title: Incidence of and temporal relationships between HIV, herpes simplex II virus, and syphilis among men who have sex with men in Bangkok, Thailand: an observational cohort.
abstract: High HIV incidence has been detected among men who have sex with men (MSM) in Thailand, but the relationship and timing of HIV, herpes simplex virus 2 (HSV-2), and syphilis is unknown. This analysis measures incidence, temporal relationships, and risk factors for HIV, HSV-2, and syphilis among at-risk MSM in the Bangkok MSM Cohort Study.
  
  
  
  Between April 2006 and December 2010, 960 men negative for HIV, HSV-2, and syphilis at entry enrolled and contributed 12-60 months of follow-up data. Behavioral questionnaires were administered at each visit; testing for HIV antibody was performed at each visit, while testing for syphilis and HSV-2 were performed at 12 month intervals. We calculated HIV, HSV-2, and syphilis incidence, assessed risk factors with complementary log-log regression, and among co-infected men, measured temporal relationships between infections with Kaplan-Meier survival analysis and paired t-test.
  
  
  
  The total number of infections and incidence density for HIV, HSV-2, and syphilis were 159 infections and 4.7 cases/100 PY (95 % Confidence Interval (CI): 4.0-5.4), 128 infections and 4.5/100 PY (95 % CI: 3.9-5.5), and 65 infections and 1.9/100 PY (95 % CI: 1.5-2.5), respectively. Among men acquiring >1 infection during the cohort period, mean time to HIV and HSV-2 infection was similar (2.5 vs. 2.9 years; p = 0.24), while syphilis occurred significantly later following HIV (4.0 vs. 2.8 years, p < 0.01) or HSV-2 (3.8 vs. 2.8 years, p = 0.04) infection. The strongest independent predictor of any single infection in adjusted analysis was acquisition of another infection; risk of syphilis (Adjusted Hazards Ratio (AHR) = 3.49, 95 % CI: 1.89-6.42) or HIV (AHR = 2.26, 95 % CI: 1.47-3.48) acquisition during the cohort was significantly higher among men with incident HSV-2 infection. No single independent behavioral factor was common to HIV, HSV-2, and syphilis acquisition.
  
  
  
  HIV and HSV-2 incidence was high among this Thai MSM cohort. However, acquisition of HIV and co-infection with either HSV-2 or syphilis was low during the time frame men were in the cohort. Evaluation of behavioral risk factors for these infections suggests different risks and possible different networks.
authors.affiliation: HIV/STD Research Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, DDC 7 Building, 4th floor, Ministry of Public Health, Soi 4, Nonthaburi, 11000, Thailand.
authors.forename: Warunee
authors.initials: W
authors.lastname: Thienkrua
authors.affiliation: FHI 360 Asia-Pacific Regional Office, 9th Floor, Tower 3, Sindhorn Building, 130-132 Wireless Road, Lumpini, Phatumwan, Bangkok, 10330, Thailand. ctodd@fhi360.org.
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Todd
authors.affiliation: HIV/STD Research Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, DDC 7 Building, 4th floor, Ministry of Public Health, Soi 4, Nonthaburi, 11000, Thailand.
authors.forename: Wannee
authors.initials: W
authors.lastname: Chonwattana
authors.affiliation: HIV/STD Research Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, DDC 7 Building, 4th floor, Ministry of Public Health, Soi 4, Nonthaburi, 11000, Thailand.
authors.forename: Wipas
authors.initials: W
authors.lastname: Wimonsate
authors.affiliation: HIV/STD Research Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, DDC 7 Building, 4th floor, Ministry of Public Health, Soi 4, Nonthaburi, 11000, Thailand.
authors.forename: Supaporn
authors.initials: S
authors.lastname: Chaikummao
authors.affiliation: HIV/STD Research Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, DDC 7 Building, 4th floor, Ministry of Public Health, Soi 4, Nonthaburi, 11000, Thailand.
authors.forename: Anchalee
authors.initials: A
authors.lastname: Varangrat
authors.affiliation: Department of Disease Control, DDC 7 Building, 1st Floor Ministry of Public Health, Nonthaburi, 11000, Thailand.
authors.forename: Anupong
authors.initials: A
authors.lastname: Chitwarakorn
authors.affiliation: Thai Red Cross HIV Research Center, 104 Rajdamri Road, Pathum Wan, Bangkok, 10330, Thailand.|Division of Preventive Medicine and Public Health, School of Medicine, University of California-San Francisco, 50 Beale Street, Ste 1200, San Francisco, 94105, CA, USA.
authors.forename: Frits
authors.initials: F
authors.lastname: van Griensven
authors.affiliation: HIV/STD Research Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, DDC 7 Building, 4th floor, Ministry of Public Health, Soi 4, Nonthaburi, 11000, Thailand.|Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, 30329, GA, USA.
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Holtz
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D060085:Coinfection / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology*; D015497:HIV-1 / Q000302:isolation & purification; D006558:Herpes Genitalis / Q000453:epidemiology*; D006561:Herpes Simplex / Q000453:epidemiology; D018258:Herpesvirus 2, Human / Q000302:isolation & purification; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013587:Syphilis / Q000453:epidemiology*; D013785:Thailand / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
keywords: HIV incidence; HSV-2 incidence; Men who have sex with men; Syphilis incidence; Thailand