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HIV Incidence Risk Index for MSM (HIRI-MSM)

What is this tool?

The HIV Incidence Risk Index for men who have sex with men (HIRI-MSM) tool is a clinical scoring tool that can help identify men who have sex with men  who may have a higher chance of getting HIV. The HIRI-MSM clinical scoring calculator is one tool used in British Columbia to determine eligibility for free (provincially-funded) HIV PrEP.

A higher HIRI-MSM score is associated with a higher chance of getting HIV. For example, in the Momentum study, an HIV research study in Vancouver, BC, a HIRI-MSM score of:

  • 10 or higher was associated with an HIV risk of about 2% per year.  This means that of 100 people who had a HIRI-MSM score of 10 or more, 2 people acquired HIV in one year. 
  • over 25 was associated with an HIV risk of about 7% per year.

Calculate a Score

How is the calculator used?

A HIRI score can help to estimate a person’s chances of getting HIV. However, it should not be used as a definitive decision-making tool when trying to figure out the likelihood of getting HIV or eligibility for HIV PrEP.

The HIRI-MSM tool should be a part of a comprehensive sexual health history and broader discussion between health care provider and client to determine both risk of HIV infection and areas for harm reduction and health promotion activities.

Interpreting the HIRI score

If the HIRI score is 10 or higher, and a person is HIV negative:

  • Starting HIV PrEP is recommended and should be discussed further between health care provider and client. There may be a higher chance of getting HIV.
  • People who live in BC may be eligible for free (provincially-funded) HIV PrEP. Further details are available at the British Columbia Centre for Excellence in HIV/AIDS.

If the HIRI score is less than 10, and a person is HIV negative:

  • Consider other factors that may mean a person would benefit from HIV PrEP. This includes a history of syphilis, rectal gonorrhea or rectal chlamydia, and recent changes in relationship status or sexual practices.
  • Re-evaluate the HIRI score as needed.  Circumstances change over time and a person’s HIRI score today may not equal their HIRI score in the future.

Always consider other HIV prevention strategies such as condoms and regular HIV/STI testing.  Improving knowledge about sexual health and healthy relationships is also helpful, including learning about other available resources and treatment as prevention for partners who may be HIV positive.

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