Spike Protein from mRNA COVID Shots Detected in Placenta and Fetal Cells

A new peer-reviewed study has found spike protein and vaccine-derived mRNA in human placental tissue and fetal immune cells, including in mothers who were vaccinated before pregnancy and had no documented SARS-CoV-2 infection. The study, published Mar. 5, 2026 in PLOS One, analyzed 106 placentas from women who delivered between 2020 and 2022 and used immunohistochemistry and RNA-detection techniques, which are laboratory staining methods. Those techniques allow scientists to visually detect specific proteins and genetic material inside tissue samples under a microscope to examine placental tissue for spike protein and genetic material associated with mRNA COVID-19 shots.¹

Among the 106 placentas examined, 31 samples (29 percent) tested positive for spike protein by immunohistochemistry. The study also detected spike protein in 37 percent of placentas from vaccinated mothers with no documented infection, with 77 percent of spike-positive placentas showing the protein inside fetal immune cells (known as Hofbauer cells).¹

In some cases, researchers also detected traces of vaccine-derived mRNA in placental tissue in the absence of detectable viral RNA, suggesting the signal was unlikely to have come from an active infection and may instead be associated with vaccination.  The authors say findings may indicate cellular uptake or possible transplacental transfer. In other words, the material appeared to be absorbed by placental cells and may have crossed the placenta from mother to fetus.¹

Spike-Positive Placentas Higher in Vaccinated Mothers Without SARS-CoV-2 Infection Than in Unvaccinated Mothers Without Infection

“Particularly notable was the subgroup of vaccinated women who never tested positive for COVID-19 during pregnancy,” epidemiologist Nicolas Hulscher, MPH said in a Substack post analyzing the study. “Within this group, 11 of 30 placentas (approximately 37 percent) contained detectable spike protein, indicating that spike protein presence in placental tissue cannot be explained solely by viral infection. The supplemental dataset also documents at least one spike-positive placenta from a mother vaccinated before pregnancy who had no documented COVID-19 infection during pregnancy.”²

Hulscher continued, “For comparison, among the unvaccinated women who experienced COVID-19 infection during pregnancy, spike protein was detected in 3 of 14 placentas (21 percent). In this dataset, the proportion of spike-positive placentas was therefore higher in vaccinated mothers without infection than in mothers who were infected but not vaccinated.”²

New Findings on Spike Protein in Placental Tissue Associated With Poor Reproductive Health Outcomes

Hulscher also connected the study findings to reported increases in infant mortality observed around 2021, during widespread COVID vaccination. “Governments, pharmaceutical companies, and regulatory agencies have committed a grave disservice to future generations. The widespread fetal uptake of mRNA through maternal injection introduces unknown and potentially catastrophic consequences for human development. The long-term risks of in utero exposure to highly pathogenic spike protein of modified mRNA are unknown, yet these experimental injections were recklessly pushed onto pregnant women without adequate safety data.”²

The study follows multiple large-scale studies that have identified reproductive and fertility effects among individuals who received an mRNA COVID shot. A June 2025 Israeli study found that women who received their first mRNA COVID shot during early pregnancy, specifically between weeks eight and 13, were significantly more likely to experience pregnancy loss than expected.^{3 4}

The study, which was the first national-scale analysis to examine gestational timing in relation to mRNA vaccination, found nearly four additional losses per 100 pregnancies in this group. This  represented a roughly 40% increase over the baseline rate. Most of these losses occurred during later stages of pregnancy, with the majority happening after 20 weeks gestation and nearly half after 25 weeks, which placed them in the category of stillbirths.^{3 4}

Around the same time, a large-scale population study out of the Czech Republic, published in the International Journal of Risk & Safety in Medicine, found that women who received a COVID-19 vaccine prior to conception were significantly less likely to achieve a successful pregnancy compared to unvaccinated women.⁴

The U.S. Secretary of Health and Human Services, Robert F. Kennedy, Jr., later called for a federal ban on administering COVID shots during pregnancy, citing insufficient long-term fertility safety data, which prompted the CDC to revise its vaccination guidance for children and pregnant women.⁵

Stillbirth Rates 17 Percent Higher Than Previously Reported in U.S.

More recently, a JAMA study published Oct. 27, 2025 found that a significant number of stillbirths occur in pregnancies the medical system labels as low risk and at a 17 percent higher rate in the U.S. than previously reported. According to the study, stillbirth rates have not declined despite modern prenatal care, and while most losses involved at least one identifiable clinical risk factor, a substantial share had none, particularly those occurring at or beyond 40 weeks’ gestation. Nearly half of term stillbirths occurred in people with no identifiable clinical risk factors, and many of these deaths are considered potentially preventable.⁶

Scientists Say Findings Warrant Further Research Investigating COVID Shot Effects on Mothers and Children

These newest findings renew longstanding questions about how vaccine-generated spike protein or genetic material may interact with placental and fetal tissues during pregnancy. The placenta is a highly active organ that regulates nutrient transfer, immune signaling, and protection of the developing fetus. Hofbauer cells, the fetal immune cells where spike protein was most frequently detected, play an important role in shaping the fetal immune system and responding to inflammation.¹

The presence of spike protein or vaccine-derived mRNA in these cells, scientists say, warrants further research to determine whether such exposure could influence placental immune activity, fetal immune development, or pregnancy outcomes, and what it could mean for both mothers and their children.¹

If you would like to receive an e-mail notice of the most recent articles published in The Vaccine Reaction each week, click here.