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The Three Percent Conundrum: Are 22,500 People in San Francisco Really Using Injection Drugs?

Why the city’s estimates aren’t as reliable as they seem.


This story is part of our special report on the private tragedies and public toll of our injection drug epidemic. Read more of One City, Under the Syringe here.


22,500: That’s the Department of Public Health’s go-to number for injection drug users in San Francisco, a figure frequently repeated by media outlets. And while it’s inarguable that the number of people shooting up in public has skyrocketed in recent years, with the city now collecting more than 10,000 syringes per month—triple the number from a year ago—that 22,500 statistic astounds. It means that approximately 3 percent of the city’s adult population as counted in the 2010 census—or 1 out of every 33 adults—currently injects drugs. Is this possible?

Theoretically, yes—given that many people inject drugs without ever developing a substance use disorder. “People start in a fun space, and many people never leave that fun space and recreationally use indefinitely,” says Paul Harkin, HIV services manager at Glide. But it’s also possible that that widely cited statistic is simply wrong. “Lots of people ask for these numbers,” says Alex Kral, an epidemiologist. “But it is very, very hard to pin down a number for something like this because it is an illegal activity; it is a highly stigmatized activity. So we can’t just go and count people.”

The figure comes from a study conducted by researchers from UCSF and the San Francisco Department of Public Health and published in the journal AIDS and Behavior in December 2015. It uses three different statistical methods and data from multiple sources. But the margin of error for the resulting count is so high that it’s impossible to say whether the 22,500 figure is accurate, or even whether the population of people injecting drugs in San Francisco has increased. (The same study found 10,000 injectors in 2005, but the margin of error also makes that figure unreliable.)

While some on-the-ground providers give credence to the 22,500 finding, researchers are skeptical. “It’s not a very good number,” Dan Ciccarone, a professor at the UCSF School of Medicine, says. “That’s one of my big criticisms of how we’re handling the current epidemic. Nationwide we know that people are dying—there are all these body counts—but we don’t know what the rate of death is because we don’t have a good understanding of what we call ‘the population at risk.’” Ciccarone has been researching heroin users in San Francisco since the early 2000s; he pegs the injection drug user population at closer to 10,000. That, however, is simply a guesstimate.

So what do we know for sure? We know that in 2016, six syringe-access programs in the city gave out 4.7 million sterile syringes, and that harm reduction teams from Glide and the San Francisco AIDS Foundation met with clients more than 62,000 times over 12 months. These numbers don’t yield a final tally of how many people in the city inject drugs. But it’s safe to say that it’s thousands.

It’s also safe to say it’s growing. For this we can point to some familiar culprits: the housing crisis, worsening homelessness, and more prevalent drug use by homeless people. When Kral started studying Bay Area injection drug users in the 1990s, one-third of them were homeless. “Now it’s moved to three-quarters,” he says. And when more and more people who live on the streets are also hooked on drugs, we all can feel it.


Originally published in the October issue of San Francisco

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