A COVID-19 infection has the ability to reach the male genital tract, causing health problems in the penis, testicles and prostate, according to a new study from Northwestern Medicine.

The study found that coronavirus infection caused testicular pain, erectile dysfunction, reduced sperm count and decreased fertility in a number of subjects.

Northwestern warned that “millions” of men could be affected by the study results and that men previously infected with COVID should “evaluate their sexual health.”

Previously, it was unclear whether fertility issues were due to fever and inflammation, which can accompany COVID. However, Northwestern’s study using a PET scan showed that the side effects were a direct result of the virus.

“These results indicate that testicular pain, erectile dysfunction, hypogonadism, reduced sperm count and quality, and decreased fertility associated with SARS-CoV-2 infection are a direct consequence of infection of male reproductive tract cells and not indirect mechanisms such as fever and inflammation,” said lead researcher Thomas Hope, professor of cell and developmental biology at Northwestern University Feinberg School of Medicine.

Hope added that mumps, Ebola, Zika, SARS-COV-1, as well as other viruses, can also infect the male reproductive tract and fertility.

According to the study, which was carried out on large animal models, 10 to 20 percent of men infected with COVID-19 show symptoms related to dysfunction of the male genital tract.

Northwestern said the discovery means tens of millions of men would need to see a doctor to have their sexual health and fertility checked “to determine if additional therapies might prevent or alleviate future problems.”

“The potential impact of SARS-CoV-2 infection on sexual and reproductive health should be part of everyone’s decision to get vaccinated to minimize the risk of death, serious illness and hospitalization, and infection of the prostate, penis, testicles and vascular system (blood supply) to the testicles,” Hope said.

The Northwestern study was the first PET probe capable of identifying SARS-CoV-2 infection in a live animal, the authors said in a statement.

The Centers for Disease Control and Prevention previously noted that pregnant women who contract COVID-19 “have an increased risk of serious illness,” including the risk of infection that can lead to ICU admission, mechanical ventilation, and possibly the death.

Pregnant women with COVID-19 could also face an increased risk of adverse pregnancy outcomes, such as preterm delivery, the agency added.

According to preliminary results of a National Institutes of Health study, pregnant women who experienced severe symptoms of COVID-19 had a higher risk of complications during and after pregnancy.

“Compared to non-pregnant women who have the same health status and age, a woman infected with COVID is approximately 1.3 to 1.4 times more likely to end up in hospital when pregnant” , said Mayo Clinic obstetrician Dr. Regan Theiler in a statement.

On the other hand, the University of Chicago Medicine reports that for some people who are vaccinated late in pregnancy, “it is likely that the antibodies your body produces in response to the vaccine will be passed to the fetus through the placenta and may provide some protection. against COVID-19, the same way a flu shot can help protect your baby against the flu.”