Craigslist Linked With Increase in Reported HIV Cases

Entry of web site into particular market correlates with increase in new cases.

A popular classified advertisements web site may lead to an increase in the number of HIV cases, recent analysis indicates.

A study found that the entry of Craigslist into a particular market results in a 15.9% rise in reported cases of HIV. The study, published in the December issue of MIS Quarterly, estimated that when these numbers are mapped at the national level, more than 6000 yearly cases of HIV with approximate treatment costs between $62 million and $65.3 million can be linked to the web site.

"I actually think that the creators of Craigslist had no intent of harming society. They came in with good intentions," co-lead researcher Jason Chan, assistant professor of Information and Decision Sciences at the Carlson School of Management, said in a press release. "At the same time, they did not anticipate that users could use the features in an unexpected way with unintended consequences."

Craigslist offered a unique natural experiment construct for researchers to uncover the connection due to its random entry into individual markets with respect to HIV trends, the study noted. The researchers constructed the analysis after examining data from 33 states between 1999 and 2008.

After conducting a series of tests to preclude other potential causes that may drive HIV trends, such as increased testing in a community, the data revealed an upward shift influenced by ads in the Craigslist personals sections, not the escort service ads on the site. The finding was in line with prior research that indicates internet-facilitated sex workers are less likely to use risky sexual practices with clients.

The researchers noted that the study results offer insights for practitioners on how to effectively direct efforts to decrease disease transmission facilitated through classified ad sites. Additionally, the CDC posted a preliminary version of the paper on its web site.

"Our study results suggest that there is a new social route of HIV transmission that is taking place in this digital era," Chan said. "Health care practitioners and policymakers have to look more closely at online platforms to assess how its usage may facilitate the spread of HIV and STDs across the country."