A new study out this week has suggested that COVID-19 may negatively affect the quality of sperm and fertility in men.

Invasion of the testes, interference of cellular activity, inflammation and stress are the four major ways COVID could affect male fertility, a medical study says. Already, several reports have confirmed that some men reported low sexual ability after contracting the virus, which has sickened over 100 million people and claimed at least two million others since it broke out in China around November 2019.

Behzad Maleki of the Justus-Liebig-University in Germany studied for indicators that showed the possibility of the virus affecting male fertility. These findings were published on Friday in Reproduction, a health journal.

Pulling findings from analysis done at 10-day intervals from 84 men with COVID-19, the sperm cells from the infected men showed a spike in inflammation and oxidative stress, as opposed to the data from the 105 healthy men in a control group.

Oxidative stress is a chemical imbalance that can damage DNA and proteins in the body.

“These effects on sperm cells are associated with lower sperm quality and reduced fertility potential,” said Maleki in a statement. “Although these effects tended to improve over time, they remained significantly and abnormally higher in COVID-19 patients.”

The studies concluded that the male reproductive system could be targeted and damaged by the virus, as the receptors found in the testicles are also used to access lung tissue.

Mr. Maleki added that male genitalia “should be considered a vulnerable route of COVID-19 infection and declared a high-risk organ by the World Health Organisation.”

COVID-19 causes respiratory illness, especially in older people and those with underlying health conditions. The virus attacks and damages the heart, intestines, kidneys and the lungs.

The virus has claimed over two million lives globally since its outbreak in China at the end of 2019. Mutants of the virus are being discovered in countries like Britain, Brazil and Portugal.