News | Study refutes claims that vaccines cause infertility or affect fetal development, adding strong evidence for COVID-19 vaccine safety in fertility and pregnancy
News | Study refutes claims that vaccines cause infertility or affect fetal development, adding strong evidence for COVID-19 vaccine safety in fertility and pregnancy
Claims that COVID-19 vaccines may affect female fertility or that vaccination during pregnancy may cause fetal abnormalities or growth restriction continue to circulate widely on social media. A study led by Yale School of Medicine clearly refutes this misinformation.
Published in PLOS Biology and led by Alice Lu-Culligan, PhD, an expert in immunology and pregnancy, the study analyzed data from mouse models and human blood samples. It concluded that COVID-19 vaccines do not cause abnormal fetal development or female infertility by attacking a placental protein.
Mouse experiments: vaccines did not cause fetal abnormalities and transferred protective antibodies to fetuses
The team first administered an mRNA COVID-19 vaccine to mice in early pregnancy. The results showed:
Vaccination did not affect fetal weight or cause birth defects;
Antibodies produced by vaccinated mothers crossed the placenta effectively and provided fetal protection;
By contrast, injecting another group of pregnant mice with poly(I:C), a substance that mimics viral infection, significantly restricted fetal growth.
Dr. Lu-Culligan said: “These results further support that vaccination is safer for both pregnant women and fetuses and carries far less risk than actual COVID-19 infection.”
The findings are also highly consistent with conclusions from the U.S. Centers for Disease Control and Prevention (CDC) and multiple human studies of vaccine safety during pregnancy.
The study also examined whether vaccines could induce antibodies that attack the placental protein syncytin-1 and thereby cause female infertility.
The team collected blood samples from vaccinated and unvaccinated volunteers and tested for antibodies against syncytin-1. The results showed:
Neither vaccinated nor unvaccinated volunteers had abnormally elevated anti-syncytin-1 antibodies;
This means the vaccine does not activate an immune attack against the placenta and has no biological mechanism for causing infertility.
Dr. Lu-Culligan said: “This rumor has been thoroughly disproven scientifically. Our data again show that COVID-19 vaccination does not affect fertility in women preparing for pregnancy.”
Ongoing safety evaluation is needed, but current data already provide strong practical guidance
The authors emphasized that although this study was conducted in mice, together with existing human clinical data it provides clear reassurance for women receiving COVID-19 vaccines, especially those planning pregnancy or already pregnant.
As more real-world data and ongoing clinical studies accumulate, the evidence on vaccine safety will continue to strengthen.
Dr. Lu-Culligan concluded: “Our study not only provides evidence of COVID-19 vaccine safety in early pregnancy, but also directly refutes rumors that discourage vaccination among women who are not pregnant. Responding to the pandemic requires both science and clarity.”
News | Study refutes claims that vaccines cause infertility or affect fetal development, adding strong evidence for COVID-19 vaccine safety in fertility and pregnancy
News | Study refutes claims that vaccines cause infertility or affect fetal development, adding strong evidence for COVID-19 vaccine safety in fertility and pregnancy
Claims that COVID-19 vaccines may affect female fertility or that vaccination during pregnancy may cause fetal abnormalities or growth restriction continue to circulate widely on social media. A study led by Yale School of Medicine clearly refutes this misinformation.
Published in PLOS Biology and led by Alice Lu-Culligan, PhD, an expert in immunology and pregnancy, the study analyzed data from mouse models and human blood samples. It concluded that COVID-19 vaccines do not cause abnormal fetal development or female infertility by attacking a placental protein.
Mouse experiments: vaccines did not cause fetal abnormalities and transferred protective antibodies to fetuses
The team first administered an mRNA COVID-19 vaccine to mice in early pregnancy. The results showed:
Vaccination did not affect fetal weight or cause birth defects;
Antibodies produced by vaccinated mothers crossed the placenta effectively and provided fetal protection;
By contrast, injecting another group of pregnant mice with poly(I:C), a substance that mimics viral infection, significantly restricted fetal growth.
Dr. Lu-Culligan said: “These results further support that vaccination is safer for both pregnant women and fetuses and carries far less risk than actual COVID-19 infection.”
The findings are also highly consistent with conclusions from the U.S. Centers for Disease Control and Prevention (CDC) and multiple human studies of vaccine safety during pregnancy.
No antibody response attacks placental proteins; infertility claim lacks scientific basis
The study also examined whether vaccines could induce antibodies that attack the placental protein syncytin-1 and thereby cause female infertility.
The team collected blood samples from vaccinated and unvaccinated volunteers and tested for antibodies against syncytin-1. The results showed:
Neither vaccinated nor unvaccinated volunteers had abnormally elevated anti-syncytin-1 antibodies;
This means the vaccine does not activate an immune attack against the placenta and has no biological mechanism for causing infertility.
Dr. Lu-Culligan said: “This rumor has been thoroughly disproven scientifically. Our data again show that COVID-19 vaccination does not affect fertility in women preparing for pregnancy.”
Ongoing safety evaluation is needed, but current data already provide strong practical guidance
The authors emphasized that although this study was conducted in mice, together with existing human clinical data it provides clear reassurance for women receiving COVID-19 vaccines, especially those planning pregnancy or already pregnant.
As more real-world data and ongoing clinical studies accumulate, the evidence on vaccine safety will continue to strengthen.
Dr. Lu-Culligan concluded: “Our study not only provides evidence of COVID-19 vaccine safety in early pregnancy, but also directly refutes rumors that discourage vaccination among women who are not pregnant. Responding to the pandemic requires both science and clarity.”
Source:
Collected online