Maternal Vaccination Research Articles

Reduced pertussis disease severity in infants following the introduction of pertussis vaccination of pregnant women in Spain, 2015–2019

BackgroundMaternal pertussis vaccination during the third trimester of pregnancy was implemented in 2015 in Spain, reaching a national coverage of 84% in 2019. In this ecological study, we investigated whether there was a change in the disease severity for pertussis in infants upon introduction of prenatal pertussis vaccination. MethodsWe performed a time-trend analysis of infant pertussis hospitalizations during 2005–2019 in Spain using national register data. Annual hospitalization rates per 100,000 population and the mean length of hospitalization were calculated for infants < 3 months of age (target group benefiting from the prenatal vaccination) and a reference group aged 3–11 months. We compared overall rates and annual percent changes of the above variables in both groups for the time period before (2005–2014) and after vaccination introduction (2015–2019), using segmented Poisson regression. ResultsDuring the pre-vaccination period, infants aged 0–2 months had a 5-times higher rate of pertussis hospitalization and spent on average 50 % longer in hospital than the reference group. After the maternal vaccination introduction, the hospitalization rate decreased more rapidly in infants aged 0–2 months than in infants aged 3–11 months: annual reduction of 34 % (95 % CI: 31–38) versus 26 % (95 % CI: 21–31) in the hospitalization rate and 13 % (95 % CI: 11–15) versus 6 % (95 % CI: 2–9) in the mean hospital stay, respectively. In 2019, the mean hospital stay for pertussis was about 4.5 days in both groups. ConclusionsMaternal pertussis vaccination in Spain led to a reduction in disease severity in the target group as compared to older infants, highlighting the need for increased efforts on educating healthcare professionals on the importance of maternal vaccinations.

Preservation of Anti-SARS-CoV-2 Neutralizing Antibodies in Breast Milk: Impact of Maternal COVID-19 Vaccination and Infection.

Objectives: To investigate specific immunoglobulin A (sIgA), specific immunoglobulin G (sIgG), and neutralizing antibodies (NAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in breast milk and compare immunity in mothers with hybrid immunity (infection and vaccination) versus those solely vaccinated (coronavirus disease [COVID]-naïve). Methods: A longitudinal study was conducted among lactating mothers who received at least two doses of the coronavirus disease 2019 (COVID-19) vaccine or tested positive for SARS-CoV-2. Details of vaccination and infection were collected through questionnaires and interviews. Fifteen milliliters of breast milk samples, self-collected at 1, 3, and 6 months postvaccination or infection, were sent to analysis for sIgA, sIgG, and NAbs using enzyme-linked immunosorbent assay. Results: In total, 119 lactating mothers (202 milk samples) were enrolled; 82 participants had hybrid immunity, and 32 were COVID-19-naïve. Two-thirds received a combination of different vaccines and booster shots. Breast milk retained sIgA, sIgG, and NAbs for up to 6 months post-COVID vaccination or infection. At 3 months, mothers with hybrid immunity had significantly higher sIgA and NAbs compared with COVID-naïve mothers (geometric mean [95% confidence interval (CI)] of sIgA 2.72 [1.94-3.8] vs. 1.44 [0.83-2.48]; NAbs 86.83 [84.9-88.8] vs. 81.28 [76.02-86.9]). No differences in sIgA, sIgG, and NAbs were observed between lactating mothers receiving two, three, or more than or equal to three doses, regardless of hybrid immunity or COVID-naïve status. Conclusion: sIgA, sIgG, and NAbs against SARS-CoV-2 in breast milk sustained for up to 6 months postimmunization and infection. Higher immunity was found in mothers with hybrid immunity. These transferred immunities confirm in vitro protection, supporting the safety of breastfeeding during and after COVID-19 vaccination or infection.

RSV Prefusion F Protein–Based Maternal Vaccine — Preterm Birth and Other Outcomes

BackgroundVaccination against respiratory syncytial virus (RSV) during pregnancy may protect infants from RSV disease. Efficacy and safety data on a candidate RSV prefusion F protein–based maternal vaccine (RSVPreF3-Mat) are needed.MethodsWe conducted a phase 3 trial involving pregnant women 18 to 49 years of age to assess the efficacy and safety of RSVPreF3-Mat. The women were randomly assigned in a 2:1 ratio to receive RSVPreF3-Mat or placebo between 24 weeks 0 days and 34 weeks 0 days of gestation. The primary outcomes were any or severe medically assessed RSV-associated lower respiratory tract disease in infants from birth to 6 months of age and safety in infants from birth to 12 months of age. After the observation of a higher risk of preterm birth in the vaccine group than in the placebo group, enrollment and vaccination were stopped early, and exploratory analyses of the safety signal of preterm birth were performed.ResultsThe analyses included 5328 pregnant women and 5233 infants; the target enrollment of approximately 10,000 pregnant women and their infants was not reached because enrollment was stopped early. A total of 3426 infants in the vaccine group and 1711 infants in the placebo group were followed from birth to 6 months of age; 16 and 24 infants, respectively, had any medically assessed RSV-associated lower respiratory tract disease (vaccine efficacy, 65.5%; 95% credible interval, 37.5 to 82.0), and 8 and 14, respectively, had severe medically assessed RSV-associated lower respiratory tract disease (vaccine efficacy, 69.0%; 95% credible interval, 33.0 to 87.6). Preterm birth occurred in 6.8% of the infants (237 of 3494) in the vaccine group and in 4.9% of those (86 of 1739) in the placebo group (relative risk, 1.37; 95% confidence interval [CI], 1.08 to 1.74; P=0.01); neonatal death occurred in 0.4% (13 of 3494) and 0.2% (3 of 1739), respectively (relative risk, 2.16; 95% CI, 0.62 to 7.56; P=0.23), an imbalance probably attributable to the greater percentage of preterm births in the vaccine group. No other safety signal was observed.ConclusionsThe results of this trial, in which enrollment was stopped early because of safety concerns, suggest that the risks of any and severe medically assessed RSV-associated lower respiratory tract disease among infants were lower with the candidate maternal RSV vaccine than with placebo but that the risk of preterm birth was higher with the candidate vaccine. (Funded by GlaxoSmithKline Biologicals; ClinicalTrials.gov number, NCT04605159.)

Perinatal outcomes and sinopharm BBIBP-CorV vaccination during pregnancy

BackgroundAfter the outbreak of COVID-19, a huge part of the health care services was dedicated to preventing and treating this disease. In case of COVID-19 infection, severe COVID-19 is reported more in pregnant individuals. Afterward, Vaccination against SARS-CoV-2 became a hot topic due to known effects in preventing severe COVID-19 during pregnancy.Vaccination of pregnant individuals started in August 2021 with the Sinopharm vaccine in Iran. The aim of current study was to determine the incidence of perinatal outcomes in women who were vaccinated during pregnancy.MethodThis retrospective cohort study included 129,488 singleton births from March 21, 2021, until March 21, 2022, in Tehran, Iran.The data was obtained from the Iranian Maternal and Neonatal (IMaN) Network and the Maternal Vaccination Registry.Adverse perinatal outcomes investigated in this study include preterm birth, extremely preterm birth, low birth weight, very low birth weight, intrauterine growth restriction, stillbirth, neonatal intensive care unit admission, congenital anomaly, neonatal death and low 5-minute Apgar score. The risk of all perinatal outcomes was evaluated using multiple logistic regression. The analysis was done using STATA version 14.ResultsOf all 129,488 singleton births included in this study, 17,485 (13.5%) were vaccinated against SARS-CoV-2 (all with Sinopharm (BBIBP-CorV)). The exposure to the Sinopharm vaccine during pregnancy caused a significant decrease in the incidence of preterm birth (P =0.006, OR=0.91 [95% CI, 0.85 to 0.97]), extremely preterm birth (P =<0.001,OR=0.55 [95% CI, 0.45 to 0.66]), and stillbirth (P =<0.001, OR=0.60 [95% CI, 0.47 to 0.76]). Exposure to vaccination during the first trimester was associated with an increased risk of preterm birth (P =0.01, OR=1.27 [95% CI, 1.04 to 1.55])Maternal vaccination during pregnancy was not associated with an increased risk of other adverse perinatal outcomes included in this study.ConclusionThe finding of this population-based study indicated no adverse pregnancy outcome due to vaccination with the Sinopharm vaccine during the second and third trimesters of pregnancy. Overall risk of adverse pregnancy outcomes were lower in the vaccinated individuals compared to the unvaccinated group. Also, vaccination during the first trimester was associated with an increased risk of preterm birth.

Influential Social Determinants of Adherence to Preventive and Health Promotion Activities during Pregnancy and the First Year of Life: Systematic Review.

Effective monitoring throughout pregnancy and the first year of life is a crucial factor in achieving lower rates of maternal and infant mortality. Currently, research on socioeconomic factors that influence the lack of adherence to preventive and control measures during pregnancy and the first year of life is limited. The objective of this review is to examine the available evidence on social determinants that influence participation in health promotion and preventive activities throughout the pregnancy journey and in infants during their first year of life. We performed a systematic review of the literature searching in the major scientific databases (PubMed, Scopus, EMBASE, WOS, and Cochrane Library) for articles from February 2017 to May 2023 containing information on health inequities that impact participation in health promotion and preventive measures from pregnancy through the first year of an infant's life. A total of 12 studies were selected; these studies were performed in ten different countries on five different continents. The selected studies cover preventive measures during maternal care, vaccination, and immunization during pregnancy and the first year of life, newborn screening, and follow-up of the first 12 months of life. The social factors associated with low adherence to health promotion activities during pregnancy and the first year of life include education, income, ethnicity, place of residence, and family characteristics. Despite the diverse geographical distribution, it is observed that there are common social factors linked to a decrease in the adherence to preventive measures during pregnancy and in the early years of life.

Early Estimate of Nirsevimab Effectiveness for Prevention of Respiratory Syncytial Virus-Associated Hospitalization Among Infants Entering Their First Respiratory Syncytial Virus Season - New Vaccine Surveillance Network, October 2023-February 2024.

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among infants in the United States. In August 2023, CDC's Advisory Committee on Immunization Practices recommended nirsevimab, a long-acting monoclonal antibody, for infants aged <8 months to protect against RSV-associated lower respiratory tract infection during their first RSV season and for children aged 8-19 months at increased risk for severe RSV disease. In phase 3 clinical trials, nirsevimab efficacy against RSV-associated lower respiratory tract infection with hospitalization was 81% (95% CI = 62%-90%) through 150 days after receipt; post-introduction effectiveness has not been assessed in the United States. In this analysis, the New Vaccine Surveillance Network evaluated nirsevimab effectiveness against RSV-associated hospitalization among infants in their first RSV season during October 1, 2023-February 29, 2024. Among 699 infants hospitalized with acute respiratory illness, 59 (8%) received nirsevimab ≥7 days before symptom onset. Nirsevimab effectiveness was 90% (95% CI = 75%-96%) against RSV-associated hospitalization with a median time from receipt to symptom onset of 45 days (IQR = 19-76 days). The number of infants who received nirsevimab was too low to stratify by duration from receipt; however, nirsevimab effectiveness is expected to decrease with increasing time after receipt because of antibody decay. Although nirsevimab uptake and the interval from receipt of nirsevimab were limited in this analysis, this early estimate supports the current nirsevimab recommendation for the prevention of severe RSV disease in infants. Infants should be protected by maternal RSV vaccination or infant receipt of nirsevimab.

Maternal GBS vaccination for preventing group B streptococcus disease in newborns: A mini review of current evidence.

Group B streptococcus (GBS) poses a significant threat to neonates, leading to morbidity and mortality. Intrapartum antibiotics, although effective, have limitations, prompting the exploration of maternal vaccination. This study reviews the current evidence for maternal GBS vaccination in the prevention of early-onset GBS disease in newborns. A search on Google Scholar, PubMed, and Scopus identified studies assessing the impact of maternal GBS vaccination on early-onset GBS disease. Inclusion criteria comprised English-language clinical trials or observational studies. Data extraction included study details, immunogenicity profiles, effectiveness, safety outcomes, and relevant findings. Qualitative synthesis was employed for data analysis. Five studies meeting the inclusion criteria were reviewed. Maternal GBS vaccines demonstrated efficacy with sustained immunogenicity. Adverse events, although documented, were predominantly non-severe. Variability in immune responses and maternal-to-infant antibody ratios show the need for tailored vaccination approaches. Long-term follow up and surveillance are essential to assess persistence and identify unintended effects. Positive outcomes in vaccine efficacy support GBS vaccination integration into maternal health programs. Implementation challenges in diverse healthcare infrastructures require tailored approaches, especially in resource-limited settings. Overcoming cultural barriers and ensuring healthcare provider awareness are crucial for successful vaccination.

Pharmacists’ role in maternal immunization

Maternal immunization is an important strategy to safeguard infants against vaccine-preventable diseases such as pertussis, which poses a significant economic burden on the health care system. Although the Tetanus, Diphtheria, and Pertussis vaccine has been recommended for pregnant individuals since 2018, uptake varies widely across Canadian provinces. As 4.5 million Canadians do not have access to a regular physician, there is a need to find alternate ways of informing pregnant individuals about maternal immunization schedules. Given the wide accessibility of pharmacists across Canada, they should have a leading role in informing pregnant individuals about maternal vaccines. Training guidelines for pharmacists would ensure informative and effective conversations about vaccinations and promote vaccine safety and benefits, facilitating administration. Increased participation from pharmacists can significantly contribute to improving maternal and child health outcomes, with the goal of reducing the burden of vaccine-preventable diseases in Canada.

A qualitative study of pregnant women’s perceptions and decision-making regarding COVID-19 vaccination in Thailand

To identify pregnant women’s attitudes towards, and acceptance and rejection of, COVID-19 vaccination. This prospective, descriptive, implementation study was conducted in the Antenatal clinic of Siriraj Hospital, Bangkok, Thailand. In Phase I, 40 pregnant women were interviewed. Phase II consisted of questionnaire development and data validation. In Phase III, the questionnaire was administered to 400 participants. Pregnant women’s attitudes towards and acceptance and rejection of COVID-19 vaccination. Most pregnant women were uncertain about the potential harm of vaccination to themselves or their unborn child, including risks such as miscarriage or premature birth (59–66/101 [58.4%–65.3%]; OR 2.53–8.33; 95% CI 1.23–3.60, 5.17–19.30; P < 0.001) compared to those who disagreed with vaccination. Their vaccination decisions were significantly influenced by social media information regarding vaccination complications in pregnant women (74/101 [73.3%]; OR 15.95; 95% CI 2.15–118.55; P = 0.001) compared to those who disagreed with vaccination. Most pregnant women opined that they should not receive a COVID-19 vaccination during pregnancy (adjusted odds ratio [AOR] 6.57; 95% CI 2.44–17.70; P = 0.001). Most also rejected vaccination despite being aware of its benefits (AOR 17.14; 95% CI 6.89–42.62; P < 0.001). Social media messages and obligatory vaccination certifications influence maternal vaccination decisions. Pregnant women believe vaccination helps prevent COVID-19 infection and reduces its severity. Nevertheless, the primary reason for their refusal was concern about potential harm to their unborn child or themselves during pregnancy.The Thai clinical trials registry: TCTR20211126006.

Prenatal maternal inactivated COVID-19 vaccination: the maternal and neonatal outcomes, a retrospective cohort study.

Background: Despite the widespread adoption of COVID-19 vaccination, a comprehensive understanding of potential vaccine-induced adverse effects, particularly in the context of pregnancy, remains a critical area of investigation. Elevated concerns surround the maternal and neonatal outcomes subsequent to prenatal maternal COVID-19 vaccination. While existing studies have provided insights into the safety profile of COVID-19 mRNA vaccines, the extrapolation of these conclusions to inactivated COVID-19 vaccines poses uncertainties. Notably, limited data are available regarding the maternal and neonatal effects associated with inactivated COVID-19 vaccines. Objective: To evaluate the prenatal maternal inactivated COVID-19 vaccination and the impact on maternal and neonatal outcomes. Methods: This was a retrospective cohort study of women who delivered between January and June 2022 at a single university-affiliated hospital. Those who have completed at least one dose of inactivated vaccine before or during pregnancy were included in "vaccinated group," and those who were not vaccinated were included in "unvaccinated group," the maternal, pregnancy and neonatal outcomes were evaluated. Propensity score matching (PSM) was performed to balance the baseline parameters of the two groups. Results: A total of 1926 women were enrolled in this study, 827 (42.94%) women were prenatally vaccinated, and 1099 (57.06%) unvaccinated. The gestational week of delivery were slightly lower in the vaccinated group, 38.61 ± 1.89weeks in the vaccinated group and 38.93 ± 1.49weeks in the unvaccinated group. There was a higher rate of overall preterm delivery in the vaccinated group (aOR 1.61, 95% CI 1.07-2.42; p = 0.02), however, the probability of delivery before 34 weeks and before 32weeks (early preterm delivery) were similar (p > 0.05). A total of 2009 infants were born, 851 in the vaccinated group and 1158 in the unvaccinated group. There were similar neonatal outcomes in the two groups. Conclusion: Although we found a slightly lower gestational week of delivery and a possible increased rate of late preterm birth in the vaccination group, there was no difference in mean neonatal weight, incidence of low birth weight infants and other neonatal adverse complications. Meanwhile, there was no difference in pregnancy and maternal outcomes between the two groups.

Prenatal Maternal Immunization for Infant Protection: A Review of the Vaccines Recommended, Infant Immunity and Future Research Directions.

Prenatal maternal immunization is an effective tool to protect mothers and infants from poor health outcomes due to infectious diseases. We provide an overview of the rationale for the use of prenatal vaccines, discuss the immunologic environment of the maternal-fetal interface including the impact of maternal vaccines prenatally and subsequently on the infant's immune response, and review vaccines currently recommended in pregnancy and landscape for the future of maternal vaccination. This review aims to provide an understanding of the recent history and progress made in the field and highlight the importance of continued research and development into new vaccines for pregnant populations.

Maternal vaccination against COVID-19 and neonatal outcomes during Omicron: INTERCOVID-2022 study

In early 2023, when Omicron was the variant of concern, we showed that vaccinating pregnant women decreased the risk for severe COVID-19-related complications and maternal morbidity and mortality. This study aimed to analyze the impact of COVID-19 during pregnancy on newborns and the effects of maternal COVID-19 vaccination on neonatal outcomes when Omicron was the variant of concern. INTERCOVID-2022 was a large, prospective, observational study, conducted in 40 hospitals across 18 countries, from November 27, 2021 (the day after the World Health Organization declared Omicron the variant of concern) to June 30, 2022, to assess the effect of COVID-19 in pregnancy on maternal and neonatal outcomes and to assess vaccine effectiveness. Women diagnosed with laboratory-confirmed COVID-19 during pregnancy were compared with 2 nondiagnosed, unmatched women recruited concomitantly and consecutively during pregnancy or at delivery. Mother-newborn dyads were followed until hospital discharge. The primary outcomes were a neonatal positive test for COVID-19, severe neonatal morbidity index, severe perinatal morbidity and mortality index, preterm birth, neonatal death, referral to neonatal intensive care unit, and diseases during the neonatal period. Vaccine effectiveness was estimated with adjustment for maternal risk profile. We enrolled 4707 neonates born to 1577 (33.5%) mothers diagnosed with COVID-19 and 3130 (66.5%) nondiagnosed mothers. Among the diagnosed mothers, 642 (40.7%) were not vaccinated, 147 (9.3%) were partially vaccinated, 551 (34.9%) were completely vaccinated, and 237 (15.0%) also had a booster vaccine. Neonates of booster-vaccinated mothers had less than half (relative risk, 0.46; 95% confidence interval, 0.23-0.91) the risk of being diagnosed with COVID-19 when compared with those of unvaccinated mothers; they also had the lowest rates of preterm birth, medically indicated preterm birth, respiratory distress syndrome, and number of days in the neonatal intensive care unit. Newborns of unvaccinated mothers had double the risk for neonatal death (relative risk, 2.06; 95% confidence interval, 1.06-4.00) when compared with those of nondiagnosed mothers. Vaccination was not associated with any congenital malformations. Although all vaccines provided protection against neonatal test positivity, newborns of booster-vaccinated mothers had the highest vaccine effectiveness (64%; 95% confidence interval, 10%-86%). Vaccine effectiveness was not as high for messenger RNA vaccines only. Vaccine effectiveness against moderate or severe neonatal outcomes was much lower, namely 13% in the booster-vaccinated group (all vaccines) and 25% and 28% in the completely and booster-vaccinated groups, respectively (messenger RNA vaccines only). Vaccines were fairly effective in protecting neonates when given to pregnant women ≤100 days (14 weeks) before birth; thereafter, the risk increased and was much higher after 200 days (29 weeks). Finally, none of the neonatal practices studied, including skin-to-skin contact and direct breastfeeding, increased the risk for infecting newborns. When Omicron was the variant of concern, newborns of unvaccinated mothers had an increased risk for neonatal death. Neonates of vaccinated mothers had a decreased risk for preterm birth and adverse neonatal outcomes. Because the protective effect of COVID-19 vaccination decreases with time, to ensure that newborns are maximally protected against COVID-19, mothers should receive a vaccine or booster dose no more than 14 weeks before the expected date of delivery.

Promoting informed decision making about maternal pertussis vaccination: the systematic development of an online tailored decision aid and a centering-based group antenatal care intervention.

Maintaining and enhancing vaccine confidence continues to be a challenge. Making an informed decision not only helps to avoid potential future regret but also reduces susceptibility to misinformation. There is an urgent need for interventions that facilitate informed decision-making about vaccines. This paper describes the systematic development of two interventions designed to promote informed decision making and indirectly, acceptance of maternal pertussis vaccination (MPV) in the Netherlands. The 6-step Intervention Mapping (IM) protocol was used for the development of an online tailored decision aid and Centering Pregnancy-based Group Antenatal Care (CP) intervention. A needs assessment was done using empirical literature and conducting a survey and focus groups (1), intervention objectives were formulated at the behavior and determinants levels (2), theoretical methods of behavior change were selected and translated into practical applications (3), which were further developed into the two interventions using user-centered design (4). Finally, plans were developed for implementation (5), and evaluation (6) of the interventions. The needs assessment showed that pregnant women often based their decision about MPV on information sourced online and conversations with their partners, obstetric care providers, and peers. Responding to these findings, we systematically developed two interactive, theory-based interventions. We created an online tailored decision aid, subjecting it to four iterations of testing among pregnant women, including those with low literacy levels. Participants evaluated prototypes of the intervention positively on relevance and usability. In addition, a CP intervention was developed with midwives. Using IM resulted in the creation of an online decision aid and CP intervention to promote informed decision making regarding MPV. This description of the systematic development of the interventions not only serves to illustrate design rationales, it will also aid the interpretation of the evaluation of the interventions, the development of future interventions promoting informed decision and acceptance of vaccines, and comparisons with other interventions.

The effectiveness of maternal pertussis vaccination for protecting Aboriginal and Torres Strait Islander infants against infection, 2012-2017: a retrospective cohort study.

To evaluate the effectiveness of maternal pertussis vaccination for preventing pertussis infections in Aboriginal and Torres Strait Islander infants under seven months of age. Retrospective cohort study; analysis of linked administrative health data. Mother-infant cohort (Links2HealthierBubs) including all pregnant women who gave birth to live infants (gestational age ≥ 20 weeks, birthweight ≥ 400 g) in the Northern Territory, Queensland, and Western Australia during 1 January 2012 - 31 December 2017. Proportions of women vaccinated against pertussis during pregnancy, rates of pertussis infections among infants under seven months of age, and estimated effectiveness of maternal vaccination for protecting infants against pertussis infection, each by Indigenous status. Of the 19 892 Aboriginal and Torres Strait Islander women who gave birth to live infants during 2012-2017, 7398 (37.2%) received pertussis vaccine doses during their pregnancy, as had 137 034 of 259 526 non-Indigenous women (52.8%; Indigenous v non-Indigenous: adjusted odds ratio, 0.66; 95% confidence interval [CI], 0.62-0.70). The annual incidence of notified pertussis infections in non-Indigenous infants declined from 16.8 (95% CI, 9.9-29) in 2012 to 1.4 (95% CI, 0.3-8.0) cases per 10 000 births in 2017; among Aboriginal and Torres Strait Islander infants, it declined from 47.6 (95% CI, 16.2-139) to 38.6 (95% CI, 10.6-140) cases per 10 000 births. The effectiveness of maternal vaccination for protecting non-Indigenous infants under seven months of age against pertussis infection during 2014-17 was 68.2% (95% CI, 51.8-79.0%); protection of Aboriginal and Torres Strait Islander infants was not statistically significant (36.1%; 95% CI, -41.3% to 71.1%). During 2015-17, maternal pertussis vaccination did not protect Aboriginal and Torres Strait Islander infants in the NT, Queensland, and WA against infection. Increasing the pertussis vaccination rate among pregnant Aboriginal and Torres Strait Islander women requires culturally appropriate, innovative strategies co-designed in partnership with Indigenous organisations and communities.

Attitudes and behaviors of maternal Tdap vaccination in Panama, Peru, and Colombia: An international cross-sectional study

IntroductionDespite a recommendation by PAHO for Tdap vaccination in pregnant women since 2019, uptake remains suboptimal across Latin America. This study evaluated the knowledge and attitudes of women towards maternal Tdap vaccination in Colombia, Peru, and Panama to identify the critical behavioral and social drivers of Tdap vaccine uptake during pregnancy. MethodsA cross-sectional online survey was undertaken between December 8, 2022, and January 11, 2023, targeting women in Colombia, Peru, or Panama with a child 12 months or under. We collected data on respondents’ demographics, social and behavioral determinants of vaccine acceptance, determinants of vaccine uptake (using the validated 5As taxonomy), and previous vaccination experience. ResultsIn the 938 respondents who completed the survey (Panama, n = 325; Peru, n = 305; Colombia, n = 308), 73–80 % had received the influenza vaccine, whereas only 30–39 % had received a Tdap vaccine. Significant correlates of Tdap vaccine uptake common to all three countries included a health professional recommendation, knowledge of the vaccine and location of vaccination, perceived vulnerability to pertussis infection, perceived importance of immunization, and receipt of a reminder. In specific countries, nonvaccinated women were more likely to cite issues with ease of access (Panama, Colombia), affordability (opportunity costs; Peru, Colombia), and understanding the rationale for vaccination in pregnancy (Panama, Colombia). ConclusionTo increase maternal Tdap vaccine uptake, health professionals should be encouraged to recommend vaccination consistently, and pregnant women should receive reminders explaining why and where to be vaccinated.

“Why has this new vaccine come and for what reasons?” key antecedents and questions for acceptance of a future maternal GBS vaccine: Perspectives of pregnant women, lactating women, and community members in Kenya

ABSTRACT Group B streptococcus (GBS) is a leading global cause of neonatal sepsis and meningitis, stillbirth, and puerperal sepsis. While intrapartum antibiotic prophylaxis (IAP) is a currently available GBS disease prevention strategy, IAP is programmatically complex to implement, precluding use in low- and middle-income countries. In Kenya, 2% of stillbirths are attributable to GBS infection. Two maternal GBS vaccines are in late-stage clinical development. However, licensure of a maternal GBS vaccine does not translate into reduction of disease. We conducted 28 in-depth interviews with pregnant people, lactating people, and community members across two counties in Kenya to better understand the attitudes and informational needs of primary vaccine beneficiaries. We identified two emerging themes from the data. The first focused on antecedents to maternal GBS vaccine acceptability. The most common antecedents focused on the vaccine’s ability to protect the baby and/or the mother, followed by community sensitization before the vaccine was available. The second key theme focused on questions that would need to be addressed before someone could accept a maternal GBS vaccine. Three key categories of questions were identified, including vaccine safety compared to vaccine benefits, who gets the vaccine, and how the vaccine works. Realizing the potential benefits of a future GBS maternal vaccine will require a multifactorial approach, including ensuring that communities are aware of GBS-related harms as well as the safety and effectiveness of a maternal GBS vaccine. Our study contributes to informing this multifactorial approach by elucidating the attitudes and concerns of key populations.

A scaled kernel density estimation prior for dynamic borrowing of historical information with application to clinical trial design.

Incorporating historical data into a current data analysis can improve estimation of parameters shared across both datasets and increase the power to detect associations of interest while reducing the time and cost of new data collection. Several methods for prior distribution elicitation have been introduced to allow for the data-driven borrowing of historical information within a Bayesian analysis of the current data. We propose scaled Gaussian kernel density estimation (SGKDE) prior distributions as potentially more flexible alternatives. SGKDE priors directly use posterior samples collected from a historical data analysis to approximate probability density functions, whose variances depend on the degree of similarity between the historical and current datasets, which are used as prior distributions in the current data analysis. We compare the performances of the SGKDE priors with some existing approaches using a simulation study. Data from a recently completed phase III clinical trial of a maternal vaccine for respiratory syncytial virus are used to further explore the properties of SGKDE priors when designing a new clinical trial while incorporating historical data. Overall, both studies suggest that the new approach results in improved parameter estimation and power in the current data analysis compared to the considered existing methods.

Maternal COVID-19 Vaccination and Prevention of Symptomatic Infection in Infants.

Maternal vaccination may prevent infant coronavirus disease 2019 (COVID-19). We aimed to quantify protection against infection from maternally derived vaccine-induced antibodies in the first 6 months of an infant's life. Infants born to mothers vaccinated during pregnancy with 2 or 3 doses of a messenger RNA COVID-19vaccine (nonboosted or boosted, respectively) had full-length spike (Spike) immunoglobulin G (IgG), pseudovirus 614D, and live virus D614G, and omicron BA.1 and BA.5 neutralizing antibody (nAb) titers measured at delivery. Infant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was determined by verified maternal-report and laboratory confirmation through prospective follow-up to 6 months of age between December 2021 and July 2022. The risk reduction for infection by dose group and antibody titer level was estimated in separate models. Infants of boosted mothers (n = 204) had significantly higher Spike IgG, pseudovirus, and live nAb titers at delivery than infants of nonboosted mothers (n = 271), and were 56% less likely to acquire infection in the first 6 months (P = .03). Irrespective of boost, for each 10-fold increase in Spike IgG titer at delivery, the infant's risk of acquiring infection was reduced by 47% (95% confidence interval 8%-70%; P = .02). Similarly, a 10-fold increase in pseudovirus titers against Wuhan Spike, and live virus nAb titers against D614G, and omicron BA.1 and BA.5 at delivery were associated with a 30%, 46%, 56%, and 60% risk reduction, respectively. Higher transplacental binding and nAb titers substantially reduced the risk ofSARS-CoV-2 infection in infants, and a booster dose amplified protection during a period of omicron predominance. Until infants are age-eligible for vaccination, maternal vaccination provides passive protection against symptomatic infection during early infancy.

Influenza vaccine during pregnancy, recommendations from healthcare providers, and race/ethnicity in the United States.

We examined racial/ethnic differences in the association between influenza vaccine recommendations from healthcare providers and maternal vaccination uptake. This cross-sectional study examined data from the Pregnancy Risk Assessment Monitoring System. We categorized respondents as non-Hispanic (NH) Whites, NH-Blacks, NH-Asians, American Indians/Alaska Natives, NH Other non-Whites, and Hispanics. We conducted multivariable logistical regression models to evaluate adjusted odds ratios (AOR) and 95% confidence intervals (CI). Covariates included maternal age, marital status, education, insurance status before pregnancy, the number of previous live births, the number of prenatal care visits, and smoking status during pregnancy. The prevalences of receiving influenza vaccine recommendations from healthcare providers and maternal vaccine were 80.01% and 50.42%, respectively. NH-Blacks are less likely to receive provider recommendations (AOR = 0.82; 95%CI 0.77-0.87) and be vaccinated (AOR = 0.76; 95%CI 0.72-0.80) than NH-Whites. Receiving provider recommendations was significantly associated with increased maternal influenza vaccine uptake (AOR = 15.50; 95% CI 14.51-16.55). The associations were significant for all racial/ethnic groups, with the highest among NH-Asians (AOR = 22.04; 95% CI 17.88-27.16) and the lowest among NH Other non-Whites (AOR = 11.07; 95% CI 8.25-14.86). Within NH-Asians, effectiveness among Chinese was highest (AOR = 29.39; 95% CI 18.10-47.71). Racial/ethnic disparities in maternal influenza vaccine uptake and receiving vaccine recommendations from healthcare providers persisted. Further studies on the racial/ethnic disparities in maternal vaccination were warranted and tailored strategies are required to reduce this health disparity.

Effectiveness of Maternal Influenza Vaccination During Pregnancy Against Influenza-Associated Emergency Department Visits and Hospitalizations in Infants

Effectiveness of Maternal Influenza Vaccination During Pregnancy Against Influenza-Associated Emergency Department Visits and Hospitalizations in Infants <6 Months of Age