Written By: Dr. Bernstien
Since this pandemic began about a year ago, we have continued to advise breast-feeding patients (and all patients actually) to wear masks, wash hands, social distance, avoid large gatherings etc. We have had strict policies in our office and very limited access to our office from patients’ loved ones. Now, as I’m writing this blog, the first Americans started receiving Covid-19 vaccines. Currently employees in the healthcare setting are being vaccinated around the country (and world) against Covid-19. Approximately 75% of healthcare workers are women, and the CDC estimates that over 300,000 healthcare workers are pregnant, will be pregnant, or will have recently given birth as the Covid-19 vaccine becomes more widely available to them. Thus, this first round of vaccinations will include many lactating or soon-to-be lactating women. Later, it will be other higher exposure-risk jobs like teachers and other essential workers. Questions are pouring in from our pregnant and recently delivered moms about the safety of these new vaccines while breastfeeding.
Were lactating women included in the vaccine trials?
Women who were breastfeeding were excluded from the Pfizer and Moderna studies.
How effective are the available vaccines?
The two vaccines approved at the time of writing this blog (Pfizer and Moderna), are both very effective. They seem to prevent Covid-19 in 95% of those who receive both doses of the vaccine. While they are effective in preventing symptomatic Covid-19 disease, it is still unclear whether the vaccines will be able to prevent you from getting an asymptomatic infection or spreading the virus silently to others. Thus, the precautions we already take are not going to be stopped any time soon.
How does the vaccine work?
The Pfizer and Moderna vaccines are in a category of vaccine called mRNA. These types of vaccines have been studied for years. The vaccine is made of lipid nanoparticles that contain mRNA for a Covid-19 spike protein. This is a protein that is required for the virus to attack cells. The mRNA sequence only encodes this protein. The particles are injected into muscles, where the nanoparticles are taken up by cells in the muscle. The muscle cells then produce this spike protein. Since this is a foreign protein to the body, an immune response is made to attack the protein and antibodies are eventually formed. Since this is an important protein for the virus to use to enter our cells, the antibodies now present can protect against a future encounter with the real virus. So no live virus is injected during vaccination, thus making it impossible to get Covid-19 from the vaccine itself. The injected mRNA breaks down quickly, so it lasts only a brief time in the body, just enough time to make the protein required for an antibody response. This mRNA never enters the nucleus of human cells and thus cannot alter the DNA (genetic makeup) of those vaccinated.
What does science tell us about the vaccine in lactation?
It is unlikely that the vaccine lipid would enter the bloodstream and reach the breast tissue. If it does, it is even less likely that either the intact nanoparticle or mRNA would get into breast milk. If THAT happens, then it would be digested by the child and would unlikely have any biological effects. That is a lot of “IFs”. Thus while there is little plausible risk based on our best understanding of the science, there is a biological benefit. Antibodies and T-cells stimulated by the vaccine may transfer to the child in the milk and protect it. After vaccinations against other viruses, antibodies are detectable in milk within a week. These antibodies, in theory, protect the child.
What are the side effects of the vaccine?
Side effects from the vaccine include injection site reactions (84%), fatigue (63%), chills (32%), muscle aches (38%), joint pain (24%), headache (55%), and fever (3.7% after the first dose and 15.8% after the second dose). Remember, having side effects of the vaccine does NOT mean you have a Covid-19 infection, but rather your body is responding appropriately to a vaccine.
Who should not get the vaccine?
If you have had a life-threatening response like anaphylaxis to previous injections or immunizations, you should not receive the vaccine until you have spoken to a specialist. Please note, people who have more common allergies to food, pollen, or medications taken orally are still eligible for vaccination.
What are the professional organizations saying?
ACOG (American College of Obstetrics and Gynecology)
- ACOG recommends Covid-19 vaccines be offered to lactating individuals similar to non-lactating individuals when they meet criteria for receipt of the vaccine based on prioritization groups outlined by the ACIP (advisory committee on immunization practices).
- Theoretical concerns regarding the safety of vaccinating lactating individuals do not outweigh the potential benefits of receiving the vaccine.
- There is no need to avoid initiation or discontinue breastfeeding in patients who receive a Covid-19 vaccine.
SMFM (Society for Maternal Fetal Medicine, high risk pregnancy experts)
- Vaccination is recommended for lactating persons. Counseling should balance the lack of data on vaccine safety and a person’s individual risk for infection and severe disease.
- The theoretical risks regarding the safety of vaccinating lactating people do not outweigh the potential benefits of the vaccine.
ABM (Academy of Breastfeeding Medicine)
- The ABM does not recommend cessation of breastfeeding for individuals who are vaccinated against Covid-19.
- Individuals who are lactating should discuss the risks and benefits of vaccination with their health care provider, within the context of their risk of contracting Covid-19 and its complications, the risks to the mother and child of cessation of breastfeeding, and the biological plausibility of vaccine risks and benefits to the breastfed child.
What is my opinion?
As of this moment, I am very comfortable saying that the benefits of these first Covid-19 vaccinations for lactating women FAR outweigh the potential risks. I would be very comfortable with my loved ones getting a vaccine while nursing. I also understand the concerns about the unknowns that still exist and will be respectful of any woman that chooses not to get vaccinated. You need to make the choice for yourself, based on your individual risk factors and infection risks. That being said, the science is on the side of vaccination being safe while breastfeeding.