaccination of children requires the consent of parents or guardians, and levels of consent may ebb and flow over the course of the pandemic. This exploratory study examines predictors of parental intentions to vaccinate their children and the speed with which they would have them vaccinated during the fifth wave of the pandemic when vaccines were just being approved for use in children using a convenience sample of 641 parents reporting on 962 children. Multi-level regression analyses demonstrated regional differences in likelihood, with those in the Northeast reporting higher likelihood than those in the West. Parents with a conservative belief system were less likely to want to have their children vaccinated. Parents were more likely to have their child vaccinated if the child had COVID-19-related health risks, their child had a more complete vaccination history, and COVID-19 was perceived to be a greater threat to oneself and one's family. Faster intended vaccination speed was associated with regional urbanicity, liberal belief systems, more complete vaccination histories, and parental COVID-19 vaccination history. Higher levels of parental anxiety and lower levels of perceived vaccine danger were associated with increased speed. The severity of the COVID-19 pandemic within one's county was marginally related to speed, but not likelihood. These results underscore the importance of regular assessment of parental intentions across the pandemic, for practitioners to probe parental anxiety levels when discussing vaccination, to explicitly address risk/benefit analyses when communicating with parents, and to target previously routine unvaccinated parents and those in more rural areas to increase vaccine uptake. Comparisons are made with Galanis et al.'s (2022) recent meta-analysis on the topic.

Effect of psychological factors on COVID-19 vaccine hesitancy

BACKGROUND

Vaccine hesitancy can prevent full immunization against coronavirus infectious disease-19 (COVID-19). We hypothesized that multiple factors, including an individual's personality and psychological factors, are associated with vaccine hesitancy.

METHODS

A total of 275 non-vaccinated individuals were recruited for this study. Participants completed a self-report questionnaire including sociodemographic factors, health status, COVID-19 literacy and psychological factors (depressive symptoms, generalized anxiety, somatization, illness anxiety, temperament and character). In a hierarchical logistic regression analysis, a discrete set of hierarchical variables with vaccine acceptance or hesitancy as the dependent variable was added to the demographic factors for Model 1; Model 1 + health status for Model 2; Model 2 + COVID-19 literacy for Model 3 and Model 3 + psychological factors for Model 4.

RESULTS

Models 3 and 4 could predict vaccine hesitancy. High scores on the Generalized Anxiety Disorder-7 and the Illness Attitude Scale, low confidence, low collective responsibility and low reward dependence were risk factors for vaccine hesitancy.

CONCLUSIONS

The present study demonstrates that psychological factors play critical roles in vaccine hesitancy. In addition to conventional policies that emphasize COVID-19 vaccines' safety and efficacy and the collective benefits of vaccination, a more individualized approach that considers an individual's emotions and personality is necessary.

Randomised controlled trials of behavioural nudges delivered through text messages to increase influenza and COVID-19 vaccines among pregnant women (the EPIC study): study protocol

BACKGROUND

Influenza and COVID-19 infections during pregnancy may have serious adverse consequences for women as well as their infants. However, uptake of influenza and COVID-19 vaccines during pregnancy remains suboptimal. This study aims to assess the effectiveness of a multi-component nudge intervention to improve influenza and COVID-19 vaccine uptake among pregnant women.

METHODS

Pregnant women who receive antenatal care at five tertiary hospitals in South Australia, Western Australia and Victoria will be recruited to two separate randomised controlled trials (RCTs). Women will be eligible for the COVID-19 RCT is they have received two or less doses of a COVID-19 vaccine. Women will be eligible for the influenza RCT if they have not received the 2023 seasonal influenza vaccine. Vaccination status at all stages of the trial will be confirmed by the Australian Immunisation Register (AIR). Participants will be randomised (1:1) to standard care or intervention group (n = 1038 for each RCT). The nudge intervention in each RCT will comprise three SMS text message reminders with links to short educational videos from obstetricians, pregnant women and midwives and vaccine safety information. The primary outcome is at least one dose of a COVID-19 or influenza vaccine during pregnancy, as applicable. Logistic regression will compare the proportion vaccinated between groups. The effect of treatment will be described using odds ratio with a 95% CI.

DISCUSSION

Behavioural nudges that facilitate individual choices within a complex context have been successfully used in other disciplines to stir preferred behaviour towards better health choices. If our text-based nudges prove to be successful in improving influenza and COVID-19 vaccine uptake among pregnant women, they can easily be implemented at a national level.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT05613751. Registered on November 14, 2022.

Implications for COVID-19 vaccine uptake: A systematic review

BACKGROUND

Globally, increasing coronavirus disease (COVID-19) vaccination coverage remains a major public health concern in the face of high rates of COVID-19 hesitancy among the general population. We must understand the impact of the determinants of COVID-19 vaccine uptake when designing national vaccination programmes. We aimed to synthesise nationwide evidence regarding COVID-19 infodemics and the demographic, psychological, and social predictors of COVID-19 vaccination uptake.

METHODS

We systematically searched seven databases between July 2021 and March 2022 to retrieve relevant articles published since COVID-19 was first reported on 31 December 2019 in Wuhan, China. Of the 12,502 peer-reviewed articles retrieved from the databases, 57 met the selection criteria and were included in this systematic review. We explored COVID-19 vaccine uptake determinants before and after the first COVID-19 vaccine roll-out by the Food and Drug Authority (FDA).

RESULTS

Increased COVID-19 vaccine uptake rates were associated with decreased hesitancy. Concerns about COVID-19 vaccine safety, negative side effects, rapid development of the COVID-19 vaccine, and uncertainty about vaccine effectiveness were associated with reluctance to be vaccinated. After the US FDA approval of COVID-19 vaccines, phobia of medical procedures such as vaccine injection and inadequate information about vaccines were the main determinants of COVID-19 vaccine hesitancy.

CONCLUSION

Addressing effectiveness and safety concerns regarding COVID-19 vaccines, as well as providing adequate information about vaccines and the impacts of pandemics, should be considered before implementation of any vaccination programme. Reassuring people about the safety of medical vaccination and using alternative procedures such as needle-free vaccination may help further increase vaccination uptake.

Psychological and situational factors associated with COVID-19 vaccine intention among postpartum women in Pakistan: a cross-sectional study

OBJECTIVES

Contributing factors to COVID-19 vaccination intention in low-income and middle-income countries have received little attention. This study examined COVID-19-related anxiety and obsessive thoughts and situational factors associated with Pakistani postpartum women's intention to get COVID-19 vaccination.

DESIGN

Cross-sectional study administering a survey by a telephone interview format between 15 July and 10 September 2020.

SETTING

Four centres of Aga Khan Hospital for Women and Children-Garden, Kharadar, Karimabad and Hyderabad-in Sindh Province, Pakistan.

PARTICIPANTS

Women who were enrolled in our longitudinal Pakistani cohort study were approached (n=1395), and 990 women (71%) participated in the survey, of which 941 women who were in their postpartum period were included in the final analysis.

PRIMARY OUTCOME MEASURE AND FACTORS

COVID-19 vaccine intention, sociodemographic and COVID-19-related factors, Coronavirus anxiety, obsession with COVID-19 and work and social adjustment were assessed. Multiple multinomial logistic regression analysis was used to identify factors associated with women's intentions.

RESULTS

Most women would accept a COVID-19 vaccine for themselves (66.7%). Only 24.4% of women were undecided about vaccination against COVID-19, and a small number of women rejected the COVID-19 vaccine (8.8%). Women with primary education were less likely to take a COVID-19 vaccine willingly than those with higher education. COVID-19 vaccine uncertainty and refusal were predicted by having no experience of COVID-19 infection, childbirth during the pandemic, having no symptoms of Coronavirus anxiety and obsession with COVID-19. Predictors for women's intention to vaccinate themselves and their children against COVID-19 were similar.

CONCLUSION

Understanding the factors shaping women's intention to vaccinate themselves or their children would enable evidence-based strategies by healthcare providers to enhance the uptake of the COVID-19 vaccine and achieve herd immunity against Coronavirus.

Severe mental disorders and vaccinations - a systematic review

OBJECTIVES

People with severe mental illnesses (SMI: schizophrenia, depressive disorder, bipolar disorder) have a high risk of being infected by viruses and suffer a more severe infection illness course than the general population. The aim of this literature review was to elucidate rates as well as immunogenicity and side effects of vaccinations in SMI.

METHODS

All studies in the English or German language, which investigated either prevalence rates or effects of vaccinations in the target groups, were systematically searched in the databank PubMed by three independent authors using the PRISMA guidelines and discussed in more detail.

RESULTS

The search found 24 studies reporting epidemiological data and 16 investigating immunogenicity of vaccinations. The results on prevalence rates, antibody production, inflammation response and side effects were inconsistent. About interactions with psychotropic medication, only two studies on clozapine were found.

CONCLUSIONS

Only a few trials with heterogeneous samples have investigated prevalence and effects of vaccinations in SMI. Sex, age and other factors such as somatic comorbidities and special vaccination programmes have not been considered continuously and may influence rates as well. As individuals with SMI might be at special risk, further research on the willingness to be vaccinated as well as efficacy of vaccinations is needed.

COVID-19 Vaccination and Mental Disorders, What Has Been Accomplished and Future Direction

The consequences of the pandemic on mental health are among the most important side effects of COVID-19. Wide concerns have emerged both regarding vaccine hesitation in the general population, and the vaccine's implementation plan. The aim of this study is to evaluate how the scientific community has investigated the relationship between the COVID-19 vaccine and mental disorders. Contrary to expectations, having a full-blown psychiatric pathology seems to positively affect the attitude towards the vaccine, except for PTSD. The intense fear that accompanied the current world emergency has made this pandemic unique; we discuss how it might be one of the factors involved in this result. Further experimental investigations are needed to estimate how personality traits, hyperarousal, and negative emotions influence vaccine compliance both in the general population and in people living with mental disorders.

Covid-19 vaccine acceptance and associated factors among pregnant women in Pennsylvania 2020

Data on factors associated with vaccine acceptance among pregnant women are critical to the rapid scale up of interventions to improve vaccine uptake. When COVID-19 vaccines were still in the testing phases of research, we surveyed pregnant women accessing prenatal care at an academic medical institution in Central Pennsylvania, United States to examine factors associated with vaccine acceptance. Willingness to receive a COVID-19 vaccine once a vaccine became available was asked as part of an ongoing study on the COVID-19 pandemic and pregnancy (n = 196). Overall, 65% of women reported they would be willing or somewhat willing to receive the COVID-19 vaccine. Women who had received an influenza vaccine within the past year were more likely to be willing to receive the COVID-19 vaccine than women who had never received an influenza vaccine or those who received it over one year ago (aOR 4.82; 95% CI 2.17, 10.72). Similarly, women who were employed full-time were more willing to receive the COVID-19 vaccine than women who were not employed full time (aOR 2.22; 95% CI 1.02, 4.81), and women who reported feeling overloaded were more willing to receive the COVID-19 vaccine than women who did not feel overloaded (aOR 2.18; 95% CI 1.02, 4.68). Our findings support the need to increase vaccination education among pregnant women before vaccines are rolled out, especially those who have not received an influenza vaccine within the past year. Improved understanding of willingness to vaccinate among pregnant women will improve future pandemic responses and current vaccination efforts.

Association between COVID-19 vaccine hesitancy and generalized trust, depression, generalized anxiety, and fear of COVID-19

Background

Although numerous studies have been published on the predictors of COVID-19 vaccine hesitancy, some possible predictors remain underexplored. In this study, we explored the associations of unwillingness and indecisiveness regarding COVID-19 vaccination with generalized trust, mental health conditions such as depression and generalized anxiety, and fear of COVID-19.

Methods

Data of wave 1 (from October 27 till November 6, 2020) and wave 3 (from April 23 till May 6, 2021) of a longitudinal online study conducted in Japan were used for the analyses. Unvaccinated participants were asked at wave 3 about their willingness to be vaccinated, with possible responses of willing, unwilling, or undecided. These three responses were used as the outcome variable, and multinomial logistic regression analyses were conducted with willingness to be vaccinated as the reference group. Explanatory variables included generalized trust, depression, generalized anxiety, and fear of COVID-19 both at wave 1 and 3, and sociodemographic and health-related variables.

Results

Of the 11,846 valid respondents, 209 (1.8%) answered that they had already been vaccinated against COVID-19, 7089 (59.8%) responded that they were willing to be vaccinated, 3498 (29.5%) responded that they were undecided, and 1053 (8.9%) responded that they were unwilling to be vaccinated. After adjusting for covariates, we found that: (1) participants with lower levels of generalized trust at wave 1 and 3 were more likely to be undecided or unwilling at wave 3; (2) respondents with moderately severe or severe depression at wave 1 and 3 were more likely to be undecided at wave 3; (3) participants with moderate or severe levels of generalized anxiety at wave 3 but not at wave 1 were more likely to be unwilling at wave 3; and (4) respondents with high levels of fear of COVID-19 at wave 1 and 3 were less likely to be undecided and unwilling at wave 3.

Conclusions

Generalized trust, mental health conditions such as depression and generalized anxiety, and low level of fear of COVID-19 are associated with unwillingness or indecision regarding being vaccinated against COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12479-w.

dTap vaccination uptake during pregnancy: Pregnant women-focused and health professionals-focused predictors in the Veneto Region (Italy)

BACKGROUND

Despite recommendations, the uptake of dTap maternal vaccination is still low in many countries. The reasons for this must be investigated both on the patient's and the healthcare professionals' sides.

METHODS

A record linkage study was performed linking Birth Assitance Certificates and dTap mothers' vaccination records (5183 deliveries) to describe the influence of socioeconomical and obstetrical-gynecological factors after the recommendations concerning dTap vaccination in pregnancy issued by the Italian Ministry of Health (August 2018). An interview was also administered to a subgroup of 656 new mothers on the occasion of the first vaccination of their newborns, in order to assess the dTap vaccination advice received from maternal care providers during pregnancy. A generalized linear model (binomial family, log link) was implemented to give a correct estimate of the mother's relative risk of being vaccinated.

RESULTS

Several pregnant women-focused factors are evident, but the most important ones are related to maternal care providers' practices: after mutual adjustment, the explicit advice towards dTap maternal vaccination given by the Obstetrician-Gynecologist or the Midwife is associated with a 12-fold increase in the dTap coverage.

CONCLUSIONS

Multiprofessional training is essential to make Obstetricians-Gynecologists and Midwives more confident in recommending dTaP maternal immunization.

Parental psychological distress and attitudes towards COVID-19 vaccination: A cross-sectional survey in Shenzhen, China

BACKGROUND

Parental attitudes towards the vaccines play a key role in the success of the herd immunity for the COVID-19. Psychological health seems to be a controversial determinant of vaccine hesitancy and remains to be investigated. This study attempted to measure parental psychological distress, attitudes towards the COVID-19 vaccine, and to explore the potential associations.

METHODS

An online survey using convenience sampling method was conducted among parents within the school public health network of Shenzhen. Demographic information and attitudes towards COVID-19 vaccination were collected. The Patient Health Questionnaire (PHQ-4) was applied to measure psychological distress.

RESULTS

Overall, 4,748 parents were included (average age: 40.28, standard deviation: 5.08). More than one fifth of them demonstrated psychological distress, in which only 3.3% were moderate to severe symptom. The proportions of COVID-19 vaccine hesitancy for themselves, their spouses, and their children were 25.2%, 26.1%, and 27.3%, respectively. Parents with psychological distress were more likely to suffer vaccine hesitancy for themselves (OR: 1.277, 95%CI: 1.091~1.494), for their spouses (OR:1.276, 95%CI: 1.088~1.496) and children (OR:1.274, 95%CI: 1.092~1.486). These associations tended to be more significant among parents with mild or severe psychological distress.

LIMITATION

Non-random sampling limited the generalization of our findings to all parents.

CONCLUSION

Parents had a low level of psychological distress but relatively high willingness of COVID-19 vaccination when there was no local epidemic but persistent risk of imported cases. Targeted health education and intervention strategies should be provided to people with vaccine hesitancy, especially for those who are susceptible to psychological distress.

Demographic, psychological, and experiential correlates of SARS-CoV-2 vaccination intentions in a sample of Canadian families

The COVID-19 pandemic has been ongoing for close to a year, with second waves occurring presently and many viewing vaccine uptake as the most likely way to curb successive waves and promote herd immunity. Reaching herd immunity status likely necessitates that children, as well as their parents, receive a vaccine targeting SARS-CoV-2. In this exploratory study, we investigated the demographic, experiential, and psychological factors associated with the anticipated likelihood and speed of having children receive a SARS-CoV-2 vaccine in a sample of 455 Canadian families (858 children; parents' mean age = 38.2 ± 6.82 years). Using linear mixed-effects and proportional odds logistic regression models, we demonstrated that older parental age, living in the Prairies (relative to Central Canada), more complete child vaccination history, and a greater tendency to prioritise the risks of the disease relative to the risks of side effects (i.e. lower omission bias) were associated with higher likelihoods of intention to vaccinate participants' children, with trend-level associations with lower perceived danger of the vaccine and higher psychological avoidance of the pandemic. Faster speed of intended vaccination was predicted by a similar constellation of variables with an additional predictor of a child in the family having a COVID-19 related health risk being associated with slower intended speed. Results are discussed concerning public health knowledge mobilisation and the unique Canadian health landscape.

Influenza and pertussis vaccine uptake during pregnancy among Australian women in south-east Queensland, Australia

OBJECTIVES

Population-specific studies of vaccine uptake in pregnancy are necessary to monitor progress and ensure enablers to vaccination are locally relevant. We aimed to determine the uptake of influenza and pertussis vaccine during pregnancy in women in south-east Queensland and the reasons why women were choosing not to vaccinate.

METHODS

A secondary analysis of data collected in a prospective cohort study. Data were collected at enrolment during pregnancy and within six weeks of giving birth. The primary outcome was the proportion of women vaccinated during pregnancy.

RESULTS

Among 310 pregnant women, 45.8% and 69.7% were vaccinated against influenza and pertussis, respectively; 123 (39.7%) had received both vaccines. The common predictor of vaccine uptake for influenza, pertussis or both was having had any vaccine in the 12 months prior to pregnancy. Not considering the vaccines necessary and perceptions of the risk of infection were common reasons for not intending to vaccinate.

CONCLUSIONS

Antenatal vaccine uptake remains suboptimal in women in south-east Queensland. Barriers to vaccination during pregnancy are complex and vary depending on context and population. Implications for public health: More efforts are needed to promote antenatal uptake, particularly for influenza vaccine and having both the influenza and pertussis vaccines during pregnancy.

SARS-CoV-2 Vaccine Willingness among Pregnant and Breastfeeding Women during the First Pandemic Wave: A Cross-Sectional Study in Switzerland

As pregnant women are at high risk of severe SARS-CoV-2 infection and COVID-19 vaccines are available in Switzerland, this study aimed to assess the willingness of Swiss pregnant and breastfeeding women to become vaccinated. Through a cross-sectional online study conducted after the first pandemic wave, vaccination practices and willingness to become vaccinated against SARS-CoV-2 if a vaccine was available were evaluated through binary, multi-choice, and open-ended questions. Factors associated with vaccine willingness were evaluated through univariable and multivariable analysis. A total of 1551 women responded to questions related to the primary outcome. Only 29.7% (153/515) of pregnant and 38.6% (400/1036) of breastfeeding women were willing to get vaccinated against SARS-CoV-2 if a vaccine had been available during the first wave. Positive predictors associated with SARS-CoV-2 vaccine acceptance were an age older than 40 years, a higher educational level, history of influenza vaccination within the previous year, having an obstetrician as the primary healthcare practitioner, and being in their third trimester of pregnancy. After the first pandemic wave, Switzerland had a low SARS-CoV-2 vaccination acceptance rate, emphasizing the need to identify and reduce barriers for immunization in pregnant and breastfeeding women, particularly among the youngest and those with a lower educational level.

Safety of maternal pertussis vaccination on pregnancy and birth outcomes: A prospective cohort study

OBJECTIVE

To evaluate the safety of maternal pertussis vaccination on pregnancy and birth outcomes.

METHODS

The study population comprised 1272 healthy nulliparous pregnant women who participated in Screening Tests to identify poor Outcomes in Pregnancy (STOP) study at two obstetric hospitals in South Australia between 2015 and 2018. Participants were followed prospectively, with vaccination (confirmed by medical records), extensive amounts of pregnancy and birth outcome data collected by research midwives. Adjusted relative risks (aRRs) and hazard ratios (aHRs) were estimated accounting for time-varying vaccine exposure and the temporal nature of each outcome.

RESULTS

Of the 1272 women included in this study, 80.1% (n = 1019) received maternal pertussis vaccination. Vaccinated women had an average 0.22 weeks (95% CI 0.001, 0.44) longer gestation at delivery compared to unvaccinated women. Maternal pertussis vaccination was not associated with chorioamnionitis (aRR 0.71, 95% CI 0.27,1.82), gestational hypertension (aHR 1.24, 95% CI, 0.66, 2.30), preeclampsia (aHR 0.75, 95% CI 0.47, 1.18) nor preterm birth (aHR 0.99, 95% CI 0.47, 2.07). Neither risk of low birth weight (aHR 0.72, 95% CI 0.41, 1.27) nor small for gestational age infants (aHR 0.67,95% CI 0.29, 1.55) were increased following maternal pertussis vaccination. No associations between pertussis vaccination during pregnancy and adverse birth outcomes including admission to the neonatal care unit, low Apgar scores, and mechanical ventilation were observed. Results were not materially changed after adjustment for maternal influenza vaccination.

CONCLUSION

Our study provides reassuring evidence of the safety of maternal pertussis vaccination with no increased risk of adverse pregnancy and birth outcomes. These findings support recommendations for pertussis vaccination during pregnancy to prevent morbidity and mortality associated with early-infant pertussis disease.