Influenza vaccination coverage among pregnant women--National 2009 H1N1 Flu Survey (NHFS)

Influenza vaccination during pregnancy and risk of selected major structural noncardiac birth defects, National Birth Defects Prevention Study 2006-2011

PURPOSE

To assess associations between influenza vaccination during etiologically-relevant windows and selected major structural non-cardiac birth defects.

STUDY DESIGN

We analyzed data from the National Birth Defects Prevention Study, a multisite, population-based case-control study, for 8233 case children diagnosed with a birth defect and 4937 control children without a birth defect with delivery dates during 2006-2011. For all analyses except for neural tube defects (NTDs), we classified mothers who reported influenza vaccination 1 month before through the third pregnancy month as exposed; the exposure window for NTDs was 1 month before through the first pregnancy month. For defects with five or more exposed case children, we used logistic regression to estimate propensity score-adjusted odds ratios (aORs) and 95% confidence intervals (CIs), adjusting for estimated delivery year and season; plurality; maternal age, race/ethnicity, smoking and alcohol use, low folate intake; and, for NTDs, folate antagonist medications.

RESULTS

There were 334 (4.1%) case and 197 (4.0%) control mothers who reported influenza vaccination from 1 month before through the third pregnancy month. Adjusted ORs ranged from 0.53 for omphalocele to 1.74 for duodenal atresia/stenosis. Most aORs (11 of 19) were ≤1 and all adjusted CIs included the null. The unadjusted CIs for two defects, hypospadias and craniosynostosis, excluded the null. These estimates were attenuated upon covariate adjustment (hypospadias aOR: 1.25 (95% CI 0.89, 1.76); craniosynostosis aOR: 1.23 (95% CI: 0.88, 1.74)).

CONCLUSIONS

Results for several non-cardiac major birth defects add to the existing evidence supporting the safety of inactivated influenza vaccination during pregnancy. Under-reporting of vaccination may have biased estimates downward.

Public health spending, primary care, and perceived risk promoted vaccination against H1N1

The purpose of this study is to examine factors affecting the intent to vaccinate during the 2009 H1N1 pandemic and to leverage the results to inform public health policy decisions aimed at increasing vaccine uptake during the COVID-19 pandemic. Using the National 2009 H1N1 Flu Survey data and state-level administrative data, we employ logistic regression and mediation models to estimate the association between vaccine uptake and state level public health spending, political ideology, and H1N1 case and death rates as well as a set of individual and household characteristics. We find that higher public health spending can significantly increase the intent to vaccinate, mainly through raising concerns about the pandemic and promoting vaccine relevant doctor patient interactions. We conclude that physicians, especially primary care physicians, should play more important roles in the ongoing vaccination efforts against the COVID-19 virus.

Seasonal Influenza Vaccine in Pregnant Women: Views and Experiences of Obstetrician-Gynecologists

Background: Seasonal influenza vaccination rates among pregnant women remain well below the Healthy People 2020 target of 80%. Obstetrician-gynecologist (OB/GYN) recommendations are a critical means of encouraging pregnant women to get vaccinated, but there are limited data about their views. Materials and Methods: A nationally representative survey of 506 practicing OB/GYNs was completed between October 26, 2015, and May 8, 2016. Analyses included univariate distributions and comparisons based on age, size of practice, and academic affiliation using all-pairs, dependent t-tests. Results: A majority of OB/GYNs report they "strongly recommend" seasonal influenza vaccination for their pregnant patients in the first (79%) or second and third trimesters (81%). Among those who do not strongly recommend the flu vaccine in the first trimester, many say this is because of their own concerns (28%) or their patients' concerns (44%) about safety. Older OB/GYNs, those in smaller practices, and those without academic affiliation were less likely to recommend the vaccine and more likely to have safety concerns. For example, 72% of those age 60+ strongly recommended the vaccine in the second and third trimester, compared with 86% of those ages 30-44 and 83% of those ages 45-59 (p < 0.05 for all comparisons). Conclusions: OB/GYNs across the country largely support seasonal flu vaccination among pregnant women. Nonetheless, safety is a concern for them and their patients. Outreach to support clinician decisions and conversations with pregnant patients may be most needed among older physicians, those in smaller practices, and those without academic affiliation.

Identifying epidemic spreading dynamics of COVID-19 by pseudocoevolutionary simulated annealing optimizers

At the end of 2019, a new coronavirus (COVID-19) epidemic has triggered global public health concern. Here, a model integrating the daily intercity migration network, which constructed from real-world migration records and the Susceptible–Exposed–Infected–Removed model, is utilized to predict the epidemic spreading of the COVID-19 in more than 300 cities in China. However, the model has more than 1800 unknown parameters, which is a challenging task to estimate all unknown parameters from historical data within a reasonable computation time. In this article, we proposed a pseudocoevolutionary simulated annealing (SA) algorithm for identifying these unknown parameters. The large volume of unknown parameters of this model is optimized through three procedures co-adapted SA-based optimization processes, respectively. Our results confirm that the proposed method is both efficient and robust. Then, we use the identified model to predict the trends of the epidemic spreading of the COVID-19 in these cities. We find that the number of infections in most cities in China has reached their peak from February 29, 2020, to March 15, 2020. For most cities outside Hubei province, the total number of infected individuals would be less than 100, while for most cities in Hubei province (exclude Wuhan), the total number of infected individuals would be less than 3000.

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.

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.

Social Networks and the Emergence of Health Inequalities Following a Medical Advance: Examining Prenatal H1N1 Vaccination Decisions

Health inequalities persist, in part, because people in socioeconomically advantageous positions possess resources to avoid new health risks when medicine advances. Although these health decisions rarely occur in isolation, we know less about the specific role of networks. We examine whether social capital mediates the relationship between individual educational attainment and decisions about a medical advance: H1N1 vaccination during pregnancy. Building on prior work that defines social capital as the resources of network members, we examine two mechanisms through which social capital may affect health decisions, facilitating information flow and exerting influence. Using egocentric network data collected from 225 pregnant women during the 2009-10 H1N1 pandemic, we measure social capital as the proportion of networks that are college-educated H1N1 discussants (information flow) and the proportion of college-educated H1N1 supporters (influence). Findings reveal that college-educated women knew more college-educated H1N1 discussants and supporters. Further, both measures of social capital predicted higher probabilities of vaccination, with the latter mechanism emerging as a particularly strong predictor. Our findings provide evidence that health decisions are shaped by individual resources as well as social capital available through network ties, offering a unique perspective of the ways that social networks contribute to producing, and potentially reproducing, unequal health.

Influenza Vaccination Coverage Among Pregnant Women in the U.S., 2012-2015

INTRODUCTION

Pregnant women are at increased risk for severe illness from influenza and influenza-related complications. Vaccinating pregnant women is the primary strategy to protect them and their infants from influenza. This study aims to assess influenza vaccination coverage during three influenza seasons (2012-2015) from a national probability-based sampling survey and evaluate potential factors that influence vaccination uptake among pregnant women.

METHODS

Data from the 2012 through 2015 National Health Interview Surveys were analyzed in 2017. Pregnant women aged 18-49 years were included in the analysis. The Kaplan-Meier survival analysis procedure was used for vaccination coverage in each season. Bivariate and multivariable logistic regression analyses were performed to examine factors associated with vaccination. Adjusted vaccination coverage and adjusted prevalence ratios are reported with corresponding 95% CIs.

RESULTS

In the 2012-2013, 2013-2014, and 2014-2015 influenza seasons, 40.4%, 45.4%, and 43.1% of pregnant women were vaccinated, respectively. Multivariable analysis indicated that factors independently associated with a lower likelihood of vaccination included having only a high school education, having three or less provider visits, and having no usual place of care (p<0.05). Less than half of women with ten or more visits were vaccinated (48.6%).

CONCLUSIONS

Vaccination coverage among pregnant women from this nationally representative sample was suboptimal during recent influenza seasons. Vaccination coverage was lower among certain sociodemographic, access-to-care subgroups. Multifactorial vaccination barriers may exist. Interventions, such as assessing vaccination history at every visit and implementing reminder-recall systems, standing orders, and addressing vaccination hesitancy, are needed to increase vaccination uptake among pregnant women.

A systematic review of interventions to improve uptake of pertussis vaccination in pregnancy

BACKGROUND

Maternal pertussis vaccination has been introduced in several countries to prevent pertussis morbidity and mortality in infants too young to be vaccinated. Our review aimed to systematically collect and summarize the available evidence on the effectiveness of interventions used to improve pertussis vaccination uptake in pregnant women.

METHODS

We conducted a systematic search of MEDLINE/PubMed, PMC and CINAHL. Before and after studies and those with a concurrent control group were considered for inclusion. Standardized effect sizes were described as the ratio of the odds to be vaccinated in the intervention group compared with the standard care group and absolute benefit increase (ABI) were calculated.

RESULTS

Six studies were included in the review, of which three were randomized controlled trials (RCTs). Strategies to improve uptake were focused on healthcare providers, pregnant women, or enhancing vaccine access. Healthcare provider interventions included provider reminder, education, feedback and standing orders. Interventions directed at pregnant women focused solely on education. Observational studies showed: (1) the provision of maternal pertussis vaccination by midwives at the place of antenatal care has improved uptake of pertussis vaccine during pregnancy from 20% to 90%; (2) introduction of an automated reminder within the electronic medical record was associated with an improvement in the pertussis immunization rate from 48% to 97%; (3) an increase in prenatal pertussis vaccine uptake from 36% to 61% after strategies to increase provider awareness of recommendations were introduced. In contrast to these findings, interventions in all three RCTs (2 involved education of pregnant women, 1 had multi-component interventions) did not demonstrate improved vaccination uptake.

CONCLUSIONS

Based on the existing research, we recommend incorporating midwife delivered maternal immunization programs at antenatal clinics, use of a provider reminder system to target unvaccinated pregnant women and include maternal pertussis immunization as part of standard antenatal care.

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.

Clinicians' and Pharmacists' Reported Implementation of Vaccination Practices for Adults

INTRODUCTION

Despite the proven effectiveness of immunization in preventing morbidity and mortality, adult vaccines remain underutilized. The objective of this study was to describe clinicians' and pharmacists' self-reported implementation of the Standards for Adult Immunization Practice ("the Standards"; i.e., routine assessment, recommendation, and administration/referral for needed vaccines, and documentation of administered vaccines, including in immunization information systems).

METHODS

Two Internet panel surveys (one among clinicians and one among pharmacists) were conducted during February-March 2017 and asked respondents about their practice's implementation of the Standards. T-tests assessed associations between clinician medical specialty, vaccine type, and each component of the Standards (March-August 2017).

RESULTS

Implementation of the Standards varied substantially by vaccine and provider type. For example, >80.0% of providers, including obstetrician/gynecologists and subspecialists, assessed for and recommended influenza vaccine. However, 24.3% of obstetrician/gynecologists and 48.9% of subspecialists did not stock influenza vaccine for administration. Although zoster vaccine was recommended by >89.0% of primary care providers, <58.0% stocked the vaccine; by contrast, 91.6% of pharmacists stocked zoster vaccine. Vaccine needs assessments, recommendations, and stocking/referrals also varied by provider type for pneumococcal; tetanus, diphtheria, acellular pertussis; tetanus diphtheria; human papillomavirus; and hepatitis B vaccines.

CONCLUSIONS

This report highlights gaps in access to vaccines recommended for adults across the spectrum of provider specialties. Greater implementation of the Standards by all providers could improve adult vaccination rates in the U.S. by reducing missed opportunities to recommend vaccinations and either vaccinate or refer patients to vaccine providers.

Enhanced Immune Responses Conferring Cross-Protection by Skin Vaccination With a Tri-Component Influenza Vaccine Using a Microneedle Patch

Skin vaccination using biodegradable microneedle patch (MNP) technology in vaccine delivery is a promising strategy showing significant advantages over conventional flu shots. In this study, we developed an MNP encapsulating a 4M2e-tFliC fusion protein and two types of whole inactivated influenza virus vaccines (H1N1 and H3N2) as a universal vaccine candidate. We demonstrated that mice receiving this tri-component influenza vaccine via MNP acquired improved IgG1 antibody responses with more balanced IgG1/IgG2a antibody responses and enhanced cellular immune responses, including increased populations of IL-4 and IFN-γ producing cells and higher frequencies of antigen-specific plasma cells compared with intramuscular injection. In addition, stronger germinal center reactions, increased numbers of Langerin-positive migratory dendritic cells, and increased cytokine secretion were observed in the skin-draining lymph nodes after immunization with the tri-component influenza MNP vaccine. The MNP-immunized group also possessed enhanced protection against a heterologous reassortant A/Shanghai/2013 H7N9 (rSH) influenza virus infection. Furthermore, the sera collected from 4M2e-tFliC MNP-immunized mice were demonstrated to have antiviral efficacy against reassortant A/Vietnam/1203/2004 H5N1 (rVet) and A/Shanghai/2013 H7N9 (rSH) virus challenges. The immunological advantages of skin vaccination with this tri-component MNP vaccine could offer a promising approach to develop an easily applicable and broadly protective universal influenza vaccine.

Implementation of maternal influenza immunization in El Salvador: Experiences and lessons learned from a mixed-methods study

INTRODUCTION

The World Health Organization (WHO) recommends that countries prioritize pregnant women for influenza vaccination, yet few low- or middle-income countries (LMICs) have implemented maternal influenza immunization programs. To inform vaccine decision-making and operational planning in LMICs, there is a need to document and share experiences from countries that provide seasonal influenza vaccine to pregnant women, particularly those with high coverage, like El Salvador.

METHODS

In 2015 and 2016, PATH and country researchers conducted a mixed-methods study to document the experience and lessons learned from maternal influenza immunization delivery and acceptance in El Salvador as part of a collaborative effort between WHO and PATH. Researchers conducted focus group discussions, semi-structured interviews, antenatal clinic exit interviews, and key informant interviews with 326 participants from two municipalities in each of the country's three regions. Respondents included pregnant and recently pregnant women, family members, community leaders, health personnel, public health managers and partners, and policymakers.

RESULTS

Factors perceived as positively influencing maternal influenza immunization delivery and acceptance in El Salvador include the use of multiple vaccine delivery strategies, targeted education and community engagement efforts, and a high degree of trust between the community and health care providers. Influenza vaccine acceptance by pregnant women is high and has improved over time, largely attributed to education targeting health care advisors. Perceived challenges to pregnant women receiving health care and vaccination include the need for permission to attend services and limited access to health services in insecure areas related to the presence of criminal gang activity.

CONCLUSIONS

We identified approaches and barriers perceived to affect maternal influenza vaccine delivery in El Salvador. This information will be useful to public health decision-makers and implementers in El Salvador and other countries considering introduction of new maternal vaccines or striving to increase coverage of vaccines currently provided.

Impact of pregnancy on observed sex disparities among adults hospitalized with laboratory-confirmed influenza, FluSurv-NET, 2010-2012

INTRODUCTION

Previous FluSurv-NET studies found that adult females had a higher incidence of influenza-associated hospitalizations than males. To identify groups of women at higher risk than men, we analyzed data from 14 FluSurv-NET sites that conducted population-based surveillance for laboratory-confirmed influenza-associated hospitalizations among residents of 78 US counties.

METHODS

We analyzed 6292 laboratory-confirmed, geocodable (96%) adult cases collected by FluSurv-NET during the 2010-12 influenza seasons. We used 2010 US Census and 2008-2012 American Community Survey data to calculate overall age-adjusted and age group-specific female:male incidence rate ratios (IRR) by race/ethnicity and census tract-level poverty. We used national 2010 pregnancy rates to estimate denominators for pregnant women aged 18-49. We calculated male:female IRRs excluding them and IRRs for pregnant:non-pregnant women.

RESULTS

Overall, 55% of laboratory-confirmed influenza cases were female. Female:male IRRs were highest for females aged 18-49 of high neighborhood poverty (IRR 1.50, 95% CI 1.30-1.74) and of Hispanic ethnicity (IRR 1.70, 95% CI 1.34-2.17). These differences disappeared after excluding pregnant women. Overall, 26% of 1083 hospitalized females aged 18-49 were pregnant. Pregnant adult females were more likely to have influenza-associated hospitalizations than their non-pregnant counterparts (relative risk [RR] 5.86, 95% CI 5.12-6.71), but vaccination levels were similar (25.5% vs 27.8%).

CONCLUSIONS

Overall rates of influenza-associated hospitalization were not significantly different for men and women after excluding pregnant women. Among women aged 18-49, pregnancy increased the risk of influenza-associated hospitalization sixfold but did not increase the likelihood of vaccination. Improving vaccination rates in pregnant women should be an influenza vaccination priority.

Intention to accept pertussis vaccine among pregnant women in Karachi, Pakistan

BACKGROUND

Maternal immunization against pertussis is a potential strategy to protect young infants from severe disease. We assessed factors associated with intention to accept pertussis vaccination among pregnant women in Karachi, Pakistan.

METHODS

We conducted a cross-sectional survey between May and August 2013 in pregnant women who visited healthcare centers in urban slums of Karachi city. Women completed a survey examining socio-demographic factors, vaccination history, knowledge on pertussis disease, perception of vaccine recommendation sources, and potential influences on vaccine decision-making.

RESULTS

Of the 283 participants, 259 (92%) provided their intention to either accept or decline pertussis vaccination. Eighty-three percent women were willing to accept the pertussis vaccine if offered during pregnancy. About half (53%) of the participants had ever heard of pertussis disease. Perceptions of pertussis vaccine efficacy, safety, and disease susceptibility were strongly associated with intention to accept pertussis vaccine (p<0.01). Healthcare providers, Ministry of Health, and mass media were considered as highly reliable sources of vaccine recommendation and associated with intention to accept antenatal pertussis vaccination (p<0.001). Healthcare provider recommendation was a common reason cited by respondents for pregnant women to accept antenatal pertussis vaccination (p=0.0005). However, opinion of primary decision-makers in the family (husbands and in-laws) was a crucial reason cited by respondents for pregnant women to reject pertussis vaccination in pregnancy (p=0.003).

CONCLUSION

Antenatal pertussis vaccination initiatives in South Asia should strongly consider inclusion of family members, healthcare providers, national health ministries, and mass media to help implement new vaccination programs.

From Variation of Influenza Viral Proteins to Vaccine Development

Recurrent influenza epidemics and occasional pandemics are one of the most important global public health concerns and are major causes of human morbidity and mortality. Influenza viruses can evolve through antigen drift and shift to overcome the barriers of human immunity, leading to host adaption and transmission. Mechanisms underlying this viral evolution are gradually being elucidated. Vaccination is an effective method for the prevention of influenza virus infection. However, the emergence of novel viruses, including the 2009 pandemic influenza A (H1N1), the avian influenza A virus (H7N9), and the highly pathogenic avian influenza A virus (HPAI H5N1), that have infected human populations frequently in recent years reveals the tremendous challenges to the current influenza vaccine strategy. A better vaccine that provides protection against a wide spectrum of various influenza viruses and long-lasting immunity is urgently required. Here, we review the evolutionary changes of several important influenza proteins and the influence of these changes on viral antigenicity, host adaption, and viral pathogenicity. Furthermore, we discuss the development of a potent universal influenza vaccine based on this knowledge.

A boosting skin vaccination with dissolving microneedle patch encapsulating M2e vaccine broadens the protective efficacy of conventional influenza vaccines

The biodegradable microneedle patch (MNP) is a novel technology for vaccine delivery that could improve the immunogenicity of vaccines. To broaden the protective efficiency of conventional influenza vaccines, a new 4M2e-tFliC fusion protein construct containing M2e sequences from different subtypes was generated. Purified fusion protein was encapsulate into MNPs with a biocompatible polymer for use as a boosting vaccine. The results demonstrated that mice receiving a conventional inactivated vaccine followed by a skin-applied dissolving 4M2e-tFliC MNP boost could better maintain the humoral antibody response than that by the conventional vaccine-prime alone. Compared with an intramuscular injection boost, mice receiving the MNP boost showed significantly enhanced cellular immune responses, hemagglutination-inhibition (HAI) titers, and neutralization titers. Increased frequency of antigen-specific plasma cells and long-lived bone marrow plasma cells was detected in the MNP boosted group as well, indicating that skin vaccination with 4M2e-tFliC facilitated a long-term antibody-mediated immunity. The 4M2e-tFliC MNP-boosted group also possessed enhanced protection against high lethal dose challenges against homologous A/PR/8/34 and A/Aichi/2/68 viruses and protection for a majority of immunized mice against a heterologous A/California/07/2009 H1N1 virus. High levels of M2e specific immune responses were observed in the 4M2e-tFliC MNP-boosted group as well. These results demonstrate that a skin-applied 4M2e-tFliC MNP boosting immunization to seasonal vaccine recipients may be a rapid approach for increasing the protective efficacy of seasonal vaccines in response to a significant drift seen in circulating viruses. The results also provide a new perspective for future exploration of universal influenza vaccines.

Recommendations and offers for adult influenza vaccination, 2011-2012 season, United States

BACKGROUND

Provider recommendations and offers for influenza vaccination improve adult influenza vaccination coverage. Analysis was performed to describe receipt of influenza vaccination recommendations and offers among adults who visited a healthcare provider (HCP) during the 2011-2012 influenza season and describe differences between those receiving and not receiving recommendations and offers for influenza vaccination. Associations between influenza vaccination and receipt of recommendations and offers were examined.

METHODS

Respondents to a random digit dial telephone survey who had visited a HCP since July 1, 2011 were asked if they had received a recommendation for influenza vaccination. Those receiving a recommendation were asked if they received an offer for vaccination. Participants were characterized by demographic and access to health care variables. Logistic regression was used to examine the relationships between participant characteristics and recommendation alone, between participant characteristics and recommendation and offer, and between influenza vaccination and recommendation and offer.

RESULTS

Of those who reported visiting a HCP, 43.8% reported receiving a recommendation for influenza vaccination. Of those who reported receiving a recommendation, 76.6% reported receiving an offer for influenza vaccination. Persons with high-risk conditions and persons over 65 years were more likely to receive recommendations for influenza vaccination when compared to those without high-risk conditions and 18-49 year olds, respectively. Those reporting receipt of a recommendation and offer for influenza vaccination were 1.76 times more likely and those reporting receipt of a recommendation but no offer were 1.72 times more likely to report being vaccinated for influenza controlling for all patient characteristics.

CONCLUSIONS

Less than half of respondents reported receipt of recommendations and offers of influenza vaccination during the 2011-2012 influenza season and disparities exist between groups. All healthcare providers seeing adults should recommend or offer influenza vaccination for all patients at every visit during the influenza season.

Surveillance of Adverse Events After Seasonal Influenza Vaccination in Pregnant Women and Their Infants in the Vaccine Adverse Event Reporting System, July 2010-May 2016

INTRODUCTION

Routine immunization of pregnant women with seasonal inactivated influenza vaccines (IIVs) is recommended in all trimesters of pregnancy. A review of the Vaccine Adverse Event Reporting System (VAERS) during 1990-2009 did not find any unexpected patterns of pregnancy complications or fetal outcomes after administration of IIV or live attenuated influenza vaccines (LAIVs). During the 2009-2010 pandemic influenza A (H1N1) vaccination campaign, a study noted that the number of VAERS reports from pregnant women who received the H1N1 2009 inactivated monovalent vaccine (n = 288) increased compared with 1990-2009 seasonal IIV pregnancy reports (n = 148).

OBJECTIVES

The objective of this study was to assess the safety of seasonal influenza vaccines in pregnant women and their infants whose reports were submitted to VAERS during 2010-2016.

METHODS

We searched VAERS for US reports of adverse events (AEs) in pregnant women who received IIV or LAIV from 1 July 2010 through 6 May 2016. Clinicians reviewed reports and available medical records and assigned a primary clinical category for each report. Reports were coded as serious based on the Code of Federal Regulations.

RESULTS

We identified 671 reports after seasonal influenza vaccines administered to pregnant women: 544 after IIV and 127 after LAIV. Serious events occurred among 61 (11.2%) reports following IIV and one (0.8%) report following LAIV. No deaths were reported. Among reports with trimester information (n = 296), IIV was administered during the first trimester in 116 (39.2%). Among IIV reports, the most frequent pregnancy-specific AE was spontaneous abortion in 62 (11.4%) reports, followed by stillbirth in ten (1.8%) and preterm delivery in six (1.1%). The most common non-pregnancy-specific AEs were injection-site reactions (55 [10.1%]). Neonatal or infant outcomes were reported in 22 (4.0%) reports, seven of which had major birth defects of different types and no neonatal deaths.

CONCLUSION

As in 2009-2010, no new or unexpected patterns in maternal or fetal outcomes were observed during 2010-2016.

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.

Lack of Availability of Antenatal Vaccination Information on Obstetric Care Practice Web Sites

OBJECTIVE

To estimate the proportion of obstetric practice web sites in the United States providing information on antenatal influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination.

METHODS

Using www.healthgrades.com, a national random sample of 1,003 obstetric practice web sites was examined for provision of information on antenatal vaccination and other preventive prenatal health topics. Data were collected for this cross-sectional study between September 25, 2014, and November 12, 2014. χ tests and odds ratios were calculated to determine significance and magnitude of associations between provision of antenatal vaccination information and other practice characteristics.

RESULTS

Of 1,003 web sites examined, 229 (22.8%) posted information pertaining to antenatal vaccinations. Only 105 web sites (10.5%) provided up-to-date information about both antenatal influenza and Tdap vaccination. Compared with the proportion posting on antenatal vaccination, significantly more web sites posted on safe foods (40.8%; P<.001), safe medications (36.9%; P<.001), and safe exercise (38.5%; P<.001) during pregnancy. When compared with web sites not mentioning these other prenatal health topics, web sites mentioning these topics were more likely to also mention antenatal vaccination (safe foods: 45.7% compared with 7.1%; odds ratio [OR] 11.07, 95% confidence interval [CI] 7.65-16.01; safe medications: 45.4% compared with 9.6%; OR 7.8, CI 5.58-10.89; safe exercise: 45.9% compared with 8.4%; OR 9.2, CI 6.5-13.03).

CONCLUSION

A majority of obstetric care practice web sites do not provide information on antenatal vaccinations. Obstetric practices should consider using their web sites to provide reliable information on antenatal vaccinations as many already do for other prenatal health topics.

Influenza vaccine acceptance among pregnant women in urban slum areas, Karachi, Pakistan

BACKGROUND

Facilitators and barriers to influenza vaccination among pregnant women in the developing world are poorly understood, particularly in South Asia. We assessed intention to accept influenza vaccine among ethnically diverse low-income pregnant women in Pakistan.

METHODS

From May to August 2013, we conducted a cross-sectional survey of pregnant women who visited health centers in urban slums in Karachi city. We assessed intention to accept influenza vaccine against socio-demographic factors, vaccination history, vaccine recommendation sources, and other factors.

RESULTS

In an unvaccinated study population of 283 respondents, 87% were willing to accept the vaccine, if offered. All except two participants were aware of symptoms typically associated with influenza. Perceived vaccine safety, efficacy, and disease susceptibility were significantly associated with intention to accept influenza vaccine (p<0.05). Regardless of intention to accept influenza vaccine, 96% rated healthcare providers as highly reliable source of vaccine information. While a recommendation from a physician was critical for influenza vaccine acceptance, parents-in-law and husbands were often considered the primary decision-makers for pregnant women seeking healthcare including vaccination.

CONCLUSIONS

Maternal influenza vaccination initiatives in South Asia should strongly consider counseling of key familial decision-makers and inclusion of healthcare providers to help implement new vaccination programs.

The association between influenza vaccination and other preventative health behaviors in a cohort of pregnant women

OBJECTIVES

Although pregnant women are a high-priority group for seasonal influenza vaccination, vaccination rates in this population remain below target levels. Previous studies have identified sociodemographic predictors of vaccine choice, but relationships between preconception heath behaviors and seasonal influenza vaccination are poorly understood. This prospective cohort study followed pregnant women during the 2010-2011 influenza season to determine if certain health behaviors were associated with vaccination status.

METHOD

Participants were pregnant women receiving prenatal care from Kaiser Permanente Northwest and Kaiser Permanente Northern California. Women were surveyed about preconception smoking, alcohol consumption, and vitamin/supplement use. Vaccination data were obtained from health plan databases and state immunization records.

RESULTS

Data from 1,204 women were included in this analysis. Most participants (1,204; 66.4%) received a seasonal influenza vaccine during the study period. Women vaccinated prior to pregnancy were more likely to use a supplement containing folic acid (80%) or vitamin D (30%) compared with women who were vaccinated during pregnancy (72% and 15%, respectively) or unvaccinated women (62% and 12%, respectively, p < .001). Women vaccinated prior to or during pregnancy were more likely (75%) to have never smoked compared with women who were not vaccinated (70%, p = .005). There were no significant differences in alcohol use or household cigarette smoke exposure by vaccination group.

CONCLUSIONS

Women who engaged in specific preconception health behaviors were more likely to receive seasonal influenza vaccination. Failure to participate in these health behaviors could alert health care practitioners to patients' increased risk of remaining unvaccinated during pregnancy.

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.

Determinants of healthcare provider recommendations for influenza vaccinations

OBJECTIVE

Investigate determinants of receiving healthcare provider (HCP) recommendations for seasonal and H1N1 influenza vaccinations.

METHODS

Using a United States national sample of adults 18 + from the National 2009 H1N1 Flu Survey, multivariate regression models estimated the likelihood of receiving a HCP recommendation. Covariates included demographics, socioeconomic status, and Advisory Committee on Immunization Practices (ACIP) priority groups.

RESULTS

Adults age 55-64 and 65 + were more likely to report a HCP recommendation when compared to adults age 18-34 (OR: 1.483, 95%CI: 1.237-1.778 and OR: 1.738, 95%CI: 1.427-2.116, respectively). Chronically ill adults had 58.0% (95%CI: 1.414-1.765) higher odds of receiving a HCP recommendation than non-chronically ill adults. Patients visiting a doctor once and twice had 28.7% (95%CI: 0.618-0.821) and 17.1% (95%CI: 0.721-0.952) lower odds of receiving a HCP recommendation when compared to adults visiting their doctor at least four times. And, compared to Non-Hispanic Whites, Non-Hispanic Blacks had 28.4% (95%CI: 1.064-1.549) higher odds of receiving a recommendation.

CONCLUSIONS

ACIP priority groups experienced higher rates of recommendations compared to non-ACIP groups. Racial differences in HCP recommendations cannot explain racial disparities in flu vaccination rates.

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.

Enhanced immune responses by skin vaccination with influenza subunit vaccine in young hosts

Skin has gained substantial attention as a vaccine target organ due to its immunological properties, which include a high density of professional antigen presenting cells (APCs). Previous studies have demonstrated the effectiveness of this vaccination route not only in animal models but also in adults. Young children represent a population group that is at high risk from influenza infection. As a result, this group could benefit significantly from influenza vaccine delivery approaches through the skin and the improved immune response it can induce. In this study, we compared the immune responses in young BALB/c mice upon skin delivery of influenza vaccine with vaccination by the conventional intramuscular route. Young mice that received 5 μg of H1N1 A/Ca/07/09 influenza subunit vaccine using MN demonstrated an improved serum antibody response (IgG1 and IgG2a) when compared to the young IM group, accompanied by higher numbers of influenza-specific antibody secreting cells (ASCs) in the bone marrow. In addition, we observed increased activation of follicular helper T cells and formation of germinal centers in the regional lymph nodes in the MN immunized group, rapid clearance of the virus from their lungs as well as complete survival, compared with partial protection observed in the IM-vaccinated group. Our results support the hypothesis that influenza vaccine delivery through the skin would be beneficial for protecting the high-risk young population from influenza infection.

Disparities in influenza vaccination coverage among women with live-born infants: PRAMS surveillance during the 2009-2010 influenza season

OBJECTIVES

Vaccination during pregnancy significantly reduces the risk of influenza illness among pregnant women and their infants up to 6 months of age; however, many women do not get vaccinated. We examined disparities in vaccination coverage among women who delivered a live-born infant during the 2009-2010 influenza season, when two separate influenza vaccinations were recommended.

METHODS

Pregnancy Risk Assessment Monitoring System (PRAMS) data from 29 states and New York City, collected during the 2009-2010 influenza season, were used to examine uptake of seasonal (unweighted n=27,153) and pandemic influenza A(H1N1)pdm09 (pH1N1) (n=27,372) vaccination by racially/ethnically diverse women who delivered a live-born infant from September 1, 2009, through May 31, 2010.

RESULTS

PRAMS data showed variation in seasonal and pH1N1 influenza vaccination coverage among women with live-born infants by racial/ethnic group. For seasonal influenza vaccination, coverage was 50.5% for non-Hispanic white, 30.2% for non-Hispanic black, 42.1% for Hispanic, and 48.2% for non-Hispanic other women. For pH1N1, vaccination coverage was 41.4% for non-Hispanic white, 25.5% for non-Hispanic black, 41.1% for Hispanic, and 43.3% for non-Hispanic other women. Compared with non-Hispanic white women, non-Hispanic black women had lower seasonal (crude prevalence ratio [cPR] = 0.60, 95% confidence interval [CI] 0.55, 0.64) and pH1N1 (cPR=0.62, 95% CI 0.57, 0.67) vaccination coverage; these disparities diminished but remained after adjusting for provider recommendation or offer for influenza vaccination, insurance status, and demographic factors (seasonal vaccine: adjusted PR [aPR] = 0.80, 95% CI 0.74, 0.86; and pH1N1 vaccine: aPR=0.75, 95% CI 0.68, 0.82).

CONCLUSION

To reduce disparities in influenza vaccination uptake by pregnant women, targeted efforts toward providers and interventions focusing on pregnant and postpartum women may be needed.

Safety of inactivated monovalent pandemic (H1N1) 2009 vaccination during pregnancy: a population-based study in Taiwan

BACKGROUND

Pregnant women were prioritized for H1N1 vaccination during the 2009-2010 pandemic. Safety concerns exist with vaccinating pregnant women, particularly in their first trimesters.

METHODS

We linked computerized data on H1N1 vaccination, National Health Insurance, and Taiwan Birth Registry and identified events of spontaneous abortions (SABs) and all singleton births that occurred/delivered during November 1, 2009-September 30, 2010. The observation period for each case of SAB (6-19 weeks gestation) was divided into period at risk (1-28 days after vaccination) and control periods (the remaining person-days until SAB). The self-controlled case series method for truncated observational periods assessed the incidence rate ratio (IRR) of SAB during the 1-28 days compared with those in the control period. The case-control design matched each case of adverse fetal outcomes to up to 10 controls on fetal sex and year/month of pregnancy onset, and calculated matched odds ratio (OR) on H1N1 vaccination at <14 or ≥14 weeks gestation.

RESULTS

Sixty-five women with SAB had received H1N1 vaccination at 6-19 weeks gestation. The IRR of SAB for the risk period 1-28 days was 1.03 (95% confidence interval [CI] 0.55-1.93). Among the 147,294 live births and 1354 stillbirths, maternal H1N1 vaccine receipt at <14 weeks gestation was associated with significantly reduced likelihood of small for gestational age (SGA) birth (OR 0.72, 95% CI 0.61-0.84) and birth defect (OR 0.46, 95% CI 0.22-1.00), whereas receipt at ≥14 weeks gestation was associated with significantly reduced likelihood of stillbirth (OR 0.63, 95% CI 0.46-0.86), prematurity (OR 0.90, 95% CI 0.83-0.97), low birth weight (OR 0.81, 95% CI 0.74-0.88), and SGA birth (OR 0.90, 95% CI 0.84-0.97).

CONCLUSIONS

H1N1 vaccination during pregnancy did not increase risk of SAB or adverse fetal outcomes.

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.

Monovalent H1N1 influenza vaccine safety in pregnant women, risks for acute adverse events

OBJECTIVE

To assess risks for acute adverse events and pregnancy complications in pregnant women following monovalent 2009 H1N1 inactivated influenza (MIV) vaccination.

METHODS

Within the Vaccine Safety Datalink, we compared rates of pre-specified medically attended events (MAE) occurring within 42 days of MIV vaccination to those occurring in matched cohorts that at the same gestational age were either unvaccinated or received seasonal trivalent inactivated influenza (TIV) vaccine. Using generalized estimating equation method, with a Poisson distribution and log link, we calculated adjusted incident rate ratios (AIRR).

RESULTS

Among 9349 women receiving MIV in any trimester, only one MAE occurred 0-3 days following MIV, an allergic reaction. No cases of Guillain-Barré syndrome, Bell's palsy, or transverse myelitis occurred 1-42 days after MIV. Compared to women receiving TIV and to unvaccinated women, risks for acute MAEs were not increased following MIV for any outcome. Hyperemesis was the most common adverse event in the MIV, TIV, and unvaccinated groups, occurring at a rate of about 4% over a 42-day period in all groups. Over a 42-day window, among all groups, incident gestational diabetes occurred at a rate of 3% and thrombocytopenia occurred at a rate of approximately 0.3%. Among women receiving MIV during pregnancy, increased risks for these and other less common obstetric events were not detected.

CONCLUSION

In this large cohort of pregnant women no acute safety signals were identified within 6 weeks of receipt of MIV.

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.

Influenza vaccination during pregnancy: a qualitative study of the knowledge, attitudes, beliefs, and practices of general practitioners in Central and South-Western Sydney

BACKGROUND

Pregnant women have an increased risk of influenza complications. Influenza vaccination during pregnancy is safe and effective, however coverage in Australia is less than 40%. Pregnant women who receive a recommendation for influenza vaccination from a health care provider are more likely to receive it, however the perspectives of Australian general practitioners has not previously been reported. The aim of the study was to investigate the knowledge, attitudes, beliefs, and practices of general practitioners practicing in South-Western Sydney, Australia towards influenza vaccination during pregnancy.

METHODS

A qualitative descriptive study was conducted, with semi-structured interviews completed with seventeen general practitioners in October 2012. A thematic analysis was undertaken by four researchers, and transcripts were analysed using N-Vivo software according to agreed codes.

RESULTS

One-third of the general practitioners interviewed did not consider influenza during pregnancy to be a serious risk for the mother or the baby. The majority of the general practitioners were aware of the government recommendations for influenza vaccination during pregnancy, but few general practitioners were confident of their knowledge about the vaccine and most felt they needed more information. More than half the general practitioners had significant concerns about the safety of influenza vaccination during pregnancy. Their practices in the provision of the vaccine were related to their perception of risk of influenza during pregnancy and their confidence about the safety of the vaccine. While two-thirds reported that they are recommending influenza vaccination to their pregnant patients, many were adopting principles of patient-informed choice in their approach and encouraged women to decide for themselves whether they would receive the vaccine.

CONCLUSIONS

General practitioners have varied knowledge, attitudes, and beliefs about influenza vaccination during pregnancy, which influence their practices. Addressing these could have a significant impact on improving vaccine uptake during pregnancy.

Obstetricians and the 2009-2010 H1N1 vaccination effort: implications for future pandemics

Our objective was to describe the experiences of obstetricians during the 2009–2010 H1N1 vaccination campaign in order to identify possible improvements for future pandemic situations. We conducted a cross-sectional mail survey of a national random sample of 4,000 obstetricians, fielded in Summer 2010. Survey items included availability, recommendation, and patient acceptance of H1N1 vaccine; prioritization of H1N1 vaccine when supply was limited; problems with H1N1 vaccination; and likelihood of providing vaccine during a future influenza pandemic. Response rate was 66 %. Obstetricians strongly recommended H1N1 vaccine during the second (85 %) and third (86 %) trimesters, and less often during the first trimester (71 %) or the immediate postpartum period (76 %); patient preferences followed a similar pattern. H1N1 vaccine was typically available in outpatient obstetrics clinics (80 %). Overall vaccine supply was a major problem for 30 % of obstetricians, but few rated lack of thimerosal-free vaccine as a major problem (12 %). Over half of obstetricians had no major problems with the H1N1 vaccine campaign. Based on this experience, 74 % would be “very likely” and 12 % “likely” to provide vaccine in the event of a future influenza pandemic. Most obstetricians strongly recommended H1N1 vaccine, had few logistical problems beyond limited vaccine supply, and are willing to vaccinate in a future pandemic. Addressing concerns about first-trimester vaccination, developing guidance for prioritization of vaccine in the event of severe supply constraints, and continued facilitation of the logistical aspects of vaccination should be emphasized in future influenza pandemics.

Vaccinations given during pregnancy, 2002-2009: a descriptive study

BACKGROUND

A number of studies have described influenza vaccination coverage during pregnancy but few publications have described rates of other vaccinations.

PURPOSE

To describe vaccination rates during pregnancy in the Vaccine Safety Datalink (VSD), with particular focus on vaccinations contraindicated during pregnancy.

METHODS

Pregnancies ending in 2002 through 2009 and vaccinations administered during these pregnancies were identified in the VSD. Vaccination rates per 1000 pregnancies during the study period were calculated by vaccine type, recommendation category, pregnancy year, maternal age, and trimester. Analyses were conducted in 2012-2013.

RESULTS

In the VSD, 669,695 pregnancies and 141,389 vaccinations were identified. Trivalent inactivated influenza (TIV) was the most commonly administered vaccination (174.1 doses per 1000 pregnancies) and was most often administered during the 2nd and 3rd trimesters. The most common vaccines in the "consider if indicated" category were tetanus-diphtheria (6.1 per 1000) and hepatitis B (3.7 per 1000). Contraindicated vaccination was infrequent, and the majority of these were measles-mumps-rubella (MMR) (1.2 per 1000); varicella (1.0 per 1000); and live-attenuated influenza vaccine (LAIV) (0.3 per 1000). Both "consider if indicated" and contraindicated vaccines were more frequently administered during early pregnancy.

CONCLUSIONS

TIV was the most commonly administered vaccine. With the exception of TIV, other vaccines were most frequently administered during early pregnancy and among younger women, suggesting that vaccination may occur when the woman and/or provider are unaware of the pregnancy. Contraindicated vaccines were infrequently administered during pregnancy; however, given that some women received contraindicated vaccines later in pregnancy, clearer recommendations and improved provider education may be needed.

Intention to accept Bordetella pertussis booster vaccine during pregnancy in Mexico City

OBJECTIVE

Adult booster vaccination against pertussis can help prevent severe infections in young infants. We examined influences on intention to accept pertussis booster vaccination among pregnant women in Mexico City.

METHODS

We conducted a cross-sectional survey, recruiting convenience samples of pregnant women receiving prenatal care from three public healthcare centers between March and May 2012. Our primary outcome was intention to accept pertussis vaccination during pregnancy. We examined socio-demographic factors, vaccination history, pertussis knowledge, perceptions of vaccine information sources, and other potential influences on vaccine decision-making.

RESULTS

A total of 402 pregnant women agreed to participate, of which 387 (96%) provided their intention to accept or decline pertussis vaccination. Among respondents, 57% intended to accept a pertussis booster vaccine if offered, but only 16% had ever heard of pertussis, and only 2% knew someone who had contracted this disease. Over 80% of respondents would accept pertussis vaccination if recommended by an obstetrician-gynecologist. The most frequently selected reasons to refuse pertussis vaccination were concerns that the vaccine might harm the unborn baby or pregnant woman. In multivariate analysis, rating doctors and nurses as good sources of vaccine information, and having ever heard of pertussis, were independently associated with intention to accept pertussis vaccination.

CONCLUSIONS

Promoting patient awareness about pertussis disease and vaccine safety, and encouraging general practitioners, nurses and obstetricians to recommend pertussis booster vaccine, may increase vaccine uptake among pregnant women.

Maintaining the momentum: key factors influencing acceptance of influenza vaccination among pregnant women following the H1N1 pandemic

This survey study compared pre- and post-pandemic knowledge, attitudes, beliefs, and intended behaviors of pregnant women regarding influenza vaccination (seasonal and/or pandemic) during pregnancy in order to determine key factors influencing their decision to adhere to influenza vaccine recommendations. Only 36% of 662 pre-pandemic respondents knew that influenza was more severe in pregnant women, compared to 62% of the 159 post-pandemic respondents. Of the pre-pandemic respondents, 41% agreed or strongly agreed that that it was safer to wait until after the first 3 months to receive the seasonal influenza vaccine, whereas 23% of the post-pandemic cohort agreed or strongly agreed; 32% of pre-pandemic participants compared to 11% of post-pandemic respondents felt it was best to avoid all vaccines while pregnant. Despite 61% of the pre-pandemic cohort stating that they would have the vaccine while pregnant if their doctor recommended it and 54% citing their doctor/nurse as their primary source of vaccine information, only 20% said their doctor discussed influenza vaccination during their pregnancy, compared to 77% of the post-pandemic respondents who reported having this conversation. Women whose doctors discussed influenza vaccine during pregnancy had higher overall knowledge scores (P<0.0001; P=0.005) and were more likely to believe the vaccine is safe in all stages of pregnancy (P<0.0001; P=0.001) than those whose doctors did not discuss influenza vaccination. The 2009 H1N1 pandemic experience appeared to change attitudes and behaviours of health care providers and their pregnant patients toward influenza vaccination.

Trends in influenza vaccine coverage in pregnant women, 2008 to 2012

CONTEXT

Pregnant women are at increased risk of severe influenza-related complications and hospitalizations and are a priority group for influenza vaccination.

OBJECTIVE

To examine coverage of seasonal and pandemic influenza A (H1N1) vaccines in pregnant women in a managed care setting, from 2008 to 2012.

DESIGN

Retrospective cohort study of 10,145 pregnant women.

MAIN OUTCOME MEASURES

H1N1 and seasonal influenza vaccination rates.

RESULTS

Seasonal influenza vaccine coverage increased from 38% to 63% between the 2008-2009 and 2010-2011 seasons, and then dropped to 61% in 2011-2012. Vaccine coverage was higher in women considered at high risk of influenza complications, increasing from 43% in 2008-2009 to 71% in 2010-2011, before decreasing to 69% in 2011-2012. H1N1 vaccine coverage was greater than seasonal influenza coverage in 2009-2010 in the overall pregnant population (61% vs 53%) and in the high-risk group (64% vs 59%). We observed statistically significant differences in vaccination rates by trimester, gravidity, maternal age, and race/ethnicity.

CONCLUSIONS

Vaccination rates increased significantly from 2008 to 2011, then dropped slightly in 2011-2012. Continued efforts are needed to ensure adequate vaccination coverage in this high-risk population.

Seasonal influenza vaccination coverage among adult populations in the United States, 2005-2011

The most effective strategy for preventing influenza is annual vaccination. We analyzed 2005-2011 data from the National Health Interview Survey (NHIS), using Kaplan-Meier survival analysis to estimate cumulative proportions of persons reporting influenza vaccination in the 2004-2005 through 2010-2011 seasons for persons aged ≥18, 18-49, 50-64, and ≥65 years, persons with high-risk conditions, and health-care personnel. We compared vaccination coverage by race/ethnicity within each age and high-risk group. Vaccination coverage among adults aged ≥18 years increased from 27.4% during the 2005-2006 influenza season to 38.1% during the 2010-2011 season, with an average increase of 2.2% annually. From the 2005-2006 season to the 2010-2011 season, coverage increased by 10-12 percentage points for all groups except adults aged ≥65 years. Coverage for the 2010-2011 season was 70.2% for adults aged ≥65 years, 43.7% for adults aged 50-64 years, 36.7% for persons aged 18-49 years with high-risk conditions, and 55.8% for health-care personnel. In most subgroups, coverage during the 2010-2011 season was significantly lower among non-Hispanic blacks and Hispanics than among non-Hispanic whites. Vaccination coverage among adults under age 65 years increased from 2005-2006 through 2010-2011, but substantial racial/ethnic disparities remained in most age groups. Targeted efforts are needed to improve influenza vaccination coverage and reduce disparities.

Influenza vaccination during pregnancy: coverage rates and influencing factors in two urban districts in Sydney

BACKGROUND

Pregnant women have an increased risk of complications from influenza. Influenza vaccination during pregnancy is considered effective and safe; however estimates of vaccine coverage are low. This study aimed to determine influenza vaccination coverage and factors associated with vaccine uptake in pregnant women in two Sydney-based health districts.

METHODS

A random sample of women who delivered a baby in a public hospital in Sydney and South-Western Sydney Local Health Districts between June and September 2012 were surveyed using a computer assisted telephone interviewing service.

RESULTS

Of the 462 participants (participation rate 92%), 116 (25%) reported receiving the influenza vaccine during their pregnancy. In univariate analysis, vaccination coverage varied significantly depending on antenatal care type, hospital of birth, and parity (p<0.05), but not for age category, highest level of education, country of birth, language spoken at home, or Aboriginal status. Women who received antenatal care through a general practitioner (GP) had 2.3 (95% CI 1.4-3.6) times the odds (unadjusted) of receiving the influenza vaccination than those who received their antenatal care through a public hospital. The main reason cited for vaccination was GP recommendation (37%), while non-recommendation (33%) and lack of knowledge (26%) were cited as main reasons for not receiving the vaccination. 30% of women recalled receiving a provider recommendation for the vaccination and these women had 33.0 times the odds (unadjusted) of receiving the vaccination than women who had not received a recommendation. In a multivariate model a provider recommendation was the only variable that was significantly associated with vaccination (OR 41.9; 95% CI 20.7-84.9).

CONCLUSION

Rates of influenza vaccination during pregnancy are low. There is a significant relationship between healthcare provider recommendation for the vaccination and vaccine uptake. Increasing provider recommendation rates has the potential to increase coverage rates of influenza vaccination in pregnant women.

Prevalence and predictors of maternal seasonal influenza vaccination in Hong Kong

BACKGROUND

Pregnant women infected with influenza virus are more likely to experience severe complications when compared with their non-pregnant peers. Yet influenza vaccine uptake is low among pregnant women. The purpose of this study was to assess the prevalence of seasonal influenza vaccine uptake among pregnant women in Hong Kong and to identify predictors of vaccine uptake.

METHODS

Using a multi-center cross-sectional design, we recruited 2822 new mothers during their immediate postpartum stay from all eight public obstetric hospitals in Hong Kong. We assessed antenatal maternal influenza vaccination status as well as health beliefs and perceptions toward influenza and influenza vaccination. Bivariable and multivariable logistic regression was used to identify the predictors of vaccination uptake.

RESULTS

Only 49 (1.7%; 95% CI 1.3-2.3%) participants were vaccinated during their pregnancy. Fear that the vaccine would cause harm to the fetus or themselves were the most common reasons for not being vaccinated. Being aware of the vaccination recommendations (OR=2.69; 95% CI 1.06-6.82), being advised by a health-care provider (OR=6.30; 95% CI 3.19-12.46), history of vaccination (OR=2.47; 95% CI 1.25-4.91), perceived susceptibility to influenza infection (OR=3.67; 95% CI 1.64-8.22), and perceived benefits of influenza vaccination (OR=9.98; 95% CI 3.79-26.24) were all independently associated with vaccination. Perceived barriers to vaccination (OR=0.17; 95% CI 0.07-0.40) were strongly associated with failure to vaccinate.

CONCLUSIONS

Low seasonal influenza vaccination uptake among Hong Kong pregnant women was related to a number of factors, all of which are amenable to interventions. Vaccination promotion strategies need to focus on encouraging health-care providers to discuss vaccination with their pregnant clients and in providing pregnant women with accurate and unbiased information about the risks of influenza infection and the benefits of vaccination.

Determination of vaccination status of pregnant women during pregnancy and the affecting factors

AIMS AND OBJECTIVES

To determine the vaccination status of pregnant women during pregnancy and factors affecting their vaccination.

BACKGROUND

Immunisation provided through vaccination is one of the most effective ways to reduce or prevent the risks of disease, disability and death. Maternal and newborn health may be protected and morbidity may be decreased through vaccinating pregnant women when necessary.

DESIGN

This was a descriptive and cross-sectional survey.

METHODS

This study was conducted in a university hospital in Ankara, Turkey, between 01 March and 31 May 2010. The study was carried out with 198 healthy pregnant women who had completed the 26th week of gestation. Data were collected using the data collection form composed of questions enquiring about the demographic and obstetric features of pregnant women and whether or not they knew that vaccinations could be given during pregnancy, and which vaccines could be used during pregnancy, which vaccine/vaccines they had previously received and the reasons for having been vaccinated or not.

RESULTS

Approximately half of the participants had received at least one of the vaccines that may be used in pregnancy (52·0%). The pregnant women received vaccinations for tetanus (47·0%), H1N1 (9·1%), seasonal influenza (3·0%) and hepatitis B (0·5%), respectively. The pregnant women who had been educated about vaccinations had been vaccinated at a statistically significantly higher rate compared with those who had not.

CONCLUSION

This study revealed that pregnant women's knowledge about the required vaccines during pregnancy affected their behaviour towards vaccination. Acquiring knowledge about vaccines that may be used during pregnancy from health personnel is effective to increase vaccination. This result may be interpreted as 'acquired information affects behaviour towards vaccination'.

RELEVANCE TO CLINICAL PRACTICE

Providing information about immunisation to pregnant women at the antenatal clinic is important in terms of maternal and newborn health. Nurses and midwives working in the antenatal field should be sufficiently educated about immunisation.

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.

Maternal safety of trivalent inactivated influenza vaccine in pregnant women

OBJECTIVE

To estimate the risks for medically attended events occurring within 42 days of receiving trivalent inactivated influenza vaccine and to evaluate specific risks of first-trimester vaccination.

METHODS

This retrospective observational cohort study compared rates of medically attended adverse events in trivalent inactivated influenza-vaccinated and unvaccinated pregnant women in the Vaccine Safety Datalink. Using a Poisson distribution and log link, we calculated maternal adjusted incident rate ratios for composite safety outcomes for the full cohort and the subset vaccinated during the first trimester.

RESULTS

The cohort included 75,906 vaccinated (28.4% in the first trimester) and 147,992 unvaccinated women matched by age, site, and pregnancy start date. In the first 3 days after vaccination, trivalent inactivated influenza vaccine was not associated with increased risk of specified medically attended events, including allergic reactions, cellulitis, and seizures (full cohort adjusted incident rate ratio 1.12, 95% confidence interval [CI] 0.81-1.55; P=.48; first-trimester adjusted incident rate ratio .97, 95% CI 0.53-1.78; P=.93). In the first 42 days, no incident cases of Guillain-Barré syndrome, optic neuritis, transverse myelitis, or Bells palsy were identified. Trivalent inactivated influenza vaccine was not associated with thrombocytopenia (full cohort adjusted incident rate ratio 0.90, 95% CI 0.68--1.19; P=.45; first-trimester adjusted incident rate ratio 0.56, 95% CI 0.22-1.39; P=.21) or an acute neurologic event (full cohort adjusted incident rate ratio 0.92, 95% CI 0.54-1.6; P=.75; first-trimester adjusted incident rate ratio 1.05, 95% CI 0.46-2.38; P=.91).

CONCLUSIONS

Receipt of trivalent inactivated influenza vaccine during pregnancy was not associated with increased risk of adverse events in the 42 days after vaccination, supporting its safety for the mother.

Pregnancy dose Tdap and postpartum cocooning to prevent infant pertussis: a decision analysis

BACKGROUND

Infants <2 months of age are at highest risk of pertussis morbidity and mortality. Until recently, the US Advisory Committee on Immunization Practices (ACIP) recommended protecting young infants by "cocooning" or vaccination of postpartum mothers and other close contacts with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis, adsorbed (Tdap) booster vaccine. ACIP recommends pregnancy vaccination as a preferred and safe alternative to postpartum vaccination. The ACIP cocooning recommendation has not changed.

METHODS

We used a cohort model reflecting US 2009 births and the diphtheria-tetanus-acellular pertussis schedule to simulate a decision and cost-effectiveness analysis of Tdap vaccination during pregnancy compared with postpartum vaccination with or without vaccination of other close contacts (ie, cocooning). We analyzed infant pertussis cases, hospitalizations, and deaths, as well as direct disease, indirect, and public health costs for infants in the first year of life. All costs were updated to 2011 US dollars.

RESULTS

Pregnancy vaccination could reduce annual infant pertussis incidence by more than postpartum vaccination, reducing cases by 33% versus 20%, hospitalizations by 38% versus 19%, and deaths by 49% versus 16%. Additional cocooning doses in a father and 1 grandparent could avert an additional 16% of cases but at higher cost. The cost per quality-adjusted life-year saved for pregnancy vaccination was substantially less than postpartum vaccination ($414 523 vs $1 172 825).

CONCLUSIONS

Tdap vaccination during pregnancy could avert more infant cases and deaths at lower cost than postpartum vaccination, even when postpartum vaccination is combined with additional cocooning doses. Pregnancy dose vaccination is the preferred alternative to postpartum vaccination for preventing infant pertussis.

Socio-demographic differences in opinions about 2009 pandemic influenza A (H1N1) and seasonal influenza vaccination and disease among adults during the 2009-2010 influenza season

BACKGROUND

In April 2009, a novel influenza A virus emerged in the United States. By the end of July, influenza A (H1N1) 2009 monovalent (2009 H1N1) vaccine had been developed, licensed, and recommended by the Advisory Committee on Immunization Practices. Initial target groups for vaccination were identified and the first vaccine was publicly available in early October 2009.

OBJECTIVE

This study examines socio-demographic differences in opinions about 2009 pandemic influenza A (H1N1) (pH1N1) and seasonal influenza disease and vaccines and the association with receipt of influenza vaccinations during the 2009-2010 influenza season. Changes in opinions over the course of the pH1N1 pandemic were also examined.

METHODS

Data from the 2009 National H1N1 Flu Survey (NHFS) were analyzed. The NHFS was a CDC-sponsored telephone survey initiated in response to the 2009 pH1N1 pandemic to obtain weekly within-season estimates of vaccination coverage, opinions, and other information.

RESULTS

Opinions about influenza vaccine and disease varied significantly by race/ethnicity, income, and education level. In multivariable logistic regression analysis, adjusted 2009 H1N1 vaccination coverage was most strongly associated with opinions about the effectiveness of the vaccine and personal risk of disease, varying from 7 to 11% among adults who believed the vaccine to have low effectiveness and themselves at low risk of influenza, to 50-53% among those who thought vaccine effectiveness to be high and themselves at high risk of influenza.

CONCLUSION

Improving communication about personal risk and the effectiveness of influenza vaccines may improve vaccination coverage. The findings of difference in opinions could be used to target communication.