A small study says the virus that causes COVID-19 can be found in semen.

The report from China published Thursday in JAMA Network Open doesn't address whether the virus can be spread through sex.

Doctors detected the virus in semen from six of 38 men hospitalized with COVID-19. Four were still very sick while two were recovering. There was no long-term follow-up.

The results contrast with a study last month involving 34 Chinese men with milder disease. Their semen was virus-free up to almost three months after diagnosis.

Authorities believe the coronavirus mainly spreads from droplets produced when infected people cough.