The COVID vaccine, Pregnancy and Breastfeeding
So much is unknown these days. Everyone is questioning what is safe and what isn’t safe —and wisely so. There are few times that a parent feels more sensitive than during pregnancy and while breastfeeding. There is an urgency both to do the right thing and to make every decision and action count.
COVID amplifies these fears, because much is unknown both about the disease and about the vaccines to counteract the disease. Moms — pregnant and postpartum — are wondering which is the greater harm versus the greater good: to get vaccinated or not to get vaccinated? Here is the data you need to make an informed decision.
Before getting started, here is a quick review of biology terms. Antibodies are immune cells created by the body to help recognize viral antigens (the attacking parts of viruses) and can “neutralize” the virus by blocking viral cell entry. IgG and IgA are two different types of antibodies. T-cells are another type of immune cell that help the body both recognize the virus and destroy infected cells. Please refer to my prior blog on mRNA vaccines and how they trigger these immune responses. Both Pfizer and Moderna are mRNA vaccines.
The first questions are: what is the harm of the COVID virus to pregnant women? Are they at greater risk from COVID than non-pregnant women?
Pregnant women with symptomatic COVID-19 have a higher risk of intensive care unit admission, mechanical ventilation, and death compared with other women in their reproductive years, according to data first published in November, 2020 (https://pubmed.ncbi.nlm.nih.gov/33151921/). According to a systematic review study in the British Journal of Medicine (BMJ) moms with COVID-19 were 3 times more likely to have a preterm or stillbirth than a mom without COVID-19 (https://pubmed.ncbi.nlm.nih.gov/32873575/).
The second question is: Is it safe for pregnant and breastfeeding women to get the Pfizer and Moderna mRNA vaccines?
The New England Journal of Medicine (NEJM) published a study on April 21, 2021 that reviewed vaccine safety in 35, 691 pregnant who received one of the two mRNA vaccines (https://www.nejm.org/doi/full/10.1056/NEJMoa2104983). The preliminary results showed that there was no increased incidence of adverse events in the vaccinated group of pregnant women versus a similar population of women prior to COVID.
A study in the American College of Obstetrics and Gynecology (ACOG), published May 11, 2021 of 84 pregnant women and 116 non-pregnant women demonstrated no evidence that the vaccine triggered any negative response in the placentas of the pregnant women (https://journals.lww.com/greenjournal/Fulltext/9900/Severe_Acute_Respiratory_Syndrome_Coronavirus_2.206.aspx).
The third question is: do the mRNA vaccines work as effectively in non-pregnant women as pregnant and lactating women?
A study in the Journal of the American Medical Association (JAMA) was published on May 13, 2021 of 103 women, 30 of whom were pregnant and 16 of whom were lactating (https://jamanetwork.com/journals/jama/fullarticle/2780202). This study found that the both mRNA vaccines were equally effective at eliciting immune responses in both non-pregnant and pregnant and lactating women.
The May 11 ACOG study showed that the mRNA vaccines worked equally well n pregnant and non-pregnant women in triggering an immune response.
A previous ACOG study in March, 2021 of 84 pregnant, 31 lactating and 14 non-pregnant women who received either the Pfizer or the Moderna mRNA vaccines had similar findings (https://www.ajog.org/article/S0002-9378(21)00187-3/pdf).
The fourth question is: do the mRNA vaccines provide protection to the babies of the mothers who received the mRNA vaccines while pregnant and while breastfeeding?
The JAMA study found that binding and neutralizing antibodies were found in infant cord blood and breast milk. This study was also able to show that binding and neutralizing antibodies were present if reduced against newer COVID variants.
The March ACOG study found that the vaccine induced responses were significantly greater than the response to natural infection in the babies of women who received the vaccines while pregnant or breastfeeding for one type of antibody response, and similar for a second type of antibody response.
The fifth question is: does the immune response passed from the mother to her baby, either during pregnancy or while breastfeeding then actually provide protection against COVID?
This remains unknown. But from what is known about maternal immune transference during pregnancy and breastfeeding, this is likely the case.
Key take away points:
1) Pregnant moms are more likely to get sick from COVID-19, and to experience preterm and/or stillborn births.
2) The mRNA vaccines appear safe in pregnant women.
3) The mRNA vaccines are equally effective in non-pregnant, pregnant and lactating women.
4) Maternal immune responses to the vaccine transfer both prenatally to the newborn baby and through breastmilk to the nursing child.
5) It remains unclear how effective the transferred maternal immune factors are at protecting the child against COVID.
