Co-factors that affect the risk of transmission

As well as the viral load of the person with HIV (covered in the previous section), a number of other co-factors may make sexual transmission more or less likely, including:

  • sexually transmitted infections
  • bacterial vaginosis
  • vaginal practices such as washing and drying
  • male circumcision
  • use of hormonal contraception
  • use of poppers (a recreational drug).