Editor's Note: This article has the following correction:

"In the December 1, 2019 Supplement 2 of JAIDS Journal of Acquired Immune Deficiency Syndromes, in the article titled 'Using Interrupted Time Series Analysis to Measure the Impact of Legalized Syringe Exchange on HIV Diagnoses in Baltimore and Philadelphia', the authors mistakenly reported the estimated cost savings for Baltimore to be $62.4 million annually and $624 million over 10 years, and the 1-year return on investment (ROI) factoring in the cost of syringe exchange programs to be $46.8 million. The correct cost savings estimates are $43.4 million annually and $434.3 million over 10 years, and the correct 1-year ROI estimate is $32 million."

Following is the original, uncorrected quote:

"Our findings also demonstrate that averted HIV diagnoses translated to cost savings for cities where most PLWH are recipients of publicly funded healthcare. The forecasts estimated an average of 1059 HIV diagnoses in Philadelphia and 189 HIV diagnoses in Baltimore averted annually. Multiplying the lifetime costs of HIV treatment per person ($229,800)25 by the average number of diagnoses averted annually in both cities yields an estimated annual saving of $243.4 million for Philadelphia and $62.4 million for Baltimore. Considering diagnoses averted over the 10-year modeled period, the lifetime cost savings associated with averted HIV diagnoses stemming from policy change to support SEPs may be more than $2.4 billion and $624 million dollars for Philadelphia and Baltimore, respectively. Because SEPs are relatively inexpensive to operate,26 overall cost savings are substantial even when deducting program operational costs from the total amount. Considering annual program expense ($390,000 in 2011 for Philadelphia27 and $800,000 estimated in FY 2017 for Baltimore28) (Kathleen Goodwin, Baltimore City Health Department, personal communication, January 3, 2017) and cost savings in each city, and a conservative estimate that 75% of these savings would be experienced in the public sector, the 1-year return on investment in SEPs remains in the hundreds of millions of dollars ($182.5 M for Philadelphia, $46.8 M for Baltimore). Small investments in SEPs may yield large savings in HIV treatment costs, so implementing SEPs may liberate resources for other important interventions, such as expanded access to medication-assisted treatment, overdose prevention, and housing.

"Another implication pertains to how variations in SEP implementation may have influenced intervention effectiveness. Policies governing SEPs affect not only the overall number of syringes distributed annually but also the ability of PWID to obtain sufficient coverage for all injection events. For example, PPP's clients may exchange syringes for themselves and others; recent data show that the mean number of syringes exchanged per exchange event increased from 1.53 in 1999 to 1.82 in 2014.13 In addition, PPP's annual syringe distribution has consistently increased from approximately 811,000 in 1999 to 1.2 million in 2014,13 allowing for greater coverage of injection events and more opportunities for disease prevention.

"By contrast, Baltimore's SEP had a one-for-one (1:1) exchange policy from 1994 to 1999 but, in 2000, switched to a more restrictive policy, where clients were allowed 1:1 exchange for program-distributed syringes but could receive 1 sterile syringe in exchange for 2 nonprogram syringes. From 2005 to 2014, the SEP returned to the less restrictive 1:1 policy, after which they shifted to a need-based distribution model whereby PWID could access as many syringes as needed. Baltimore City's health commissioner estimated that moving from the 1:1 to the needs-based distribution policy could increase coverage of injection events from 42% to 61%.29 More flexible approaches to syringe access in Baltimore could have resulted in greater injection coverage and more dramatic declines in IDU-associated HIV diagnoses earlier. Regulations limiting clean needle and syringe distribution are important operational issues to consider if policy changes supporting harm reduction for PWID are to have optimal impact."


Ruiz, Monica S. PhD, MPHa; O'Rourke, Allison MPHb; Allen, Sean T. DrPH, MPHc; Holtgrave, David R. PhDc; Metzger, David PhDd,e; Benitez, Jose MSWf; Brady, Kathleen A. MDg; Chaulk, C. Patrick MD, MPHh; Wen, Leana S. MDi. Using Interrupted Time Series Analysis to Measure the Impact of Legalized Syringe Exchange on HIV Diagnoses in Baltimore and Philadelphia. JAIDS Journal of Acquired Immune Deficiency Syndromes 82():p S148-S154, December 1, 2019. | DOI: 10.1097/QAI.0000000000002176