Trends in Tdap vaccination among privately insured pregnant women in the United States, 2009-2016

Maternal Tdap and influenza vaccination uptake 2017-2021 in the United States: Implications for maternal RSV vaccine uptake in the future

BACKGROUND

Assessment of maternal vaccine coverage is important for understanding and quantifying the impact of currently recommended vaccines as well as modeling the potential impact of future vaccines. However, existing data lack detail regarding uptake according to week of gestational age (wGA). Such granularity is valuable for more accurate estimation of vaccine impact.

OBJECTIVE

To summarize contemporary maternal Tdap vaccination uptake, overall, yearly, and by wGA, and maternal influenza vaccination uptake, overall, by influenza observation year, immunization month, and delivery month, in the US.

METHODS

Female patients 18-49 years of age with a pregnancy resulting in a live born infant (i.e., delivery) between 2017 and 2021 were selected from the Optum electronic health records (EHRs) database. Recently published gestational age algorithms were utilized to estimate wGA.

RESULTS

Of 1,021,260 deliveries among 886,660 women between 2017-2021, 55.1% had Tdap vaccination during pregnancy; vaccine coverage varied slightly by year (2017: 56.6%; 2018: 55.2%; 2019: 55.2%; 2020: 54.7%; 2021: 52.1%). Most (64.4%) maternal Tdap vaccinations occurred 27-32 wGA; 79.5% occurred during the entire 10-week recommended vaccination window (27-36 wGA). In the evaluation of influenza vaccination uptake (n=798,113 deliveries; 714,841 women), 33.5% of deliveries had influenza vaccination during influenza observation years 2017-2021, most (73.0%) of which occurred during influenza peak activity months (October-January) with approximately one-quarter (27.0%) of vaccinations having occurred during the off-peak months, mostly in September.

CONCLUSIONS

In this large contemporary analysis of EHR data, uptake of Tdap vaccination during pregnancy was consistent with previously published estimates; notably, most vaccination occurred early in the recommended 27-36 wGA window. Maternal influenza vaccination uptake largely correlated with peak influenza activity months and not gestational age. These study findings may have important implications for estimating the potential uptake and impact of future maternal vaccines.

Effectiveness of maternal immunisation with a three-component acellular pertussis vaccine at preventing pertussis in infants in the United States: Post-hoc analysis of a case-control study using Bayesian dynamic borrowing

BACKGROUND

Immunisation during pregnancy with a tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine can protect infants against pertussis between birth and paediatric vaccination. We aimed to estimate the vaccine effectiveness (VE) of third-trimester pregnancy immunisation with the three-component acellular pertussis (Td3ap) vaccine at preventing pertussis in infants <2 months in the United States (US), to support a label update.

METHODS

We performed a post-hoc sub-analysis of a case-control study conducted in six US Emerging Infections Program Network states between 2011 and 2014. Our analysis included only cases and controls whose mothers were either vaccinated with Td3ap or did not receive any Tdap vaccine. The association between Td3ap maternal immunisation and pertussis in infants was assessed for US data using a frequentist method with conditional logistic regression. A robustified analysis was conducted using Bayesian dynamic borrowing of non-US data, considering a mixing-weighted prior of 90% for historical non-US VE data, and of 10% for a vague prior. VE was estimated as (1-odds ratio) × 100%. Sensitivity analyses accounting for the impact of each non-US study, different mixing weights and missing/ambiguous data were performed.

RESULTS

We included 108 cases and 183 controls. Based on US data, the estimated VE of third-trimester maternal immunisation with Td3ap at preventing pertussis in infants <2 months was 78.0% (95% confidence interval: -38.0; 96.5). VE estimated by Bayesian dynamic borrowing of non-US data (with a 90% weight for historical data) was 83.4% (95% credible interval: 55.7; 92.5); sensitivity analyses produced similar VE estimates.

CONCLUSIONS

Effectiveness of third-trimester pregnancy immunisation with Td3ap at preventing infant pertussis in the US is very likely to be ≥ 50% and is most likely ∼ 80%. Bayesian dynamic borrowing of non-US VE data allowed overcoming the limited power (due to small sample size) of a brand-specific sub-analysis by considering additional evidence.

A Descriptive Study of Maternal Vaccination Uptake, Attitudes, and Beliefs in Pregnancy Among Persons Delivering at an Urban Safety Net Hospital

Objective

To estimate uptake of influenza, tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap), and COVID-19 vaccines during pregnancy and describe vaccine attitudes and beliefs among predominantly racial and ethnic minority individuals delivering at a publicly funded hospital.

Methods

We collected survey and electronic medical record data for English-speaking postpartum individuals who delivered a live-born infant from July 7, 2022, through August 21, 2022, and agreed to participate in our study. The 58-item survey included questions about general vaccine attitudes and beliefs as well as vaccine-specific questions. We calculated rates of influenza, Tdap, and COVID-19 vaccinations and compared distributions of survey responses by number (no vaccines, one vaccine, or two or three of the recommended vaccines) and type of vaccines received during pregnancy.

Results

Of the 231 eligible individuals, 125 (54.1%) agreed to participate. Rates of influenza, Tdap, and COVID-19 vaccination were 18.4%, 48.0%, and 5.6% respectively. A total of 61 (48.8%) did not receive any recommended vaccines during pregnancy, 40 (32.0%) received one vaccine, and 24 (19.0%) received two or three vaccines. Approximately 66.1% of the no vaccine group, 81.6% of the one vaccine group, and 87.5% of the two or three vaccine group strongly agreed or agreed that they trusted the vaccine information provided by their obstetrician or midwife. While most (>69.2%) agreed that the vaccine-preventable diseases were dangerous for pregnant women, only 24.0%, 29.3%, and 40.3% agreed that they were worried about getting influenza, whooping cough, or COVID-19, respectively, while pregnant.

Discussion

Vaccine uptake in our population was low and may be due, in part, to low perceived susceptibility to vaccine-preventable diseases. Obstetricians and midwives were trusted sources of vaccine information, suggesting that enhanced communication strategies could be critical for addressing maternal vaccine hesitancy, particularly in communities of color justifiably affected by medical mistrust.

Tetanus, Diphtheria, and Acellular Pertussis Vaccination Coverage Among Publicly Insured Pregnant Women, U.S., 2016-2019

Introduction

Vaccination with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine during pregnancy is highly effective against Bordetella pertussis in young infants. We aimed to evaluate the uptake of maternal tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccination during the recommended gestation period of 27 through 36 weeks among women enrolled in a public medical insurance plan in the U.S.

Methods

In this analysis using Centers for Medicare and Medicaid Services insurance claims data, we identified women aged 15 through 49 years who delivered a live-born infant from 2016 through 2019. We identified claims for tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccination to calculate the proportion of women who were vaccinated during Weeks 27 through 36 of gestation in each calendar year. We also assessed the average annual maternal tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis coverage by age group, race and ethnicity, U.S. Census region of residence, and plan type. Data were analyzed in 2021.

Results

Among 4,318,823 deliveries, the 4-year national average for tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccination was 26%, improving from 22% in 2016 to 31% in 2019 (p<0.001). Within subgroups, the lowest 4-year average coverage was among women aged 15 through 18 years (22%); Black, non-Hispanic (23%) and Hispanic women (24%); those residing in the South (18%); those enrolled in a Children's Health Insurance Program plan (22%); and those covered by a fee-for-service plan (19%). Coverage increased across all subgroups from 2016 through 2019.

Conclusions

Although maternal tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis coverage among publicly insured women in the U.S. increased from 2016 through 2019, it remained considerably lower than estimated national coverage, with notable differences by race and ethnicity.

Factors Influencing Maternal Antepartum Tdap Vaccination

INTRODUCTION

Antepartum Tdap remains low despite national recommendations. This prospective observational study aims to identify factors associated with lower antepartum Tdap rates.

METHODS

Maternal demographics, personal health beliefs, Tdap vaccination status, and recall of in-office obstetric provider actions were collected from a convenience sample of postpartum women in a New York metropolitan hospital. Bivariate and multivariable logistic regression were used to identify significant factors and adjusted odds ratios (OR) for recorded Tdap; OR > 1 reflects elements with increased odds of not receiving antepartum Tdap, while OR < 1 demonstrates increased odds of receipt.

RESULTS

Surveys were collected (n = 1682) from a study population demographically similar to New York City and more diverse in race/ethnicity than the national population. Demographic analysis showed Hispanic women less likely than white, non-Hispanic women to vaccinate (OR 2.44, CI 1.54-3.88). Health beliefs associated with non-receipt of antepartum Tdap included "It is dangerous for pregnant women to get vaccines" (OR 1.68, CI 1.01-2.77), and "I worry about the safety of the Tdap vaccine" (OR 1.59, CI 1.12-2.24). Obstetric provider actions associated with vaccination included receiving an OB recommendation (OR 0.39, CI 0.23-0.65), getting written information about Tdap (OR 0.44, CI 0.30-0.64), and having Tdap offered in office (OR 0.24, CI 0.15-0.37). Health beliefs associated with antepartum Tdap included "I generally do what my OB/GYN provider recommends" (OR 0.49, CI 0.30-0.80), and "Pregnant women should get the Tdap (pertussis) vaccine" (OR 0.17, CI 0.09-0.33).

DISCUSSION

Maternal race/ethnicity, personal health beliefs, and obstetric provider actions predict antepartum Tdap.

Vaccine exposure during pregnancy among privately and publicly insured women in the United States, 2016-2018

BACKGROUND

Vaccine use during pregnancy affects maternal and infant health. Many women do not receive vaccines recommended during pregnancy; conversely, inadvertent exposure to vaccines contraindicated or not recommended during pregnancy may occur. We assessed exposure to two recommended vaccines and two vaccines not recommended during pregnancy among privately and Medicaid-insured women in the United States.

METHODS

This study includes a retrospective cohort of pregnancies in women aged 12-55 years resulting in live birth, spontaneous abortion, or stillbirth identified in the IBM® MarketScan® Commercial, Blue Health Intelligence® (BHI®) Commercial, and IBM MarketScan Multi-State Medicaid Databases from August 1, 2016, to December 31, 2018. Gestational age at vaccination was determined using a validated algorithm. We examined vaccines (1) recommended by the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices (ACIP) (tetanus, diphtheria, and acellular pertussis [Tdap]; inactivated influenza) and (2) not recommended (human papillomavirus [HPV]) or contraindicated (measles, mumps, and rubella [MMR]).

RESULTS

We identified 496,771 (MarketScan Commercial), 858,961 (BHI), and 289,573 (MarketScan Medicaid) pregnancies (approximately 75% aged 20-34 years). Across these three databases, 52.1%, 50.3%, and 31.3% of pregnancies, respectively, received Tdap, most often at a gestational age of 28 weeks, and influenza vaccination occurred in 32.1%, 30.8%, and 18.0% of pregnancies, respectively. HPV vaccination occurred in < 0.2% of pregnancies, mostly in the first trimester among women aged 12-19 years, and MMR was administered in < 0.1% of pregnancies. Use of other contraindicated vaccines per ACIP (e.g., varicella, live attenuated influenza) was rare.

CONCLUSION

Maternal vaccination with ACIP-recommended vaccines was suboptimal among privately and Medicaid-insured patients, with lower vaccination coverage among Medicaid-insured pregnancies than their privately insured counterparts. Inadvertent exposure to contraindicated vaccines during pregnancy was rare. This study evaluated only vaccinations reimbursed among insured populations and may have limited generalizability to uninsured populations.

Coverage and Timing of Influenza Vaccination Among Privately Insured Pregnant Women in the United States, 2010-2018

OBJECTIVE

Pregnant women are at increased risk of serious complications from influenza and are recommended to receive an influenza vaccination during pregnancy. The objective of this study was to assess trends, timing patterns, and associated factors of influenza vaccination among pregnant women.

METHODS

We used 2010-2018 MarketScan data on 1 286 749 pregnant women aged 15-49 who were privately insured to examine trends and timing patterns of influenza vaccination coverage. We examined descriptive statistics and identified factors associated with vaccination uptake by using multivariate log-binomial and Cox proportional hazard models.

RESULTS

In-plan influenza vaccination coverage before delivery increased from 22.0% during the 2010-2011 influenza season to 33.2% during the 2017-2018 influenza season. About two-thirds of vaccinated women received the vaccine in September or October during each influenza season. For women who delivered in September through May, influenza vaccination coverage increased rapidly at the beginning of influenza season and flattened after October. For women who delivered in June through August, influenza vaccination coverage increased gradually until February and flattened thereafter. Most vaccinated women who delivered before January received the vaccine in the third trimester. Increased likelihood of being vaccinated was associated with age 31-40, living in a metropolitan statistical area, living outside the South, enrollment in a consumer-driven or high-deductible health plan, being spouses or dependents of policy holders, and delivery in November through January.

CONCLUSIONS

Despite increases during the past several years, vaccination uptake is still suboptimal, particularly after October. Health care provider education on timing of vaccination and recommendations throughout influenza seasons are needed to improve influenza vaccination coverage among pregnant women.

Pertussis epidemiological pattern and disease burden in Brazil: an analysis of national public health surveillance data

Objective: We described pertussis epidemiological trends in Brazil between 2010 and 2015. We also assessed tetanus, diphtheria and acellular pertussis (Tdap) vaccine coverage among pregnant women from 2014, the year of the introduction of Tdap maternal immunization recommendation in Brazil, to 2016.Methods: Epidemiological data for incidence, prevalence, hospitalization, mortality, and maternal vaccination coverage were calculated based on the Brazilian public surveillance databases.Results: The epidemiological data analysis results showed that the pertussis average incidence rate (IR) was 2.19/100,000 inhabitants for all ages, with a peak in 2014 (4.03/100,000 inhabitants) and highest incidence in <1-year-old children (IR = 175.20/100,000). 97.6% of pertussis deaths (405/415) were in <1-year-old children. Maternal immunization coverage was 9.2% in 2014, 40.4% in 2015, and 33.8% in 2016.Conclusions: Pertussis incidence and pertussis-related deaths increased in Brazil from 2010 to 2014 and decreased in 2015. In the two years, 2015 and 2016 that followed the NIP recommendation, Tdap vaccination coverage of pregnant women was low and varying from region to region. More efforts and national plans would help increase awareness and maternal immunization coverage.