mRNA in breastmilk. That's okay. And more on COVID19 vaccines and pregnancy
A ridiculous amount of misinformation has recently surfaced online regarding COVID-19 vaccinations, pregnancy, and breastfeeding. This is due to a number of bad players intentionally spreading false information as well as some solid players poorly writing tweets.
Regardless of what you see on social media, it is still strongly recommended that all pregnant and breastfeeding people get the COVID-19 vaccine.
I partnered with Dr. Viki Male, an immunologist and lecturer on pregnancy and reproductive immunology at Imperial College London. She updates a fantastic multi-page document with the latest evidence regarding pregnancy and COVID-19 vaccines. Here are answers to some questions circulating right now.
I am pregnant. What are the risks if I get COVID during pregnancy?
There is evidence that COVID infection increases the risk of miscarriage (here, here), although not all studies have been able to find this (here, here). Preterm birth and stillbirth occur more often in pregnant patients with COVID-19, and their babies are more likely to be admitted to the neonatal unit. Pregnant patients with COVID-19 also more likely to need intensive care than COVID-19 patients who are not pregnant.
Can the COVID-19 vaccine cross the placenta?
One study of 19 people who received the COVID vaccine during pregnancy could not detect any vaccine mRNA or spike protein in placenta or cord blood. Babies of vaccinated mothers do not have any anti-spike IgM (a type of antibody), indicating that the vaccines themselves do not cross the placenta. (You can see the data on this here, here, and here, and an explanation on the interpretation of the studies here).
A study of 48 placentas collected shortly after vaccination was unable to detect any spike protein or mRNA. Vaccination is also not associated with any placental abnormalities (here, here).
Is it safe to get the COVID vaccine during pregnancy?
Yes. The safety of COVID vaccination during pregnancy is being monitored in a number of ways:
Passive monitoring systems, such as Yellow Card in the UK and VAERS in the USA, collect information that doctors, patients, and their families report. Neither have detected adverse events occurring more often following COVID vaccination than they normally do in pregnancy.
Twenty-seven studies have been conducted across eight countries and 316,470 people vaccinated during pregnancy and tracked outcomes of pregnancy. None of these studies have found any increased risk of miscarriage, preterm birth, stillbirth, or babies being born smaller than expected or with congenital abnormalities following COVID-19 vaccination. A meta-analysis pooling many of these studies found that COVID vaccination actually reduces the rate of stillbirth by 15%, presumably because it prevents stillbirths that occur because of COVID infection.
Registry studies recruit people at vaccination, track the outcomes of their pregnancies, and compare the outcomes to those we normally see in pregnancy. No registry has found an increase risk of miscarriage, preterm birth, stillbirth, or babies needing intensive care or dying:
In the U.S., V-SAFE examined the outcomes for 5,096 people vaccinated in pregnancy and their babies. The first report found the rates of adverse events were the same as we normally see. A follow-up study looking at outcomes of people vaccinated before 20 weeks of pregnancy found no increased risk of miscarriage following vaccination. A second follow up of 1,634 births found that the rates of adverse events at birth remained normal.
In Canada, the BORN Ontario registry comprises 64,234 people vaccinated during pregnancy and showed no increased risk of stillbirth, preterm birth or babies being smaller than expected for their gestational age (here, here, here and here).
In Scotland, a study looked at 18,399 people vaccinated against COVID during pregnancy and found no increased risk of stillbirth, babies dying shortly after birth, or preterm birth following vaccination.
The Swiss COVI-PREG registry followed 1,012 people vaccinated during pregnancy and found no increased risk of miscarriage, preterm birth, stillbirth, or babies needing intensive care or dying.
A small registry study of 390 people vaccinated during pregnancy in Israel found no increased risk of miscarriage, preterm birth, babies being born smaller than expected or with congenital abnormalities, or needing intensive care.
Will being vaccinated while I am pregnant give my baby any protection against COVID once they are born?
We have many reports showing that antibodies the body makes after vaccination (called IgG) do cross the placenta. Early reports suggest that vaccination in pregnancy is about 61% effective at protecting babies under 6 months old from hospitalization with COVID. Two more recent studies (here, here) found vaccination in pregnancy was 80% and 38% protective against hospitalization with Delta and Omicron, respectively, and 71% and 33% effective at protecting against infection.
I am breastfeeding. Should I get the vaccine if I am offered it?
Yes. There is no known risk associated with non-live vaccines (i.e. mRNA vaccines) while breastfeeding. No safety signals have appeared in breastfeeding people or their babies.
Two studies looking for vaccine mRNA in breast milk have been unable to detect it (here and here). Three studies were able to detect it at very low levels. One study found mRNA at 2 parts per billion in 3 out of 10 milk donors. Another study found mRNA in 4 out of 31 milk donors at a maximum of 0.17 parts per billion, and the third study found mRNA in 3 out of 11 milk donors at a maximum of 0.011 parts per billion. You can read an explanation of what “parts per billion” means here, but the latest study means this is roughly equivalent to a single tear in an Olympic pool. (Note that mRNA is part of our everyday life, outside of vaccines. For example, it’s in meat we eat, and our stomach acid is strong enough to break it down.)
A study that looked for the chemical PEG, which is used to stabilize mRNA vaccines, in the breast milk of 13 people found that levels did not increase after vaccination. (Note that PEG is commonly found in many cosmetics, so was found in some milk samples from unvaccinated donors.)
Together, this means those who are breastfeeding do not need to “pump and dump” within 48 hours of vaccination.
A number of studies have shown antibodies get into breast milk at high concentrations. You can find them summarized in this systematic review. One of these studies found that antibodies could persist in breast milk for as long as 6 months after vaccination. There is also some evidence that T cells that respond to COVID-19 get into breast milk (here, here). These antibodies and T cells give your baby some protection against COVID19, although more research is being done to confirm this.
More questions
For questions about COVID-19 vaccine safety before pregnancy, including questions about fertility and menstrual cycles, and answers to more questions about vaccines during and after pregnancy, be sure to check out this live document on the latest evidence. It’s updated in almost real time.
Bottom line
The vaccines are safe and effective before pregnancy, during pregnancy, and after pregnancy. For both the parent and the baby. The new bivalent vaccine does not change this. Be sure to get your vaccine!
Love, YLE and Dr. Viki Male
Viki Male, PhD, is faculty of Medicine, Department of Metabolism, Digestion and Reproduction at Imperial College London and holds the Borne-funded Lectureship in Reproductive Immunology. During the pandemic, she has been involved in collating and communicating information on the effect of SARS-CoV2 infection and COVID vaccination on fertility, pregnancy, and breastfeeding, and in research on how COVID vaccination affects the menstrual cycle.
“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, MPH PhD—an epidemiologist, biostatistician, wife, and mom of two little girls. During the day she works at a nonpartisan health policy think tank, and at night she writes this newsletter. Her main goal is to “translate” the ever-evolving public health science so that people will be well equipped to make evidence-based decisions. This newsletter is free thanks to the generous support of fellow YLE community members.
Here's the problem - A year ago the CDC, Twitter Med, and a variety of news outlets promoted the vaccine to pregnant people specifically because a study found mRNA did *not* pass through the breast milk. This was the metric used to prove it was safe to breastfeed.
"No traces of mRNA COVID-19 vaccines found in breast milk: Research"
https://www.dailysabah.com/life/health/no-traces-of-mrna-covid-19-vaccines-found-in-breast-milk-research
“We didn’t detect the vaccine associated mRNA in any of the milk samples tested,” said lead author Yarden Golan, PhD, a postdoctoral fellow at UCSF. “These finding provide an experimental evidence regarding the safety of the use of mRNA-based vaccines during lactation.”
https://www.ucsf.edu/news/2021/07/421041/no-sign-covid-19-vaccine-breast-milk
"We show here that the mRNA from anti-COVID BNT162b2 (Pfizer) and mRNA-1273 (Moderna) vaccines is not detected in human breast milk samples collected 4-48 hours post-vaccine. These results strengthen the recommendation of ABM and WHO that lactating individuals who receive the anti-COVID-19 mRNA-based vaccine should continue to breastfeed their infants uninterrupted."
https://www.medrxiv.org/content/10.1101/2021.03.05.21252998v1
I always had the same question Krista O asked in earlier comment - "Why is mRNA in breastmilk (even if a small amount) a bad thing?
I propose that lay people would assume it must be a bad thing considering the studies set out to prove this did not happen, and argued it was safe specifically *because* "...mRNA from anti-COVID BNT162b2 (Pfizer) and mRNA-1273 (Moderna) vaccines is not detected in human breast milk samples collected 4-48 hours post-vaccine."
Now that this has turned out to be incorrect, rather than digging into to how this was missed on the study which promoted this apparently false claim, concern is essentially dismissed as "well that's not a big deal anyway". Can you see how they may feel "gaslit"?
If this wasn't a concern in the first place, why was it pursued at all? Why didn't the original claim say "we don't find it so far, but even if it was present it doesn't matter because of x, y, z"?
Why isn't there more focus on how the original study could have missed this in the first place? Why do I have to read conspiracists to get a good understanding of the flaws of the original study and how they were avoided in an attempt to replicate? [1]
Covid vaccine enthusiasm has clearly plummeted among the general public. We saw this when the <12 kids never passed 30%. We saw this again when the <2 got stuck at 5%. Few countries even authorized for this cohort. The latest booster has far lower demand than expected. Switzerland is discarding unused doses, Denmark stopped offering to anyone under 50.
I don't think this reluctance can be blamed on "antivaxx" sentiment. I argue it is due to the erosion of trust in our scientific institutions, and this is just the latest example of why there is a breakdown in trust. It should have been communicated much better, with more humility.
[1] Example of the type of research and examination I would hope to see elsewhere: https://igorchudov.substack.com/p/bill-gates-funded-scientists-found
Katelyn Jetelina advocates giving what the FDA in 2020 considered experimental gene therapy to the most vulnerable members of our population.
In her article on the mRNA trials in babies aged from 6 months, she cites reasons other than protection from severe disease, even, bizarrely, the reduced requirement to socially distance.
Any product that doesn’t reduce transmission and requires repeated dosing is a therapy. The gold standard primary endpoint for any trial in any therapy is ALL CAUSE mortality and morbidity.
The MRNA drugs' original trials in adults didn’t show benefit in all cause mortality. The primary endpoint wasn’t even reduced risk of severe disease caused by Covid.
Any parent or prospective parent has a duty to discuss the data RCTs with an immunologist who knows their own or their child’s personal history. Parents should ask for clear evidence of efficacy in reduced risk of severe disease shown by blood work (T cell response) and how long the protection lasts.
Blood Work should be available for each participant and, in cases where the second dose wasn’t given, the reasons should be clear. That's why raw data is so important.
As for the evidence that the shots are safe for reproductive health, in pregnancy, for nursing infants…
the above article cites a meta analysis “pooling many of these studies'. Prasad et al. exclude many, whittling them down to just 23. One notable exclusion is the Shimabukkuro et al. study, which was touted early in the roll out as evidence the mRNA shots were safe in pregnancy. The authors' own data, however, didn’t support their conclusions and a correction was issued, although the paper hasn’t been retracted.
Prasad et al. say one of the strengths of their study is that they use “grey” literature such as government reports (Are we to trust government reports coming from bodies that pushed the covid shots so hard?)
The authors include one large Canadian study where the number of doses is unspecified (In Canada and the US, vaccination status is unreliable because many hospitals record patients as “unvaccinated” until two weeks after the second dose.)
Immunologist Dr. Male cites the study by Gat et al that DID find a negative effect on sperm. The authors’ conclusion is that it was temporary and therefore of no concern but the data do not support that:
https://boriquagato.substack.com/p/pfizer-vaccine-effects-on-total-motile
How long was the follow-up? We were told vaccine-induced myocarditis was “mild” and “temporary” before we even had evidence from MRIs and subsequent studies have found fibrosis and fatal heart attacks from the shots.
Another major limitation of the meta analysis by Prasad et al. and the Swiss study by Favre et al. ( a poor quality study being “observational”) that the authors say themselves is that they don’t focus on health outcomes for infants.
What about the sexual health of the infants, comparing size of testes, incidence of myocarditis, respiratory and neurological conditions?
What about the long-term effects (such as cancer) for anyone? If a product is marketed as a vaccine then certain safety studies don't need to be done:
https://www.ema.europa.eu/en/documents/assessment-report/spikevax-previously-covid-19-vaccine-moderna-epar-public-assessment-report_en.pdf
https://phmpt.org/wp-content/uploads/2022/03/125742_S1_M2_24_nonclinical-overview.pdf
You can find reports in VAERS of severe adverse effects (including death) of nursing infants whose mothers had been jabbed. Kateyln Jetelina says these are not greater than normal. Does she know that VAERS is severely under-reported?
In the clip below, you can watch nurses giving evidence at a Health and Welfare meeting of the Louisiana House of Reps on the "terrifying" vaccine injuries they're seeing. The nurses (cardiac and general) speak at the one hour mark. They both say (and their testimony is consistent with other nurses and doctors from other countries) the injuries are not being reported to VAERS:
https://house.louisiana.gov/H_Video/VideoArchivePlayer?v=house%2F2021%2Fnov%2F1108_21_HW
Katelyn Jetelina is keen to counter "misinformation". There are over 1000 peer-reviewed papers on AEs from the shots. I'd be interested to know what she thinks of the testimony of three participants (and the mother of another) in the original trials who say severe AEs such as paralysis, cancer, pericarditis, neurological were covered up?