I’m pregnant – Should I get the new COVID-19 vaccine?
This is a tricky question, as the large phase III trials of the Pfizer and Moderna vaccines excluded pregnant women. We simply do not have high-quality human clinical data to guide our decision-making.
The CDC, the American College of Obstetricians and Gynecologists (ACOG) and the American Academy of Pediatrics (AAP) all recommend “shared decision-making” between each pregnant patient and their healthcare provider to make a decision on whether to receive the COVID-19 vaccine during pregnancy.
Main points of the ACOG recommendations include:
- That COVID-19 vaccines should not be withheld from pregnant individuals who meet criteria for vaccination.
- While a conversation between the patient and their clinical team to assist with decisions regarding use of vaccine can be helpful, this conversation should not be required prior to vaccination, as this may cause unnecessary barriers to access.
- COVID-19 vaccines should be offered to lactating individuals similar to non-lactating individuals when they meet criteria for receipt of the vaccine
- Important considerations include:
- the level of activity of the virus in the community
- the potential efficacy of the vaccine
- the risk and potential severity of maternal disease, including the effects of disease on the fetus and newborn.
- the safety of the vaccine for the pregnant patient and the fetus.
- Vaccines currently available under EUA have not been tested in pregnant women. Therefore, there is essentially no clinical safety data specific to use in pregnancy.
- Pregnant patients who decline vaccination should be supported in their decision. Regardless of their decision to receive or not receive the vaccine, these conversations provide an opportunity to remind patients about the importance of other prevention measures such as hand washing, physical distancing, and wearing a mask.
- Expected side effects should be explained as part of counseling patients, including that they are a normal part of the body’s reaction to the vaccine and developing antibodies to protect against COVID-19 illness.
- The mRNA vaccines are not live virus vaccines, nor do they use an adjuvant to enhance vaccine efficacy. These vaccines do not enter the nucleus and do not alter human DNA in vaccine recipients. As a result, mRNA vaccines cannot cause any genetic changes. Based on the mechanism of action of these vaccines and the demonstrated safety and efficacy in Phase II and Phase III clinical trials, it is expected that the safety and efficacy profile of the vaccine for pregnant individuals would be similar to that observed in non-pregnant individuals. That said, there are no safety data specific to mRNA vaccine use in pregnant or lactating individuals and the potential risks to a pregnant individual and the fetus are unknown.
The ACOG recommendation summary:
While safety data on the use of COVID-19 vaccines in pregnancy are not currently available, there are also no data to indicate that the vaccines should be contraindicated, and no safety signals were generated from DART studies for the Pfizer-BioNtech and Moderna COVID-19 vaccines. Therefore, in the interest of patient autonomy, ACOG recommends that pregnant individuals be free to make their own decision regarding COVID-19 vaccination. While pregnant individuals are encouraged to discuss vaccination considerations with their clinical care team when feasible, documentation of such a discussion should not be required prior to receiving a COVID-19 vaccine.
In terms of the ‘important considerations’ listed by ACOG above, filling in some data for each of these considerations can be helpful in decision-making. The following notes have been compiled from some of the main sources of data used by ACOG in compiling their recommendations.
- The level of activity of the virus in the community
- The potential efficacy of the vaccine
- Shown to be quite high for the mRNA vaccines – 94% efficacy in preventing COVID-19 illness in the Phase III Moderna trial and 95% efficacy in preventing COVID-19 illness in the Phase III Pfizer trial.
- The risk and potential severity of maternal disease, including the effects of disease on the fetus and newborn.
- Maternal severity of disease: CDC COVID-19 surveillance data from January 22-June 7, 2020 had pregnancy status available for 28% of the 326,000 women of reproductive age who tested positive during this time. Of these 91,000 women with pregnancy status information available, 8,000 (9%) were pregnant. Approximately ⅓ (31.5%) of pregnant women were reported to have been hospitalized compared with 5.8% of nonpregnant women. After adjusting for age, presence of underlying medical conditions, and race/ethnicity, pregnant women were significantly more likely to be admitted to the ICU (1.5%) than were nonpregnant women (0.9%). Similarly, 0.5% of pregnant women required mechanical ventilation compared with 0.3% of nonpregnant women. No difference in deaths between pregnant and nonpregnant women was found – there were 16 deaths (0.2%) reported among pregnant women, and 208 deaths (0.2%) reported among non-pregnant women. (Ellington MMWR 2020)
- Preterm delivery: COVID-19 surveillance data collected from 13 states, including California, as part of COVID-NET between March 1 – August 22, 2020 showed a higher prevalence of preterm delivery in pregnant, hospitalized COVID-19 patients (12.6%) than that observed in the general US population (10%). Note the preterm delivery rate in the study catchment area during the surveillance period would be a better comparison but it is unknown. (Delahoy MMWR 2020)
- Comorbidities: During March 1–May 30, 2020, as part of Vaccine Safety Datalink (VSD) surveillance of COVID-19 hospitalizations, among 4,408 persons hospitalized with a COVID-19 diagnosis at VSD sites, 105 (2.4%) pregnant women were identified, including 62 (59%) hospitalized for obstetric reasons (i.e., labor and delivery or another pregnancy-related indication) and 43 (41%) hospitalized for COVID-19 illness without an obstetric reason. While most pregnant women were asymptomatic, pregnant women with prepregnancy obesity or gestational diabetes were at higher risk of being hospitalized for severe COVID-19 symptoms. The prevalence of prepregnancy obesity (body mass index ≥30 kg/m2) was 36.2% overall and was higher among the 43 women hospitalized for COVID-19 symptoms (44.2%) than among the 62 hospitalized for obstetric reasons (30.6%). Similarly, prevalence of gestational diabetes was higher among women hospitalized for COVID-19 symptoms (25.6%) than among those hospitalized for obstetric reasons (8.1%). (Panagiotakopoulos MMWR 2020)
- The safety of the vaccine for the pregnant patient and the fetus.
- There are currently no completed clinical studies to answer this question
- There were a few patients who became pregnant between the first and second doses of the phase III studies of the Pfizer and Moderna vaccines and these women will be followed for any adverse events. So far, there have not been any reported, but the total number of women is small (e.g. 23 people in the Pfizer/BioNTech vaccine trials).
- Data from Developmental and Reproductive Toxicity (DART) studies for the Pfizer/BioNTech vaccine have been reported in Europe. According to the report presented to the European Medicines Agency, animal studies using the Pfizer/BioNTech vaccine Pfizer/BioNTech vaccine do not indicate direct or indirect harmful effects with respect to pregnancy, embryo/fetal development, parturition or post-natal development. The DART studies report states:
Reproductive and developmental toxicity were investigated in rats in a combined fertility and developmental toxicity study where female rats were intramuscularly administered Comirnaty prior to mating and during gestation (receiving 4 full human doses that generate relatively higher levels in rat due to body weight differences, spanning between pre-mating day 21 and gestational day 20). SARS-CoV-2 neutralizing antibody responses were present in maternal animals from prior to mating to the end of the study on postnatal day 21 as well as in foetuses and offspring. There were no vaccine-related effects on female fertility, pregnancy, or embryo-foetal or offspring development. No Comirnaty data are available on vaccine placental transfer or excretion in milk.
In summary, this is a complicated decision, and one that will ultimately be unique to each pregnant patient. A pregnant healthcare provider with no other comorbidities working on the frontline in the emergency department may decide their risk of contracting COVID-19 is high enough that the known associations between COVID-19 infection and higher risks of maternal and fetal complications outweighs any theoretical vaccine risks. A pregnant woman with gestational diabetes working from home whose household members are also able to work from home and practice strict social distancing may not feel the benefit from the vaccine, in the setting of such low exposure risk, warrants the unknown risks. We encourage our pregnant patients to contact us to further discuss their unique situation.
Jennifer Abrams, MD, February 2, 2021