Background

A key mitigation strategy to the COVID-19 pandemic has been the development and roll-out of vaccines. However, pregnant and lactating people were not included in initial vaccine trials and this population is hesitant to receive the vaccine, despite contrary recommendations from the American College of Obstetrics and Gynecology and the Centers for Disease Control and Prevention. Understanding the reasons behind this hesitancy is vital to promote vaccine uptake.

Methods

We surveyed pregnant people in California from December 2020 to January 2021 (n = 387) to describe cognitions and decision-making regarding COVID-19 vaccination. Using descriptive, regression-based analyses, we examined rates of planned uptake and reasoning among individuals who reported COVID-19 vaccine hesitancy.

Results

Overall, the pregnant Californians that we surveyed were aware of the COVID-19 vaccines. Of 387 participants, 43% reported planning to get the vaccine as soon as possible. The remaining 57% were hesitant: 27% responded that they would not receive the vaccine. Some demographic features did predict more COVID-19 vaccine hesitancy, particularly younger age (AOR = 0.95, p = 0.025) and living in a less urban context (AOR = 0.80, p = 0.041). Essential worker status also was associated with vaccine hesitancy. Having had, or intending to have, a flu vaccine was negatively associated with COVID-19 vaccine hesitancy (p < 0.001). The most commonly reported reason for COVID-19 vaccine hesitancy was "I don't know enough about the vaccine." Low levels of self-reported knowledge were highly predictive of hesitancy.

Conclusions

Terms like "vaccine hesitance" and "anti-vax" do not adequately characterize decisions regarding delaying COVID-19 vaccination. Rather, these decisions are largely based on the lack of knowledge about the impacts of vaccination on pregnancy, fetal development, and later child wellbeing. This lack of knowledge should be countered by conversations between individual healthcare providers and their pregnant patients, and better inclusion of pregnant people and children in vaccine trials.

Background

Cell-free DNA (cfDNA) testing for fetal trisomy is highly effective among high-risk women. However, there have been few direct, well-powered studies comparing cfDNA testing with standard screening during the first trimester in routine prenatal populations.

Methods

In this prospective, multicenter, blinded study conducted at 35 international centers, we assigned pregnant women presenting for aneuploidy screening at 10 to 14 weeks of gestation to undergo both standard screening (with measurement of nuchal translucency and biochemical analytes) and cfDNA testing. Participants received the results of standard screening; the results of cfDNA testing were blinded. Determination of the birth outcome was based on diagnostic genetic testing or newborn examination. The primary outcome was the area under the receiver-operating-characteristic curve (AUC) for trisomy 21 (Down's syndrome) with cfDNA testing versus standard screening. We also evaluated cfDNA testing and standard screening to assess the risk of trisomies 18 and 13.

Results

Of 18,955 women who were enrolled, results from 15,841 were available for analysis. The mean maternal age was 30.7 years, and the mean gestational age at testing was 12.5 weeks. The AUC for trisomy 21 was 0.999 for cfDNA testing and 0.958 for standard screening (P=0.001). Trisomy 21 was detected in 38 of 38 women (100%; 95% confidence interval [CI], 90.7 to 100) in the cfDNA-testing group, as compared with 30 of 38 women (78.9%; 95% CI, 62.7 to 90.4) in the standard-screening group (P=0.008). False positive rates were 0.06% (95% CI, 0.03 to 0.11) in the cfDNA group and 5.4% (95% CI, 5.1 to 5.8) in the standard-screening group (P<0.001). The positive predictive value for cfDNA testing was 80.9% (95% CI, 66.7 to 90.9), as compared with 3.4% (95% CI, 2.3 to 4.8) for standard screening (P<0.001).

Conclusions

In this large, routine prenatal-screening population, cfDNA testing for trisomy 21 had higher sensitivity, a lower false positive rate, and higher positive predictive value than did standard screening with the measurement of nuchal translucency and biochemical analytes. (Funded by Ariosa Diagnostics and Perinatal Quality Foundation; NEXT ClinicalTrials.gov number, NCT01511458.).