PandemicPreparedness

22 December: A study published in JAMA Pediatrics found that in pregnant women who received the Pfizer/BioNTech vaccine during their second trimester, antibodies were transferred to the baby. This follows a previous study that found similar results in women who were vaccinated during their third trimester. The study was conducted from May to July 2021 at the Carmel Medical Center in Haifa, Israel. The cohort included 130 pregnant women. Their findings showed that the "antibody titers were positive for all women during delivery, and furthermore, neonatal titers were approximately 2.6 times higher than maternal titers, representing 100% placental antibody transfer." This supports past research that vaccination during pregnancy is beneficial to both mother and baby.  

22 October: A correspondence published in the New England Journal of Medicine details that COVID-19 vaccination during the first trimester did not lead to an increased risk of miscarriage. The study was conducted on data from over 18,000 pregnant women in Norway. The authors conclude their findings “[support] Covid-19 vaccination during pregnancy.”

Two small studies published in Science Translational Medicine have found that pregnancy and breastfeeding may affect the level of antibody responses and passing of antibodies to the baby, with a larger effect on mothers carrying male foetuses. Further studies are needed to ensure that vaccination timing and booster strategies are made that optimise the mother and baby’s immune response.

10 September: Several studies have shown pregnant people who get COVID-19 vaccines are not at elevated risk for miscarriage. One, published in JAMA, looked at data from around 105,000 pregnancies. Eight percent of the women who had continuing pregnancies had been vaccinated, compared to 8.6 people who had miscarriages. Miscarriages were not more common than continuing pregnancies in the 28 days after vaccination.

CDC researchers published a letter to the New England Journal of Medicine providing details of some 2,500 vaccinated people enrolled in their vaccine safety pregnancy registry. Most were healthcare workers. Data showed the risk of miscarriage "were within the expected risk range" and that the findings "add to the accumulating evidence about the safety of mRNA COVID-19 vaccination in pregnancy."

12 May: In a study, published in Obstetrics and Gynecology, researchers evaluated the frequency of key placental changes in patients who received SARS-CoV-2 vaccination in pregnancy. Eighty four women who tested negative for SARS-CoV-2 infection and who received a vaccine; and a control group of 116 unvaccinated women who tested negative for SARS-CoV-2 infection (past and present infection) were recruited. Examination of the placenta after delivery showed no increased incidence of blood flow issues or presence of lesions or malformations in women who had the vaccine. Researchers concluded ” Receipt of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination was not associated with placental histopathologic lesions.”

The U.S. CDC state “Although the overall risk of severe illness is low, pregnant people are at an increased risk for severe illness from COVID-19 when compared to non-pregnant people".

27 March: A study published in the American Journal of Obstetrics & Gynecology has found mRNA COVID-19 vaccines (such as the Moderna and Pfizer-BioNTech vaccines) are able to generate immune responses in pregnant and lactating mothers. Over 130 women were included in the largest study published to date. Samples of blood, breast milk and umbilical cord blood were examined pre and post vaccination.

Immune responses and side effects were comparable between pregnant/lactating women and controls. The placenta and breastmilk were also able to transfer antibodies to the babies. The level of antibodies were significantly higher for the pregnant and lactating mothers than those who had prior COVID-19 infection, but a booster vaccine dose increased antibody levels. The authors recommend further studies to “develop evidence-based recommendations for the administration of vaccines […] during pregnancy” including the optimal window to ensure immunity for the babies.

18 February: The mRNA vaccine developed by Pfizer and BioNTech has begun testing in pregnant women according to a press release published today. The vaccine’s safety profile has not yet been evaluated for pregnant women. The study has enrolled about 4,000 healthy pregnant women over the age of 18. The mothers will be vaccinated with two doses during weeks 24-34 of pregnancy. The first participants have already received the first dose.

29 January 2021: The World Health Organization (WHO) now says pregnant people should consider a COVID vaccine. Previously, WHO "did not recommend vaccination of pregnant women" unless they were at high risk for serious COVID due to other conditions besides pregnancy. The new guidance says, "Based on what we know about this kind of vaccine, we don’t have any specific reason to believe there will be specific risks that would outweigh the benefits of vaccination for pregnant women." This is more in line with the recommendations of the US CDC.

18 December 2020:Medscape reports (limited access site) that: "COVID-19 vaccines should not be withheld from people who are pregnant or lactating and want to be vaccinated, despite a lack of safety data in these populations, according to guidance from the Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists (ACOG), and the Society for Maternal-Fetal Medicine.

"Pregnant women who opt not to receive the vaccine should be supported in that decision as well, a practice advisory from ACOG recommends.

"Pregnant women who experience fever following vaccination should be counseled to take acetaminophen (aka paracetamol)," the ACOG advisory notes.

"In addition, women do not need to avoid pregnancy after receiving the Pfizer-BioNTech COVID-19 vaccine, according to the CDC's interim clinical considerations for its use."