Maternal Influenza Research Articles

Obstetric Provider Attitudes and Office Practices for Maternal Influenza and Tdap Vaccination.

Background: Although maternal vaccination with influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines improve health outcomes for pregnant individuals and infants, maternal vaccination rates are low. This study assessed obstetric providers' attitudes and practices related to influenza and Tdap vaccination in four large health systems in New York (NY) and California (CA). Methods: We conducted a cross-sectional survey of all obstetric providers within four health systems (two in NY, two in CA) to evaluate provider attitudes and office systems used for Tdap and influenza vaccination. The survey assessed perceptions of influenza and Tdap vaccination based on the Health Belief Model, and assessed office systems (reminders, prompts, standing orders, and patient education) and communication with pregnant patients related to influenza and Tdap vaccines. Results: We had 112 responses (52% response rate) for analyses. Respondents strongly supported vaccination during pregnancy but viewed influenza disease as less of a concern for newborns than for pregnant individuals (40% vs. 67% considered influenza disease to be very significant, p < 0.001). Only 84% agreed that giving influenza vaccine in the first trimester is very safe. Patient vaccine refusal was the most commonly named barrier for both influenza and Tdap vaccination. Providers frequently used office system prompts, but did not frequently use standing orders, patient educational materials, vaccine champions, and feedback on vaccination rates. Conclusions: While most providers consider influenza and Tdap vaccination important during pregnancy, there is room for improvement in focusing on the importance of maternal vaccination to the health of the infant, and increasing the use of office systems to improve vaccination during pregnancy.

Knowledge, Perceptions, Attitudes and Practices of Midwives Regarding Maternal Influenza and Pertussis Vaccination: A Qualitative Study.

The coverage of maternal vaccination against pertussis and, particularly, influenza is lower than expected. The lack of recommendation from healthcare providers conditions non-vaccination in pregnant women. The purpose was to determine the knowledge, perceptions, attitudes and practices of midwives regarding maternal influenza and pertussis vaccination. A qualitative descriptive study based on semi-structured, face-to-face interviews with seventeen midwives was conducted, including purposive sampling and thematic analyses. Midwives had disparate knowledge and perceptions about the severity of influenza and pertussis in pregnant women, and influenza was not considered very serious. The vaccines were generally considered safe. However, because midwives did not have enough information about the safety of the influenza vaccine, there was a tendency not to recommend it. While most midwives had a positive attitude toward vaccination, their advocation for vaccination against influenza was not as clear as it was for pertussis. Not wanting to influence the decision and assuming an informative–facilitating role also led providers to recommend the influenza vaccine less frequently. Midwives are among the main sources of professional advice for pregnant women. Addressing their understanding and professional practices regarding maternal vaccination is key to change the attitude of pregnant women and thus increase vaccine uptake among them, particularly for influenza.

O-054 COVID-19 during pregnancy, maternal immune response and neonatal cell-specific immunity

Pathogens are a major threat to maternal health and the progression of pregnancy. The immune response during normally progressing pregnancies, primarily the suppression of inflammation, likely accounts for this high susceptibility of pregnant women to infections. An increased morbidity and mortality related to influenza, COVID-19 and malaria has been reported for pregnant women, compared to non-pregnant women. Especially influenza infections during pregnancy have been well studied, as humans are severely and recurrently affected by seasonal epidemics and random pandemics. Besides severe maternal symptoms such as acute cardiopulmonary events, pneumonia, and acute respiratory distress syndrome, maternal influenza infection also causes foetal complications, such as intrauterine growth restriction, preterm birth or even foetal death. However, vertical transmission of the influenza virus across the placenta and infection of the foetus has not been observed, suggesting that the pregnancy pathologies are maternally derived.In addition to influenza-mediated adverse conditions, the recent COVID-19 pandemic has underscored that infection with the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) can also lead to severe illnesses in pregnant women, accompanied by a higher risk for foetal loss or preterm birth. Fortunately, with the ongoing pandemic, large cohort studies and meta-analyses revealed that vertical transmission and related fetal infection is a rare complication affecting only 1-3% of SARS-CoV-2 infections in pregnancy. These low risk for placental infection is likely due to the inefficient SARS-CoV-2 virus replication in placental tissues. Since understanding SARS-CoV-2-related pathogenicity during pregnancy is highly relevant, we initiated a study early in 2020, to which we have recruited more than 160 pregnant women with COVID-19. Our comprehensive placental analyses unearthed a paucity of SARS-CoV-2 viral expression ex vivo in term placentae under acute infection and in convalescent pregnant women. Furthermore, we could show inefficient SARS-CoV-2 replication in placental tissues in vitro, which provides a rationale for the low ex vivo viral expression. We detected specific SARS-CoV-2 T cell responses in mothers within a few days upon infection, which is undetectable in cord blood. Reports by others have shown that maternal SARS-CoV-2 during pregnancy may cause placental insufficiency, defined by increased perivillous fibrin deposition, histiocytic intervillositis and trophoblast necrosis. These changes can cause extensive placental damage leading to placental malperfusion and insufficiency that is incompatible with intrauterine survival. Considering that multiple SARS-CoV-2 variants of concern which emerged until today may affect pregnant women differently and bear a differential risk for pregnancy complication. This, continuous vigilance is needed in order to provide best protection of the highly vulnerable group of pregnant women and their unborn children.Trial registration number

The risk of major structural birth defects associated with seasonal influenza vaccination during pregnancy: A population-based cohort study.

Seasonal inactivated influenza vaccine (IIV) is routinely recommended during pregnancy to protect both mothers and infants from complications following influenza infection. While previous studies have evaluated the risk of major structural birth defects in infants associated with prenatal administration of monovalent pandemic IIV, fewer studies have evaluated the risk associated with prenatal seasonal IIV. We conducted a population-based cohort study of 125,866 singleton births between 2012 and 2016 in Western Australia. Birth registrations were linked to the state's registers for congenital anomalies and a state prenatal vaccination database. We estimated prevalence ratios (PR) of any major structural birth defect and defects by organ system. Vaccinated pregnancies were defined as those with a record of IIV in the first trimester. Inverse probability treatment weighting factored for baseline probability for vaccination. A Bonferroni correction was applied to account for multiple comparisons. About 3.9% of births had a major structural birth defect. Seasonal IIV exposure during the first trimester was not associated with diagnosis of any major structural birth defect diagnosed within 1 month of birth (PR 0.98, 95% CI: 0.77, 1.28) or within 6 years of life (PR 1.02, 95% CI: 0.78, 1.35). We identified no increased risk in specific birth defects associated with seasonal IIV. Based on registry data for up to 6 years of follow-up, results suggest there is no association between maternal influenza vaccination and risk of major structural birth defects. These results support the safety of seasonal IIV administration during pregnancy.

Maternal influenza vaccination and child mortality: Longitudinal, population-based linked cohort study

Influenza vaccination is recommended to protect mothers and their infants from influenza. Few studies have evaluated the association between maternal influenza vaccination and child mortality. We aimed to evaluate the association between in utero exposure to seasonal inactivated influenza vaccine (IIV) and mortality among young children. This longitudinal, population-based cohort study included 191,247 maternal-child pairs in Western Australia between April 2012 and December 2017. Maternal vaccine information was obtained from a state-wide antenatal vaccination database. Mortality was defined as a record of a death registration. We used Cox proportional hazard models, weighted by the inverse-probability of treatment (vaccination), to estimate the hazard ratio of child mortality associated with in utero exposure to seasonal IIV. This study found no association between in utero exposure to seasonal IIV and mortality through age five years.

Influenza Vaccination Results in Differential Hemagglutinin Stalk-Specific Fc-Mediated Functions in Individuals Living With or Without HIV

Influenza virus hemagglutinin (HA) stalk-specific antibodies have been shown to potently induce Fc-mediated effector functions which are important in protection from disease. In placebo-controlled maternal influenza (MatFlu) vaccination trials of pregnant women living with or without HIV, reduced risk of influenza illness was associated with high HA stalk antibody titers following trivalent inactivated vaccination (TIV). However, the mechanisms of immunity conferred by the HA stalk antibodies were not well understood. Here, we investigated HA stalk-specific Fc effector functions including antibody-dependent cellular phagocytosis (ADCP), antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent complement deposition (ADCD), and FcγRIIa and FcγRIIIa binding in response to seasonal influenza vaccination. These were measured pre- and 1-month post-vaccination in 141 HIV-uninfected women (67 TIV and 74 placebo recipients) and 119 women living with HIV (WLWH; 66 TIV and 53 placebo recipients). In contrast to HIV-uninfected women, where HA stalk-specific ADCP and FcγRIIa binding were significantly boosted, WLWH showed no increase in response to vaccination. HA stalk-specific ADCC potential and FcγRIIIa binding were not boosted regardless of HIV status but were higher in WLWH compared with HIV-uninfected women prior to vaccination. HA stalk-specific ADCD was significantly increased by vaccination in all women, but was significantly lower in the WLWH both pre- and post- vaccination. Co-ordination between HA stalk-specific ADCP and ADCD in WLWH was improved by vaccination. Fc polyfunctionality was enhanced by vaccination in HIV-uninfected women and driven by the HA stalk antibody titers. However, in the WLWH, higher pre-vaccination Fc polyfunctionality was maintained post-vaccination but was decoupled from titer. Overall, we showed differential regulation of Fc effector HA stalk responses, suggesting that HIV infection results in unique humoral immunity in response to influenza vaccination, with relevance for future strategies that aim to target the HA stalk in this population.

Prenatal influenza vaccination and allergic and autoimmune diseases in childhood: A longitudinal, population-based linked cohort study.

Few studies have evaluated the effect of maternal influenza vaccination on the development of allergic and autoimmune diseases in children beyond 6 months of age. We aimed to investigate the association between in utero exposure to seasonal inactivated influenza vaccine (IIV) and subsequent diagnosis of allergic and autoimmune diseases. This longitudinal, population-based linked cohort study included 124,760 singleton, live-born children from 106,206 mothers in Western Australia (WA) born between April 2012 and July 2016, with up to 5 years of follow-up from birth. In our study cohort, 64,169 (51.4%) were male, 6,566 (5.3%) were Aboriginal and/or Torres Strait Islander children, and the mean age at the end of follow-up was 3.0 (standard deviation, 1.3) years. The exposure was receipt of seasonal IIV during pregnancy. The outcomes were diagnosis of an allergic or autoimmune disease, including asthma and anaphylaxis, identified from hospital and/or emergency department (ED) records. Inverse probability of treatment weights (IPTWs) accounted for baseline probability of vaccination by maternal age, Aboriginal and/or Torres Strait Islander status, socioeconomic status, body mass index, parity, medical conditions, pregnancy complications, prenatal smoking, and prenatal care. The models additionally adjusted for the Aboriginal and/or Torres Strait Islander status of the child. There were 14,396 (11.5%) maternally vaccinated children; 913 (6.3%) maternally vaccinated and 7,655 (6.9%) maternally unvaccinated children had a diagnosis of allergic or autoimmune disease, respectively. Overall, maternal influenza vaccination was not associated with diagnosis of an allergic or autoimmune disease (adjusted hazard ratio [aHR], 1.02; 95% confidence interval [CI], 0.95 to 1.09). In trimester-specific analyses, we identified a negative association between third trimester influenza vaccination and the diagnosis of asthma (n = 40; aHR, 0.70; 95% CI, 0.50 to 0.97) and anaphylaxis (n = 36; aHR, 0.67; 95% CI, 0.47 to 0.95).We did not capture outcomes diagnosed in a primary care setting; therefore, our findings are only generalizable to more severe events requiring hospitalization or presentation to the ED. Due to small cell sizes (i.e., <5), estimates could not be determined for all outcomes after stratification. In this study, we observed no association between in utero exposure to influenza vaccine and diagnosis of allergic or autoimmune diseases. Although we identified a negative association of asthma and anaphylaxis diagnosis when seasonal IIV was administered later in pregnancy, additional studies are needed to confirm this. Overall, our findings support the safety of seasonal inactivated influenza vaccine during pregnancy in relation to allergic and autoimmune diseases in early childhood and support the continuation of current global maternal vaccine programs and policies.

Preventing severe influenza in Australian infants: Maternal influenza vaccine effectiveness in the PAEDS-FluCAN networks using the test-negative design

• First multi-state study from Australia on maternal vaccine effectiveness against severe infant influenza. • Influenza vaccination in pregnancy provides greatest protection for infants aged < 2 months. • Despite free availability of the influenza vaccine, uptake in pregnant women remains low.

Are fetal arrhythmias associated with maternal influenza viral infections during pregnancy?—A systematic review and report of two cases

Background: Influenza virus infection during pregnancy is associated with adverse pregnancy outcomes, including congenital anomalies early in pregnancy; however, fetal arrhythmias have not been previously described in these pregnant women. In non-pregnant women, influenza viral infections are associated with arrhythmias and limited data exists regarding fetal arrhythmias secondary to maternal influenza infection. Methods: We performed an online systematic literature review, using PubMed, Google Scholar and Medline search engines to identify all listed publications that meet our inclusion criteria and identified a total of 40 articles. We reviewed abstracts, case reports, case series, surveillance or outbreak reports and observational cohort studies, and exlcuded non-English articles, as well as any unpublished reports, narrative reviews, irrelevant topics, and letter or editorials. We proposed to answer whether or not there is a possible association between maternal acquisition of influenza infection and fetal arrhythmias? Using the data search engines listed above, we identified a total of 40 articles through this search, of which 39 articles that did not meet our inclusion criteria. Thus, we identified only a single article that illustrated the key findings pertaining to our systematic review. In addition, we describe a case series of two additional cases. Results: Three cases were identified that demonstrate a possible association between maternal acquisition of influenza infection and fetal arrhythmias. In our case series, both cases required antiarrhythmic treatment during pregnancy and postnatally to achieve cardioversion to normal sinus rhythm. Neither of these pregnant women received vaccination against influenza at the time of their initial presentation. Conclusions: Fetal arrhythmias can lead to adverse pregnancy outcomes and can be treated early to allow for pregnancy prolongation and overall well-being improvement and chance for intact survival for the fetus and neonate. Based on our systematic review findings and current case series described here, we believe that there is a possible association between maternal influenza infection and fetal arrhythmias, thus, it seems reasonable to assess for concurrent maternal influenza infection in cases of fetal arrhythmias should other maternal symptoms be present for this infection. Larger observational studies are needed to assess if there truly is an association and whether or not a causal link can be established.

Efficacy of a Smartphone Application to Promote Maternal Influenza Vaccination: A Randomized Controlled Trial

The maternal vaccine coverage rate has been low in Taiwan. We developed an “Influenza Vaccination Reminder Application” and evaluated its efficacy in improving vaccination intention among pregnant women in Taiwan. A randomized controlled trial was conducted to compare the positive change in vaccination intention between the experimental group and the control group. Pregnant women who were more than 20 years old and at less than 32 weeks of gestation were recruited from four regional hospitals in southern Taiwan during November 2020 to April 2021. Pregnant women were randomly assigned to the experimental group, to whom the “Influenza Vaccination Reminder Application” was provided for at least two months, while pregnant women in the control group received regular maternal education only. The differences in knowledge about influenza and its vaccines, attitudes towards maternal influenza vaccination, and behavior intention of influenza vaccination among pregnant women before and after the experiment intervention were compared between two groups. The results included 126 women in the experimental group and 117 women in the control group and showed that the “Influenza Vaccination Reminder Application” increased pregnant women’s knowledge about influenza and vaccines (percentage increase in the experimental group and control group: 11.64% vs. 7.39%), strengthened their positive attitudes towards maternal influenza vaccination (percentage increase: 5.39% vs. 1.44%), and promoted positive behavioral intention toward influenza vaccination (proportion of participants with positive change in vaccination intention: 17.46% vs. 7.69%). The study supports use of “Influenza Vaccination Reminder Application” to promote the behavior intention of influenza vaccination among pregnant women in Taiwan.

Association between vaccination status, symptom identification and healthcare use: Implications for test negative design observational studies

AimTo test the internal validity of the test-negative design (TND) by investigating associations between maternal influenza vaccination, and new virus detection episodes (VDEs), acute respiratory illness, and healthcare visits in their children. MethodsEighty-five children from a birth cohort provided daily symptoms, weekly nasal swabs, and healthcare use data until age 2-years. Effect estimates are summarised as incidence rate ratios (IRR). ResultsThere was no association between maternal vaccination and VDEs in children (IRR = 1.1; 95 %CI = 0.9–1.2). Influenza-vaccinated mothers were more likely than unvaccinated mothers to both report, and seek healthcare for, acute lower respiratory illness in their children, IRR = 2.4; 95 %CI = 1.2–4.8 and IRR = 2.2; 95 %CI = 1.1–4.3, respectively. ConclusionA key assumption of the TND, that healthcare seeking behaviour for conditions of the same severity is not associated with vaccine receipt, did not hold. Further studies of the performance of the TND in different populations are required to confirm its validity.

Prenatal Influenza Vaccination or Influenza Infection and Autism Spectrum Disorder in Offspring.

As prenatal vaccinations continue to be given more frequently, it is important to assess long-term safety events. We investigated the association between prenatal influenza vaccination or infection and autism spectrum disorder (ASD) in offspring. A retrospective cohort study of mother-child pairs with deliveries between 1 January 2011 and 31 December 2014 at Kaiser Permanente Southern California was performed. Children aged >1 year were followed through 31 December 2018. Maternal influenza vaccination or infection during pregnancy was obtained from electronic health records. ASD was defined by International Classification of Diseases, Ninth or Tenth Revisions, Clinical Modification, codes after age 1 year. Cox proportional hazard models estimated the crude and inverse probability of treatment weighted (IPTW) hazard ratios (HR) for the association between maternal influenza vaccination or infection and ASD. There were 84739 mother-child pairs included in the final analytic sample. Of the 46257 women vaccinated, 32.4% were vaccinated during the first trimester, 41.8% during the second trimester, and 25.8% during the third trimester. ASD was diagnosed in 1930 (2.3%) children. The IPTW analyses showed no association between prenatal influenza vaccination or infection and ASD in offspring (HR, 1.04; 95% confidence interval [CI], .95-1.13; HR, 1.12; 95% CI, .66-1.89, respectively). Prenatal influenza vaccination or infection was not associated with ASD risk in offspring. The findings support recommendations to vaccinate pregnant women to protect themselves and their infants, both of whom are vulnerable to severe morbidity following infection.

Views and experiences of maternal healthcare providers regarding influenza vaccine during pregnancy globally: A systematic review and qualitative evidence synthesis.

The World Health Organization (WHO) recommends that pregnant women receive influenza vaccination; however, uptake of the vaccine remains low. Maternity health care professionals (MHCPs) play an important role in motivating pregnant women to receive the influenza vaccine. However, factors such as MHCPs' views and knowledge about the vaccine, and time constraints due to workload may influence MHCPs' practices and opinions about women receiving the influenza vaccine during pregnancy. To date, the qualitative evidence exploring MHCPs' views and experiences around influenza vaccine uptake in pregnant women has not been synthesised. To systematically review and thematically synthesise qualitative evidence that explores the views and experiences of MHCPs involved in the provision of the maternal influenza vaccine worldwide. Five databases (MEDLINE, EMBASE, PsycINFO, CINAHL, Web of Science) were searched, supplemented with searches of included paper reference lists and grey literature. Study selection was conducted by up to three researchers applying pre-specified inclusion/exclusion criteria. Quality assessment was undertaken, data were extracted, coded and synthesised to develop descriptive and analytical themes. Eight studies involving 277 participants were included. Seventeen descriptive themes were interpreted, embedded within six analytical themes. MHCPs perceived that maternal influenza vaccination delivery can be facilitated by trusting relationships, good communication, knowledge about the vaccine leading to confidence in recommending vaccine, electronic vaccination prompts, and presence of national guidelines. However, workload, time constraints, MHCP's perception of pregnant women's concerns, and social/cultural/environmental influences could prevent the likelihood of delivery of influenza vaccine. Knowledgeable MHCPs who were regularly updated about vaccination based on scientific evidence were more confident when discussing and recommending the influenza vaccine to pregnant women. In addition, the presence of national policies and guidelines and electronic prompts for maternal influenza vaccination would enhance the delivery of the vaccine. Our findings suggest that approaches to enhance the vaccination uptake rate in pregnant women include addressing MHCPs barriers to discussing influenza vaccination through education, sufficient time for discussions, and electronic prompts about vaccination, as well as evidence based local and national guidelines.

Association of BNT162b2 COVID-19 Vaccination During Pregnancy With Neonatal and Early Infant Outcomes

Pregnant women were excluded from the BNT162b2 messenger RNA (mRNA) COVID-19 vaccine (Pfizer-BioNTech) preauthorization trial. Therefore, observational data on vaccine safety for prenatally exposed newborns are critical to inform recommendations on maternal immunization. To examine whether BNT162b2 mRNA vaccination during pregnancy is associated with adverse neonatal and early infant outcomes among the newborns. Population-based cohort study comprising all singleton live births in March through September 2021, within a large state-mandated health care organization in Israel, followed up until October 31, 2021. Maternal BNT162b2 mRNA vaccination during pregnancy. Risk ratios (RR) of preterm birth, small birth weight for gestational age (SGA), congenital malformations, all-cause hospitalizations, and infant death. Stabilized inverse probability weighting was used to adjust for maternal age, timing of conception, parity, socioeconomic status, population subgroup, and maternal influenza immunization status. The cohort included 24 288 eligible newborns (49% female, 96% born at ≥37 weeks' gestation), of whom 16 697 were exposed (n = 2134 and n = 9364 in the first and second trimesters, respectively) to maternal vaccination in utero. Median (IQR) follow-up after birth was 126 days (76-179) among exposed and 152 days (88-209) among unexposed newborns. No substantial differences were observed in preterm birth rates between exposed and unexposed newborns (RR = 0.95; 95% CI, 0.83-1.10) or SGA (RR = 0.97; 95% CI, 0.87-1.08). No significant differences were observed in the incidence of all-cause neonatal hospitalizations (RR = 0.99; 95% CI, 0.88-1.12), postneonatal hospitalizations after birth (RR = 0.95; 95% CI, 0.84-1.07), congenital anomalies (RR = 0.69; 95% CI, 0.44-1.04), or infant mortality over the study period (RR = 0.84; 95% CI, 0.43-1.72). This large population-based study found no evident differences between newborns of women who received BNT162b2 mRNA vaccination during pregnancy, vs those of women who were not vaccinated, and contributes to current evidence in establishing the safety of prenatal vaccine exposure to the newborns. Interpretation of study findings is limited by the observational design.

Exploring Tdap and influenza vaccine uptake and its determinants in pregnancy: a cross-sectional study.

The literature claims that an increased risk of complications from pertussis and influenza exists for pregnant women and infants. Maternal tetanus, diphtheria, and acellular pertussis (Tdap) and influenza vaccines seem to decrease this risk so that several countries are committed to increase vaccination uptake, but not all of them know their own vaccination coverage and factors that motivate this population to vaccination. A cross-sectional survey was conducted. We conducted this survey to estimate among pregnant women: 1) the vaccine coverage, 2) the availability of information, 3) the knowledge about maternal Tdap and influenza vaccination, 4) the factors that could have driven unvaccinated pregnant women to have themselves vaccinated. In addition, determinants of Tdap and influenza vaccine uptake and correct knowledge about vaccine-preventable diseases and vaccination in pregnancy were assessed using univariate and multivariate analyses. Of the 250 women included in the present study, only 58 (23.2%, 95% Confidence Interval (CI): 18-28.4%) and 21 (8.1%, 95% CI: 5-11.8%) reported that they had been vaccinated with Tdap and influenza vaccine, respectively, during their current pregnancy. The most common reasons cited for getting themselves vaccinated was having background knowledge of the health problems due to the diseases prevented by Tdap and influenza vaccines, awareness regarding these vaccines being recommended in pregnancy, knowledge of their effectiveness and/or side effects, and having been informed about vaccination by a healthcare professional. Influenza and Tdap vaccine uptake among pregnant women in Italy is low, however, the present study showed that women are available to get vaccinated during pregnancy when adequately informed about the vaccines recommended.

Determinants of maternal influenza vaccination in the context of low- and middle-income countries: A systematic review.

Pregnancy and early infancy are considered to be the vulnerable phases for severe influenza infection causing morbidity and mortality. Despite WHO recommendations, influenza is not included in the immunization programs of many low- and middle-income countries. This systematic review is aimed at identifying barriers and facilitators for maternal influenza vaccination amongst the perinatal women and their health care providers in low- and middle-income countries. We selected 11 studies from the 1669 records identified from PubMed, CABI, EMBASE and Global Health databases. Studies related to both pandemic and routine influenza vaccination and studies conducted amongst women in the antenatal as well as postnatal period were included. Both qualitative, quantitative, cross-sectional and interventional studies were included. Knowledge about influenza disease, perception of the disease severity during pregnancy and risk to the foetus/newborn and perceived benefits of influenza vaccination during pregnancy were associated with increased uptake of influenza vaccination during pregnancy. Recommendation by health care provider, vaccination in previous pregnancy and availability of vaccine in public health system facilitated vaccine uptake. High parity, higher education, vaccination in the later months of pregnancy, less than 4 antenatal visits, concerns about vaccine safety and negative publicity in media were identified as barriers for influenza vaccination. Lack of government recommendation, concerns about safety and effectiveness and distrust in manufacturer were the barriers for the healthcare providers to recommend vaccination. While availability of influenza vaccine in public health system can be a key to the success of vaccine implementation program, increasing the awareness about need and benefits of maternal influenza vaccination amongst pregnant women as well as their health care providers is crucial to improve the acceptance of maternal influenza vaccination in low and middle-income countries.

Attitudes toward year-round influenza vaccination in pregnant women.

Influenza virus circulates year-round, yet uptake of maternal influenza vaccination decreases outside of influenza season. This prospective study of 62 pregnant women provides insight into the possible underlying reasons for this. Despite knowledge of benefits for maternal and infant outcomes, we observed a lack of understanding of rates of influenza infection outside influenza season, concerns about safety in relation to receiving multiple vaccinations during the same pregnancy, and lack of healthcare provider recommendation to be vaccinated outside influenza season. These findings can help tailor public health education targeting pregnant women and their healthcare providers to improve influenza vaccine uptake.

Effectiveness of maternal vaccination with quadrivalent inactivated influenza vaccine in pregnant women and their infants in 2019-2020

ABSTRACT Objectives Influenza is associated with an increased risk for serious illness, hospitalization, and death in pregnant women and young infants. Our aim was to estimate the effectiveness of a quadrivalent inactivated influenza vaccine (QIV) in pregnant women and their infants during 2019–2020. Methods A QIV vaccine was offered to pregnant women followed in a maternity hospital. Women were contacted weekly during the influenza season and asked about symptoms. Polymerase chain reaction testing in pharyngeal samples was offered to pregnant women and infants with influenza-like illness. A Bayesian beta-binomial model was used. Results We studied 636 pregnant women (406 vaccinated and 230 unvaccinated) and 474 infants (281 of mothers vaccinated in pregnancy and 193 of unvaccinated mothers). Using a Bayesian beta-binomial model, it was estimated that influenza vaccination of pregnant women reduced their logit to develop laboratory-confirmed influenza by −4.2 (95% CI −3,7 − 4,7) and the logit of their infants to develop laboratory-confirmed influenza by −4.2 (95% CI −3.6, −4.9). The QIV effectiveness against laboratory-confirmed influenza was 43.5% in pregnant women and 31.4% in infants. Conclusion Maternal influenza vaccination with QIV in pregnancy reduced the odds of pregnant women and their infants to develop influenza. Clinical trial registration www.clinicaltrials.gov identifier is NCT04723771.

Influences on Pregnant Women's and Health Care Professionals' Behaviour Regarding Maternal Vaccinations: A Qualitative Interview Study.

The uptake of maternal influenza and pertussis vaccinations is often suboptimal. This study explores the factors influencing pregnant women’s and health care professionals’ (HCPs) behaviour regarding maternal vaccinations (MVs). Pregnant/recently pregnant women, midwives, pharmacists and general practice staff in Waikato, New Zealand, were interviewed. The analysis used the behaviour change wheel model. Interviews of 18 women and 35 HCPs revealed knowledge about MVs varied with knowledge deficiencies hindering the uptake, particularly for influenza vaccination. HCPs, especially midwives, were key in raising women’s awareness of MVs. Experience with vaccinating, hospital work (for midwives) and training increased HCPs’ knowledge and proactivity about MVs. A “woman’s choice” philosophy saw midwives typically encouraging women to seek information and make their own decision. Women’s decisions were generally based on knowledge, beliefs, HCPs’ emphasis and their perceived risk, with little apparent influence from friends, family, or online or promotional material. General practice’s concentration on children’s vaccination and minimal antenatal contact limited proactivity with MVs. Busyness and prioritisation appeared to affect HCPs’ proactivity. Multi-pronged interventions targeting HCPs and pregnant women and increasing MV access are needed. All HCPs seeing pregnant women should be well-informed about MVs, including how to identify and address women’s questions or concerns about MVs to optimise uptake.

Mapping the maternal vaccination journey and influencing factors for Māori women in Aotearoa New Zealand: a qualitative study.

Introduction Uptake of maternal vaccinations (MVs) is suboptimal in Aotearoa New Zealand, particularly for Māori. Aim To describe Māori women's journeys regarding maternal pertussis and influenza vaccinations and explore influences on uptake. Methods Semi-structured interviews were conducted in Waikato, Aotearoa New Zealand, with pregnant or recently pregnant Māori women, and separately with Māori healthcare professionals (HCPs) to understand women's decisions regarding MVs and enablers and barriers to uptake. Results Nine women and nine HCPs were interviewed. Verbal communications from midwives, general practice and pharmacy strongly influenced women's journeys. Women's decisions appeared largely straight-forward, with influences including awareness, knowledge, underlying beliefs and previous MVs. Enablers for MV uptake included HCPs' discussions, pro-vaccination beliefs, and accessibility. Barriers for MV uptake included poverty (and transport), lack of awareness, insufficient knowledge of benefits, late presentation to the midwife and other commitments or challenges in the women's lives affecting prioritisation of the vaccine. Misconceptions, seasonality, and lower HCP emphasis impaired influenza vaccination uptake. Discussion With multiple barriers to accessing MVs, HCPs who see pregnant women are the primary resource to improve awareness, knowledge, and access through kōrero (discussions) with the woman and, where possible, being able to administer the vaccinations. These HCPs need to be well-informed, aware of likely concerns women may have and how to address them, encourage these discussions and preferably be trusted.