PT - JOURNAL ARTICLE AU - Hao-Hsin Wu AU - Yi-Ting Shen AU - Chien-Shun Chiou AU - Chi-Tai Fang AU - Yi-Chun Lo TI - Shigellosis outbreak among MSM living with HIV: a case–control study in Taiwan, 2015–2016 AID - 10.1136/sextrans-2017-053410 DP - 2019 Feb 01 TA - Sexually Transmitted Infections PG - 67--70 VI - 95 IP - 1 4099 - http://sti.bmj.com/content/95/1/67.short 4100 - http://sti.bmj.com/content/95/1/67.full SO - Sex Transm Infect2019 Feb 01; 95 AB - Objectives Outbreaks of shigellosis among men who have sex with men (MSM) have been reported since the late 1990s. HIV infection is an important risk factor. Since 2014, the global shigellosis epidemic has intensified. Whether chemsex (the use of crystal methamphetamine, γ-hydroxybutyrate or mephedrone to enhance sex) is a new risk factor has not been previously examined.Methods We conducted a population-based, case–control study in Taiwan. Acute shigellosis cases diagnosed during the 2015 outbreak among MSM living with HIV were compared with those without shigellosis. CD4+ counts, plasma viral load (pVL), gonorrhoea, syphilis and amoebiasis records were obtained from the Notifiable Disease Surveillance System database. We invited cases/controls to provide information on illicit drug use and sexual behaviours, using a structured questionnaire.Results Seventy-five shigellosis cases were compared with 225 controls. High pVL (>100 000 copies/mL; adjusted OR (aOR): 4.9, 95% CI 1.4 to 16.9), gonorrhoea (aOR: 29.4, 95% CI 2.3 to 340.2) and syphilis (aOR: 4.3, 95% CI 1.6 to 11.6) were independent risk factors of shigellosis. Twenty shigellosis cases and 59 controls completed the questionnaire. Oral-to-anal sex (aOR: 15.5, 95% CI 3.6 to 66.7), chemsex (aOR: 5.6, 95% CI 1.4 to 22.7) and poppers use (aOR: 10.9, 95% CI 1.9 to 64.2) within 12 months were independent behavioural risk factors of shigellosis.Conclusions Chemsex is a new risk factor for shigellosis among MSM living with HIV, as identified in the 2015–2016 outbreak. Additional risk factors include poppers use, sexual risk behaviours and high pVL. Further studies on chemsex among MSM, which is a rising public health concern, are urgently required.