A new study suggests that one-in-five men has been infected with a virus that can cause fertility issues – and most have no idea.
Human papillomavirus (HPV) is the most common sexually transmitted infection in the UK. It’s estimated that around 80 percent of us will be infected with at least one strain of HPV at some point in our lives.
Scientists have known for a long time that HPV can cause a range of cancers. It’s also been believed it might be the cause of some cases of infertility.
However, previous research into HPV’s effects on fertility has focused on women. But a new research study has found that high-risk HPV strains – thought to be carried by one in five men – can also affect sperm quality, reports The Sun.
It quotes a study, published in Frontiers in Cellular and Infection Microbiology which found high-risk HPV strains can suppress the immune system in the male genital tract. This could hinder the body’s ability to get rid of the infection – a process that can take up to a year.
Now scientists believe this immune system suppression raises the risk of catching other diseases that can damage male fertility. Professor Virginia Rivero from the National University of Córdoba in Argentina is one of the study’s authors.
She said: “Individuals often have no symptoms or signs, yet still carry HPV in the male genital tract.”
Professor Virginia and her team examined the sperm samples of 205 men with an average age of 35 who had suffered fertility issues or treatment for urinary tract problems. They found that 39 of the men – 19 percent – tested positive for HPV.
The scientists identified 20 men among them who had high-risk strains – and seven with low-risk HPV. On closer examination of the semen, they found they found clues suggesting why high-risk HPV strains might impact male fertility.
Men with high-risk HPV strains had lower levels of specific immune cells in their semen. This suggests the virus had hampered the body’s ability to fight it off, said the study.
It’s thought this may have also raised the risk of other infections that could further reduce their fertility. There were also signs that the sperm of the men with high-risk HPV had been damaged by oxidative stress – a condition that occurs when the body has too many free radicals and not enough antioxidants to neutralize them.
Scientists say this could explain why these men had higher levels of dead sperm than men who didn’t have the virus.
Most people don’t know they have HPV. This is because it doesn’t tend to cause symptoms or problems.
There are about 200 strains of the disease, most of which are harmless. However, some high-risk strains – including HPV16 and HPV18 – can cause cancers of the throat, neck, head, penis, vagina and anus.
Analysis published in The Lancet Global Health in 2023 suggested that 21 percent – or more than one-in-five – of men aged 15 and over in the UK are infected with at least one high-risk strain.
An HPV vaccine is offered to Year 8 school children in the UK. It is hoped this will reduce HPV-related cancer cases in the future.