Factors associated with COVID-19 vaccination likelihood during pregnancy

OBJECTIVE

To identify maternal background, medical and gynecological characteristics associated with COVID-19 vaccination likelihood, in the context where COVID-19 vaccination rates among pregnant women are significantly lower than the general population.

METHODS

In a retrospective cohort study, including all women who delivered between January and September 2021, background and medical history, including current and previous pregnancies diagnoses, were compared between vaccinated and unvaccinated women. Multivariable logistic models were used to identify factors associated with vaccination for the entire population, and for the two distinctive populations included in the study (Bedouin Arabs and Jewish women).

RESULTS

The study population included 7017 women, of whom 1925 (27.4%) were vaccinated during pregnancy. According to the multivariable analysis, unvaccinated mothers were younger with lower socioeconomic score. They were more likely to be Bedouin Arabs, have a poor obstetrical history or recurrent pregnancy loss, and insufficient prenatal care. Additional risk factors were inconsistent between the two ethnicities included in the study.

CONCLUSIONS

Ethnicity, insufficient prenatal care, and having a poor obstetric history were consistently associated with lower vaccination among pregnant women. These factors should be considered in future plans aimed at increasing vaccination among pregnant women.

Protecting pregnant people & infants against influenza: A landscape review of influenza vaccine hesitancy during pregnancy and strategies for vaccine promotion

Before COVID-19, influenza vaccines were the most widely recommended vaccine during pregnancy worldwide. In response to immunization during pregnancy, maternal antibodies offer protection against potentially life-threatening disease in both pregnant people and their infants up to six months of age. Despite this, influenza vaccine hesitancy is common, with few countries reporting immunization rates in pregnant people above 50%. In this review, we highlight individual, institutional, and social factors associated with influenza vaccine hesitancy during pregnancy. In addition, we present an overview of the evidence evaluating interventions to address influenza vaccine hesitancy during pregnancy. While some studies have indicated promising results, no single intervention has consistently effectively increased influenza vaccine uptake during pregnancy. Using a social-ecological model of health framework, future strategies addressing multiple levels of vaccine hesitancy will be needed to realize the potential health benefits of prenatal immunization programs.

Strategies to increase uptake of maternal pertussis vaccination

INTRODUCTION

Pertussis is a highly contagious respiratory disease that results in disproportionate morbidity and mortality in infants who have yet to receive the primary diphtheria-tetanus-pertussis vaccine series. In the preceding decades numerous countries began to pursue either prenatal vaccination of pregnant women or postpartum vaccination of caregivers to protect infants. Despite proven benefit, maternal uptake of pertussis vaccine continues to remain suboptimal.

AREAS COVERED

Many studies have been conducted to address the suboptimal uptake of maternal pertussis vaccination. This systematic review was undertaken to systematically identify those studies, highlight the most successful strategies and find the knowledge gaps that need to be filled over the coming years to improve vaccine uptake. Twenty-five studies were identified from six different databases.

EXPERT OPINION

Five different interventions were shown to be successful in promoting uptake of pertussis vaccination: (1) standing orders, (2) opt-in orders, (3) provider education, (4) on-site vaccination and (5) interactive patient education. Three major knowledge gaps were also identified that need to be filled over the coming years: (1) lack of studies in low- and middle-income countries, (2) lack of studies targeting midwives and/or home birth and (3) lack of studies on the process of vaccine communication.

The Association of Prenatal Tetanus, Diphtheria, and Acellular Pertussis (Tdap) Vaccination With Attention-Deficit/Hyperactivity Disorder

As prenatal vaccinations become more prevalent, it is important to assess potential safety events. In a retrospective cohort study of Kaiser Permanente Southern California (Pasadena, California) mother-child pairs with birth dates during January 1, 2011-December 31, 2014, we investigated the association between prenatal tetanus, diphtheria, and acellular pertussis (Tdap) vaccination and risk of attention-deficit/hyperactivity disorder (ADHD) in offspring. Information on Tdap vaccination during pregnancy was obtained from electronic medical records. ADHD was defined by International Classification of Diseases codes (Ninth or Tenth Revision) and dispensed ADHD medication after age 3 years. Children were followed to the date of their first ADHD diagnosis, the end of Kaiser Permanente membership, or the end of follow-up (December 31, 2018). In Cox proportional hazards models, we estimated unadjusted and adjusted hazard ratios for the association between maternal Tdap vaccination and ADHD, with inverse probability of treatment weighting (IPTW) used to adjust for confounding. Of 128,756 eligible mother-child pairs, 85,607 were included in the final sample. The ADHD incidence rate was 3.41 per 1,000 person-years in the Tdap-vaccinated women and 3.93 per 1,000 person-years in the unvaccinated (hazard ratio = 1.01, 95% confidence interval: 0.88, 1.16). The IPTW-adjusted analyses showed no association between prenatal Tdap vaccination and ADHD in offspring (hazard ratio = 1.00, 95% confidence interval: 0.88, 1.14). In this study, prenatal Tdap vaccination was not associated with ADHD risk in offspring, supporting recommendations to vaccinate pregnant women.

Effectiveness of Prenatal Versus Postpartum Tetanus, Diphtheria, and Acellular Pertussis Vaccination in Preventing Infant Pertussis

BACKGROUND

 Most severe and fatal cases of pertussis occur in infants <8 weeks of age, before initiation of the primary pertussis vaccine series. Women are recommended to receive tetanus, diphtheria, and acellular pertussis (Tdap) vaccine at the start of the third trimester of each pregnancy to optimize transplacental transfer of antibodies to the fetus. This recommendation was made by the Advisory Committee for Immunization Practices based on immunogenicity data, and no studies in the United States have yet evaluated the effectiveness of this strategy in reducing pertussis incidence in infants.

METHODS

 We evaluated a cohort of mothers with documented Tdap vaccination histories in the California Immunization Registry to determine whether infants whose mothers received Tdap vaccine at 27-36 weeks gestation had a lower risk of pertussis at <8 weeks of age than infants born to women who received Tdap vaccine within 14 days post partum.

RESULTS

 Tdap vaccination received at 27-36 weeks gestation was found to be 85% (95% confidence interval, 33%-98%) more effective than postpartum Tdap vaccination at preventing pertussis in infants <8 weeks of age . Vaccination at 27-36 weeks gestation was more effective at preventing pertussis in infant than vaccination during the second trimester.

CONCLUSIONS

 Tdap vaccination at 27-36 weeks gestation was 85% more effective than postpartum vaccination at preventing pertussis in infants <8 weeks of age. Efforts should be made by prenatal care providers to provide Tdap vaccine to pregnant women during routine prenatal visits at the earliest opportunity between 27 and 36 weeks gestation.