How Risky Is It?

This installment of my reference series is narrower in scope than recent installments like Discharge Planning and Reentry, HIV/AIDS Education, and Trangender Resources.  But it deals with a tricky line of question that the AIDS Library sometimes gets: “How likely is [some behavior] to transmit HIV?”

This question is tricky for a few reasons.  First, people often ask for a percentage of risk for some sexual act, but in reality a number like that can’t be calculated (and anyway the risk is defined by more than just the specific act).  Second, we want to encourage caution in the face of HIV, but we don’t want HIV-negative folks to fear HIV-positive folks.  Third, we know that the safest choice is usually total abstinence from risky behavior, but if we believe in harm reduction we want to give individuals answers that “meet them where they’re at,” not answers that preach things that won’t work for everyone.  As a result of all these issues we have the potential for confusion and mixed messages when many clients just want to hear “yes, that’s risky” or “no, that isn’t risky.”

So the information below collects resources to help craft good answers to these how-risky-is-it questions.

Explaining Why Risk Statistics Aren’t Precise

As with so many topics, AIDS Info Net gives a clearly written introduction, How Risky Is It?, which includes a section explaining “What the Numbers Mean,” explaining that “these calculations only give a general idea of risk.”

Go Ask Alice, the Columbia Health Services excellent health Q&A site has a good response to someone Confused About HIV Transmission Statistics, which does a good job of explaining why transmission statistics are imprecise, what some of the factors that make a single sexual act more or less risky, and that the virus doesn’t “jump over to the other side” as soon as it gets a chance.

For those more interested in academic epidemiology, the University of California San Francisco’s HIV InSite hosted an interesting roundtable discussion on The Risk of HIV Infection Through Receptive Oral Sex, with full transcript online.  In addition to covering receptive oral sex risk, the researchers discuss the many challenges (even more than I listed above!) to quantifying infection risk.

Estimates of Risk by Behavior

HIV InSite has a page listing Safer-Sex Methods, sorted by No-Risk, Extremely Low-Risk, Low-Risk, and High-Risk Practices.

HIV Insite also publishes, in somewhat technical language, the HIV Risks Associated with Specific Sexual Practices, broken down to:

HIV InSite also fully footnotes the studies and research that their text is based on, for those who want to go deeper in to the research about risk behavior.

For a wider range of behaviors, The Body archives the questions it answers about HIV Risks From The Body’s “Ask the Experts” Forums, and break the questions down by topics:

Specific Risk Issues

STIs – The likelihood of HIV transmission is increased by the presence of other sexually transmitted infections.  The CDC has a webpage, The Role of STD Detection and Treatment in HIV Prevention, which explains this.  The page also includes a link to All Their STD Fact Sheets.

Condoms – Some questions about possible risk turn out to be questions about condoms effectiveness.  Here are some sources of information about this issue:

Antiretroviral Therapy – If an HIV-positive person is in treatment, they are less likely to be able to transmit the virus to someone else. This may of particular interest to people in serodiscordant relationships (where one person is positive and the other negative).  A few resources on this topic:

Circumcision – Male circumcision significantly reduces the risk of HIV acquisition by men during penile-vaginal sex.

Unknown HIV Status – The CDC estimates that 21% of HIV-positive people aren’t aware of their infection (others have put this number even higher).  That CDC report is very technical, however, so try this NPR story for a clear explanation of the 21% statistic.

Injection Drug Use – Sharing needles is a major method of transmitting HIV, but by definition no statistics exist for just how risky any individual injection is.  Here are a few useful resources on IDU risk:


Risk Non-Issues – For the people who want to know how risky it is to play contact sports or get bitten by mosquitoes, refer to the CDC’s HIV Transmission page and AIDS InfoNet’s HIV Myths & Misunderstandings page, which give nice clear NOs to some questions that still come up after all these years.

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