Semen in the time of COVID-19: a narrative review of current evidence and implications for fertility and reproductive health

Abstract

Historically, viruses have impaired the functionality of human systems. The discovery of novel viruses and the resurgence of established strains heighten concerns about their implications for reproduction. In the aftermath of COVID-19, research efforts have intensified to broaden the understanding of the severe acute respiratory syndrome coronavirus-2’s (SARS-CoV-2) effect on male reproduction across diverse populations. Various findings have been reported, with more studies highlighting the adverse impact of SARS-CoV-2 on semen parameters and, consequently, male fertility. This review aims to comprehensively assess and consolidate existing evidence on the impact of SARS-CoV-2 on semen quality and male fertility. It highlights the potential mechanism of action and further underscores the implications for assisted reproductive technology. A thorough literature search was conducted across various electronic databases, including PubMed, Scopus, Google Scholar, Embase, and Web of Science. Studies published between January 2020 and May 2024 were included if they explored the impact of SARS-CoV-2 on semen quality. Twenty-nine (29) studies were included in the review. These studies varied in findings but delineated a pattern and trend. While most studies noted a decline in sperm parameters—motility, count, concentration—altered morphology, hormonal imbalances, and increased DNA fragmentation in COVID-19 patients, others reported normal semen parameters 3 to 6 months post-recovery. Few studies reported no change in semen parameters, especially with mild disease. Potential mechanisms underscoring these effects include the presence of fever and consequent release of pro-inflammatory cytokines—interleukin 1β, tumor necrosis factor (TNF), and interferon-gamma (IFNγ). In addition, the activities of the angiotensin-converting enzyme 2 (ACE2) and the transmembrane serine protease 2 (TMPRSS2) receptors have been implicated as gateway mechanisms for viral entry. The long-term consequences and comparisons with other viral infections highlight the complexity of drawing definite conclusions. The different findings on semen changes have implications for assisted reproduction and family planning. Research suggests potential negative effects on gonadal function, emphasizing the need for long-term follow-up studies to understand the persistent effects on male fertility biomarkers. A multidisciplinary approach is essential to optimizing male reproductive health during and after SARS-CoV-2 infection. This includes incorporating assessments into vaccine safety studies to address fertility concerns.