Sociodemographic and health-related determinants of seasonal influenza vaccination in pregnancy: A systematic review and meta-analysis of the evidence since 2000

Exploration of individual socioeconomic and health-related characteristics associated with human papillomavirus vaccination initiation and vaccination series completion among adult females: A comprehensive systematic evidence review with meta-analysis

INTRODUCTION

Human papillomavirus (HPV) vaccination rates among females are lower than the World Health Organization target and vaccination rates specifically among adult females are even much lower.

METHODS

We systematically evaluated individual socioeconomic and health-related characteristics associated with HPV vaccination initiation and vaccination series completion among adult females (PROSPERO: CRD42023445721). We performed a literature search on December 14, 2022, and supplemented the search on August 1, 2023. We pooled appropriate multivariable-adjusted results using an inverse variance random-effects model and expressed the results as odds ratios with associated 95 % confidence intervals. A point pooled significantly increased/decreased odds of 30-69 % was regarded to be strongly associated, and ≥ 70 % was very strongly associated.

RESULTS

We included 63 cross-sectional studies. There were strongly increased odds of vaccination initiation among White women compared with Black or Asian women, and those with higher education, health insurance, a history of sexually transmitted infection (STI), receipt of influenza vaccination in the preceding year, not married/cohabiting, not smoking, using contraception, and having visited a healthcare provider in the preceding year. We observed very strongly increased odds of vaccination initiation among those younger and having been born in the country of study. Similarly, there were strongly increased odds of completing the vaccination series for the same variables as initiating vaccination, except for higher education, prior STI, smoking and contraception use. Additional variables associated with strongly increased odds of vaccination series completion not seen in initiation were higher annual household income, being lesbian/bisexual, and having a primary care physician. We observed very strongly increased odds of vaccination series completion similar to vaccination initiation but including for White compared with Black women, higher education, and prior cervical cancer screening.

CONCLUSIONS

These individual characteristics may be the key to identifying women at increased risk of not being vaccinated against HPV and could inform targeted messaging to drive HPV vaccination.

COVID-19 and influenza vaccine uptake among pregnant women in national cohorts of England and Wales

Vaccines against COVID-19 and influenza can reduce the adverse outcomes caused by infections during pregnancy, but vaccine uptake among pregnant women has been suboptimal. We examined the COVID-19 and influenza vaccine uptake and disparities in pregnant women during the COVID-19 pandemic to inform vaccination interventions. We used data from the Oxford-Royal College of General Practitioners Research and Surveillance Centre database in England and the Secure Anonymised Information Linkage Databank in Wales. The uptake of at least one dose of vaccine was 40.2% for COVID-19 and 41.8% for influenza among eligible pregnant women. We observed disparities in COVID-19 and influenza vaccine uptake, with socioeconomically deprived and ethnic minority groups showing lower vaccination rates. The suboptimal uptake of COVID-19 and influenza vaccines, especially in those from socioeconomically deprived backgrounds and Black, mixed or other ethnic groups, underscores the necessity for interventions to reduce vaccine hesitancy and enhance acceptance in pregnant women.

Determinants of non-vaccination against seasonal influenza during pregnancy

OBJECTIVE

The objective of this study was to identify the determinants of influenza non-vaccination during pregnancy in Canada.

METHODS

Biological mothers of children born between December 2018 and March 2019 were surveyed about vaccinations they had received during pregnancy, reasons for non-vaccination, obstetrical history, and demographics. Simple and multiple logistic regression models were used to measure associations between various sociodemographic factors as well as obstetrical history, and non-vaccination against influenza. We analyzed data from 2361 mothers.

RESULTS

Factors associated with non-vaccination included being followed during pregnancy by a midwife compared to by an obstetrician-gynecologist (OR 2.02; 95% CI, 1.17‒3.50); having two or more past live births compared to none (OR 1.58; 95% CI, 1.01‒2.49); having an education level below high school diploma compared to a bachelor's degree or above (OR 2.50; 95% CI, 1.06‒5.90); and having a household income below $60,000 (OR 2.46; 95% CI, 1.42‒4.24) or between $60,000 and $99,999 (OR 2.77; 95% CI, 1.70‒4.52) compared to a household income of $140,000 or more. The province or territory of prenatal care proved to be an important factor in non-vaccination, with statistically significant odds ratios for certain provinces: OR 7.50 (95% CI, 1.40‒40.26) for Ontario, 8.23 (95% CI, 1.53‒44.23) for Newfoundland and Labrador, and 11.39 (95% CI, 2.14‒60.60) for Quebec, as compared to the territories.

CONCLUSION

Despite universal access to influenza vaccines in Canada during pregnancy, regional variations and socioeconomic disparities in non-vaccination are still observable.

Characteristics and determinants of seasonal influenza vaccination in Manitoba, Canada: A population-wide record-linkage study

Background

Seasonal influenza vaccine (SIV) uptake (receipt of vaccine) in Manitoba, Canada is consistently low notwithstanding vaccine availability and free-of-charge vaccination. Despite, there is a lack of published evidence on the determinants of uptake of the vaccine. We sought to assess the association between SIV uptake and certain population and primary care physician (PCP) characteristics in Manitoba.

Methods

We conducted a longitudinal study utilizing Manitoba administrative health databases. We summarized SIV uptake from 2000/01-2019/20 influenza seasons across subpopulations defined by socioeconomic, health-related and PCP characteristics. Utilizing multivariable generalized estimating equation logistic regression models, we assessed the association between SIV uptake and the socioeconomic, health-related and PCP characteristics, stratified by age group (<5-, 5-17-, 18-44-, 45-64-, ≥65-year-olds) and sex. Results are adjusted odds ratios with associated 95 % confidence intervals.

Results

SIV uptake percentage increased over time with 4.4 %, 13.1 %, 17.5 % and 21.7 % of < 5-year-olds, 2 %, 4.9 %, 9.7 % and 13.1 % of 5-17-year-olds, 5.4 %, 8.8 %, 10.7 % and 13.5 % of 18-44-year-olds, 16.8 %, 21.3 %, 23.6 % and 24.6 % of 45-64-year-olds receiving the SIV in 2000-2004, 2005-2009, 2010-2014 and 2015-2019, respectively. There was a decline among ≥ 65-year-olds from 58.5 % to 53.5 %. We observed a similar pattern across subpopulations. There were significantly increased odds of SIV uptake among females within the age groups ≥ 18 years, in higher income quintiles, mostly with increased contact with a PCP/hospitalization within age groups ≥ 18 years, among those who had older or female PCPs (the opposite observation among ≥ 65-year-olds) and whose PCP administered at least one SIV in prior influenza season. These observations were largely consistent irrespective of sex.

Conclusion

SIV uptake in Manitoba appears to increase with age, and many socioeconomic, health-related and PCP characteristics appear to be associated with it. These findings may inform targeted vaccination programs to optimize influenza vaccination in Manitoba and similar Canadian jurisdictions.

Factors Associated With Influenza Vaccination During Pregnancy: A Real-World Evidence-Based Study

Pregnant women are at increased risk of influenza-related complications. However, the rate of influenza vaccination among pregnant women in Taiwan is low. By analyzing real-world data in this study, we investigated the factors associated with influenza vaccination during pregnancy in Taiwan. This study was a cross-sectional study. We collected real-world data from 2 databases in Taiwan: the Birth Certificate Database and the National Health Insurance Research Database. The study population was pregnant between October 2014 and December 2016 in Taiwan. The multivariate logistic regression was performed to identify factors associated with influenza vaccination, including maternal sociodemographics, trimester, comorbidities, and health-care utilization. The vaccination rate of among pregnant women was 8.2%. Factors significantly associated with a high likelihood of influenza vaccination were age between 30 and 34 years (odds ratio [OR]: 1.14; 95% confidence interval [CI]: 1.10-1.19), second trimester (OR: 1.80; 95% CI: 1.75-1.85), income equal to or exceeding NT$ 38 201 (OR: 1.92; 95% CI: 1.86-1.99), hypertension (OR: 1.16; 95% CI: 1.05-1.29), cardiovascular disease (OR: 1.29; 95% CI: 1.17-1.42), autoimmune disease (OR: 1.47; 95% CI: 1.38-1.58), and chronic pulmonary disease (OR: 1.24; 95% CI: 1.18-1.31). A low level of urbanization, at least 1 hospitalization in the previous year, and the presence of pregnancy complications (eg, gestational diabetes, preeclampsia, and placenta previa) were associated with a lower likelihood rate of influenza vaccination. The influenza vaccination rate among pregnant women in Taiwan was low. Age, gestational age, income level, urbanization level, hypertension, cardiovascular disease, autoimmune disease, chronic pulmonary disease, and pregnancy complications may be associated with influenza vaccination among pregnant women.

Risk of Miscarriage in Relation to Seasonal Influenza Vaccination Before or During Pregnancy

OBJECTIVE

To evaluate the association between seasonal influenza vaccination and miscarriage using data from an ongoing, prospective cohort study.

METHODS

We analyzed 2013-2022 data from PRESTO (Pregnancy Study Online), a prospective prepregnancy cohort study of female pregnancy planners and their male partners in the United States and Canada. Female participants completed a baseline questionnaire and then follow-up questionnaires every 8 weeks until pregnancy, during early and late pregnancy, and during the postpartum period. Vaccine information was self-reported on all questionnaires. Miscarriage was identified from self-reported information during follow-up. Male partners were invited to complete a baseline questionnaire only. We used Cox proportional hazard models to estimate the hazard ratio (HR) and 95% CI for the association between vaccination less than 3 months before pregnancy detection through the 19th week of pregnancy and miscarriage, with gestational weeks as the time scale. We modeled vaccination as a time-varying exposure and used propensity-score fine stratification to control for confounding from seasonal and female partner factors.

RESULTS

Of 6,946 pregnancies, 23.3% of female partners reported exposure to influenza vaccine before or during pregnancy: 3.2% during pregnancy (gestational age 4-19 weeks) and 20.1% during the 3 months before pregnancy detection. The miscarriage rate was 16.2% in unvaccinated and 17.0% among vaccinated participants. Compared with no vaccine exposure, influenza vaccination was not associated with increased rate of miscarriage when administered before (HR 0.99, 95% CI 0.81-1.20) or during (HR 0.83, 95% CI 0.47-1.47) pregnancy. Of the 1,135 couples with male partner vaccination data available, 10.8% reported vaccination less than 3 months before pregnancy. The HR for the association between male partner vaccination and miscarriage was 1.17 (95% CI 0.73-1.90).

CONCLUSION

Influenza vaccination before or during pregnancy was not associated with miscarriage.

Association between maternal influenza vaccination and neurodevelopmental disorders in childhood: a longitudinal, population-based linked cohort study

OBJECTIVE

To assess the association between in utero exposure to seasonal inactivated influenza vaccine (IIV) and the risk of a diagnosis of a neurodevelopmental disorder in early childhood.

DESIGN

Retrospective cohort study.

SETTING

Population-based birth registry linked with health administrative databases in Western Australia (WA).

PARTICIPANTS

Singleton, liveborn children born between 1 April 2012 and 1 July 2016 in WA.

EXPOSURE

Receipt of seasonal IIV during pregnancy obtained from a state-wide antenatal vaccination database.

MAIN OUTCOME MEASURES

Clinical diagnosis of a neurodevelopmental disorder was recorded from hospital inpatient and emergency department records. We used Cox proportional hazard regression, weighted by the inverse-probability of treatment (vaccination), to estimate the hazard ratio (HR) of neurodevelopmental disorders associated with in utero exposure to seasonal IIV.

RESULTS

The study included 140 514 children of whom, 15 663 (11.2%) were exposed to seasonal IIV in utero. The prevalence of neurodevelopmental disorders was 5.4%, including mental or behavioural (0.4%), neurological (5.1%), seizure (2.2%) and sleep disorders (2.7%). Maternal IIV was not associated with increased risk of neurodevelopmental disorders (HR 1.00; 95% CI 0.91 to 1.08). Children exposed in the first trimester had a lower risk of seizure disorders (adjusted HR [aHR] 0.73; 95% CI 0.54 to 0.998), and preterm children exposed any time during pregnancy had a lower risk of sleep disorders (aHR 0.63; 95% CI 0.41 to 0.98).

CONCLUSIONS

We did not observe increased risk of neurodevelopmental disorders following in utero exposure to seasonal IIV. Although we observed some evidence for lower risk of seizure and sleep disorders, additional studies are required to confirm.

Health inequalities in infectious diseases: a systematic overview of reviews

OBJECTIVES

The aim of this systematic overview of reviews was to synthesise available evidence on inequalities in infectious disease based on three dimensions of inequalities; inclusion health groups, protected characteristics and socioeconomic inequalities.

METHODS

We searched MEDLINE, Embase, Web of Science and OpenGrey databases in November 2021. We included reviews published from the year 2000 which examined inequalities in the incidence, prevalence or consequences of infectious diseases based on the dimensions of interest. Our search focused on tuberculosis, HIV, sexually transmitted infections, hepatitis C, vaccination and antimicrobial resistance. However, we also included eligible reviews of any other infectious diseases. We appraised the quality of reviews using the Assessment of Multiple Systematic Reviews V.2 (AMSTAR2) checklist. We conducted a narrative data synthesis.

RESULTS

We included 108 reviews in our synthesis covering all the dimensions of inequalities for most of the infectious disease topics of interest, however the quality and volume of review evidence and consistency of their findings varied. The existing literature reviews provide strong evidence that people in inclusion health groups and lower socioeconomic status are consistently at higher risk of infectious diseases, antimicrobial resistance and incomplete/delayed vaccination. In the protected characteristics dimension, ethnicity, and sexual orientation are important factors contributing to inequalities across the various infectious disease topics included in this overview of reviews.

CONCLUSION

We identified many reviews that provide evidence of various types of health inequalities in different infectious diseases, vaccination, and antimicrobial resistance. We also highlight areas where reviews may be lacking. The commonalities in the associations and their directions suggest it might be worth targeting interventions for some high risk-groups that may have benefits across multiple infectious disease outcomes rather than operating purely in infectious disease siloes.

Barriers and facilitators of vaccine hesitancy for COVID-19, influenza, and pertussis during pregnancy and in mothers of infants under two years: An umbrella review

BACKGROUND

Vaccination during pregnancy has been repeatedly demonstrated to be safe and effective in protecting against infection and associated harms for the mother, developing baby, and subsequent infant. However, maternal vaccination uptake remains low compared to the general population.

OBJECTIVES

An umbrella review to explore the barriers and facilitators to Influenza, Pertussis and COVID-19 vaccination during pregnancy and within 2 years after childbirth, and to inform interventions to encourage uptake (PROSPERO registration number: CRD42022327624).

METHODS

Ten databases were searched for systematic reviews published between 2009 and April 2022 exploring the predictors of vaccination or effectiveness of interventions to improve vaccination for Pertussis, Influenza, or COVD-19. Both pregnant women and mothers of infants under two years were included. Barriers and facilitators were organised using the WHO model of determinants of vaccine hesitancy through narrative synthesis, the Joanna Briggs Institute checklist assessed review quality, and the degree of overlap of primary studies was calculated.

RESULTS

19 reviews were included. Considerable overlap was found especially for intervention reviews, and the quality of the included reviews and their primary studies varied. Sociodemographic factors were specifically researched in the context of COVID-19, exerting a small but consistent effect on vaccination. Concerns around the safety of vaccination particularly for the developing baby were a main barrier. While key facilitators included recommendation from a healthcare professional, previous vaccination, knowledge around vaccination, and communication with and support from social groups. Intervention reviews indicated multi-component interventions involving human interaction to be most effective.

CONCLUSION

The main barriers and facilitators for Influenza, Pertussis and COVID-19 vaccination have been identified and constitute the foundation for policy development at the international level. Ethnicity, socioeconomic status, concerns about vaccine safety and side effects, and lack of healthcare professionals' recommendations, are the most relevant factors of vaccine hesitancy. Adapting educational interventions to specific populations, person-to-person interaction, healthcare professionals' involvement, and interpersonal support are important strategies to improve uptake.

Protecting pregnant people & infants against influenza: A landscape review of influenza vaccine hesitancy during pregnancy and strategies for vaccine promotion

Before COVID-19, influenza vaccines were the most widely recommended vaccine during pregnancy worldwide. In response to immunization during pregnancy, maternal antibodies offer protection against potentially life-threatening disease in both pregnant people and their infants up to six months of age. Despite this, influenza vaccine hesitancy is common, with few countries reporting immunization rates in pregnant people above 50%. In this review, we highlight individual, institutional, and social factors associated with influenza vaccine hesitancy during pregnancy. In addition, we present an overview of the evidence evaluating interventions to address influenza vaccine hesitancy during pregnancy. While some studies have indicated promising results, no single intervention has consistently effectively increased influenza vaccine uptake during pregnancy. Using a social-ecological model of health framework, future strategies addressing multiple levels of vaccine hesitancy will be needed to realize the potential health benefits of prenatal immunization programs.

Understanding drivers of influenza vaccine hesitancy among pregnant women in China: evidence from an extended theory of planned behavior

BACKGROUND

Pregnant women have a low uptake of influenza vaccination, although being recommended as a priority.

RESEARCH DESIGN AND METHODS

We conducted a cross-sectional questionnaire survey in China from June to July 2021. Hierarchical regression analysis and structural equation modeling were performed based on the extended theory of planned behavior, in which attitudes, subjective norms, perceived behavioral control, and intention each affect the vaccine hesitancy; four variables of response efficacy, knowledge, vulnerability, and severity were added as extended dimensions; vaccination history played a moderator role in this model-to test the validity of the framework.

RESULTS

Totally, 1283 pregnant women participated in this study. The intention existed as a mediator between attitude [β_indirect=0.142 (95% confidence interval (CI): 0.084, 0.206), P<0.001], subjective norms [β_indirect=0.568 (95%CI: 0.424, 0.754), P<0.001], perceived behavioral control [β_indirect=0.070 (95%CI: 0.025, 0.118), P=0.004] and vaccine hesitancy. Further, the differences in indirect effect between the two dimensions of attitude (P<0.001), perceived behavioral control (P<0.001), and subjective norms were each statistically significant. Vaccination history did not moderate the association between attitude (P=0.679), subjective norms (P=0.645), and hesitancy.

CONCLUSIONS

The subjective norms dimension has a strong association with influenza vaccine hesitancy. Vaccination history had limited ability to reduce hesitancy during pregnancy.

Trends of influenza vaccination coverage in pregnant women: a ten-year analysis from a French healthcare database

Pregnant women have a high risk of severe influenza, associated with obstetrical complications. The World Health Organization (WHO) has recommended influenza vaccination for all pregnant women since 2012. The vaccination coverage remains low worldwide, and in Europe, due to a lack of proposition from the health care providers, and a high refusal rate from the women. The primary aim of this study was to estimate the influenza vaccination coverage (IVC) in a population of pregnant women in France, and to analyse its evolution from 2009 to 2018. The secondary objective was to describe the vaccinated population and to find determinants associated with the vaccination. This retrospective cohort study is based on the EGB French health care database, a representative sample of the French population containing data from the health insurance system. All pregnant women who delivered medically or spontaneously over the 2009–2018 period were included. In the 2009–2018 period, only 1.2% pregnant women were vaccinated against influenza (n = 875/72,207; 95% CI 1.14–1.30). The IVC slightly increased after the 2012 WHO recommendation, from 0.33 to 1.79% (p < 0.001) but remained extremely low (4.1% in 2018). Women younger than 25 years old had a low coverage (0.6%) whereas women over 35 years old were more likely to get the influenza vaccine (1.7%; OR: 2.82, 95% CI 2.14–3.71). The vaccination behavior was not influenced by multifetal pregnancy or parity, but socio-economically deprived women were less likely to be vaccinated (OR: 0.81, 95% CI: 0.67–0.98). Women with pre-existing medical conditions had an overall higher vaccination rate (2.5%; OR: 2.32, 95% CI: 1.94–2.77). The vaccine was mainly prescribed by family physicians (58%). Influenza vaccination in pregnant women in France remains very low, particularly in younger, healthy women, and measures such as information campaigns towards pregnant women and studies of the knowledge, attitudes, and practices of the health care professionals need to be undertaken to improve the coverage.

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

Objective

Methods

Results

Conclusions

Influenza and Pertussis Maternal Vaccination Coverage and Influencing Factors in Spain: A Study Based on Primary Care Records Registry

The purpose was to determine the coverage of maternal vaccination against influenza and pertussis, and the characteristics associated with being vaccinated, in a health area of Catalonia, Spain. Some 36,032 anonymized and computerized clinical records registries of pregnant women from Primary Care Centres (e-CAP database) were analysed, from between 2015 and 2018. Vaccination coverage and the association with sociodemographic variables and clinical conditions were estimated using a Poisson regression model. Maternal vaccination coverage against influenza ranged between 11.9% in 2015 and 6.8% in 2018, following a decreasing trend (p < 0.001). Coverage with the tetanus toxoid, diphtheria toxoid, and acellular pertussis vaccine varied between 49.8% in 2016 and 79.4% in 2018, following an increasing trend (p < 0.001). Having living children and suffering from obesity were factors associated with not being vaccinated against both infections. The predictive variables of vaccination against influenza were diabetes (IRR: 2.17, 95% CI: 1.42−3.30) and asthma (IRR: 2.05, 95% CI: 1.76−2.38); and for pertussis, it was asthma (IRR: 1.10, 95% CI: 1.03−1.17). Different socio-demographic factors and chronic conditions in pregnant women were associated with maternal vaccination, and which will have to be taken into account in clinical practice when implementing strategies to improve the coverage of the programme.

Changes in Attitudes and Beliefs Concerning Vaccination and Influenza Vaccines between the First and Second COVID-19 Pandemic Waves: A Longitudinal Study

Perceptions of the risks of vaccine-preventable diseases and preventive behaviors change over time. The ongoing COVID-19 pandemic may have modified laypeople's attitudes towards routine vaccinations. In this longitudinal study, we aimed to assess changes in attitudes and beliefs concerning (influenza) vaccines between the first and second COVID-19 pandemic waves. A total of 1979 participants completed both 2020 and 2021 surveys. After one year, more interviewees agreed that vaccines were fundamental and should be mandatory (77.3% vs. 75.0%). Analogously, willingness to undergo influenza vaccination increased (p < 0.001) from 44.1% to 48.6%. This increase was seen in subjects aged ≥35 years. Previous influenza vaccinations, receipt of a COVID-19 vaccine, positive attitudes towards (influenza) vaccination, male sex, and older age were the main correlates of willingness to receive the 2021/22 influenza vaccine. Totals of 12.6% and 11.8% had no intention to receive the next seasonal influenza and COVID-19 vaccines, respectively. Most respondents favored a hypothetical combined influenza/COVID-19 vaccine (73.7%) or influenza and COVID-19 vaccine co-administration (67.5%). In Italy, influenza and COVID-19 vaccination hesitancy and refusal are common. Effective public health strategies to pursue higher uptake of both vaccines are urgently needed.

Current Resources for Evidence-Based Practice, September 2021

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes an assessment of safety of birth centers in the United States and commentaries on reviews focused on aspirin prophylaxis in pregnancy and the new gestational weight gain evidence summary from the United States Preventive Services Task Force.