COVID Vaccines and Breast-Feeding

[A friend raised this topic, and I thought it was time to revisit it and see the current state of research. Enjoy the good news!]

Skeptics have argued that because there were no samples of breast-feeding mothers in vaccine trials, it is unknown as to whether vaccines are safe when nursing.


These concerns are theoretical; the engineering in the vaccines is real.

The argument for safety of vaccines is based on the genetic engineering used to produce this generation of COVID products. Vaccines based on mRNA technology simply don’t have the risks associated with older products developed through culturing eggs. That’s also why mRNA vaccines are much faster in production. We’re not going through the cumbersome and time consuming process of impregnating chickens, waiting for eggs, collecting eggs and harvesting the vaccine from them. Instead, we’re using computer science to directly produce what we want. Everything you know about vaccines from the past was based on the egg process. As Dorothy said, we’re not in Kansas anymore.

The egg process also explains why there was only one flu vaccine option each year. If the dominant virus turned out to be something different, there wasn’t enough time to produce another vaccine with the egg technology to meet the immediate need. The mRNA approach cuts the time required by more than half.

That said, we know how the US and Europeans are producing these vaccines. We don’t know about production elsewhere.

So what are scientists saying about getting the vaccine while breast-feeding? Here’s a review. The commentary from the University of Rochester Medical Center is particularly worth reading.

Centers for Disease Control

Based on how these vaccines work in the body, COVID-19 vaccines are thought not to be a risk to lactating people or their breastfeeding babies. Therefore, lactating people can receive a COVID-19 vaccine. Recent reports have shown that breastfeeding people who have received COVID-19 mRNA vaccines have antibodies in their breastmilk, which could help protect their babies.

Washington University of St. Louis

Nursing mothers who receive a COVID-19 vaccine may pass protective antibodies to their babies through breast milk for at least 80 days following vaccination, suggests new research from Washington University School of Medicine in St. Louis.

“Our study showed a huge boost in antibodies against the COVID-19 virus in breast milk starting two weeks after the first shot, and this response was sustained for the course of our study, which was almost three months long,” said first author Jeannie Kelly, MD, assistant professor of obstetrics and gynecology. “The antibodies levels were still high at the end of our study, so the protection likely extends even longer.”

University of Rochester Medical Center

The vaccines do not contain the actual virus, just a protein fragment that fools the immune system into thinking the virus is present. That protein disintegrates quickly in the body.

For anyone who still worries about a COVID vaccine somehow affecting a newborn, Dr. Rosen-Carole explained why the science can put that fear to rest.

“There are so many layers it would have to go through. It has to get into the mother’s blood. Then into the milk. Then stay in the milk and get into the baby. And then be active in the baby … That’s just not plausible.” Again, that’s because what triggers the immune system to form a defense against COVID is a tiny piece of protein in the vaccine that is quickly broken down. That’s also why it’s impossible to get COVID from the vaccines.

And the UR research showed that, in people with COVID, the virus itself was not transferred to breast milk, let alone the protein fragment that’s contained in the vaccine.

The American College of Obstetricians and Gynecologists

ACOG recommends COVID-19 vaccines be offered to lactating individuals. While lactating individuals were not included in most clinical trials, COVID-19 vaccines should not be withheld from lactating individuals who otherwise meet criteria for vaccination. 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 (ABM 2020).

A new study from the University of California, San Diego of 180 breast-feeding mothers reported side effects from the vaccines, typically, one or more of the following:

  • Chills,
  • Muscle aches,
  • Vomiting,
  • In a few women, a temporary reduction in milk volume, and
  • Swelling or itching at the injection site.

There were also reports of irritability and drowsiness in children. All of the effects for both mother and child were over within 72 hours and none required medical attention.


When we compare this to the risk of toxic shock in a child from the virus (see previous post), well there is no comparison.

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