[super_mario]

Apparently, protein (Syncytin-1) present in the spike of SARS-COV2 is also present in human placenta. If the vaccine produces anti-bodies for this protein, it could also lead to infertility in women.

I think the answer to this questions would be nice to have.

"Several vaccine candidates are expected to induce the formation of humoral antibodies against spike proteins of SARS-CoV-2. Syncytin-1 (see Gallaher, B., “Response to nCoV2019 Against Backdrop of Endogenous Retroviruses” - http://virological.org/t/response-to-ncov2019- against-backdrop-of-endogenous-retroviruses/396), which is derived from human endogenous retroviruses (HERV) and is responsible for the development of a placenta in mammals and humans and is therefore an essential prerequisite for a successful pregnancy, is also found in homologous form in the spike proteins of SARS viruses. There is no indication whether antibodies against spike proteins of SARS viruses would also act like anti-Syncytin-1 antibodies. However, if this were to be the case this would then also prevent the formation of a placenta which would result in vaccinated women essentially becoming infertile. To my knowledge, Pfizer/BioNTech has yet to release any samples of written materials provided to patients, so it is unclear what, if any, information regarding (potential) fertility-specific risks caused by antibodies is included."

[kypro]

Occurring to the AP this is inaccurate,

> Jacob Yount, an associate professor of the department of microbial infection and immunity at Ohio State University, College of Medicine, has studied the syncytin proteins as well as SARS-CoV-2. Yount said the COVID vaccines do not contain syncytin-1 protein or mRNA encoding syncytin-1, and thus there is no reason to think that an immune response against syncytin-1 would be developed.

> “We don’t see infertility with the flu vaccine and that is also targeting a viral fusion protein in a similar way that the spike is a viral fusion protein of the coronavirus,” he said.

https://apnews.com/article/fact-checking-9856420671

[hajile]

We do know the vaccine DOES contain PART of the syncytin-1 sequence. Is it going to be a problem? We do not know.

This professor doesn't know about how much of the sequence is copied. He doesn't know the widespread affect of mRNA vaccines because we're in new territory here and it's possible that the risk of autoimmune responses is higher with such vaccines. He should know better than to equate mRNA vaccines with more traditional vaccines.

With every vaccine, a small percentage of people suffer adverse and autoimmune effects.

As that professor well knows, we're NOT discussing possibility (with that billions of people lined up, it's all but inevitable). Instead, we're discussing PROBABILITY that it will happen and how many people will be adversely affected.

I'm not saying the vaccine is bad or that people should freak out and not get vaccinated (even some vaccines with high complication rates have historically been much more helpful than harmful). I'm pointing out that while the intentions of the professor may be good, they're definitely not speaking the absolute truth and aren't actually in a position to know all the actual details about the vaccine.

[kypro]

I shared the link because I hadn't heard about the infertility risk before and I found a lot of conflicting information when I looked it up – with many main stream sources dismissing the claim out of hand.

My understanding is that, yes, the proteins are similar, but not the same, and that a similar protein also exists in influenza which does not cause infertility when targeted by our antibodies. I assume this doesn't mean that it couldn't cause infertility in the case of a COVID-19 vaccine, but it would suggest it's perhaps unlikely.

Is there any reason to believe an mRNA vaccine would be anymore likely to cause our antibodies to target the syncytin-1 spike protein as opposed to a more traditional vaccine?

I do agree with your point that it's more a question of the probability of side effects than a possibility. This is something that's bothered me about the attacks on those who are hesitant on the safety of these vaccines. Although I'm sure there's a very low risk that someone will suffer any adverse effects from these vaccines there is almost certainly going to be some cases of adverse side effects, so in the interest of public trust in the COVID-19 vaccines and all future vaccines we should be ensuring the public understand the risks fully and not attacking anyone for asking questions or expressing doubts, because if it does turn out that some of those doubts did indeed hold merit then no one will trust a word the media or professors have to say on this in the future.