Surprising Ways That Craigslist Increases HIV Rates

Online Usage and Selection Practices Associated With Increased HIV Risk

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Photograph © Johan Viirok

Online hookup sites such as Craigslist, Gaydar and the geosocial dating apps Grindr and Tinder, have become the predominant platforms for many individuals—gay, straight or bisexual—seeking to connect socially and/or sexually. So vast are these networks that Grindr, for example, is today reported to have well over six million registered users who log onto the site an average of eight times per day.

Online hookup sites provide access to larger social and sexual networks than a person would otherwise  find offline, enabling casual sex with both ease and a certain amount of invisibility. As a result, concerns have been raised about the impact of such hookups on the rate of HIV and other sexually transmitted infections among online users, with presumably higher rates of multiple sex partners, substance abuse and seroguessing (i.e., the practice of choosing a sexual partner based on the assumption of HIV status).

Craigslist Personals Linked to Increased HIV Rates

A number of studies have looked specifically at the San Francisco-based Craigslist, which operates one of the largest personal ad sites in the U.S. One such study, conducted by New York University and the Carlson School of Business, suggested that HIV prevalence in 33 U.S. states had risen by some 15.9 percent over a ten-year period (1999-2002) as a result of Craigslist hookups.

The analysis further suggested that as many as 6,130 to 6,455 HIV infections could be directly attributed to Craigslist, with most of the infections related to casual, non-paid sex (as opposed to escort services or prostitution, which appeared to have a negative association with HIV rates).

A 2015 study from the University of Maryland's Robert H.

Smith School of Business supported these findings by suggesting that Craigslist hookups resulted in a rise in HIV prevalence of 13.5% in Florida over a four-year period—or roughly 1,149 new HIV infections.

The investigators were also able to identify the types of users who were at greatest risk, the results of which appeared largely counterintuitive. Among their conclusions:

  • African American online users, who represented 63 percent of the infections but, as a population group, generally use the internet the least of all group.
  • Higher-income users with private health insurance, who were more likely to be infected than lower-income users covered by Medicaid.

While the findings were difficult to explain, the researchers suggested that higher-income people, who face greater social penalty for casual sex, may have greater sexual disinhibition as result of the "freedom" the internet provides. It also seems to suggest that access to the internet affects socioeconomic groups in entirely different ways.

Online Practices Associated with Increased Risk

In terms of risk behavior within online hookup communities, most of the research to date has focused on men who have sex with men (MSM).

According to research from the Center for HIV/AIDS Educational Studies and Training (CHEST) at the City University of New York, MSM tend to use the internet more to find casual sex than through offline options. Craigslist was cited as the most frequently used option among New York City MSM (81%), followed by bathhouses (64%) and bars or clubs (47%).

When looking at specific online behavior, MSM tended to ascertained the HIV status of a sex partners through either a review of online profiles (85%), communication before sex (82%), communication after sex 42%), or seroguessing based on clues from the user's profile (29%). Not surprisingly, seroguessing was associated with the highest rates of unprotected anal sex.

Research from the University of New South Wales in Australia largely supported these findings by concluding that both HIV-positive and HIV-negative MSM are more likely to engage in unprotected anal sex if the potential partner simply informs him that he is of the same status.

As a result of these and other studies, advocates recommend that risk reduction messages highlight the limitations by which the selection of online sex partners—and the presumption of HIV status and risk—--can place an individual at a greater risk of infection or transmission.

Key to this is the negotiation of safer sex practices among casual sex partners, while exploring the biomedical means to reduce HIV transmission risk (including the use of HIV pre-exposure prophylaxis).


Pink News. "Study: Six million users log onto Grindr an average of eight times a day." Published online March 27, 2013.

Chan, J. and Ghose, A., "Internet’s Dirty Secret: Assessing the Impact of Online Intermediaries on HIV Transmission." MIS Quarterly. September 27, 2013; 38(4);955-976.

Greenwood, B. and Agarwal, R. "Matching Platforms and HIV Incidence: An Empirical Investigation of Race, Gender, and Socio-Economic Status." Management Science. May 20, 2015; published online ahead of print.

Grov, C. and Crow, T. "Attitudes About and HIV Risk Related to the “Most Common Place” MSM Meet Their Sex Partners: Comparing Men from Bathhouses, Bars/Clubs, and Craigslist.Org." AIDS Education and Prevention. April 2012, 24(2):102-116.

Horvath, K.; Nygaard, A.; and Rosser, S. "Ascertaining Partner HIV Status and its Association with Sexual Risk Behavior Among Internet-Using Men Who Have Sex with Men." AIDS and Behavior. November 17, 2009; 14(6):1376-1383

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