This study provides more evidence that Covid vaccination is safe for both current and future pregnancies, and shows in a mouse model that immunization during the earliest stages of pregnancy provides antiviral antibodies to the fetus throughout the rest of pregnancy.
Image Credit: Hannah J. Lee (CC-BY 4.0)
Two of the bogus antivaxxer claims with which the politically-motivated covidiot antivaxxer movement is trying to scare women into not getting vaccinated against COVID-19 are:
- The vaccines cause birth defects if given during pregnancy.
- The vaccines reduce fertility or cause sterility in women by producing antibodies against the protein syncytin-1, which in humans and related primates is involved in attaching the placenta during pregnancy.
The second piece of disinformation was based on the fact that a small part of the SARS-CoV-2 spike protein that antibodies are produced against by the vaccines has a short sequence of amino acids that is also found in syncytin-1.
This is hardly surprising since syncytin-1 is the remnant of an ancient retrovirus that has been co-opted to aid in the attachment of the placenta in many primates. In fact, it's one of many pieces of evidence of common descent since it is present in all the old-world primates, but not in the new-world primates. The Wikipedia entry for syncytin-1 reads:
Syncytin-1 also known as enverin is a protein found in humans and other primates that is encoded by the ERVW-1 gene (endogenous retrovirus group W envelope member 1). Syncytin-1 is a cell-cell fusion protein whose function is best characterized in placental development.[3][4] The placenta in turn aids in embryo attachment to the uterus and establishment of a nutrient supply.
The gene encoding this protein is an endogenous retroviral element that is the remnant of an ancient retroviral infection integrated into the primate germ line. In the case of syncytin-1 (which is found in humans, apes, and Old World but not New World monkeys), this integration likely occurred more than 25 million years ago.[5] Syncytin-1 is one of two known syncytin proteins expressed in catarrhini primates (the other being syncytin-2) and one of many viral genomes incorporated on multiple occasions over evolutionary time in diverse mammalian species.[6]
ERVW-1 is located within ERVWE1,[7][8] a full length provirus on chromosome 7 at locus 7q21.2 flanked by long terminal repeats (LTRs) and is preceded by ERVW1 gag (Group AntiGen) and pol (POLymerase) within the provirus, both of which contain nonsense mutations rendering them non-coding.[9][10] Syncytin-1 is also implicated in a number of neurological pathologies, most notably, multiple sclerosis, as an immunogen.
According to information made available ahead of publication by PLOS, Lu-Culligan and her colleagues:
… first conducted experiments in pregnant mice. They found that administering a COVID-19 vaccine early in pregnancy did not affect the size of the fetus, nor was it associated with any birth defects. In addition, they found that fetuses had high levels of antibodies against COVID-19 infection, suggesting that the protective effects of vaccination passed from pregnant mice to their fetuses. These findings are consistent with a growing body of data on pregnant humans reported by the US Centers for Disease Control and other research groups.
The scientists also injected other pregnant mice with a substance known as poly(I:C) [polyinosinic-polycytidylic acid], which simulates viral infection; fetuses from these mice had reduced growth. Overall, the mouse experiments suggest that vaccination during pregnancy is safer for both mother and fetus than infection during pregnancy.
Next, the researchers collected blood samples from both vaccinated and unvaccinated human volunteers. They found that those who had been vaccinated did not have elevated levels of antibodies against the protein syncytin-1, suggesting that fears of reduced fertility due to COVID-19 vaccination’s effects on this protein are unfounded.
The authors note that, as more people are vaccinated and clinical trials progress, the resulting data will continue to help address widespread concerns about vaccination. In particular, they note, it will be useful to confirm that COVID-19 vaccination is safe at all stages of pregnancy.
The team's published results can be read here. In the abstract they say:
AbstractSo, yet more evidence of the duplicitousness of the QAnon-Trumpanzee-Talibangelical antivaxxer movement and how they distort and misrepresent whatever fragments of science they can abuse for their purposes. And, so long as we have a large number of unvaccinated people in which the virus can breed new variants, it is only a matter of time before a wave of an even more contagious variant sweeps the world and kills another few tens of thousands of people, most of whom won't be vaccinated and many of whom will be pregnant women.
The impact of Coronavirus Disease 2019 (COVID-19) mRN vaccination on pregnancy and fertility has become a major topic of public interest. We investigated 2 of the most widely propagated claims to determine (1) whether COVID-19 mRNA vaccination of mice during early pregnancy is associated with an increased incidence of birth defects or growth abnormalities; and (2) whether COVID-19 mRNA-vaccinated human volunteers exhibit elevated levels of antibodies to the human placental protein syncytin-1. Using a mouse model, we found that intramuscular COVID-19 mRNA vaccination during early pregnancy at gestational age E7.5 did not lead to differences in fetal size by crown-rump length or weight at term, nor did we observe any gross birth defects. In contrast, injection of the TLR3 agonist and double-stranded RNA mimic polyinosinic-polycytidylic acid, or poly(I:C), impacted growth in utero leading to reduced fetal size. No overt maternal illness following either vaccination or poly(I:C) exposure was observed. We also found that term fetuses from these murine pregnancies vaccinated prior to the formation of the definitive placenta exhibit high circulating levels of anti-spike and anti-receptor-binding domain (anti-RBD) antibodies to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) consistent with maternal antibody status, indicating transplacental transfer in the later stages of pregnancy after early immunization. Finally, we did not detect increased levels of circulating anti-syncytin-1 antibodies in a cohort of COVID-19 vaccinated adults compared to unvaccinated adults by ELISA. Our findings contradict popular claims associating COVID-19 mRNA vaccination with infertility and adverse neonatal outcomes.
Lu-Culligan A, Tabachnikova A, Pérez-Then E, Tokuyama M, Lee HJ, Lucas C, et al. (2022)
No evidence of fetal defects or anti-syncytin-1 antibody induction following COVID-19 mRNA vaccination.
PLoS Biol 20(5): e3001506. DOI: 10.1371/journal.pbio.3001506
Copyright: © 2022 The authors. Published by PLoS. Open access
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
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