According to a preliminary report posted on MedRxix, the virus attaches itself to a protein that occurs in high levels in the testicles.

This protein, known as angiotensin-converting enzyme 2, or ACE2, is present in the lungs, the gastrointestinal tract and the heart in addition to large quantities in the testicles.

But since testicles are walled off from the immune system, the virus could harbour there for longer periods than the rest of the body, according to the study.

Adding that these findings explain why women bounce back from the virus more quickly than men.

They determined that the average amount of time for female patients to be cleared of the virus was four days, while men saw recoveries that on average were two days longer, the report said.

“These observations demonstrate that male subjects have delayed viral clearance,” the authors wrote, adding that the testicles may be serving as “reservoirs” for the virus.