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The coronavirus could linger in the testicles, making men prone to longer, more severe cases of the illness, according to a new study.

Researchers tracked the recovery of 68 patients in Mumbai, India, to study the gender disparity of the virus, which has taken a worse toll on men, according to a preliminary report posted on MedRxix, which hosts unpublished medical research papers that have not been peer reviewed.

Dr. Aditi Shastri, an oncologist at Montefiore Medical Center in the Bronx, and her mother, Dr. Jayanthi Shastri, a microbiologist at the Kasturba Hospital for Infectious Diseases in Mumbai, said 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 harbor there for longer periods than the rest of the body, according to the study.

The mother-daughter researchers said these findings may 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.

The study may offer an explanation for reports out of Italy, South Korea and New York City that men are dying at higher rates from the virus.

Others have suggested that men are more vulnerable because they are more likely to smoke, have high blood pressure or suffer coronary artery disease.