Originally, I did not intend to take a detailed position on general topics related to COVID 19 or the vaccine in the MS-DocBlog. However, I have also repeatedly noticed uncertainty in my office hours regarding the COVID 19 vaccination and its effects on fertility. The assertion of vaccine opponents has been in the room for quite some time, it has already been conclusively refuted, but still persists in public perception. Since MS often affects women of childbearing age and with a desire to have children, the question is quite relevant. Therefore, I would like to use this forum to make a clear statement and explain why the claim “The COVID19 vaccination makes you infertile” is wrong.
The argument of vaccine opponents often begins with them complaining that the technical information of the vaccine under section 4.6 Fertility, Pregnancy and Breastfeeding contains the statement that there are only limited data on the effect of a vaccination during pregnancy. Therefore – so the conspiracy narrators – there would probably be a problem. Otherwise, one would find clear information here.
Vaccines are usually first tested on healthy subjects
However, it is understandable that the effect of the vaccines – especially because the vaccine development had to proceed very quickly – is first tested on healthy subjects and does not primarily turn to vulnerable groups such as pregnant women or children. These groups will certainly be closely examined in the course (as is already the case with children). But it is otherwise a standard procedure in clinical trials to not include sensitive groups in the initial phase (which we are still in). This has absolutely nothing to do with the fact that the vaccine manufacturers want to hide something or that there is an unrecognized danger. Such misinformation campaigns by vaccine skeptics are perfidious and undermine trust in the COVID19 vaccination.
No immunological cross-reaction
The second line of argument of the vaccine skeptics is much more difficult for the medical layman to evaluate. Here it is claimed that the COVID 19 vaccine would lead to an immunological cross-reaction (so-called “molecular mimicry”) with components of the human placenta – specifically with the molecule Syncitin-1 – and thereby cause infertility and miscarriages. Syncitin-1 is a fusion protein (historically of viral origin) that is needed for the placenta to implant into the maternal uterus. The spike protein of SARS-CoV2, against which the COVID 19 vaccines build an immune response, is also a fusion protein. It is needed for SARS-CoV2 to penetrate human cells. But this is where the similarities end
Nevertheless, vaccine skeptics claim that the antibodies formed by the new vaccines cause cross-reactions with the placenta, although there is no evidence for this. To make it clear, the antibodies that are formed after vaccination against the spike protein of SARS-CoV do not lead to a blockade of Syncitin-1.
An important piece of evidence for this statement can be considered that during the pandemic no increased abortion rates were observed. What applies to the vaccination should certainly apply to the real infection. In addition, there are now cohort studies showing that infection with the SARS-Coronavirus 2 in pregnant women does not lead to a changed course of pregnancy and no abnormalities were observed at the placenta. For those who want to read more about this, see for example the following publication: Adhikari et al. (2020). Pregnancy outcomes among women with and without severe acute respiratory syndrome Coronavirus 2 infection. JAMA Network Open, 3(11), e2029256.
In addition, a sequence analysis can be performed to identify homologies between the spike protein of SARS-CoV2 and human proteins. The so-called Basic Local Alignment Search Tool (BLAST) is used for this. If you apply such a BLAST analysis to the sequence of the spike protein of SARS-CoV-2, you will not find any matching human reference sequence. Wise guys could now claim that the B cell receptor recognizes quaternary (spatial) structures that are not detected by analyzing a linear protein sequence. This is not wrong, but on the one hand T cells recognize linear epitopes and T cells are essential for a sufficient B cell response. One can assume a so-called “linked recognition”. In addition, there is the rule of thumb that one must already demonstrate pronounced sequence homology to postulate a “molecular mimicry”. This is simply not the case with the spike protein of SARS-CoV2 and Syncitin-1.
Pretty complicated – but it shows how destructively certain vaccine skeptics act in order to undermine public trust and to work socially corrosive with misinformation. This is very depressing.
