Influenza Vaccination In Pregnancy Research Articles

Summary of the National Advisory Committee on Immunization (NACI) Updated Guidance on Influenza Vaccination During Pregnancy.

Seasonal influenza infection can lead to serious complications and adverse outcomes for pregnant individuals, the developing fetus and infants younger than six months of age. This supplemental statement provides an evidence summary on the safety and effectiveness of influenza vaccination in pregnant individuals, and the benefits and risks to the pregnant person, the developing fetus and infants younger than six months of age. A systematic review was conducted on the effectiveness and safety of influenza vaccination in pregnancy. The National Advisory Committee on Immunization (NACI)'s evidence-based process was used to assess the quality of eligible studies, summarize and analyze the findings, and apply an ethics, equity, feasibility and acceptability lens to develop recommendations. The evidence suggests that influenza vaccination during pregnancy is effective in reducing the risk of laboratory-confirmed influenza infection and hospitalization in both pregnant individuals and their infants up to six months postpartum. The evidence also suggests that influenza vaccination during pregnancy does not increase the risk of non-obstetric serious adverse events in pregnant persons, infant death, spontaneous abortion, stillbirth, preterm birth, small for gestational age, low birth weight and congenital anomalies. Based on this body of evidence, NACI reaffirms the safety and importance of influenza vaccination during pregnancy. NACI recommends that individuals at any stage of pregnancy should receive an age-appropriate inactivated, unadjuvanted or recombinant influenza vaccine each influenza season. Influenza vaccination may be given at the same time as, or at any time before or after administration of another vaccine, including the coronavirus disease 2019 (COVID-19) or pertussis vaccines.

Midwives’ perceptions of enablers and barriers to pertussis and influenza vaccination in pregnancy and information sharing

Background: Vaccination in pregnancy against influenza and pertussis protects the pregnant woman/person and their infant against severe disease. Aotearoa New Zealand has a lower uptake of vaccination in pregnancy than some other countries, despite this immunisation being publicly funded. Coverage is also inequitable, with Māori, Pacific people, and people from high deprivation areas less likely to be vaccinated. Many barriers exist to vaccinations in pregnancy, e.g., access barriers and lack of knowledge about vaccination. Discussions about recommended vaccines with healthcare professionals, particularly midwives, may have a positive impact on vaccine decision-making. Aim: This study aimed to investigate midwives’ perceptions of enablers and barriers with discussions about vaccinations in pregnancy, barriers to vaccination in pregnancy, and influences on vaccine decision-making in pregnancy. The study also aimed to gather midwives’ insights into what might improve vaccination uptake. Method: A structured questionnaire was developed containing a mix of closed and open-ended questions. The questionnaire was sent out to 3002 midwives registered in Aotearoa New Zealand in October 2021, using REDCap electronic data capture tools. Simple descriptive statistics were undertaken on the quantitative data. The answers to the open-ended questions were analysed using a direct, qualitative content analysis approach. Findings: Fifty-one midwives’ responses were included in the analysis (1.8% response rate). Almost all reported sufficient knowledge of vaccinations in pregnancy but had varying levels of confidence when discussing them. The most common enablers to conversations were good relationships, easy communication, and having the time and resources available. Respondents perceived that barriers to conversations were negative preconceptions, communication difficulties and lack of time. Lack of awareness, cost to access services and competing priorities for time were also thought to reduce the likelihood of vaccination in pregnancy. To improve vaccine uptake, respondents identified the need for accessible and suitable vaccination venues, appropriate information and the support of all healthcare professionals involved in maternal healthcare. Conclusion: Midwives surveyed understand the importance of vaccination in pregnancy but there may be lack of confidence, time or resources to effectively engage in discussions. A trusting relationship is important but this can be affected by disengagement or late presentation to healthcare services. Resources to counter pre-existing negative ideas and support communication would help midwives to provide useful information about vaccination. Furthermore, respect and cultural understanding of hapū Māori and their needs will positively support their ability to make informed decisions.

Progress in research of influenza vaccination in pregnant women

Influenza is an acute respiratory infectious disease caused by influenza virus. Pregnancy is associated with physiologic and immunological changes that may increase the risk for influenza virus infection and influenza-related complications. Influenza vaccination is the most effective way to prevent influenza virus infection. WHO and many countries have classified pregnant women as a priority population for influenza vaccination, however, there are still many challenges for promoting influenza vaccination in pregnant women in China, influenza vaccination coverage in pregnant women remains low and some influenza vaccine package inserts list pregnancy as an absolute contraindication. In this paper, we summarize the research progress in the effects of influenza infection and influenza vaccination during pregnancy both at home and abroad, then discuss the strategies to promote influenza vaccination in pregnancy for the purpose of providing reference for the related research and policy development in China.

Vaccination against influenza in pregnant women in a maternity hospital in the Czech Republic in the season 2020–2021

ObjectivesPregnant women are among the priority groups to receive influenza vaccines in the Czech Republic since 2011, data on vaccination coverage are not yet available. The aim of the study was to determine the influenza vaccination coverage (IVC) and provide source data for further activities.MethodsA prospective observational study was performed in a large maternity hospital in Prague. The self-completed questionnaire was distributed to 5,475 pregnant women between September 1, 2020 and August 31, 2021. Questions included maternal sociodemographic characteristics, influenza vaccination status and sources of maternal vaccination recommendations during pregnancy.ResultsA total of 4,617 completed questionnaires have been analysed. The median age of study participants (N = 4,592) was 33 years (range: 18–51 years). The majority (69.7%) of women had completed their university education, most women were childless (58.5%) or had one child (32.5%) before the start of the study. Less than 2% of women reported being vaccinated against influenza during their pregnancy (1.5%; 95% CI, 1.1–1.9%). Only 21% of women knew that it’s possible to get vaccinated against influenza during pregnancy. Participants considered influenza vaccination in pregnancy as important (3.3%), useful (41.1%) and useless (44.4%). Out of 959 pregnant women who had information about influenza vaccination during pregnancy, only 6.9% were vaccinated, while among those who did not have this information, 0.1% were vaccinated during pregnancy (p < 0.001). The most frequent source of information was Internet, then media and a general practitioner.ConclusionsThe IVC during pregnancy in our study was extremely low. In order to improve IVC among pregnant women, it is necessary to increase awareness of recommendations and vaccination options among the public and professionals and incorporating vaccination recommendation in routine antenatal practice.

The use of test-negative case-control studies to determine the effectiveness of influenza vaccination in pregnancy: results from a systematic review and meta-analysis

The use of test-negative case-control studies to determine the effectiveness of influenza vaccination in pregnancy: results from a systematic review and meta-analysis

Vaccination uptake for pertussis and influenza vaccines in pregnancy among different practices at a single institution.

The authors investigated tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) and influenza vaccination during pregnancy following Advisory Committee on Immunization Practices' (ACIP's) recommendation for antenatal pertussis vaccination. A retrospective chart review was performed in 2019 of women receiving prenatal care at our institution between January 1, 2014 and December 31, 2018. Receipt of ACIP-recommended vaccines were examined using Current Procedural Terminology codes to identify initiation of prenatal care, then administration of Tdap and influenza vaccines. Data were examined by individual practice (university faculty, community physicians, obstetrics and gynecology (OBGYN) residents, and family medicine residents, practice staff composition, vaccination protocol use, and insurance status. Statistical analyses were performed using χ2 testing and χ2 testing of linear trend. Within our cohort (n = 17 973), highest vaccination uptake occurred in the university-based OBGYN faculty practice (Tdap = 58.2%, influenza = 56.5%) with lowest uptake in the OBGYN resident practice (Tdap = 28.6%, influenza = 18.5%). Higher uptake occurred in practices with standing orders, more advanced practice providers, lower provider to nursing ratios, and lower rates of Medicaid insurance. These data demonstrated higher vaccination uptake with standing orders, more advanced practice providers, and lower provider to nurse ratios. Future work optimizing practice staff composition and vaccination protocols may increase vaccine uptake.

Interventions to increase uptake of influenza vaccination in pregnancy: A systematic review and meta-analysis.

Maternal influenza vaccination has been introduced in several countries to prevent influenza-related morbidity and mortality in pregnant women, fetuses, and infants too young to be vaccinated. To analyze the available randomized controlled trials (RCTs) on the effectiveness of pregnant women-focused interventions to increase influenza vaccination uptake during pregnancy. Medline, CINAHL, Scopus, Web of Science, and Cochrane Trial were searched on August 25, 2021. RCTs assessing the effectiveness of pregnant women-focused interventions in increasing influenza vaccination among pregnant women were included. Two independent reviewers extracted data. A random-effects meta-analysis was conducted to estimate pooled odds ratios (ORs). Seven RCTs were selected. Overall, the interventions had a significant effect in increasing influenza vaccination during pregnancy compared with standard care (OR 1.78, 95% confidence interval [CI] 1.25-2.54; P= 0.001; I2 = 67%). However, subgroup analysis suggested that influenza vaccination uptake only was associated with educational interventions (OR 2.71, 95% CI 1.93-3.81; P< 0.001; I2 = 0%). We found that several educational interventions for pregnant women can effectively increase influenza vaccination uptake in this population. Specifically, pamphlets, websites, and brief one-to-one education can be effective tools. CRD42021269478.

Knowledge, Attitude, Perceptions, and Concerns of Pregnant Women Regarding the Influenza Vaccination in Kocaeli, Turkey.

IntroductionIn order to better understand the barriers to influenza vaccination, we have designed a study to investigate pregnant women's knowledge, attitude, perceptions, and concerns towards the inactivated influenza vaccine.Materials and methodsIn this prospective study, carried out between July 1, 2019, and December 31, 2019, 252 pregnant women (≥12 weeks of gestational age), who had consented to be enrolled in the study, were asked to complete an interviewer-administered questionnaire during their stay in the hospital ward.ResultsThe lack of information about influenza vaccines (59.4%) was in the first rank among the reasons for personal and parental vaccine rejection. Most (65.1%) pregnant women either did not believe in or had doubts about the efficiency of the influenza vaccine during gestation. Most of them (80.9%) either were not sure about or did not have much confidence in the prenatally inoculated vaccine's ability to protect their babies postnatally. Some (25.6%) participants attributed their vaccinal unwillingness to fear of adverse effects, and some (11.5%) deemed gestational influenza immunization unnecessary because of their tendency to underestimate the grave consequences of influenza contracted by infants within the first six months of life. The higher the education level, the higher was the knowledge of and the willingness to be immunized against influenza.DiscussionIt is known that about one-third of pregnant women in Turkey have never heard of the influenza vaccine. Unawareness of influenza vaccination in pregnancy is significantly related to vaccine uptake in Japan. Patient education on knowledge of influenza and influenza vaccination has a booster effect on vaccination rates. Had the influenza vaccine been routinely administered to pregnant women in Turkey, the lives of the majority of the women who died of influenza in the influenza A (H1N1) pandemic in 2009 would have been saved. Low-risk perception is quoted as one of the main reasons for influenza vaccine refusal during pregnancy, which was also the case in our study. Concordant with the current literature, the education level and household income were correlated with the level of influenza vaccination uptake. Pregnant women's fear of adverse effects of the influenza vaccine might extend to the fear of birth defects.ConclusionThe acceptance of influenza vaccines by pregnant women is a consequence of complex interactions of various factors. Giving necessary information to pregnant women is one of the most important factors that can increase influenza vaccine uptake. For this reason, it should be ensured that the efficacy and safety data of the influenza vaccine are more widely included in vocational training activities of health personnel and in prenatal care textbooks and guidelines.

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.

Association of Maternal Influenza Vaccination During Pregnancy With Early Childhood Health Outcomes

Seasonal influenza vaccination in pregnancy can reduce influenza illness among pregnant women and newborns. Evidence is limited on whether seasonal influenza vaccination in pregnancy is associated with adverse childhood health outcomes. To assess the association between maternal influenza vaccination during pregnancy and early childhood health outcomes. Retrospective cohort study, using a birth registry linked with health administrative data. All live births in Nova Scotia, Canada, between October 1, 2010, and March 31, 2014, were included, with follow-up until March 31, 2016. Adjusted hazard ratios (HRs) and incidence rate ratios (IRRs) with 95% confidence intervals were estimated while controlling for maternal medical history and other potential confounders using inverse probability of treatment weighting. Seasonal influenza vaccination during pregnancy. Childhood outcomes studied were immune-related (eg, asthma, infections), non-immune-related (eg, neoplasms, sensory impairment), and nonspecific (eg, urgent or inpatient health care utilization), measured from emergency department and hospitalization databases. Among 28 255 children (49% female, 92% born at ≥37 weeks' gestation), 10 227 (36.2%) were born to women who received seasonal influenza vaccination during pregnancy. During a mean follow-up of 3.6 years, there was no significant association between maternal influenza vaccination and childhood asthma (incidence rate, 3.0 vs 2.5 per 1000 person-years; difference, 0.53 per 1000 person-years [95% CI, -0.15 to 1.21]; adjusted HR, 1.22 [95% CI, 0.94 to 1.59]), neoplasms (0.32 vs 0.26 per 1000 person-years; difference, 0.06 per 1000 person-years [95% CI, -0.16 to 0.28]; adjusted HR, 1.26 [95% CI, 0.57 to 2.78]), or sensory impairment (0.80 vs 0.97 per 1000 person-years; difference, -0.17 per 1000 person-years [95% CI, -0.54 to 0.21]; adjusted HR, 0.82 [95% CI, 0.49 to 1.37]). Maternal influenza vaccination in pregnancy was not significantly associated with infections in early childhood (incidence rate, 184.6 vs 179.1 per 1000 person-years; difference, 5.44 per 1000 person-years [95% CI, 0.01 to 10.9]; adjusted IRR, 1.07 [95% CI, 0.99 to 1.15]) or with urgent and inpatient health services utilization (511.7 vs 477.8 per 1000 person-years; difference, 33.9 per 1000 person-years [95% CI, 24.9 to 42.9]; adjusted IRR, 1.05 [95% CI, 0.99 to 1.16]). In this population-based cohort study with mean follow-up duration of 3.6 years, maternal influenza vaccination during pregnancy was not significantly associated with an increased risk of adverse early childhood health outcomes.

Knowledge, perception and maternal immunisation practices of obstetricians in Singapore for the Tdap and influenza vaccines.

Obstetricians' knowledge and perception of evidence-based recommendations may influence the uptake of antenatal tetanus, diphtheria and pertussis (Tdap) and influenza vaccination. Our survey aimed to assess the knowledge, perception and practices of local obstetricians regarding delivery of antenatal Tdap and influenza vaccines, and perceived barriers to maternal immunisation. There was generally adequate knowledge that Tdap and influenza vaccination in pregnancy was safe, effective and beneficial. However, knowledge regarding recommendations in local guidelines was poorer for Tdap compared to influenza vaccination. Lack of time for patient education was the top perceived barrier for both Tdap and influenza vaccination. A significant proportion of obstetricians cited uncertainty regarding recommendations as a reason for not routinely offering maternal immunisation. These findings demonstrate an urgent need to raise awareness of evidence-based recommendations regarding maternal immunisation, and to promote Tdap and influenza vaccination during antenatal visits so as to improve maternal immunisation rates in Singapore.

Understanding Influenza Vaccination During Pregnancy in Canada: Attitudes, Norms, Intentions, and Vaccine Uptake.

To improve uptake of influenza vaccine in pregnancy, it is important to understand the factors that predict prenatal vaccination. The aim of this study was to test the capability of the theory of planned behavior, augmented with information constructs, to predict and explain influenza vaccination uptake in a sample of 600 pregnant individuals in Canada. A baseline survey at the start of influenza season assessed beliefs, norms, perceived control, and information-seeking behavior related to influenza vaccination in pregnancy, as well as respondent demographics. A follow-up survey at the conclusion of influenza season assessed self-reported influenza vaccine uptake as well as infant vaccination intentions. Multivariable analysis indicated that attitudes toward influenza vaccination in pregnancy, subjective norms, information seeking, and past vaccination behavior predicted intentions to be vaccinated, and intentions predicted vaccine uptake. Neither perceived control nor demographics were significant predictors of intentions or vaccine uptake. These findings suggest that presumptive offering of vaccination in pregnancy by health care providers, as well as patient and public health educational interventions, may be effective in communicating norms and strengthening positive attitudes and intentions concerning influenza vaccination in pregnancy, resulting in higher vaccine coverage.

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

Vaccination is considered to be the most practical and effective preventative measure against influenza. It is highly recommended for population subgroups most at risk of developing complications, including pregnant women. However, seasonal influenza vaccine uptake remains suboptimal among pregnant women, even in jurisdictions with universal vaccination. We summarized the evidence on the determinants of seasonal influenza vaccine uptake during pregnancy to better understand factors that influence vaccine uptake among pregnant women. We systematically searched MEDLINE, Embase and CINAHL from January 2000 to February 2020 for publications in English reporting on sociodemographic and/or health-related determinants of seasonal influenza vaccine uptake during pregnancy. Two reviewers independently included studies. One reviewer extracted data and assessed study quality, and another reviewer checked extracted data and study quality assessments for errors. Disagreements were resolved through consensus, or a third reviewer. We meta-analyzed using the inverse variance, random-effects method, and reported the odds ratios (OR) and 95% confidence intervals (CI). From 1663 retrieved citations, we included 36 studies. The following factors were associated with increased seasonal influenza vaccine uptake: Older age (20 studies: OR 1.13, 95% CI 1.07-1.20), being nulliparous (13 studies: OR 1.26, 95% CI 1.15-1.38), married (8 studies: OR 1.11, 95% CI 1.07-1.15), employed (4 studies: OR 1.13, 95% CI 1.02-1.24), a non-smoker (8 studies: OR 1.25, 95% CI 1.04-1.51) and having prenatal care (3 studies: OR 3.36, 95% CI 2.25-5.02), a chronic condition (6 studies: OR 1.30, 95% CI 1.17-1.44), been previously vaccinated (9 studies: OR 4.88, 95% CI 3.14-7.57) and living in a rural area (9 studies: OR 1.09, 95% CI 1.05-1.14). Compared with being black, being white was also associated with increased seasonal influenza vaccine uptake (11 studies: OR 1.30, 95% CI 1.20-1.41). The evidence suggests that several sociodemographic and health-related factors may determine seasonal influenza vaccination in pregnancy, and that parity, history of influenza vaccination, prenatal care and comorbidity status may be influential.

89 Association of chronic comorbid disease and severe maternal morbidity among pregnant patients with influenza

Patients with chronic comorbid disease are at increased risk of morbidity and mortality from influenza, and whether this holds for pregnant patients remains to be defined. Our objective was to determine among pregnancies with influenza, whether chronic comorbid disease was associated with an increased risk of maternal morbidity. A cross sectional analysis of delivery hospitalizations complicated by influenza during pregnancy was conducted using the 2000-2015 National Inpatient Sample. Chronic comorbid conditions included chronic hypertension (cHTN), pregestational diabetes (PGDM), obesity, and obstructive lung disease (OLD). The primary outcome was severe maternal morbidity (SMM) defined by Centers for Disease Control and Prevention criteria, and secondarily, complications associated with influenza, including sepsis/shock, acute respiratory distress syndrome (ARDS), and mechanical ventilation/tracheostomy. Log linear models were used, adjusting for patient, hospital, and clinical variables. Of 62.7 million, 182,228 (0.3%) delivery hospitalizations were complicated by influenza, with a rate over 2-fold higher of 64.7 per 10,000 deliveries for patients with chronic comorbidities versus 24.4 without. Over 1 in 4 (26%, n=47, 273) deliveries with influenza had one or more chronic comorbidities and higher frequencies of SMM (2.7% vs 1.9%), ARDS (0.8% vs. 0.4%), and mechanical ventilation (0.2% vs. 0.1%) with similar rates of shock/sepsis. Among pregnant patients with influenza, those with OLD were at higher risk of SMM (adjusted risk ratio (aRR): 1.18), as well as ARDS (aRR: 1.83) and mechanical ventilation (aRR: 2.45). Patients with cHTN, obesity, and PGDM were also at elevated risks of adverse complications (Table). Among patients with influenza during pregnancy, chronic comorbid conditions, particularly obstructive lung disease, may increase the risk of maternal morbidity. Further efforts aimed at increasing influenza vaccination in pregnancy for patients with chronic comorbidities as well as optimizing pregnancy care for this population may mitigate this risk.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Assessing influenza vaccination behaviors among medically underserved obstetric patients

Background: Despite recommendations, maternal influenza vaccine acceptance has stagnated around 50%. Materials and Methods: A prospective cohort study was conducted of pregnant women seen in the clinic from September 2018 to April 2019. Primary outcomes included influenza vaccine uptake and reasons for vaccine refusal, categorized based on the Health Belief Model. We compared characteristics between three vaccination groups (never refused, refused and vaccinated, and refused and not vaccinated) by using chi-square and one-way analysis of variance. We used multivariate logistic regression to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for associations between patient characteristics and vaccine acceptance. Mixed-effects logistic regression models were used to explore the impact of provider-patient race concordance on influenza vaccine uptake. Results: Among 1666 women, 902 (54.1%) were vaccinated. Of these, 183 (20.3%) initially refused. Those who refused and were never vaccinated were more likely to be non-Hispanic black (aOR: 1.64, 95% CI: 1.05-2.56) and less likely to be Hispanic (aOR: 0.44, 95% CI: 0.24-0.81). Overall, perceived barriers were the most common reason for refusal (52.4%). Women who refused consistently were more likely to cite reasons related to perceived benefits (38.5% vs. 7.6%). Those who eventually accepted were more likely to cite cue to action (22.4% vs. 12.6%). Women who were race discordant with their provider were more likely to be vaccinated compared with those who were race concordant (57.9% vs. 52.9%, aOR: 1.16, 95% CI: 1.07-1.27). Conclusions: Women who refuse influenza vaccination in pregnancy may later choose to be vaccinated. Continued promotion of vaccination throughout pregnancy is crucial for vaccine uptake.

Influenza vaccination in pregnancy - current data on safety and effectiveness.

Pregnant women are at risk of severe and complicated influenza, and so are children aged 2-5 years. Despite numerous recommendations, influenza vaccination coverage in pregnant women is still low. The trigger for this article was the development of new quadrivalent influenza vaccines along with the publication of new studies on the safety and effectiveness of inactivated influenza vaccines in pregnant women, administered also in the first trimester of pregnancy. The inactivated quadrivalent influenza vaccine is a safe and effective measure for preventing influenza in both mother and child. Live attenuated influenza vaccines are contraindicated in pregnant women, whereas inactivated influenza vaccines should be recommended to all pregnant women, either healthy or with comorbidities. Influenza vaccines can be administered during any pregnancy trimester, at least two weeks before delivery. The time of vaccination depends on vaccine availability; however, it should not be postponed unless there are significant medical contraindications.

Time to prioritise influenza vaccination in pregnancy

Time to prioritise influenza vaccination in pregnancy

Assessing Influenza Vaccination Behaviors Among Medically Underserved Obstetric Patients.

Background: Despite recommendations, maternal influenza vaccine acceptance has stagnated around 50%. Materials and Methods: A prospective cohort study was conducted of pregnant women seen in the clinic from September 2018 to April 2019. Primary outcomes included influenza vaccine uptake and reasons for vaccine refusal, categorized based on the Health Belief Model. We compared characteristics between three vaccination groups (never refused, refused and vaccinated, and refused and not vaccinated) by using chi-square and one-way analysis of variance. We used multivariate logistic regression to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for associations between patient characteristics and vaccine acceptance. Mixed-effects logistic regression models were used to explore the impact of provider-patient race concordance on influenza vaccine uptake. Results: Among 1666 women, 902 (54.1%) were vaccinated. Of these, 183 (20.3%) initially refused. Those who refused and were never vaccinated were more likely to be non-Hispanic black (aOR: 1.64, 95% CI: 1.05-2.56) and less likely to be Hispanic (aOR: 0.44, 95% CI: 0.24-0.81). Overall, perceived barriers were the most common reason for refusal (52.4%). Women who refused consistently were more likely to cite reasons related to perceived benefits (38.5% vs. 7.6%). Those who eventually accepted were more likely to cite cue to action (22.4% vs. 12.6%). Women who were race discordant with their provider were more likely to be vaccinated compared with those who were race concordant (57.9% vs. 52.9%, aOR: 1.16, 95% CI: 1.07-1.27). Conclusions: Women who refuse influenza vaccination in pregnancy may later choose to be vaccinated. Continued promotion of vaccination throughout pregnancy is crucial for vaccine uptake.

Influenza vaccination coverage among Polish pregnant women

Abstract Background Despite strong recommendations, influenza vaccination in pregnacy is still a controversy in Poland. Therefore, this study evaluates vaccination uptake and its determinants, as well as knowledge about influenza among Polish pregnant women. Methods A cross-sectional study based on an anonymous questionnaire was conducted between September 2019-February 2020 among consecutive pregnant women admitted to obstetric wards in 2 teaching hospitals located in Szczecin, Poland. Results Response rate was 88,6%. A median age of 210 respondents was 30 years (range: 16-44); 66.7% reported chronic diseases. Only 16.7% believed that they are at risk regarding influenza, 24.3% had ever received influenza vaccine (5.9% reported receiving vaccination in the 2019/2020 season); only 9.0% were planning on being vaccinated against influenza in the following season. The main reasons for not being vaccinated were lack of confidence in vaccine effectiveness (52.8%), concerns about side effects (26.1%) and lack of information about influenza vaccination in pregnancy (23.0%). Most respondents (89.0%) had heard about influenza vaccination, however, the mean knowledge score about influenza was 8.9 out of 17. Those who had heard about influenza vaccination were more likely to be immunized than those who did not (26.7% vs 4.3% respectively; p = 0.02). The uptake in those with a vaccinated family member was higher than in the group with no vaccination in family (48.8% vs 8.6% respectively; p &amp;lt; 0.001). Respondents who had obstetrician's recommendation regarding influenza vaccination had higher immunization coverage than those who did not (57.9% vs 20.9%; p = 0.003). Conclusions The influenza vaccination uptake in the population of Polish pregnant women is disturbingly low. Improved information channels and education strategies, specifically guided by obstetricians, are needed to increase the uptake. A recommendation from family may positively influence vaccine acceptance. Key messages The influenza vaccination uptake in the pregnant women in Poland needs to be improved. Obstetricians and GPs should maximize their efforts to play a more active role in influenza immunization communication and delivery among pregnant women.

Efficacy, duration of protection, birth outcomes, and infant growth associated with influenza vaccination in pregnancy: a pooled analysis of three randomised controlled trials

SummaryBackgroundMaternal influenza immunisation can reduce morbidity and mortality associated with influenza infection in pregnant women and young infants. We aimed to determine the vaccine efficacy of maternal influenza immunisation against maternal and infant PCR-confirmed influenza, duration of protection, and the effect of gestational age at vaccination on vaccine efficacy, birth outcomes, and infant growth up to 6 months of age.MethodsWe did a pooled analysis of three randomised controlled trials done in Nepal (2011–2014), Mali (2011–2014), and South Africa (2011–2013). Pregnant women, gestational age 17–34 weeks in Nepal, 28 weeks or more in Mali, and 20–36 weeks in South Africa, were enrolled. Women were randomly assigned 1:1 to a study group, in which they received trivalent inactivated influenza vaccine (IIV) in all three trials, or a control group, in which they received saline placebo in Nepal and South Africa or quadrivalent meningococcal conjugate vaccine in Mali. Enrolment at all sites was complete by April 24, 2013. Infants and women were assessed for respiratory illness, and samples from those that met the case definition were tested for influenza by PCR testing. Growth measurements, including length and weight, were obtained at birth at all sites, at 24 weeks in South Africa, and at 6 months in Nepal and Mali. The three trials are registered with ClinicalTrials.gov, numbers NCT01430689, NCT01034254, and NCT02465190.Findings10 002 women and 9800 liveborn infants were included. Pooled efficacy of maternal vaccination to prevent infant PCR-confirmed influenza up to 6 months of age was 35% (95% CI 19 to 47). The pooled estimate was 56% (28 to 73) within the first 2 months of life, 39% (11 to 58) between 2 and 4 months, and 19% (–9 to 40) between 4 and 6 months. In women, from enrolment during pregnancy to the end of follow-up at 6 months postpartum, the vaccine was 50% (95% CI 32–63) efficacious against PCR-confirmed influenza. Efficacy was 42% (12 to 61) during pregnancy and 60% (36 to 75) postpartum. In women vaccinated before 29 weeks gestational age, the estimated efficacy was 30% (–2 to 52), and in women vaccinated at or after 29 weeks, efficacy was 71% (50 to 83). Efficacy was similar in infants born to mothers vaccinated before or after 29 weeks gestation (34% [95% CI 12 to 51] vs 35% [11 to 52]). There was no overall association between maternal vaccination and low birthweight, stillbirth, preterm birth, and small for gestational age. At 6 months of age, the intervention and control groups were similar in terms of underweight (weight-for-age), stunted (length-for-age), and wasted (weight-for-length). Median centile change from birth to 6 months of age was similar between the intervention and the control groups for both weight and length.InterpretationThe assessment of efficacy for women vaccinated before 29 weeks gestational age might have been underpowered, because the point estimate suggests that there might be efficacy despite wide CIs. Estimates of efficacy against PCR-confirmed influenza and safety in terms of adverse birth outcomes should be incorporated into any further consideration of maternal influenza immunisation recommendations.FundingBill & Melinda Gates Foundation.