It is not the vaccines but the virus that can cause reproductive problems

By Lora Fileva

Lora Fileva has been working as a journalist for, a Bulgarian news site, since 2009. She has covereda wide range of topics – from education and human rights to refugees and judiciary reform.


Katie* is a 35-year old Bulgarian and a mother of a daughter who is three and a half years old. She contracted COVID-19 from her child in March 2021. The mother had a mild case of the virus but then had palpitations for several months.

Katie follows basic anti-epidemic measures and believes that the elderly should get vaccinated in order to be protected. Her sister lives in England and she has not seen her in nearly two years. In October it was not yet clear when she would be able to travel. When asked if she had been vaccinated, Katie said:

“No. Because I want to have a second child. And that was the advice of the doctor.”

Katie, just like many other young women and men in Bulgaria, faces a wave of misinformation which often consists of half-truths and facts mixed with myths. The argument that the vaccine can cause problems in the reproductive organs of men and women has been part of the anti-vaccination rhetoric not only in Bulgaria but also around the world since the very beginning of the vaccination campaign.

A British study from March 2021, cited by Euronews, shows that about a quarter of young women do not want to be jabbed because they are worried about their fertility. In July 2021, Google searches for infertility related to COVID-19 vaccines increased by 34,900 percent.

Katie’s physician also advised her to wait with the vaccine, especially if she wants to have more children. The explanation – there was evidence that the vaccine may affect ovarian function.

In Bulgaria, information on this subject is scarce

In the fall of 2021, at least on the websites of the official institutions dedicated to the fight against coronavirus, there is neither a clear recommendation nor a scientifically based opinion.

In early August, the nationalist Vazrazhdane party, also known for its stance against vaccines, posted a video on the organization’s Facebook page from the town of Veliko Tarnovo. In it, Elena Terzieva, who is a sociologist by education but introduced herself as a nutritionist, quoted the following story, “some feedback” from party supporters:

“A young couple with reproductive problems, who have been trying to have a child for a long time, went to a foreign clinic to look for a solution to their problems. Because they often have to travel across the border, they decided to get an anti-COVID vaccine so that they wouldn’t have to be tested every time. When they went for another test, the specialists at the clinic told them that all their gametes are damaged and they would have to wait a year before resuming their attempts at having a child.”

Terzieva concluded that vaccines have not yet been sufficiently studied and it is not clear what effect they have on the reproductive abilities of men and women. The video has over 2,800 views.

In early 2021, the Expert Council on Obstetrics and Gynecology at the Ministry of Health published brief recommendations that pregnant women or women who want to become pregnant should not be vaccinated at least six months before pregnancy. This short, the written statement was not supported by any reference to literature, scientific sources, or research data.

At the same time, a number of international obstetric and gynecological organizations have published recommendations to the contrary – that pregnant women and those wishing to have children should not be denied a vaccine. You can read more on the topic in this analysis by Nadezhda Tsekulova from 19 August.

“Vaccines cannot lead to infertility or sterility. But the virus that causes COVID-19, SARS-CoV-2, not only causes problems in the lining of the upper respiratory tract and the digestive system but also severely affects the reproductive system. It attacks the testicles, reduces testosterone levels, and certainly suppresses a man’s reproductive functions,” said Bulgarian immunologist Tsvetelina Velikova. She explained that the virus can attack the ovaries because there are receptors for it there and can suppress ovulation. “The effect of the virus itself on the organs has been proven,” she said. “A number of scientific articles confirm that the virus leads to suppression of reproductive abilities for months to come. It is still unknown for how long. The truth is that the virus suppresses the reproductive abilities of people and not the vaccines.”

In their podcast, the World Health Organization explained that there was no evidence that COVID-19 vaccines could affect fertility in women and men. And according to the Centers for Disease Control and Prevention (CDC), one of the most reputable medical organizations, there is no evidence that vaccination can cause reproductive problems. The guidelines of CDC from 11 August this year report that vaccination against COVID-19 is recommended for anyone over the age of 12, including women who are trying to become pregnant now or may become pregnant in the future, as well as their partners.

In addition, the organization’s website states that “there is currently no evidence that any vaccines, including COVID-19 vaccines, cause fertility problems (problems trying to get pregnant) in women or men. If you get pregnant after receiving your first shot of a COVID-19 vaccine that requires two doses (Pfizer-BioNTech COVID-19 vaccine or Moderna COVID-19 vaccine), you should get your second shot to get as much protection as possible.” WHO refers to professional medical organizations serving people of reproductive age, including adolescents. According to these organizations, the vaccination of women who may become pregnant in the future is recommended.

Dr Mark Trolice, a reproductive specialist and Professor of Obstetrics and Gynecology at the University of Central Florida, spoke in an article on the MDedge medical site in late August this year. He explained where the claim that vaccines can lead to infertility came from:

“The same month as the vaccine’s EUA (Emergency Use Authorization), German physician Wolfgang Wodarg, who is a pulmonary specialist, and British pharmacologist Michael Yeadon, a former Pfizer chief science officer and respiratory research head, petitioned Europe’s health regulator, the European Medicines Agency, to suspend clinical trials and approval of the Pfizer/BioNTech vaccine. The two cited baseless claims of female sterilization in an online blog that has since been removed. Their contention was that the vaccine would induce the formation of antibodies against a protein called syncytin-1, which is involved in the development of the placenta in humans, and lead to infertility.

Although syncytin-1 is important for placenta formation, it bears no resemblance to the SARS-CoV-2 spike protein except for a very small amino acid sequence. Experts agree that this similarity is not enough to trigger an immune response leading to female infertility.”

In his scientific article, Dr Trolice said there was limited evidence of poor reproductive health and fertility in men after infection with the COVID-19 virus.

There is no evidence that vaccines adversely affect male fertility and sperm quality either. Research by the University of Miami among a group of healthy men who were studied after the first and second doses of an mRNA vaccine showed that there was no reduction in any semen parameters. “Because the vaccines contain mRNA and not the live virus, it is unlikely that the vaccine would affect sperm parameters,” the analysis said.

Another myth, part of the wave of misinformation, is that pregnant women can get infected from the vaccine and transmit the virus to their foetuses’.

“This logic is not true, because none of the vaccines currently on the European market contain a live virus. They contain only spike protein, which cannot connect to the reproductive organs. This is a small part of the vaccine, which remains at the injection site and reaches only the immune cells to develop an immune response,” said Dr Tsvetelina Velikova. According to her, there is no theoretical basis for believing that vaccines and the immune response they elicit will attack the placenta or the baby in the mother’s womb.

The latest data from the UK show that one in six critically ill patients hospitalized in the country is a pregnant unvaccinated woman. Therefore, the National Health Service in Great Britain has again recommended that pregnant women, as well as those who are planning a pregnancy, should be immunized.

“The medical consensus is clear – pregnant women should be vaccinated,” Dr Tsvetelina Velikova said. “There is no risk to the foetus or them. The only risk is associated with a rise in temperature in the first trimester to the 12th week, but this rarely happens and it is allowed to take paracetamol for such problems.” 

Dr Tsvetelina Velikova cited data showing that there is no increase in the number of adverse side effects on pregnancy in vaccinated women. There is no increase in the percentage of pregnancies that do not end successfully due to vaccination; on the contrary – these women are protected from COVID-19. “In this way, they also protect the baby,” the immunologist said. “The baby has antibodies for up to six months after birth, which is a very big advantage.” According to her, breast milk cannot provide as many antibodies as can vaccinating a pregnant woman in one of the trimesters:

“The antibodies are transmitted through the breast milk to a limited extent, which affects the baby’s nasopharynx and mouth and protects it at this level. But antibodies that cross the placenta to the baby during pregnancy protect his whole body for the first six months. Breast milk has its role, of course, but it is smaller. It is better for a woman to get vaccinated while pregnant than after giving birth.”

* The name has been changed by the editors.

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