Getting sick from COVID may impair male fertility, but vaccination shows no negative effect
COVID-19 infection may meaningfully affect male reproductive health, while having limited consequences for female fertility or assisted reproductive technology (ART) outcomes, according to a new umbrella review published this week in Vaccine. In contrast, COVID vaccination showed little impact on fertility in either men or women.
The review, led by a team at the Department of Reproductive
Medical Center at Sichuan University in Chengdu, China, assessed the effects of
COVID infection and COVID vaccination on fertility and ART outcomes by
analyzing data from 14 studies with 40 different fertility and ART
outcomes.
Impaired male fertility persists 3 months after infection
Among men, the data suggests, COVID infection is associated
with reductions in semen quality, including lower semen volume and
concentration, and total sperm count, viability, and motility. COVID infection
was also associated with elevated levels of the hormones estradiol and
prolactin in men, though it did not appear to significantly affect testosterone
levels.
These negative fertility outcomes in men persisted after infection. “Notably, even after recovery (over 90 days), sperm concentration and motility remained lower compared to uninfected individuals,” they write.
While the authors emphasize the need for more research because the quality of the evidence in the included studies is rated low, they note the biological plausibility of COVID infection on male fertility given the high distribution of viral-entry receptors such as angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) in male reproductive organs.
“Given the high expression of ACE2 and TMPRSS2 in the
testes…the male reproductive system is theoretically prone to SARS-CoV-2
infection,” they write. “This infection, leading to orchitis [inflammation of
the testicles] and disruption of spermatogenesis [the creation of mature
sperm], might result in reduced sperm count, motility, and overall semen
quality.”
No link between COVID vaccination, fertility outcomes
For women, COVID infection was not associated with negative
fertility outcomes. “COVID-19 showed minimal impact on female ovarian
reserve…or ART outcomes,” they write, despite ACE2 being present in ovarian
tissues and the lining of the uterus, which suggests COVID infection could
affect female reproductive organs and interfere with fertility.
The analysis did not find evidence of reproductive harm from
COVID vaccination for either men or women.
“More high-quality prospective studies with longer follow-up
periods are needed,” they write, specifying that “the findings for male
reproductive impact warrant further longitudinal investigation, especially into
long-term fertility and live birth outcomes.”
They also emphasize the lack of evidence showing an
association between COVID vaccination and fertility outcomes. “The current
evidence does not substantiate concerns linking COVID-19 vaccines to impaired
fertility or ART failure,” they conclude.
