In September 2021, rapper and amateur virologist Dr Nicki Minaj – or to give her full medical title, Nicki Minaj – shocked the medical establishment when she reported a little-known side-effect of the COVID vaccines. In a study, by which we mean a conversation with her cousin about his friend’s testicles for some reason, she had learned something incredible: that vaccines can make your testicles swell up to a huge size, completely ruining your wedding.

Of course, this was nonsense: the COVID vaccine can’t cause your balls to swell up. But in a twist of irony, a new study accepted for publication in the journal Clinical Infectious Diseases has found that the contrapositive may well be true – or to put it another way, catching COVID may actually result in some severe shrinkage in the testicular department.

“We showed that testicles were sub-clinically affected with acute decrease in sperm count and subsequent chronic asymmetric testicular atrophy … and persistently low serum testosterone and inhibin B [a protein associated with higher sperm concentrations],” the study reports. “[The] testes showed degeneration, necrosis and inflammation … with disruption of orderly spermatogenesis from 4 to 120 [days post-infection].”

Now here’s the good news – well, assuming you’re not a rodent. The study was conducted in hamsters, which, while “well established as a physiological small animal model for COVID-19,” are famously not humans. The results of the study are therefore “limited to this hamster model,” the researchers write – even if they are “consistent with the anecdotal reports of clinical orchitis and hypogonadism in recovered COVID-19 [human] males.”

There’s a bunch of research out there – not to mention the anecdotal evidence – suggesting that COVID can impact sperm count and testicular health. Doctors around the world have reported an increase in sexual dysfunction and infertility since the onset of the pandemic, and in some cases, severe testicular pain can be one of the first symptoms of the infection. Evidence of COVID-infected testicular tissue and reduced sperm counts have even been noted in the autopsies of some COVID victims.

But correlation is not causation, and the researchers wanted to prove a link between the virus and testicular damage. They performed a wide array of tests, ranging from the “aww poor hamster” level (squirting COVID up the lil guys’ noses) to the “oh dear lord” level (injecting it straight into their tiny furry balls), and they also did the same but using an influenza virus, to use as a control group.

Even though the hamsters didn’t get all that sick – the researchers reported only that they developed mild pneumonia – their balls didn’t fare so well. Their sperm counts and testosterone levels were reduced, the testes themselves had become atrophied and small, and the cells responsible for making sperm had started to die.

The researchers found that the extent of the testicular damage was similar for both Delta and Omicron variants – but the lucky hamsters who only got a dose of the flu saw no such effects at all.

So is there any good news for the betesticled among us? Yes actually: the researchers found a way to protect the hamsters from their small-balled fate. It’s really easy, too, and won’t cost you a dime – just get vaccinated. The team found that getting a vaccine even as late as three days before infection could protect the rodent goolies at a rate similar to what we see in the lungs.

“In managing convalescent COVID-19 males, it is important to be aware of possible hypogonadism (low sex drive) and subfertility,” Chair of Infectious Diseases Professor Kwok-yung Yuen, who led the research effort, told SciTechDaily. “COVID-19 vaccination can prevent this complication.”

So there you go: if the testicle owner in your life won’t get the shot for their lungs, brain, or immune system, maybe let them know that they’re risking something even more precious by shirking the vaccine.