Police on Teesside are urging women who may have had a relationship with Feston Konzani to seek medical help.
Konzani infected three women with HIV
The warning comes a day after Konzani was jailed for 10 years for infecting three women with HIV by having unprotected sex with them.
He was living in Middlesbrough when he infected the women between November 2000 and last August.
Cleveland Police said they fear there could be more women who have yet to come forward who may have been at risk.
They stress that women do not have to go to the police but want them to seek medical advice.
Konzani originally faced accusations of infecting four women but was cleared of one charge by Judge Peter Fox QC.
Konzani was convicted of causing grievous bodily harm by infecting the other three women through sexual intercourse.
A jury of eight men and four women at Teesside Crown Court took less than three hours on Friday to convict Konzani unanimously on all three charges.
The court was told that Konzani will be deported to Malawi when he has served his prison sentence.