Lower sperm count and testosterone levels due to Covid-19? Here’s what Hong Kong researchers claim

Covid-19 can disrupt testicular health, including a decrease in size, testosterone levels, and sperm count, a new study has found. The study, conducted by Department of Microbiology researchers at Hong Kong University and published on February 18 in the prestigious Clinical Infectious Diseases journal, was undertaken to investigate the SARS-CoV2 virus’ effect on hamster testicles.

The researchers delivered varying doses of the virus, responsible for Covid-19, intranasally to hamsters — only a few of which were vaccinated. The researchers then killed the hamsters between one and 120 days following the infection and examined their testicles.

The researchers found an “acute decrease” in testosterone levels and sperm count four to seven days after infection in unvaccinated hamsters. They also observed “damage” to the testicular tissue — inflammation, degeneration, and necrosis — a week after infection and persisted in samples collected on Day 120.

The infection also reduced testicular size and weight. The vaccinated hamsters did not exhibit testicular damage.

The authors concluded that SARS-CoV-2 could cause acute and chronic testicular damage in hamsters and was consistent with anecdotal reports of clinical orchitis and hypogonadism in recovered human males.

They also called for long-term sperm count and sex hormone profile follow-up of convalescent Covid-19 males.

Hamsters are common test subjects for Covid-19 studies as their bodies react to respiratory viruses in a manner similar to humans.

Testicles have been sanctuaries for several diseases such as Ebola, HIV, and Zika. The viruses can enter the testicles and linger for years without the immune system detecting them.

Research suggests that the SARS-CoV-2 virus targets angiotensin-converting enzyme 2, a type of protein in the testicles believed to be a receptor. Other SARS-CoV family viruses have also been suspected to cause testicular inflammation and dysfunction. However, reports on the testicular cells’ susceptibility to Covid-19 differ wildly.

According to research, Covid-19 can significantly reduce human sperm count, at least in the short term. One study compared median sperm count in humans not infected by the virus and found an almost five-times higher count in their ejaculate than those infected.

Researchers also studying the relationship between erectile dysfunction and Covid-19, with one study in Italy involving 100 men in Italy — of which 25 were infected by the virus and 75 who were not — finding a positive correlation.

University of Miami researchers have theorised that erectile dysfunction coinciding with Covid-19 infections resulted from restricted blood flow to the penis. Others point to the psychological impact of contracting the virus — depression and stress — as a potential cause.

Of all Covid-19 side effects reported so far, ranging from prolonged loss of taste to brain fog, the impact on male genitals and fertility is a topic of greatest public discussion.

Last year, rapper Nicki Minaj tweeted that the Covid-19 vaccine could cause impotence, citing her cousin’s friend in Trinidad and Tobago. The White House offered to address her queries following an outrage regarding the tweet, while the Trinidad and Tobago Health Minister dismissed the claims.

In January, a man claimed that his penis had shrunk more than an inch following the infection, although he appears to be the only one claiming this side effect. However, post-Covid testicular pain have been reported by men as early as 2020. A 2021 study found that testicular pain was more frequent among hospitalized Covid-19 patients.