V-safe surveillance: Local and systemic reactogenicity in pregnant women
Characteristics of people who identified themselves pregnant in the V-safe surveillance system and received a Covid-19 mRNA vaccine. 
Frequency of local and systemic reactions reported the day after Covid-19 mRNA vaccination in pregnant women.
Between December 14, 2020 and February 28, 2021, a total of 35,691 v-safe participants identified themselves as pregnant. The age distribution was similar among participants who received the Pfizer – BioNTech vaccine and those who received the Moderna vaccine, with most participants between the ages of 25 and 34 (61.9% and 60.6% for each vaccine, respectively) Hispanic White (76.2% and 75.4%, respectively); the majority of participants (85.8% and 87.4%, respectively) reported being pregnant at the time of vaccination (Table 1). Required reports of injection site pain, fatigue, headache, and myalgia were the most common local and systemic reactions after both doses for both vaccines (table 2) and were reported more frequently after dose 2 for both vaccines. The temperature measured by participants at or above 38 ° C was reported by less than 1% of participants on day 1 after dose 1 and 8.0% after dose 2 for both vaccines.
The most common local and systemic reactions reported in the V-safe surveillance system the day after vaccination with Covid-19 mRNA.
The required reactions are shown in pregnant and non-pregnant women aged 16 to 54 years who received a coronavirus messenger RNA (mRNA) vaccine for the 2019 vaccine (Covid-19) – BNT162b2 (Pfizer – BioNTech) or mRNA -1273 (Modern) – from December 14, 2020, to February 28, 2021. The percentage of respondents was calculated among those who completed a 1-day survey, with the most important events presented by pain at the injection site (pain), fatigue or tiredness (fatigue), headache, muscle or body aches (myalgia), chills and fever or feeling feverish (fever).
These reporting patterns, in terms of both the most frequently reported required reactions and the higher reporting of reactogenicity after dose 2, were similar to the patterns observed in non-pregnant women (figure 1). There were small differences in the frequency of reporting between pregnant and non-pregnant women for specific reactions (pain at the injection site was reported more frequently in pregnant women, and other systemic reactions were reported more frequently in non-pregnant women). , but the overall reactogenicity profile was similar. Pregnant women did not report severe reactions more frequently than non-pregnant women, except for nausea and vomiting, which were reported slightly more frequently only after dose 2 (Table S3).
Safe pregnancy register in V: pregnancy results and neonatal results
Characteristics of participants in the V safe load register.
As of March 30, 2021, the v-safe pregnancy registry call center attempted to contact 5,230 people who were vaccinated by February 28, 2021 and who were identified during a v-safe survey as pregnant at or shortly time after vaccination Covid-19. Of these, 912 could not be accessed, 86 refused to participate and 274 did not meet the inclusion criteria (for example, they were never pregnant, were pregnant, but received vaccination more than 30 days before last menstrual period or did not provide sufficient information to determine eligibility). The register registered 3958 vaccination participants between December 14, 2020 – February 28, 2021, of which 3719 (94.0%) identified themselves as health care personnel. Of the enrolled participants, most were 25-44 years old (98.8%), non-Hispanic white (79.0%) and, at the time of the interview, did not report a diagnosis of Covid-19 during pregnancy (97.6 %) (Table 3). Receiving a first dose of vaccine that meets the eligibility criteria for the registry was reported by 92 participants (2.3%) during conception, from 1132 (28.6%) in the first trimester of pregnancy to 1714 (43 , 3%) in the second trimester, and up to 1019 (25.7%) in the third trimester (one participant lacked information to determine when to vaccinate) (Table 3). Of the 1040 participants (91.9%) who received a vaccine in the first trimester and 1700 (99.2%) who received a vaccine in the second trimester, baseline data were collected and follow-up scheduled at the time points designated at about 10-12 weeks away; limited follow-up calls were made at the time of this analysis.
Pregnancy loss and neonatal outcomes in published studies and participants in the safe V-register of pregnancy.
Of the 827 participants who had a full pregnancy, the pregnancy resulted in a live birth in 712 (86.1%), a miscarriage in 104 (12.6%), and a stillbirth in 1 (0.1). %) and in other outcomes (induced abortion) and ectopic pregnancy) to 10 (1.2%). A total of 96 of 104 miscarriages (92.3%) occurred before 13 weeks of gestation (Table 4) and 700 of the 712 pregnancies that resulted in a live birth (98.3%) were among those who received the first eligible dose of vaccine in the third trimester. Adverse outcomes in 724 live births – including 12 sets of multiple pregnancies – were premature birth (60 of 636 of those vaccinated before 37 weeks [9.4%]), small size for gestational age (23 out of 724 [3.2%]) and major congenital anomalies (16 of 724 [2.2%]); no neonatal deaths were reported at the time of the interview. Of the participants with completed pregnancies who reported birth defects, none received the Covid-19 vaccine in the first trimester or period of conception and no specific pattern of birth defects was observed. The calculated proportions of pregnancy and neonatal outcomes appeared similar to the incidences published in the literature (Table 4).
Findings of adverse events on VAERS
During the analysis period, VAERS received and processed 221 reports involving Covid-19 vaccination among pregnant women; 155 (70.1%) involved non-pregnancy-specific adverse events, and 66 (29.9%) involved pregnancy-specific or neonatal adverse events (Table S4). The most commonly reported pregnancy-related adverse events were miscarriage (46 cases; 37 in the first trimester, 2 in the second trimester, and 7 in which the trimester was unknown or unreported), followed by stillbirth, rupture premature ejaculation of the membranes, and vaginal bleeding, with 3 reports for each. No congenital anomalies were reported to VAERS, a requirement under EUA.