A post on Instagram from former Coronation Street actor Sean Ward makes a number of claims about the Pfizer Covid-19 vaccine.
The image in his post is a screenshot of a tweet that says “NEW - Pfizer's primary mRNA injections ‘temporarily’ impair semen concentration and total motile count among donors. The scope of the study did not include the effects of additional ‘booster’ injections.”
Mr Ward’s caption adds: “MUST MEAN ITS WORKING! Depopulation season. Be wary. These men / big pharma do NOT have you back. They do NOT want to save you & never will 😤 First it was issues with women’s menstrual cycles. Now mens [sic] sperms.”
Although a study did show that some markers of semen quality temporarily reduced following Covid-19 vaccine, this is not evidence of any lasting effect on fertility.
Other studies have shown no effect of the Pfizer vaccine on semen quality. There is also no evidence that the vaccines harm female fertility.
What did the paper say?
The tweet includes a link to the paper which describes how it tested 37 sperm donors who had provided 220 samples. Their samples were then analysed at different points between Pfizer Covid-19 vaccinations.
It found that compared to before they were vaccinated, samples taken between 2.5 months and 5 months after vaccination, had lower sperm concentration, which is the number of sperm per millilitre of semen, and total motile count, which is the total number of sperm in the sample that swim.
These appear to have been temporary dips, as these levels were no longer lower in a way that was statistically significant in samples taken 5 months or more after vaccination.
It’s not clear exactly why this happens, although the paper suggests that a “systemic immune response after [the Pfizer] vaccine is a reasonable cause for transient semen concentration and [total motile count] decline”. It points to other studies that have found that illnesses involving fever can temporarily affect semen quality and says that “rather than a direct effect on testicular cells…we believe that systemic immune response is a more reasonable explanation for the temporary [sperm] concentration decline.”
Other studies have found no reduction in semen quality after vaccination with the Pfizer Covid-19 vaccine.
This paper added that “long-term prognosis remains good” and that the long term impact of the vaccine “seems safe”. The paper did not find any reduction in semen quantity or sperm motility.
It was a small study so may not show the full story
It’s important to note that this study had only 37 participants, making it relatively small. Fewer participants generally means the findings are less reliable as they are more likely to be affected by random extremes in either direction. This is particularly important in this case, as the paper says semen samples are subject to “high within- and between-subjects variations”.
The paper itself says it has several limitations, including that it only focussed on sperm donors rather than the general public.
What about the vaccines’ effect on periods?
The Medicines & Healthcare products Regulatory Agency says it is reviewing reports of period problems following Covid-19 vaccinations, but to date the data “does not support a link between changes to menstrual periods and related symptoms and COVID-19 vaccines”.
It added: “The menstrual changes reported are mostly transient in nature. There is no evidence to suggest that COVID-19 vaccines will affect fertility and your ability to have children.”
We have written before about how there’s no evidence that any of the vaccines affect female fertility.
Image courtesy of the CDC