In a recent study published in the journal PLOS ONE, researchers conducted a systematic review and meta-analyzed data on the impact of coronavirus disease 2019 (COVID-19) on male reproductive hormones and semen variables to determine whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections had an adverse impact on male fertility.
Background
The etiological agent of the COVID-19 pandemic, SARS-CoV-2, is a β-coronavirus that infects human cells by binding to the angiotensin-converting enzyme-2 (ACE-2) receptor. The ACE-2 receptor is found in the lungs, kidneys, heart, and testes, making all these organs possible entry points for the virus.
The COVID-19 pandemic was responsible for over 700 million cases and more than 7 million deaths. However, although the virus is known to primarily infect the respiratory system, research indicates that it can also adversely impact other organ systems. Studies have also found that SARS-CoV-2 infections are more severe in males than in females. Furthermore, studies have found that many males who had been infected with the earlier SARS-CoV-1 had developed orchitis or inflammation of the testes.
However, the data on the impact of SARS-CoV-2 on male reproductive health has been limited. Although some studies have reported associations between COVID-19 and decreased testosterone levels and lower semen quality, some of the findings have been considered methodologically weak.
About the study
The present study aimed to comprehensively review recent studies examining the impact of COVID-19 on male fertility and conducted a meta-analysis by comparing semen quality variables and reproductive hormone levels between infected and uninfected men to understand the influence of SARS-CoV-2 on male fertility.
The researchers used the PECO, or Population, Exposure, Comparator, and Outcomes, model to select studies that examined male patients of reproductive age who had been exposed to SARS-CoV-2. The review included both prospective and retrospective studies as long as they included COVID-19-negative controls or contained pre- and post-COVID-19 pandemic health data for the same individual. Studies that were in vitro, focused on female patients, or lacking control groups were excluded.
For the studies included in the review, the outcomes consisted of measurements of conventional semen parameters such as sperm count, ejaculate volume, sperm concentration, morphology, motility, and viability of the sperm, as well as leukocyte levels in the seminal fluid. The outcomes also included the levels of the male reproductive hormones, including testosterone, estrogen, prolactin, luteinizing hormone (LH), and follicle-stimulating hormone (FSH). The Measurements also included ratios of testosterone to LH and FSH to LH.
For the meta-analysis, the data extracted from the studies consisted of sample sizes, country of study, study design, the methods used to diagnose COVID-19, and key outcomes. The researchers used this data to calculate standardized mean differences, with extensive sensitivity analyses to avoid bias and assess sources of diversity. The parameters were also compared for changes before and after treatment for COVID-19.
Results
The review identified 40 eligible studies published from 12 different countries between 2020 and 2023 that examined the impact of SARS-CoV-2 on male reproductive health. The key findings from the meta-analysis covered the impact of COVID-19 on several aspects of male reproductive health.
The study found that COVID-19 was significantly associated with decreased ejaculate volume, with sensitivity analyses confirming consistent reductions in ejaculate volume after SARS-CoV-2 infections. However, the sensitivity analyses showed that the difference in ejaculate volume before and after COVID-19 treatment was not statistically significant, indicating that the impact of treatment may be limited. The sperm counts also decreased after SARS-CoV-2 infections, although the sensitivity analyses indicated that these reductions were marginal.
Individuals infected with SARS-CoV-2 also showed significantly lower sperm concentrations, and no changes were seen in sperm concentrations after treatment for COVID-19. This finding remained consistent even after accounting for potential study biases and diversity, reinforcing the robustness of the result. COVID-19 was also found to lower sperm viability and motility, with the difference in sperm viability remaining consistent even after the sensitivity analysis.
Comparisons between infected and uninfected individuals revealed no significant differences in sperm morphology. However, comparisons of sperm morphology in the same individual before and after SARS-CoV-2 infections revealed lower levels of morphologically normal sperm. The analysis showed that while the overall morphology differences between infected and uninfected individuals were not significant, the within-individual changes suggest that SARS-CoV-2 may have a subtle but noteworthy effect on sperm morphology.
The reproductive hormone levels were also significantly altered in COVID-19 patients, with elevated prolactin and marginally higher estrogen levels in infected men. Interestingly, the study found substantial variability in testosterone levels before and after treatment, suggesting that COVID-19’s impact on this hormone may be more complex than initially understood. However, the leukocyte levels in the seminal fluid were similar between infected and uninfected men.
Conclusions
To summarize, the study reviewed and conducted a meta-analysis of studies examining the impact of COVID-19 on male reproductive health and found that SARS-CoV-2 had a significant negative impact on male fertility, particularly on parameters such as ejaculate volume, viability, and motility of the sperm, and sperm concentration and count. Although the treatment of COVID-19 partially alleviated some of the affected parameters, the findings suggest that these improvements may not be sufficient to restore pre-infection levels, particularly for parameters like sperm concentration and motility. The study also highlighted the need for further research to fully understand the long-term effects of COVID-19 on male fertility and to explore potential therapeutic interventions.
- V. J., Ashonibare, P. J., Ashonibare, T. M., Akhigbe, & E, A. R. (2024). SARS-CoV-2 impairs male fertility by targeting semen quality and testosterone level: A systematic review and meta-analysis. PLOS ONE, 19(9), e0307396-. DOI:10.1371/journal.pone.0307396, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0307396
News
Does COVID increase the risk of Alzheimer’s disease?
Scientists discover that even mild COVID-19 can alter brain proteins linked to Alzheimer’s disease, potentially increasing dementia risk—raising urgent public health concerns. A recent study published in the journal Nature Medicine investigated whether both mild and [...]
New MRI Study Reveals How Cannabis Alters Brain Activity and Weakens Memory
A massive new study sheds light on how cannabis affects the brain, particularly during cognitive tasks. Researchers analyzed over 1,000 young adults and found that both heavy lifetime use and recent cannabis consumption significantly reduced brain [...]
How to Assess Nanotoxicity: Key Methods and Protocols
With their high surface area and enhanced physicochemical properties, nanomaterials play a critical role in drug delivery, consumer products, and environmental technologies. However, their nanoscale dimensions enable interactions with cellular components in complex and [...]
Nanotech drug delivery shows lasting benefits, reducing need for repeat surgeries
A nanotechnology-based drug delivery system developed at UVA Health to save patients from repeated surgeries has proved to have unexpectedly long-lasting benefits in lab tests – a promising sign for its potential to help human patients. [...]
Scientists Just Found DNA’s Building Blocks in Asteroid Bennu – Could This Explain Life’s Origins?
Japanese scientists detected all five nucleobases — building blocks of DNA and RNA — in samples returned from asteroid Bennu by NASA’s OSIRIS-REx mission. NASA’s OSIRIS-REx mission brought back 121.6 grams of asteroid Bennu, unveiling nitrogen-rich organic matter, including DNA’s essential [...]
AI-Designed Proteins – Unlike Any Found in Nature – Revolutionize Snakebite Treatment
Scientists have pioneered a groundbreaking method to combat snake venom using newly designed proteins, offering hope for more effective, accessible, and affordable antivenom solutions. By utilizing advanced computational techniques and deep learning, this innovative [...]
New nanosystem offers hope for improved diagnosis and treatment of tongue cancer
A pioneering study has unveiled the Au-HN-1 nanosystem, a cutting-edge approach that promises to transform the diagnosis and treatment of tongue squamous cell carcinoma (TSCC). By harnessing gold nanoparticles coupled with the HN-1 peptide, [...]
Global Trust in Science Is Stronger Than Expected – What’s Next?
A landmark global survey conducted across 68 countries has found that public trust in scientists remains robust, with significant support for their active involvement in societal and political matters. The study highlights the public’s [...]
Microplastics in the bloodstream may pose hidden risks to brain health
In a recent study published in the journal Science Advances, researchers investigated the impact of microplastics on blood flow and neurobehavioral functions in mice. Using advanced imaging techniques, they observed that microplastics obstruct cerebral blood [...]
AI Surveillance: New Study Exposes Hidden Risks to Your Privacy
A new mathematical model enhances the evaluation of AI identification risks, offering a scalable solution to balance technological benefits with privacy protection. AI tools are increasingly used to track and monitor people both online [...]
Permafrost Thaw: Unleashing Ancient Pathogens and Greenhouse Gases
Permafrost is a fascinating yet alarming natural phenomenon. It refers to ground that remains frozen for at least two consecutive years. Mostly found in polar regions like Siberia, Alaska, and Canada, permafrost plays a [...]
Frequent social media use tied to higher levels of irritability
A survey led by researchers from the Center for Quantitative Health at Massachusetts General Hospital and Harvard Medical School has analyzed the association between self-reported social media use and irritability among US adults. Frequent [...]
Australian oysters’ blood could hold key to fighting drug-resistant superbugs
Protein found in Sydney rock oysters’ haemolymph can kill bacteria and boost some antibiotics’ effectiveness, scientists discover An antimicrobial protein found in the blood of an Australian oyster could help in the fight against [...]
First U.S. H5N1 Death Sparks Urgency: Scientists Warn Bird Flu Is Mutating Faster Than Expected
A human strain of H5N1 bird flu isolated in Texas shows mutations enabling better replication in human cells and causing more severe disease in mice compared to a bovine strain. While the virus isn’t [...]
AI Breakthrough in Nanotechnology Shatters Limits of Precision
At TU Graz, a pioneering research group is leveraging artificial intelligence to drastically enhance the way nanostructures are constructed. They aim to develop a self-learning AI system that can autonomously position molecules with unprecedented precision, potentially [...]
How Missing Sleep Lets Bad Memories Haunt Your Mind
Research reveals that a lack of sleep can hinder the brain’s ability to suppress unwanted memories and intrusive thoughts, emphasizing the importance of restful sleep for mental health. Sleep deprivation has been found to [...]
