Redefining Human Immunodeficiency Virus (HIV) Preexposure Prophylaxis Failures

To the Editor—Failures of daily oral human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) with tenofovir disoproxil fumarate/emtricitabine are rare, with only 3 HIV seroconversions documented among patients adherent to PrEP at the time of infection [1–3]. However, PrEP failures could be defined more broadly as HIV infections that occur at any point along the PrEP continuum of care [4]. Here, we describe HIV infections among individuals who sought or were referred for PrEP within the Kaiser Permanente Northern California (KPNC) healthcare system.