The virus that causes COVID-19 can be found in semen, according to a small study from researchers in China.
The study, published Thursday in the journal JAMA Network Open, doesn’t address whether this means the coronavirus can be sexually transmitted.
Doctors detected the virus in semen from six of 38 men who had been hospitalized with laboratory-confirmed cases of COVID-19. Four were at the height of their infections when the samples were collected, and two had already “achieved clinical recovery,” according to the report by a team from Shangqiu Municipal Hospital in China.
The samples were collected in January and February. The researchers didn’t follow up with the men, so it’s not known how long the virus remained in their semen, or whether they could have spread it to their partners during sex.
The findings contrast with a study of 34 Chinese men with COVID-19 that was published last month in the journal Fertility and Sterility. In that study, U.S. and Chinese researchers found no evidence of the virus in semen tested eight days to nearly three months after the men were diagnosed.
Dr. James Hotaling of the University of Utah, a co-author of that report, said the new study involved much sicker men, most of whom had active infections.
Authorities believe the coronavirus mainly spreads via respiratory droplets that are produced when infected people cough. A person can become infected if they inhale those droplets, or if they touch surfaces where those droplets have landed and then touch their face without first washing their hands.
Some studies have reported finding the virus in blood, feces, tears or other fluids from COVID-19 patients.
Evidence suggesting that other viruses like Zika and Ebola might be sexually transmitted prompted researchers to investigate whether the same could be true of the coronavirus.
Hotaling said it was an important public health concern but that more research was needed to provide a definitive answer.
The American Society for Reproductive Medicine said Thurday that the new findings shouldn’t be a cause for alarm.
To be safe, though, “it may be wise to avoid sexual contact with men until they are 14 days without symptoms,” Dr. Peter Schlegel, the group’s immediate past president, said in a statement.