Predictors of H1N1 vaccination in pregnancy

COVID-19 Vaccine Hesitancy in an Underrepresented Minority Community

To assess factors influencing acceptability of COVID-19 vaccine in a population of predominantly indigent, minority, pregnant and non-pregnant people of reproductive age. Cross-sectional survey using a modified Health Belief model administered between January 2021 and January 2022 at four hospitals in Brooklyn. Participants included English-speaking reproductive aged persons attending clinics at the participating sites. Descriptive and univariate data analyses were used for analysis. 283 eligible reproductive persons were approached of whom 272 completed the survey (96%). Three quarters said they would take the vaccine under certain circumstances ("as soon as it is ready" [28.6%], "when my doctor recommends it" [21.3%] or "when enough people have received it to know if it works" [25%]), while 25% said they would never take the vaccine. When comparing persons that would take it under certain circumstances to those that never would, the "never" group was significantly more likely to note that, "they would not trust any COVID vaccine" (71.4% vs. 28.5%; p ≤ 0.0001). This greater level of distrust extended to greater distrust of doctors, government, family, newspapers, and media. However, 36% said they would be influenced by their doctor's recommendation. Pregnant participants were significantly more likely to wait until their doctor recommended it (17.6% of pregnant persons compared to 3.7% of non-pregnant p < 0.0001). Despite mistrust and other discouraging factors, many persons, under appropriate circumstances (e.g., reassurance about vaccine safety) may be motivated to take the vaccine. Even those who claimed that they wouldn't take the vaccine under any circumstance may be influenced by their health care providers.

Factors of influenza vaccine inoculation and non-inoculation behavior of community-dwelling residents in Japan: suggestions for vaccine policy and public health ethics after COVID-19

The aim of this study is to provide basic information that contributes to vaccine inoculation policy after COVID-19. We used the secondary data of the influenza vaccine inoculation behavior survey for community-dwelling adults conducted in 2011, before the COVID-19 pandemic, but after the 2009 novel influenza A (H1N1) pdm 09 pandemic. All factors such as socio-demographic characteristics, health-related behaviors, family environment, physical and social environment, and area of residence were adjusted, and factors related to vaccine inoculation behavior were analyzed. Those living with pregnant women had a significantly higher odds ratio of inoculation; this was self-evident in that those people considered infection to their family. Regarding the social environment, those aged 20–64 years with a significantly higher adjusted odds ratio of inoculation were those with “at least five people with which they interacted in the neighborhood”. This result can be interpreted in two ways relating to altruism in Japan. Finally, we indicated the importance of learning from the past, including the case of 2009.

Models of determinants of COVID-19 vaccine hesitancy in non-pregnant and pregnant population: Review of current literature"

Vaccination has proven to be the most effective tool in controlling the COVID-19 pandemic. While pregnant individuals are considered to be a high-risk population and are more likely to experience adverse effects from COVID-19, vaccination rates among pregnant individuals are significantly lower than in the general population. The Health Belief Model (HBM), Theory of Planned Behavior (TPB), 3C model, 5C model, and 5A model have been used to assess vaccination hesitancy behaviors. In this paper, we review the use of each of these models to address vaccine hesitancy, with a focus on the pregnant population and the COVID-19 vaccine. The HBM, TPB, 3C model, and 5C model have demonstrated great versatility in their ability to evaluate, explain, and modify vaccine hesitancy and behavior. Up to date, the HBM and 3C models appear to be the most effective models to study and address vaccination hesitancy within the pregnant persons.

Ideology and COVID-19 Vaccination Intention: Perceptual Mediators and Communication Moderators

Widespread COVID-19 vaccination is critical to slow the spread of the illness. This study investigates how political ideology is associated with COVID-19 vaccine intention via perceived effectiveness of the vaccine, perceived side effects, and perceived severity of the illness, three key aspects of the Health Belief Model (HBM). This study also examines how partisan information flow moderates the effects of ideology on these three HBM components. Using survey data collected from two battleground states in the 2020 election (N = 1849), regression, mediation and moderation analyses revealed that conservatives were less likely to intend to get vaccinated against COVID-19, and this association was significantly mediated by perceived effectiveness and perceived side effects of vaccination, as well as perceived severity of COVID-19. In addition, partisanship of news sources and discussion partners were significant moderators of ideology's association with perceived vaccine effectiveness, with conservatives viewing COVID-19 vaccination as less effective if they were frequently exposed to liberal news, and if they had frequent conversations with fellow conservatives. This suggests boomerang effects for cross-cutting mass media exposure, and reinforcement effect for interpersonal communication. Implications for efforts to promote COVID-19 vaccine uptake are discussed, including tailored and targeted campaign strategies.

Using the Health Belief Model to Identify Predictors of COVID-19 Vaccine Acceptance among a Sample of Pregnant Women in the U.S.: A Cross-Sectional Survey

The aim of the study was to identify factors that predict acceptance of the COVID-19 vaccine among pregnant women. Using the Health Belief Model, the authors administered a cross-sectional survey of pregnant and postpartum women in the United States during the COVID-19 pandemic. Overall, 227 women agreed to participate and completed the entire survey. Over half (59%) the participants had received the COVID-19 vaccine at the time of the study. Perceived barriers to vaccination (p < 0.001) and perceived benefits (p < 0.001) to vaccination were statistically significant predictors of vaccination. Trust in healthcare providers was also statistically predictive of vaccination (p = 0.001). Binary regression results were statistically significant (χ2(9) = 79.90, p < 0.001), suggesting that perceived benefits, barriers, severity, and susceptibility scores had a statistically significant effect on the odds of a participant being vaccinated. Results indicate a need for increased patient education regarding COVID-19 vaccination during pregnancy, including the benefits of vaccination for mother and fetus.

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 Awareness, Perceived Severity, and Behavioral Control of COVID -19 With Self-Care and Anxiety in Pregnancy: A Cross-Sectional Study

COVID-19 pandemic has caused a tidal wave of anxiety and stress among Iranians, especially pregnant women. This study aimed to assess the association between knowledge, perceived severity, and controllability of COVID-19 with self-care and health anxiety specially in pregnancy. This cross-sectional study was performed on 440 pregnant women. Data were collected using demographic-obstetrics characteristics, as well as the questionnaires of knowledge, perceived severity, and perceived controllability of the COVID-19, health anxiety, and self-care. Self-care was positively correlated with knowledge, perceived severity, and perceived controllability of the COVID-19. Nonetheless, health anxiety had a significant and inverse association with knowledge and perceived controllability, while there was a positive and significant correlation between perceived severity and health anxiety. Based on linear regression, three variables of knowledge, perceived severity, and perceived controllability of the COVID-19 could explain 46.3 and 17.5% of variations in self-care and health anxiety, respectively. It is suggested that due to the critical importance of prenatal care, managers, and health-care providers promote the use of such methods as telehealth and home-based caregivers, especially in areas with inadequate access to health care. So, the pregnant women can be followed up and receive medical care devoid of any stress and anxiety.

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

INTRODUCTION

Vaccination is considered to be the most practical and effective preventative measure against influenza. It is highly recommended for population subgroups most at risk of developing complications, including pregnant women. However, seasonal influenza vaccine uptake remains suboptimal among pregnant women, even in jurisdictions with universal vaccination. We summarized the evidence on the determinants of seasonal influenza vaccine uptake during pregnancy to better understand factors that influence vaccine uptake among pregnant women.

MATERIAL AND METHODS

We systematically searched MEDLINE, Embase and CINAHL from January 2000 to February 2020 for publications in English reporting on sociodemographic and/or health-related determinants of seasonal influenza vaccine uptake during pregnancy. Two reviewers independently included studies. One reviewer extracted data and assessed study quality, and another reviewer checked extracted data and study quality assessments for errors. Disagreements were resolved through consensus, or a third reviewer. We meta-analyzed using the inverse variance, random-effects method, and reported the odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

From 1663 retrieved citations, we included 36 studies. The following factors were associated with increased seasonal influenza vaccine uptake: Older age (20 studies: OR 1.13, 95% CI 1.07-1.20), being nulliparous (13 studies: OR 1.26, 95% CI 1.15-1.38), married (8 studies: OR 1.11, 95% CI 1.07-1.15), employed (4 studies: OR 1.13, 95% CI 1.02-1.24), a non-smoker (8 studies: OR 1.25, 95% CI 1.04-1.51) and having prenatal care (3 studies: OR 3.36, 95% CI 2.25-5.02), a chronic condition (6 studies: OR 1.30, 95% CI 1.17-1.44), been previously vaccinated (9 studies: OR 4.88, 95% CI 3.14-7.57) and living in a rural area (9 studies: OR 1.09, 95% CI 1.05-1.14). Compared with being black, being white was also associated with increased seasonal influenza vaccine uptake (11 studies: OR 1.30, 95% CI 1.20-1.41).

CONCLUSIONS

The evidence suggests that several sociodemographic and health-related factors may determine seasonal influenza vaccination in pregnancy, and that parity, history of influenza vaccination, prenatal care and comorbidity status may be influential.

The Rate of Influenza Vaccination after Face-to-Face Interview in Pregnancy

PURPOSE

Most societies recommend routine influenza vaccine to all pregnant women. In Turkey, the Ministry of Health provides the influenza vaccine free of charge to pregnant women during the second and third trimesters. Pregnant women may not be willing to accept vaccination despite their knowledge and attitudes. We aimed to investigate the rate and determining factors of influenza vaccine acceptance after receipt of face-to-face information.

METHODS

Pregnant women were informed about the benefits of the influenza vaccine and asked if they would get the vaccine.

RESULTS

A total of 353 Turkish women were involved, and 191 (54.1%) accepted influenza vaccination. There was no statistically significant difference in terms of maternal age, body mass index, gravida, number of children, socioeconomic status, smoking and occupation between groups. Women in the third trimester had lower vaccination rates compared to first- and second-trimester pregnancies (35.7% vs. 67.7-64.2%). Women with at least a university degree also had lower vaccine uptake rates (58.1% vs. 59.5-36.8%). While 82.2% of women who accepted vaccination believed the benefit of the vaccine to the baby, the rate was 54.9% in the non-vaccinated group. The most common reason for refusal was the belief that influenza was not a serious disease. Vaccination uptake was higher especially for women who understood the benefits of the influenza vaccine for the baby (OR=3.79, 95%Cl=2.34-6.14).

CONCLUSION

Women who had enough information, who had a lower education level, who had a previous history of influenza infection, and who had decided to have their babies vaccinated were more likely to accept influenza vaccine.

Psychological impact of infectious disease outbreaks on pregnant women: rapid evidence review

Objectives

Infectious disease outbreaks can be distressing for everyone, especially those deemed to be particularly vulnerable such as pregnant women, who have been named a high-risk group in the current COVID-19 pandemic. This paper aimed to summarise existing literature on the psychological impact of infectious disease outbreaks on women who were pregnant at the time of the outbreak.

Study design

The design of this study is a rapid review.

Methods

Five databases were searched for relevant literature, and main findings were extracted.

Results

Thirteen articles were included in the review. The following themes were identified: negative emotional states; living with uncertainty; concerns about infection; concerns about and uptake of prophylaxis or treatment; disrupted routines; non-pharmaceutical protective behaviours; social support; financial and occupational concerns; disrupted expectations of birth, prenatal care and postnatal care and sources of information.

Conclusions

Pregnant women have unique needs during infectious disease outbreaks and could benefit from up-to-date, consistent information and guidance; appropriate support and advice from healthcare professionals, particularly with regards to the risks and benefits of prophylaxis and treatment; virtual support groups and designating locations or staff specifically for pregnant women.

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Pregnant women may be particularly susceptible to distress during pandemics.

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Infection fears and prophylaxis concerns may exacerbate distress.

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Disrupted routines, financial concerns and uncertainty are also stressors.

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Disrupted expectations of birth and related healthcare may be distressing.

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Pregnant women may benefit from clear information/guidance and support groups.

Health Information Sources and the Influenza Vaccination: The Mediating Roles of Perceived Vaccine Efficacy and Safety

Although the influenza vaccine is widely recognized as an effective preventive measure, influenza vaccination rates among U.S. adults remain low. Moreover, influenza-related respiratory illnesses may increase the risk of adverse outcomes of COVID-19. Thus, this study examines the mechanisms involved in influenza vaccination uptake. Specifically, this study investigates how health information sources are associated with perceived vaccine efficacy and safety, which, in turn, associated with influenza vaccine uptake. Analyzing cross-sectional survey data from a national U.S. adult sample (N = 19,420), mediation analyses were conducted. Results revealed that considering vaccine efficacy, health information seekers who assigned more value to medical professionals, medical journals, and newspaper articles were more likely to perceive a vaccine as effective, thus being more likely to receive the influenza vaccine. By contrast, individuals who placed more value in social media were less likely to perceive vaccine efficacy, and, in turn, were less likely to get the influenza vaccine. Turning to vaccine safety, the value ascribed to medical professionals was positively associated with vaccine safety, which, in turn, related to influenza vaccine uptake. By contrast, social media, family or friends, and promotions were negatively associated with vaccine safety, and then influenza vaccine uptake.

Factors that influence vaccination decision-making among pregnant women: A systematic review and meta-analysis

BACKGROUND

The most important factor influencing maternal vaccination uptake is healthcare professional (HCP) recommendation. However, where data are available, one-third of pregnant women remain unvaccinated despite receiving a recommendation. Therefore, it is essential to understand the significance of other factors and distinguish between vaccines administered routinely and during outbreaks. This is the first systematic review and meta-analysis (PROSPERO: CRD 42019118299) to examine the strength of the relationships between identified factors and maternal vaccination uptake.

METHODS

We searched MEDLINE, Embase Classic & Embase, PsycINFO, CINAHL Plus, Web of Science, IBSS, LILACS, AfricaWideInfo, IMEMR, and Global Health databases for studies reporting factors that influence maternal vaccination. We used random-effects models to calculate pooled odds ratios (OR) of being vaccinated by vaccine type.

FINDINGS

We screened 17,236 articles and identified 120 studies from 30 countries for inclusion. Of these, 49 studies were eligible for meta-analysis. The odds of receiving a pertussis or influenza vaccination were ten to twelve-times higher among pregnant women who received a recommendation from HCPs. During the 2009 influenza pandemic an HCP recommendation increased the odds of antenatal H1N1 vaccine uptake six times (OR 6.76, 95% CI 3.12-14.64, I2 = 92.00%). Believing there was potential for vaccine-induced harm had a negative influence on seasonal (OR 0.22, 95% CI 0.11-0.44 I2 = 84.00%) and pandemic influenza vaccine uptake (OR 0.16, 95% CI 0.09-0.29, I2 = 89.48%), reducing the odds of being vaccinated five-fold. Combined with our qualitative analysis the relationship between the belief in substantial disease risk and maternal seasonal and pandemic influenza vaccination uptake was limited.

CONCLUSIONS

The effect of an HCP recommendation during an outbreak, whilst still powerful, may be muted by other factors. This requires further research, particularly when vaccines are novel. Public health campaigns which centre on the protectiveness and safety of a maternal vaccine rather than disease threat alone may prove beneficial.

Does the availability of influenza vaccine at prenatal care visits and of immediate vaccination improve vaccination coverage of pregnant women?

Introduction

Although vaccination against influenza is recommended for pregnant women in France because it exposes them to a risk of death and severe respiratory complications, their vaccination coverage in 2016 was estimated at 7%. This study's principal objective was to assess the association between the availability of influenza vaccination at prenatal care visits and vaccination coverage.

Material and methods

This multicenter survey took place in 3 Paris-area public hospital (AP-HP) maternity wards (A, B, and C). Only maternity ward A offered the vaccine and vaccination without charge at prenatal visits. Data were collected from parturients during 10 days in January 2017 by a self-administered anonymous questionnaire.

Results

Data from 248 women showed overall vaccination coverage of 19.4% (48/248): 35.4% (46/130) in maternity unit A, 2.7% (2/75) in B, and 0% (0/43) in C (P<0.01). After adjustment for socio-demographic characteristics, women at maternity ward A were significantly more likely to be vaccinated than those at B and C (aOR 25.52, 95%CI [5.76–113.10]). Other factors significantly associated with higher vaccination coverage were the mother’s French birth (aOR 2.37 CI [1.03–5.46]) and previous influenza vaccination (aOR 3.13, 95%CI [1.25–7.86]). Vaccinated women generally considered they had received adequate information (aOR 4.15 CI [2.10–8.22]), principally from the professional providing their prenatal care. Nonvaccination was attributed to the absence of an offer of vaccination (81.5%), fear of fetal side effects (59.5%), and inadequate information (51.4%).

Conclusion

Our results show that availability of influenza vaccination, free of charge, at prenatal consultations at the maternity ward increases vaccination coverage significantly.

A path model of psychosocial constructs predicting future Zika vaccine uptake intent

OBJECTIVE

The recent Zika virus outbreak, while no longer an international public health emergency, is still a serious threat, particularly to pregnant women and babies born to pregnant women infected with the virus. This study examined the predictive effects of psychosocial constructs on self-reported intent to get a future Zika vaccine among women of reproductive age.

METHODS

Data were collected using an online survey with a representative sample of 339 women ages 18-49 from the continental United States. The survey addressed variables originating with the Extended Parallel Processing Model (EPPM) as related to future Zika vaccine uptake intent.

RESULTS

Three quarters of all respondents reported intention to get a future Zika vaccine. Path modeling revealed a direct effect of perceived susceptibility, self-efficacy, and response efficacy on future Zika vaccine uptake intent, as well as an indirect effect of perceived susceptibility through both self-efficacy and response efficacy. In addition, the final model showed an indirect effect of perceived severity on Zika vaccine uptake intent through self-efficacy and response efficacy and accounted for 54.6% of the variance in vaccination intent.

CONCLUSIONS

These findings have implications for future Zika vaccine promotion campaigns. This study confirms the importance of perceived susceptibility, self-efficacy, and response efficacy for use in Zika vaccine uptake campaigns; in addition, when using perceived severity, both self-efficacy and response efficacy should be considered in message design.

Low awareness of influenza vaccination among pregnant women and their obstetricians: a population-based survey in Beijing, China

We assessed how an awareness of influenza vaccination might influence both the willingness of pregnant women to be vaccinated and the readiness of obstetricians to recommend antenatal influenza vaccination in Beijing, China. From March to April 2016, we surveyed pregnant women who were attending antenatal clinics at eight hospitals in Beijing, along with obstetricians at the same clinics. Demographic, attitudinal, and behavioral information regarding influenza vaccination were collected using structured questionnaires. Consent and completed questionnaires were obtained from 988 of 1009 pregnant women and 165 of 173 obstetricians. Only 113 (11.4%) pregnant women reported being willing to receive an influenza vaccine during their pregnancies. Willingness to receive an influenza vaccination was positively associated with ever having a history of vaccination or influenza (aOR=6.74, 95%CI: 1.72-26.4, P=0.006), perceiving benefits of vaccination (aOR=1.67, 95%CI: 1.00-2.79, P=0.050), and having a higher level of influenza knowledge (aOR=82.2, 95%CI: 21.7-311.1, P<0.001). Among obstetricians, only 19.4% reported being willing to recommend influenza vaccination to their pregnant patients and 15.2% reported knowledge that influenza vaccination during pregnancy was recommended by China's National Health Commission. Neither pregnant women nor their obstetricians were aware of Chinese government recommendations that antenatal influenza vaccination should be encouraged and provided. Pregnant women and their obstetricians were ill-informed of the relevant evidence. It is in emergent need to train and disseminate the updated evidence on influenza vaccination to obstetricians. It also warranted more high-quality trials regarding influenza vaccination during pregnancy to address public concern.

Understanding barriers and predictors of maternal immunization: Identifying gaps through an exploratory literature review

BACKGROUND

The Advisory Committee for Immunization Practices recommends that all pregnant women receive the seasonal influenza vaccine and the tetanus toxoid, diphtheria toxoid, and acellular pertussis (Tdap) vaccine during every pregnancy. However, vaccination coverage rates are suboptimal among pregnant women in the United States, leaving these women and their unborn children at risk of vaccine-preventable diseases and their complications.

OBJECTIVES

We sought to understand the current landscape of published literature regarding maternal immunization, including barriers to and predictors of vaccine acceptance, and identify gaps in the research in order to inform strategies for future programmatic improvement.

METHODS

We conducted a literature search using MEDLINE (OVID), PsychINFO, and CINAHL (Ebsco) databases. The search included published, English-language manuscripts that identified patient, provider, or system-level barriers to, predictors of, or interventions that improved uptake of maternal vaccines among pregnant women in the US. Studies were reviewed using an inductive thematic analysis approach.

RESULTS

We included 75 studies in our review. Pregnant women identified 25 different barriers to accepting recommended maternal immunizations; barriers related to vaccine safety perceptions were the most common. Healthcare providers identified 24 different barriers to vaccinating their pregnant patients. The most commonly cited barriers among healthcare providers were financial concerns. Eighteen different predictors of vaccine acceptance were identified. Receipt of a healthcare provider's recommendation was the factor most frequently reported as a reason for vaccination among pregnant women.

CONCLUSIONS

We were able to identify gaps in the literature regarding maternal immunization and make recommendations for future research. Efforts to address the challenges of maternal immunization in the United States should include increasing the focus on Tdap, implementing more high-level assessments of safety perceptions and associated concerns, and determining most effective interventions.

Prenatal Tdap immunization and risk of maternal and newborn adverse events

Many countries recommend combined tetanus toxoid, reduced diphtheria toxoid and acellular pertussis immunization (Tdap) during pregnancy to stimulate transplacental transmission of pertussis antibodies to newborns. The immune system can be altered during pregnancy, potentially resulting in differing immunization risks in pregnant women. The safety of widespread Tdap immunization during pregnancy needs to be established. Our objective was to assess whether prenatal Tdap immunization was associated with adverse birth outcomes, and to evaluate the effect of timing of Tdap administration on these outcomes. We identified pregnancies at delivery in a large insurance claims database (2010-2014). Tdap immunization was categorized as optimal prenatal (27+weeks), early prenatal (<27weeks), postpartum (≤7days post-delivery), or none. Medical claims were searched to identify maternal adverse immunization reactions (e.g. anaphylaxis, fever, Guillian-Barre syndrome [GBS]), adverse birth outcomes (e.g. preeclampsia/eclampsia, premature rupture or membranes, chorioamnionitis) and newborn outcomes (e.g. respiratory distress, pulmonary hypertension, neonatal jaundice). Women with optimal or early prenatal Tdap were compared to those not immunized in pregnancy, using propensity score-weighted log-binomial regression and Cox proportional hazards models to estimate risk ratios (RR) and hazard ratios (HR). We identified 1,079,034 deliveries and 677,075 linked newborns; 11.5% were immunized optimally and 2.3% immunized early. There were 1 case of post-immunization anaphylaxis, and 12 cases of maternal encephalopathy (all post- delivery); there were no cases of GBS. Optimally-timed immunization was associated with small increased relative risks of: chorioamnionitis [RR=1.11, (95% CI: 1.07-1.15), overall risk=2.8%], and postpartum hemorrhage [RR=1.23 (95% DI: 1.18-1.28), overall risk=2.4%]; however, these relative increases corresponded to low absolute risk increases. Tdap was not associated with increased risk of any adverse newborn outcome. Overall, prenatal Tdap immunization was not associated with newborn adverse events, but potential associations with chorioamnionitis consistent with one previous study and postpartum hemorrhage require further investigation.

Barriers of Influenza Vaccination Intention and Behavior - A Systematic Review of Influenza Vaccine Hesitancy, 2005 - 2016

BACKGROUND

Influenza vaccine hesitancy is a significant threat to global efforts to reduce the burden of seasonal and pandemic influenza. Potential barriers of influenza vaccination need to be identified to inform interventions to raise awareness, influenza vaccine acceptance and uptake.

OBJECTIVE

This review aims to (1) identify relevant studies and extract individual barriers of seasonal and pandemic influenza vaccination for risk groups and the general public; and (2) map knowledge gaps in understanding influenza vaccine hesitancy to derive directions for further research and inform interventions in this area.

METHODS

Thirteen databases covering the areas of Medicine, Bioscience, Psychology, Sociology and Public Health were searched for peer-reviewed articles published between the years 2005 and 2016. Following the PRISMA approach, 470 articles were selected and analyzed for significant barriers to influenza vaccine uptake or intention. The barriers for different risk groups and flu types were clustered according to a conceptual framework based on the Theory of Planned Behavior and discussed using the 4C model of reasons for non-vaccination.

RESULTS

Most studies were conducted in the American and European region. Health care personnel (HCP) and the general public were the most studied populations, while parental decisions for children at high risk were under-represented. This study also identifies understudied concepts. A lack of confidence, inconvenience, calculation and complacency were identified to different extents as barriers to influenza vaccine uptake in risk groups.

CONCLUSION

Many different psychological, contextual, sociodemographic and physical barriers that are specific to certain risk groups were identified. While most sociodemographic and physical variables may be significantly related to influenza vaccine hesitancy, they cannot be used to explain its emergence or intensity. Psychological determinants were meaningfully related to uptake and should therefore be measured in a valid and comparable way. A compendium of measurements for future use is suggested as supporting information.

Text messages for influenza vaccination among pregnant women: A randomized controlled trial

OBJECTIVE

To evaluate if text message reminders increase the likelihood of receiving the influenza vaccine among pregnant women.

METHODS

Pregnant women were randomized to either receive or not receive weekly text messages. Women were told the messages would be about health-related behavior in pregnancy. Those randomized to the intervention group received two messages weekly for four consecutive weeks reinforcing that the influenza vaccine is recommended for all pregnant women and safe during pregnancy and breastfeeding. Women were contacted six weeks postpartum to determine if they had received the vaccine. Sample size calculation determined that 108 women were required in both groups to see a 75% increase in vaccination rates over baseline in the text message group compared to the control group.

RESULTS

Recruitment began November 4, 2013, and 317 women were randomized. The mean gestational age at recruitment was 22weeks. There were 40/129 (31%) women in the text message group and 41/152 (27%) women in the control group who received the vaccine (p=0.51). Significant predictors of vaccine acceptance were being married compared to single (95% vs. 67%, p<0.001), having higher household income (55% vs. 39%, p=0.03) and having received the vaccine before (77% vs. 36%, p<0.001). Among women receiving text messages, the majority were satisfied, with only 15/129 (12%) reporting that they did not like receiving the messages, and 24/129 (19%) stating that the information in the messages was not helpful.

CONCLUSION

Weekly text messages reinforcing the recommendation for and safety of the influenza vaccine in pregnancy did not increase the likelihood of actually receiving the vaccine among pregnant women. Overall vaccination rates were low, highlighting the need for patient education and innovative techniques to improve vaccine acceptance. Registered with ClinicalTrials.gov at http://www.clinicaltrials.gov, registration number NCT 02428738.

Pertussis vaccination coverage among Australian women prior to childbirth in the cocooning era: a two-hospital, cross-sectional survey, 2010 to 2013

BACKGROUND

Recent pertussis epidemics have triggered implementation of cocooning, involving caregiver vaccination to indirectly protecting susceptible infants.

AIM

To determine patient, provider and setting factors associated with maternal pertussis booster vaccination (dTpa) within 5-10 years before childbirth.

MATERIALS AND METHODS

Cross-sectional survey using Health Belief Model constructs among postpartum women in a tertiary referral centre and a private hospital in Sydney, Australia.

RESULTS

Pertussis vaccination was current among 33.7% of the 2483 new mothers (0.5% vaccinated during pregnancy). Women were more likely to be vaccinated if they had heard of 'whooping cough' from a health professional (OR: 2.59, P < 0.001, 95% CI: 1.70-3.95), were recommended the vaccine (OR: 2.48, P < 0.00, 95% CI: 1.55-4.00), perceived pertussis as 'severe' for adults (OR: 1.21, p0.009, 95% CI: 1.05-1.39) and 'common' within their community (OR: 1.38, P < 0.001, 95% CI: 1.18-1.61). They more often agreed that it was their parental responsibility to be vaccinated (OR: 1.61, P = 0.002, 95% CI: 1.19-2.18), and this would help prevent their baby from contracting pertussis (OR: 1.22, P = 0.046, 95% CI: 1.00-1.47). Vaccinated women were less likely to report vaccination barriers: time constraints (OR: 0.75, P < 0.001, 95% CI: 0.66-0.85) and having safety concerns (OR: 0.80, P < 0.001, 95% CI: 0.69-0.92). Additionally, their partners reported three times higher uptake (76% vs 49%; P < 0.001; 95% CI: 2.66-3.85).

CONCLUSIONS

Current pertussis vaccination in only one in every three postpartum participants may indicate insufficient coverage to protect newborns. Practitioners are instrumental in raising awareness and addressing vaccine concerns. Integrating vaccination into routine obstetric care, whether antenatally or postnatally, may minimise barriers.

Promoting Tdap immunization in pregnancy: Associations between maternal perceptions and vaccination rates

OBJECTIVE

Tdap vaccine uptake among US pregnant women is low despite current recommendations. This study evaluated if a Tdap vaccine information statement (VIS) affected overall perception, vaccination intention, and components of a health behavior model associated with Tdap vaccination rates.

METHODS

A randomized, prospective study was conducted among pregnant women receiving care at two women's clinics in May-August 2014. Verbally consented participants were randomized to receive either the standard CDC Tdap VIS (sVIS) or a modified version (mVIS) before completing the first multi-part survey (T1). After T1, participants read their assigned VIS then completed the second part (T2). A 2015 chart review identified vaccinated participants. A health behavior model was hypothesized using the Reasoned Action Approach and Health Belief Model. Logistic regression, path analysis, and chi-square tests were used in the analysis.

RESULTS

279 surveys were analyzed. Average age of the participants was 26.4 years (SD=5.7) with average gestational age of 25.9 weeks (SD=9.2). 13% self-reported receiving Tdap vaccine prior to the survey. Overall perception scores significantly increased (3.1-3.4, p<0.001) after VIS review. A chart review showed that 131 (47%) received the vaccine post study. There was no significant difference in vaccination rates between the sVIS and mVIS groups (45% vs. 49%). Perceived benefits (B=0.315) and self-efficacy (B=0.197) were positively associated with the overall perception (T1), while perceived barriers (B=-0.191) were negatively associated with the overall perception (T1). Social norms (B=0.230), self-efficacy (B=0.213), and perceived benefits (B=0.117) were positively associated with vaccination intention (T1). The vaccination intention (T2) was positively associated with participants' decision to receive Tdap vaccine (B=0.223).

CONCLUSION

A VIS improved overall perception of the Tdap vaccine. Vaccination intention was a predictor of Tdap vaccination. It is crucial to provide information about immunization benefits to promote maternal Tdap vaccination.

2010 A(H1N1) vaccination in pregnant women in Brazil: identifying coverage and associated factors

We studied vaccination coverage and its associated factors in the 2010 pandemic influenza vaccination of Brazilian pregnant women. A cross-sectional study of pregnant women who had given birth was performed in a municipality in southern Brazil, in 2010. Data about vaccination against A(H1N1) and sociodemographic characteristics, morbidities and prenatal care were collected. Statistical analysis was performed using a Poisson regression. Coverage was 77.4%. Most were vaccinated in the public sector (97.6%) and in the second trimester (47%). Associated factors that increased vaccination were marriage, older age, first income quartile, prenatal care and influenza before pregnancy. Education and skin color were not significantly associated with vaccination. The vaccination campaign was extensive and exhibited no inequality. Prenatal care was the factor that most affected vaccination coverage, reflecting its importance for vaccination campaign success.

Pregnant women's attitudes toward influenza vaccination while breastfeeding

OBJECTIVE

The goal of this study was to assess the concerns pregnant women have about influenza vaccination while breastfeeding and to determine if having these concerns represents a barrier to vaccination uptake.

METHODS

The Vaccines and Medications in Pregnancy Surveillance System (VAMPSS) conducted a prospective cohort study in the US and Canada of influenza vaccine safety among pregnant women, oversampling vaccinated women. Data for the present paper are from an additional cross-sectional telephone survey completed during the 2010-2011 and 2012-2013 influenza seasons.

RESULTS

We surveyed 431 pregnant women about their attitudes regarding influenza vaccination while breastfeeding. Almost half of the participants identified one or two concerns and 4% reported three or more concerns. About one quarter reported that they would be unlikely to have an influenza vaccination while breastfeeding. In the multivariate model, those reporting 1-2 concerns (OR = 0.16, 95% CI 0.09-0.28) and those reported 3 or more concerns (OR = 0.07, 95% CI 0.02-0.22) had lower odds of being likely to vaccinate.

CONCLUSIONS

Pregnant women and postpartum women who are breastfeeding could benefit from receiving information and recommendations specific to vaccination from their healthcare providers, with a focus on discussing known risks and benefits to the baby's health.

Factors associated with seasonal influenza vaccination in pregnant women

BACKGROUND

This observational study followed a cohort of pregnant women during the 2010-2011 influenza season to determine factors associated with vaccination.

METHODS

Participants were 1105 pregnant women who completed a survey assessing health beliefs related to vaccination upon enrollment and were then followed to determine vaccination status by the end of the 2010-2011 influenza season. We conducted univariate and multivariate analyses to explore factors associated with vaccination status and a factor analysis of survey items to identify health beliefs associated with vaccination.

RESULTS

Sixty-three percent (n=701) of the participants were vaccinated. In the univariate analyses, multiple factors were associated with vaccination status, including maternal age, race, marital status, educational level, and gravidity. Factor analysis identified two health belief factors associated with vaccination: participant's positive views (factor 1) and negative views (factor 2) of influenza vaccination. In a multivariate logistic regression model, factor 1 was associated with increased likelihood of vaccination (adjusted odds ratio [aOR]=2.18; 95% confidence interval [CI]=1.72-2.78), whereas factor 2 was associated with decreased likelihood of vaccination (aOR=0.36; 95% CI=0.28-0.46). After controlling for the two health belief factors in multivariate analyses, demographic factors significant in univariate analyses were no longer significant. Women who received a provider recommendation were about three times more likely to be vaccinated (aOR=3.14; 95% CI=1.99-4.96).

CONCLUSION

Pregnant women's health beliefs about vaccination appear to be more important than demographic and maternal factors previously associated with vaccination status. Provider recommendation remains one of the most critical factors influencing vaccination during pregnancy.

Understanding pregnant women's attitudes and behavior toward influenza and pertussis vaccination

Internationally, pregnant and postpartum women have been the focus of influenza and pertussis immunization campaigns, with differing levels of vaccine acceptance. We used semistructured interviews to explore pregnant women's perspectives on influenza vaccination during pregnancy and postpartum pertussis vaccination. Many women saw pregnancy as a busy time filled with advice on what they "should" and "should not" do to ensure the health of their fetus, and vaccinating themselves was regarded as just one of these tasks needing consideration. Women were more concerned about potential risks to their infants' health before their own. They saw influenza as a disease affecting the mother, whereas they viewed pertussis as a threat to the baby and therefore comparatively more risky. They were thus more likely to intend to vaccinate against pertussis to protect their infant. Framing of vaccination information toward protection of the baby might help increase vaccine uptake among pregnant women.

Increased awareness and health care provider endorsement is required to encourage pregnant women to be vaccinated

Maternal immunization is an important strategy recommended to protect both mothers and infants from serious infectious diseases; however uptake of maternal immunization is poor in Australia. This study aimed to gain an in-depth understanding of the decision making process and factors influencing a pregnant woman's decisions about recommended immunizations. This qualitative study used semi-structured interviews with open-ended questions to interview pregnant women. Data were analyzed using thematic analysis techniques and drew on the Health Belief Model. Pregnant women (n = 17) were asked about their attitudes toward immunization during pregnancy and their perceptions about risk during pregnancy. Women were also asked to detail their decision making process and factors influencing their decisions about immunizations in relation to pregnancy. Most of the participants were not aware of the immunizations recommended during pregnancy, in pregnancy planning or after delivery. In addition to endorsement by their health care provider (HCP), perception of risk and benefit, including risk of infection, previous vaccination experiences and assessing cost benefit play a vital role in women's decisions whether to be immunized while pregnant. Although the role of the healthcare provider in advising pregnant women about immunizations was identified as vitally important, the majority of women had not been advised of recommended vaccines by their healthcare provider. Healthcare providers are key to ensuring pregnant mothers are informed about recommended vaccines and these need to be more proactively supported and encouraged by healthcare providers. This is likely to have a positive effect on acceptance and uptake of immunization by pregnant women.

A qualitative study of vaccine acceptability and decision making among pregnant women in Morocco during the A (H1N1) pdm09 pandemic

Vaccination uptake of pregnant women in Morocco during the A (H1N1) pdm09 pandemic was lower than expected. A qualitative study using open-ended questions was developed to explore the main determinants of acceptance and non-acceptance of the monovalent A (H1N1) pdm09 vaccine among pregnant women in Morocco and to identify information sources that influenced their decision-making process. The study sample included 123 vaccinated and unvaccinated pregnant women who were in their second or third trimester between December 2009 and March 2010. They took part in 14 focus group discussions and eight in-depth interviews in the districts of Casablanca and Kenitra. Thematic qualitative analysis identified reasons for vaccine non-acceptance: (1) fear of the monovalent A (H1N1) pdm09 vaccine, (2) belief in an A (H1N1) pdm09 pandemic conspiracy, (3) belief in the inapplicability of the monovalent A (H1N1) pdm09 vaccine to Moroccans, (4) lack of knowledge of the monovalent A (H1N1) pdm09 vaccine, and (5) challenges of vaccination services/logistics. Reasons for vaccine acceptance included: (1) perceived benefits and (2) modeling. Decision-making was strongly influenced by family, community, mass media, religious leaders and health providers suggesting that broad communication efforts should also be used to advocate for vaccination. Meaningful communication for future vaccine campaigns must consider these context-specific findings. As cultural and religious values are shared across many Arab countries, these findings may also provide valuable insights for seasonal influenza vaccine planning in the Middle East and North Africa region at large.

A comprehensive review of influenza and influenza vaccination during pregnancy

Influenza is a highly infectious respiratory disease that can impose significant health risks leading to increased morbidity and mortality. Receiving influenza vaccination is the most important and effective means of preventing the infection and its related complications. During pregnancy, physiological changes increase susceptibility to influenza infection, and women contracting infectious diseases during pregnancy are more likely to have adverse pregnancy and neonatal outcomes. Influenza vaccination during pregnancy is safe for both pregnant women and their fetus, and pregnant women are now the highest priority group for vaccination. Despite the accumulated evidence of the benefits and safety of influenza vaccination during pregnancy, uptake among pregnant women remains suboptimal. Concerns about the vaccine's safety persist, and the fear of birth defects remains the predominant barrier to vaccination. Targeted interventions have been shown effective in enhancing influenza vaccination uptake among pregnant women. Reluctance to be vaccinated should be addressed by offering accurate information to counteract the misperceptions about the risk of influenza infection during pregnancy as well as to educate mothers about the safety and benefits of influenza vaccination. High-quality randomized controlled trials are recommended to evaluate the effectiveness of individual or multifaceted approaches to increase vaccine uptake.

Special considerations for prophylaxis for and treatment of anthrax in pregnant and postpartum women

Clinical recommendations for the prevention and treatment of anthrax among pregnant women are updated.

In August 2012, the Centers for Disease Control and Prevention, in partnership with the Association of Maternal and Child Health Programs, convened a meeting of national subject matter experts to review key clinical elements of anthrax prevention and treatment for pregnant, postpartum, and lactating (P/PP/L) women. National experts in infectious disease, obstetrics, maternal fetal medicine, neonatology, pediatrics, and pharmacy attended the meeting, as did representatives from professional organizations and national, federal, state, and local agencies. The meeting addressed general principles of prevention and treatment for P/PP/L women, vaccines, antimicrobial prophylaxis and treatment, clinical considerations and critical care issues, antitoxin, delivery concerns, infection control measures, and communication. The purpose of this meeting summary is to provide updated clinical information to health care providers and public health professionals caring for P/PP/L women in the setting of a bioterrorist event involving anthrax.

Risk management of seasonal influenza during pregnancy: current perspectives

Influenza poses unique risks to pregnant women, who are particularly susceptible to morbidity and mortality. Historically, pregnant women have been overrepresented among patients with severe illness and complications from influenza, and have been more likely to require hospitalization and intensive care unit admission. An increased risk of adverse outcomes is also present for fetuses/neonates born to women affected by influenza during pregnancy. These risks to mothers and babies have been observed during both nonpandemic and pandemic influenza seasons. During the H1N1 influenza pandemic of 2009-2010, pregnant women were more likely to be hospitalized or admitted to intensive care units, and were at higher risk of death compared to nonpregnant adults. Vaccination remains the most effective intervention to prevent severe illness, and antiviral medications are an important adjunct to ameliorate disease when it occurs. Unfortunately, despite national guidelines recommending universal vaccination for women who are pregnant during influenza season, actual vaccination rates do not achieve desired targets among pregnant women. Pregnant women are also sometimes reluctant to use antiviral medications during pregnancy. Some of the barriers to use of vaccines and medications during pregnancy are a lack of knowledge of recommendations and of safety data. By improving knowledge and understanding of influenza and vaccination recommendations, vaccine acceptance rates among pregnant women can be improved. Currently, the appropriate use of vaccination and antiviral medications is the best line of defense against influenza and its sequelae among pregnant women, and strategies to increase acceptance are crucial. This article will review the importance of influenza in pregnancy, and discuss vaccination and antiviral medications for pregnant women.

Determinants of uptake of influenza vaccination among pregnant women - a systematic review

BACKGROUND

Pregnant women have the highest priority for seasonal influenza vaccine. However, suboptimal coverage has been repeatedly noted in this population. To improve vaccine uptake, reviewing the determinants of vaccination is of increasing importance.

METHODS

A detailed literature search was performed up to November 30, 2013 to retrieve articles related to uptake of influenza vaccination during pregnancy.

RESULTS

Forty-five research papers were included in the review. Twenty-one studies assessed the coverage of seasonal influenza vaccination, 13 studies assessed coverage of A/H1N1 pandemic vaccination and 11 studies assessed both. Vaccination uptake ranged from 1.7% to 88.4% for seasonal influenza, and from 6.2% to 85.7% for A/H1N1 pandemic influenza. Many pregnant women were unaware that they were at high risk for influenza and its complications during pregnancy. They were also more likely to underestimate the threat of influenza to themselves and their fetus. Moreover, they had substantial concerns about the safety and efficacy of the influenza vaccine during pregnancy. Negative media reports contributed to the perception that influenza vaccination during pregnancy was risky and could result in adverse pregnancy outcomes. Although health care providers' (HCPs) recommendations were consistently associated with vaccine uptake, most did not recommend the vaccine to their pregnant clients.

CONCLUSIONS

Influenza vaccination uptake among pregnant women is suboptimal and HCPs rarely recommend it. Positive vaccination recommendations from HCPs as well as direct access to the vaccine would likely substantially improve vaccination acceptance.

Knowledge, attitudes, and behaviors of low-income women considered high priority for receiving the novel influenza A (H1N1) vaccine

The primary purpose of this qualitative study was to explore the knowledge, attitudes, and behaviors of low-income women considered high priority for receiving the novel influenza A (H1N1) vaccine to improve communication in emergency preparedness and response. Researchers sought to identify the factors that affect this high priority population's ability to successfully comply with vaccination recommendations. By utilizing an existing communication framework through the special supplemental nutrition program for women, infants, and children (WIC) they were able to document the systems and infrastructure needed to foster constructive responses in a sustainable manner in the future. Six focus group discussions with WIC clients (n = 56) and 10 individual interviews with staff members were conducted at two WIC clinics in Georgia (1 urban and 1 rural). Data were collected after the 2009-2010 influenza season and analyzed using thematic analysis. Knowledge and attitudes regarding H1N1 differed among participants with regard to perceived severity and perceived risk of influenza illness. Participants identified several barriers and motivators to receiving the vaccination, as well as information needs, sources, and information-seeking behaviors. Similarities emerged among both WIC clients and staff members regarding impressions of H1N1 and the vaccine's use, suggesting that while the information may be provided, it is not effectively understood or accepted. Comprehensive education, policy and planning development regarding pandemic influenza and vaccine acceptance among low-income women is necessary, including improvements in risk communication messages and identifying effective methods to disseminate trusted information to these high priority groups.

Predictors of seasonal influenza vaccination during pregnancy

OBJECTIVE

Although pregnant women are a high-priority group for influenza vaccination, vaccination rates in this population remain below recommended levels. This prospective cohort study followed a group of pregnant women during the 2010-2011 influenza season to determine possible predictors of vaccination.

METHODS

Participants were 552 pregnant women who had not already received the influenza vaccine at the time of enrollment. Women completed a survey assessing knowledge, attitudes, and beliefs about vaccination (based on the Health Belief Model) by telephone and were then followed to determine vaccination status by the end of the 2010-2011 influenza season.

RESULTS

Forty-six percent (n=252) of the women were vaccinated, and 54% (n=300) remained unvaccinated after enrollment in the study. Few baseline characteristics, with the exception of study site, month of enrollment, and maternal ethnicity, were predictive of vaccination status. Even after adjusting for significant baseline characteristics, we found that at least one item from each domain of the Health Beliefs Model was predictive of subsequent vaccination. Specifically, women who perceived they were susceptible to influenza, that they were at risk of getting seriously ill from influenza, that they would regret not getting vaccinated, and who trusted recommended guidelines about influenza vaccination during pregnancy were more likely to get vaccinated. Women who were concerned about vaccine side effects were less likely to get vaccinated.

CONCLUSION

Trust in recommendations, perceived susceptibility to and seriousness of influenza, perceived regret about not getting vaccinated, and vaccine safety concerns predict vaccination in pregnant women.

LEVEL OF EVIDENCE

II.

Selective uptake of influenza vaccine and pregnancy outcomes

OBJECTIVE

To describe the characteristics of pregnant women who accept the influenza vaccine and evaluate the relationship between vaccination and adverse pregnancy outcomes.

METHODS

Retrospective cohort study of women receiving prenatal care during the 2009-2011 influenza seasons. Vaccination status was ascertained through our perinatal record system and clinic vaccination logs. Pregnancy outcomes included a primary composite of miscarriage, fetal demise, preterm birth (PTB) <37 weeks and neonatal demise. Stratification and logistic regression were used to adjust for potential confounders.

RESULTS

Of 3104 eligible pregnant women, 1094 (35%) received the influenza vaccine. Women vaccinated were more likely to be older, obese, primiparae, and have medical complications or a prior PTB. In univariable analyses, flu vaccination was associated with increased adverse composite outcome and PTB. After multivariable adjustments, vaccination was no longer associated with adverse outcomes in women with medical complications but remained associated with adverse outcomes among those without known co-morbidity.

CONCLUSIONS

Vaccination was associated with an increased adverse composite outcome in pregnant women without identified co-morbidity but not those with co-morbidities. This association is likely due to selection bias, which should be considered in planning of observational studies of the impact of vaccination on pregnancy outcomes.

Theory-based predictors of influenza vaccination among pregnant women

BACKGROUND

Guidelines recommend influenza vaccination for pregnant women, but vaccine uptake in this population is far below the goal set by Healthy People 2020. The purpose of this study was to examine predictors of seasonal influenza vaccination among pregnant women.

METHODS

Between 2009 and 2012, the Vaccines and Medications in Pregnancy Surveillance System (VAMPSS) conducted a prospective cohort study of influenza vaccine safety among pregnant women in the US and Canada that oversampled vaccinated women. Data for the present paper are from an additional cross-sectional telephone survey completed during the 2010-2011 influenza season. We examined predictors of influenza vaccination, focusing on Health Belief Model (HBM) constructs.

RESULTS

We surveyed 199 pregnant women, 81% of whom had received a seasonal influenza vaccine. Vaccination was more common among women who felt more susceptible to influenza (OR=1.82, 95% CI 1.10-3.01), who perceived greater vaccine effectiveness (OR=3.92, 95% CI 1.48-10.43), and whose doctors recommended they have flu shots (OR=3.06, 95% CI 1.27-7.38). Those who perceived greater barriers of influenza vaccination had lower odds of vaccination (OR=0.19, 95% CI 0.05-0.75). Perceived social norms, anticipated inaction regret, and worry also predicted uptake, though demographic characteristics of respondents did not.

CONCLUSION

The HBM provides a valuable framework for exploring influenza vaccination among pregnant women. Our results suggest several potential areas of intervention to improve vaccination rates.

Effect of influenza vaccination in the first trimester of pregnancy

OBJECTIVE

To estimate the effect of first-trimester influenza vaccination on fetal and neonatal outcomes.

METHODS

This was a retrospective cohort study examining delivery and neonatal outcomes after antepartum exposure to the seasonal trivalent inactive influenza vaccine. Data were collected and entered into an established computerized database. Outcomes by trimester of vaccination were then compared with women who did not receive the vaccine.

RESULTS

During the 5-year study period, 10,225 women received the seasonal influenza vaccine antepartum; 8,690 of these delivered at our institution, 439 in the first trimester and 8,251 in the second and third trimesters. Women vaccinated antepartum were significantly older with higher parity than women who declined vaccination. Neonates born to mothers receiving the vaccine in any trimester did not have an increase in major malformations regardless of trimester of vaccination (2% regardless of vaccination group, P=.9). Stillbirth (0.3% compared with 0.6%, P=.006), neonatal death (0.2% compared with 0.4%, P=.01), and premature delivery (5% compared with 6%, P=.004) were significantly decreased in the vaccinated group.

CONCLUSION

Influenza vaccination in the first trimester was not associated with an increase in major malformation rates and was associated with a decrease in the overall stillbirth rate. This information will aid in counseling women regarding the safety of influenza vaccination in the first trimester.

Correcting for exposure misclassification using survival analysis with a time-varying exposure

PURPOSE

Survival analysis is increasingly being used in perinatal epidemiology to assess time-varying risk factors for various pregnancy outcomes. Here we show how quantitative correction for exposure misclassification can be applied to a Cox regression model with a time-varying dichotomous exposure.

METHODS

We evaluated influenza vaccination during pregnancy in relation to preterm birth among 2267 non-malformed infants whose mothers were interviewed as part of the Slone Birth Defects Study during 2006 through 2011. The hazard of preterm birth was modeled using a time-varying exposure Cox regression model with gestational age as the time-scale. The effect of exposure misclassification was then modeled using a probabilistic bias analysis that incorporated vaccination date assignment. The parameters for the bias analysis were derived from both internal and external validation data.

RESULTS

Correction for misclassification of prenatal influenza vaccination resulted in an adjusted hazard ratio (AHR) slightly higher and less precise than the conventional analysis: Bias-corrected AHR 1.04 (95% simulation interval, 0.70-1.52); conventional AHR, 1.00 (95% confidence interval, 0.71-1.41).

CONCLUSIONS

Probabilistic bias analysis allows epidemiologists to assess quantitatively the possible confounder-adjusted effect of misclassification of a time-varying exposure, in contrast with a speculative approach to understanding information bias.

Acceptance and rejection of influenza vaccination by pregnant women in southern Iran: physicians' role and barriers

OBJECTIVE

Vaccination provides the most effective protection against maternal, fetal and neonatal complications of influenza infection. This study aimed to determine the uptake rate of influenza vaccination including 2009 pandemic H1N1 influenza and seasonal influenza vaccination and the reasons for acceptance or rejection among pregnant women.

RESULT

Mean age of the 416 pregnant women enrolled in this study was 27.06 ± 5.27 y. Only 25 (6%) of 397 women had history of vaccination. Of 383 (92.06%) pregnant women who had rejected vaccination, 116 (30.28%) declared that they lacked information about influenza vaccination and 44 (11.48%) felt that they did not need vaccination. Concerns about the safety of influenza vaccination were reported by only 2 women (0.52%). Of the 25 (6%) pregnant women who were vaccinated against influenza, 15 (60%) accepted because of advice they received from persons other than physicians, 5 (20%) believed that influenza vaccination is necessary for everyone, and 3 (12%) accepted because of a history of frequent influenza virus infections in previous years.

METHOD

This questionnaire based study was conducted at obstetrics and maternity hospitals affiliated with Shiraz University of Medical Sciences, Shiraz, Iran. Pregnant women were interviewed individually and privately. SPSS was used for data analysis.

CONCLUSION

Most of the unvaccinated and vaccinated pregnant women lacked sufficient knowledge about influenza. Education of pregnant women about influenza vaccination and encouragement from physicians may have a remarkable effect on turning poor compliance into high flu vaccination uptake among pregnant women.

Viral invasion of the amniotic cavity (VIAC) in the midtrimester of pregnancy

INTRODUCTION

The prevalence of viral infections in the amniotic fluid (AF) has not yet been ascertained. The aim of this study was to determine the prevalence of specific viral nucleic acids in the AF and its relationship to pregnancy outcome.

STUDY DESIGN

From a cohort of 847 consecutive women undergoing midtrimester amniocentesis, 729 cases were included in this study after exclusion of documented fetal anomalies, chromosomal abnormalities, unavailability of AF specimens and clinical outcomes. AF specimens were tested by quantitative real-time PCR for the presence of genome sequences of the following viruses: adenoviruses, herpes simplex virus (HSV), varicella zoster virus (VZV), human herpesvirus 6 (HHV6), human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), parvovirus B19 and enteroviruses. Viral nucleic acid testing was also performed in maternal blood and cord blood in the population of women in whom AF was positive for viruses and in a control group of 29 women with AF negative for viral nucleic acids. The relationship between the presence of viruses and pregnancy and neonatal outcome was examined. The correlation between the presence of nucleic acids of viruses in the AF and the concentration of the cytokine interleukin-6 (IL-6) and the T cell chemokine CXCL-10 (or IP-10) in AF and maternal blood were analyzed.

RESULTS

Viral genome sequences were found in 16 of 729 (2.2%) AF samples. HHV6 was the most commonly detected virus (7 cases, 1.0%), followed by HCMV (6 cases, 0.8%), parvovirus B19 (2 cases, 0.3%) and EBV (1 case, 0.1%), while HSV, VZV, enteroviruses and adenoviruses were not found in this cohort. Corresponding viral DNA was also detected in maternal blood of six out of seven women with HHV6-positive AF and in the umbilical cord plasma, which was available in one case. In contrast, viral DNA was not detected in maternal blood of women with AF positive for parvovirus B19, HCMV, EBV or of women with AF negative for viruses. HHV6 genome copy number in AF and maternal blood was consistent with genomic integration of viral DNA and genetic infection in all women. There was no significant difference in the AF concentration of IL-6 and IP-10 between patients with and without VIAC. However, for HCMV, there was a significant relationship between viral copy number and IP-10 concentration in maternal blood and AF. The group of women with AF positive for viral DNA delivered at term healthy neonates without complications in 14 out of 16 cases. In one case of HHV6 infection in the AF, the patient developed gestational hypertension at term, and in another case of HHV6 infection in the AF, the patient delivered at 33 weeks after preterm premature rupture of membranes (PPROM).

CONCLUSION

Viral nucleic acids are detectable in 2.2% of AF samples obtained from asymptomatic women in the midtrimester. HHV6 was the most frequently detected virus in AF. Adenoviruses were not detected. Vertical transmission of HHV6 was demonstrated in one case.

Fear of litigation and cesarean section rates

Both the rates of cesarean section and the rates and payouts from obstetrical malpractice suits have risen in past decades, albeit not always in tandem. A great deal of evidence suggests that physicians practice defensive medicine, and many obstetricians acknowledge that a more liberal recourse to cesarean section is one such behavior in which they sometimes engage. However the degree to which fear of litigation actually is a contributor to, or perhaps even a driver of, the rising cesarean section rate is not as clearly known. In this article I will discuss the research that has been performed that attempts to epidemiologically assess the link between lawsuits, malpractice premiums and cesarean section rates. I will also consider factors beyond dollars and cents (e.g., cognitive biases, changing risk tolerance of doctors and patients) that may lie at the base of the relationship. Finally I will offer a brief discussion of how professional ethics should inform the actions that physicians take in these difficult circumstances.

Vaccination patterns in pregnant women during the 2009 H1N1 influenza pandemic: a population-based study in Ontario, Canada

OBJECTIVES

Influenza vaccination rate among pregnant women has typically been low, and there is little population-based information on predictors of vaccination uptake within this group. This study aimed to evaluate the rate of influenza vaccination in pregnant women during the 2009 H1N1 influenza pandemic and explore predictors associated with receiving vaccination during pregnancy.

METHODS

We conducted a retrospective population-based cohort analysis involving women who gave birth in an Ontario hospital between November 2, 2009 and April 30, 2010. Rates of influenza vaccination were calculated according to maternal, obstetrical, behavioural and neighbourhood characteristics. Women who received influenza vaccination during pregnancy were compared with women who were not vaccinated using log-binomial regression to calculate adjusted relative risks (aRR) and 95% confidence intervals (CI).

RESULTS

Among 56,654 women who gave birth in the study period, 42.6% had received influenza vaccination during pregnancy. Vaccine uptake was lower among women: of age <20 (aRR=0.80, 95% CI: 0.76-0.84), in lower socio-economic status (aRR=0.93, 95% CI: 0.90-0.96), without an antenatal care provider (aRR=0.72, 95% CI: 0.59-0.88), who did not initiate antenatal care in a timely manner (aRR=0.93, 95% CI: 0.91-0.96), who smoked during pregnancy (aRR=0.92, 95% CI: 0.89-0.95), and with a history of preterm birth (aRR=0.97, 95% CI :0.94-1.00). An increased vaccination rate was observed among women with medical co-morbidities (aRR=1.10, 95% CI: 1.07-1.13) and with family physicians (vs. obstetricians) as antenatal care providers (aRR=1.08, 95% CI: 1.06-1.10).

CONCLUSION

We identified the prenatal population that may benefit from targeted public health intervention strategies to improve future vaccination rates for this priority vaccination group.

Influenza Vaccine Coverage among Pregnant Women in a Public Hospital System during the 2009-2010 Pandemic Influenza Season

The purpose of this study was to compare influenza vaccination rates of pregnant women in a public safety-net health system to national coverage rates during the 2009-2010 pandemic influenza season. A chart review of a random sample of deliveries was undertaken to determine rates of coverage and predictors of vaccine coverage of women who obtained prenatal care and delivered in our health system. Rates were calculated from deliveries from when the vaccine was first available through April 30, 2010. Coverage rates were 54% for the seasonal influenza vaccine and 51% for the H1N1 vaccine. Race/ethnicity, insurance status and language spoken did not predict the receipt of either vaccine. When we included only births which occurred through March 12, 2010, as was done in a large population-based study, the rates were 61% and 59%, respectively. Our rates are about 10% higher than the rates reported in that study. Our comprehensive strategy for promoting vaccine coverage achieved higher vaccination rates in a safety-net health system, which serves groups historically less likely to be vaccinated, than those reported for the pregnant population at large.

Acceptability of maternal immunization against influenza: the critical role of obstetricians

INTRODUCTION

Pregnant women and infants are at increased risk of vaccine-preventable complications due to influenza. In Switzerland, immunization was first recommended to all pregnant women in 2009. We assessed the acceptability of this recommendation and its determinants two seasons later.

METHODS

Women having delivered in the University Hospitals of Geneva during March 2011 were asked to fill in a questionnaire assessing their knowledge, beliefs and acceptability of influenza vaccination during pregnancy.

RESULTS

The questionnaire was completed by 261/323 (80%) women. Out of 261, 213 (82%) were aware of increased risks of influenza during pregnancy, and 119/261 (46%) knew that immunization was recommended during pregnancy. Only 110/261 (42%) recalled an immunization advise during their pregnancy and only 47/261 (18%) had been immunized. A direct recommendation was the main predictor of immunization, associated with a 107-fold increased likelihood of vaccination. Factors identified by multivariate analyses as independently associated with the likelihood of immunization were to have been recommended immunization by a private (OR 9.1) or hospital (OR 4.7) obstetrician rather than a midwife, to have no fear that immunization could cause preterm delivery (OR 0.3) and to have been immunized in previous years (OR 10.7).

CONCLUSION

Two years after the recommendation of influenza immunization during pregnancy, most post-partum women recalled being neither recommended nor adequately informed about influenza vaccine and its safety. This identifies major gaps in awareness and/or communication in healthcare workers and suggests that improving immunization safety/efficacy awareness among obstetricians as the most likely method to improve flu immunization during pregnancy.

Perceptions of pandemic influenza vaccines

Pandemic influenza A (H1N1) (pH1N1) was first identified in North America in early 2009. The pandemic flu outbreak during the 2009–2010 influenza season demonstrated how rapidly a new strain of flu can emerge and spread. Vaccination is the most effective method to prevent influenza, and vaccination during a pandemic is critical in limiting morbidity and mortality. Unfortunately, reports of vaccination rates for pH1N1 vaccines during the 2009–2010 influenza season indicated low rates for various demographic groups, including pregnant women, health care workers, child care workers, college students, and the general public. Furthermore, when asked about perceptions of pH1N1 vaccines, respondents in a variety of studies from the pH1N1 pandemic indicated common and universal misconceptions about influenza vaccines, especially in regard to perceptions of need, efficacy and safety. Therefore, if vaccination rates are to increase, an important outcome especially during pandemics, the psychological characteristics underpinning perceptions of influenza vaccines need to be understood better.

Influenza vaccination coverage rate in children: reasons for a failure and how to go forward

Based on an increasingly extensive literature expressing the large interest in the field, this paper gives an overview of different aspects of influenza prevention in children. It relies on paradoxes. First, the heaviest part of the burden is well demonstrated in the youngest infants by numerous epidemiological data elsewhere. On the contrary, with older children, the prevention by influenza vaccines is more efficacious-without notable side effects. Second, the available TIV vaccines are 60 years old and the requests of registration and regulation of vaccines have evolved. There is a specific need in children: it is time to re-discuss the pragmatic utilization of influenza vaccines (full dose in the youngest patient? More flexibility regarding the interval between the two required doses in vaccine-naïve children), and to change from a compassionate use to a targeted research and adapted vaccines considering the limits of TIV in the youngest children. Third, influenza virus transmission is the highest in children in semi-close communities (day-care centers, schools), diffusing to households and more largely to the population. A restricted policy on high risk groups (roughly 10% in a pediatric population, all medical conditions including asthma, for whom influenza vaccine coverage is a 15-75% range) is far below the estimated threshold of 45% coverage rate to limit the virus circulation by an indirect impact during seasonal epidemics. Fourth, public health decisions in the vaccination field are usually taken from top to bottom. The pandemic A/H1N1 has toughly demonstrated that "forgetting" about the perception and expectations of the public and the parents nearly created conflicts and at least a strong resistance impeding the quality of a program worked on for a long time ahead. Fifth, and not the least, HCPs are pivotal in influenza vaccination mostly trusted by the parents. Too often, they are not backed by a national and clear support and they need to reinforce their knowledge on the disease and the vaccines.

Vaccination during pregnancy to protect infants against influenza: why and why not?

Influenza is a significant cause of morbidity and mortality for pregnant women and infants worldwide. Influenza vaccination during pregnancy has been shown to be safe and highly effective and should be recommended for all pregnant women before the influenza season. Despite existing recommendations, the vaccine is underused in most countries. Obstacles to immunization include insufficient awareness of the disease burden and of the importance and safety of immunization, fear of liability and the wish to minimize interventions during pregnancy. Therefore, educational interventions for the public and health care workers are necessary to increase protection of pregnant women and young infants from influenza related complications.