Downloaded from http://sti.bmj.com/ on June 8, 2015 - Published by group.bmj.com
Epidemiology
ORIGINAL ARTICLE
Identifying recently acquired HIV infections among newly diagnosed men who have sex with men attending STI clinics in The Netherlands Jussi Sane,1,2 Titia Heijman,3 Boris Hogema,4 Maarten Koot,4 Maaike van Veen,3 Hannelore Götz,5 Johan Fennema,3 Eline Op de Coul1 ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ sextrans-2013-051420). 1
Unit of Epidemiology and Surveillance, National Institute for Public Health and Environment (RIVM), Centre for Infectious Disease Control, The Netherlands 2 European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden 3 Public Health Service of Amsterdam, Amsterdam, The Netherlands 4 Virus Diagnostic Services, Sanquin Blood Supply, Amsterdam, The Netherlands 5 Department of Infectious Disease Control, Public Health Service Rotterdam-Rijnmond, Rotterdam, The Netherlands Correspondence to Dr Eline LM Op de Coul, Epidemiology & Surveillance Unit, Centre for Infectious Disease Control, National Institute of Public Health and the Environment, PO Box 1, Bilthoven 3720 BA, The Netherlands; eline.op.de.coul@ rivm.nl Received 24 October 2013 Revised 18 December 2013 Accepted 30 December 2013 Published Online First 28 January 2014
To cite: Sane J, Heijman T, Hogema B, et al. Sex Transm Infect 2014;90:414–417. 414
ABSTRACT Objectives The current surveillance system in The Netherlands cannot differentiate recent HIV infections from established infections, which is crucial for estimating the HIV incidence; this information is needed for assessing trends of the HIV epidemic and the impact of prevention interventions. We determined the proportion of recent HIV infections (RI) and estimated HIV incidence using a recent infection testing algorithm (RITA) among men who have sex with men (MSM) newly diagnosed as having HIV attending sexually transmitted infection (STI) clinics. Methods Plasma samples collected between 2009 and 2011 were tested for RI with the Architect HIV Ag/Ab Combo immunoassay. Data on viral load, CD4 count and previous HIV testing were incorporated into the RITA. HIV incidence and 95% CIs were estimated. Logistic regression was used to identify factors associated with RI. Results Of the 251 samples tested for RI, 78/251 (31%) infections were determined as recent by the RITA. No significant change over time was observed. The estimated HIV incidence in this high-risk MSM population was 3.3 per 100 person-years (95% CI 2.5 to 4.1). The only factor associated with RI in the multivariable model was being tested for HIV ≥3 times in the past (aOR=7.4; 95% CI 2.0 to 27.8). Conclusions The proportion of RIs was comparable to studies in similar settings in Europe. Implementation of the RITA for routine surveillance in The Netherlands to assess trends in RIs over time, to study the infections in other groups and to inform public health actions, is being planned.
INTRODUCTION The current HIV surveillance system in The Netherlands largely relies on reporting new diagnoses of HIV and AIDS cases.1 In 2012, approximately 1200 newly diagnosed HIV infections were registered in The Netherlands. The number of newly diagnosed infections was highest among men who have sex with men (MSM) and has been gradually increasing in The Netherlands over the past decade.2 However, the existing surveillance cannot distinguish between an increase in HIV transmission and increased testing of previously undiagnosed infections. This system is slow to reflect potential changes in HIV transmission and is limited in showing the possible impact of public health interventions on HIV transmission.
In recent years, several serological assays that use a single laboratory specimen for identifying recent HIV infections have been developed. These assays allow the proportion of recent infections and incidence of HIV to be estimated in studies that are easier to conduct, less expensive, timely and require fewer resources.3 4 The testing algorithms, referred to as recent infection testing algorithms (RITAs), can be combined with additional laboratory, clinical or epidemiological data and have become increasingly widespread for monitoring recent HIV infections and incidence.1 Following recommendations from the European Centre for Disease Prevention and Control (ECDC) to strengthen the role of RITAs in surveillance in Europe, and to validate RITAs in The Netherlands in order to inform public health actions, we determined the proportion of recent HIV infections and provided an estimation of HIV incidence using a RITA among MSM newly diagnosed as having HIV who were tested at sexually transmitted infection (STI) clinics.
METHODS Study design and data collection HIV testing in The Netherlands occurs mainly via general practitioners, hospitals or STI clinics.2 Blood specimens of HIV-positive tests were collected as a part of another study, to which MSM newly diagnosed as having HIV attending the STI clinics in Amsterdam and Rotterdam were invited to join between February 2009 and December 2011.5 All specimens were anonymised and study participants filled out a questionnaire on demographics, sexual risk behaviour and previous HIV tests. Furthermore, data on viral load and CD4 cell count were collected at the STI clinics. Data on concurrent diagnoses of other STIs and overall HIV testing data (including recorded dates of previous tests) were only available from the Amsterdam STI clinic.
Laboratory methods To test for recent infections, the anti-HIV avidity index (AI) was measured in plasma with a fourthgeneration commercial enzyme immunoassay, Architect HIV Ag/Ab Combo (Abbott Diagnostics, Wiesbaden, Germany) using a previously implemented protocol.6 The assay-specific period for recent infections is ≤6 months from seroconversion. Thus, the mean RITA duration (window period) was 180 days.
Sane J, et al. Sex Transm Infect 2014;90:414–417. doi:10.1136/sextrans-2013-051420
Downloaded from http://sti.bmj.com/ on June 8, 2015 - Published by group.bmj.com
Epidemiology RITA and statistical methods We applied a RITA based on the guidelines presented by the ECDC.1 Data on viral load, CD4 count and previous HIV testing were incorporated in the RITA to minimise false recent rate (FRR) (figure 1). Cases with AI ≤0.80 and classified as recent based on the avidity assay were reclassified as non-recent if CD4 count was
Epidemiology
ORIGINAL ARTICLE
Identifying recently acquired HIV infections among newly diagnosed men who have sex with men attending STI clinics in The Netherlands Jussi Sane,1,2 Titia Heijman,3 Boris Hogema,4 Maarten Koot,4 Maaike van Veen,3 Hannelore Götz,5 Johan Fennema,3 Eline Op de Coul1 ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ sextrans-2013-051420). 1
Unit of Epidemiology and Surveillance, National Institute for Public Health and Environment (RIVM), Centre for Infectious Disease Control, The Netherlands 2 European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden 3 Public Health Service of Amsterdam, Amsterdam, The Netherlands 4 Virus Diagnostic Services, Sanquin Blood Supply, Amsterdam, The Netherlands 5 Department of Infectious Disease Control, Public Health Service Rotterdam-Rijnmond, Rotterdam, The Netherlands Correspondence to Dr Eline LM Op de Coul, Epidemiology & Surveillance Unit, Centre for Infectious Disease Control, National Institute of Public Health and the Environment, PO Box 1, Bilthoven 3720 BA, The Netherlands; eline.op.de.coul@ rivm.nl Received 24 October 2013 Revised 18 December 2013 Accepted 30 December 2013 Published Online First 28 January 2014
To cite: Sane J, Heijman T, Hogema B, et al. Sex Transm Infect 2014;90:414–417. 414
ABSTRACT Objectives The current surveillance system in The Netherlands cannot differentiate recent HIV infections from established infections, which is crucial for estimating the HIV incidence; this information is needed for assessing trends of the HIV epidemic and the impact of prevention interventions. We determined the proportion of recent HIV infections (RI) and estimated HIV incidence using a recent infection testing algorithm (RITA) among men who have sex with men (MSM) newly diagnosed as having HIV attending sexually transmitted infection (STI) clinics. Methods Plasma samples collected between 2009 and 2011 were tested for RI with the Architect HIV Ag/Ab Combo immunoassay. Data on viral load, CD4 count and previous HIV testing were incorporated into the RITA. HIV incidence and 95% CIs were estimated. Logistic regression was used to identify factors associated with RI. Results Of the 251 samples tested for RI, 78/251 (31%) infections were determined as recent by the RITA. No significant change over time was observed. The estimated HIV incidence in this high-risk MSM population was 3.3 per 100 person-years (95% CI 2.5 to 4.1). The only factor associated with RI in the multivariable model was being tested for HIV ≥3 times in the past (aOR=7.4; 95% CI 2.0 to 27.8). Conclusions The proportion of RIs was comparable to studies in similar settings in Europe. Implementation of the RITA for routine surveillance in The Netherlands to assess trends in RIs over time, to study the infections in other groups and to inform public health actions, is being planned.
INTRODUCTION The current HIV surveillance system in The Netherlands largely relies on reporting new diagnoses of HIV and AIDS cases.1 In 2012, approximately 1200 newly diagnosed HIV infections were registered in The Netherlands. The number of newly diagnosed infections was highest among men who have sex with men (MSM) and has been gradually increasing in The Netherlands over the past decade.2 However, the existing surveillance cannot distinguish between an increase in HIV transmission and increased testing of previously undiagnosed infections. This system is slow to reflect potential changes in HIV transmission and is limited in showing the possible impact of public health interventions on HIV transmission.
In recent years, several serological assays that use a single laboratory specimen for identifying recent HIV infections have been developed. These assays allow the proportion of recent infections and incidence of HIV to be estimated in studies that are easier to conduct, less expensive, timely and require fewer resources.3 4 The testing algorithms, referred to as recent infection testing algorithms (RITAs), can be combined with additional laboratory, clinical or epidemiological data and have become increasingly widespread for monitoring recent HIV infections and incidence.1 Following recommendations from the European Centre for Disease Prevention and Control (ECDC) to strengthen the role of RITAs in surveillance in Europe, and to validate RITAs in The Netherlands in order to inform public health actions, we determined the proportion of recent HIV infections and provided an estimation of HIV incidence using a RITA among MSM newly diagnosed as having HIV who were tested at sexually transmitted infection (STI) clinics.
METHODS Study design and data collection HIV testing in The Netherlands occurs mainly via general practitioners, hospitals or STI clinics.2 Blood specimens of HIV-positive tests were collected as a part of another study, to which MSM newly diagnosed as having HIV attending the STI clinics in Amsterdam and Rotterdam were invited to join between February 2009 and December 2011.5 All specimens were anonymised and study participants filled out a questionnaire on demographics, sexual risk behaviour and previous HIV tests. Furthermore, data on viral load and CD4 cell count were collected at the STI clinics. Data on concurrent diagnoses of other STIs and overall HIV testing data (including recorded dates of previous tests) were only available from the Amsterdam STI clinic.
Laboratory methods To test for recent infections, the anti-HIV avidity index (AI) was measured in plasma with a fourthgeneration commercial enzyme immunoassay, Architect HIV Ag/Ab Combo (Abbott Diagnostics, Wiesbaden, Germany) using a previously implemented protocol.6 The assay-specific period for recent infections is ≤6 months from seroconversion. Thus, the mean RITA duration (window period) was 180 days.
Sane J, et al. Sex Transm Infect 2014;90:414–417. doi:10.1136/sextrans-2013-051420
Downloaded from http://sti.bmj.com/ on June 8, 2015 - Published by group.bmj.com
Epidemiology RITA and statistical methods We applied a RITA based on the guidelines presented by the ECDC.1 Data on viral load, CD4 count and previous HIV testing were incorporated in the RITA to minimise false recent rate (FRR) (figure 1). Cases with AI ≤0.80 and classified as recent based on the avidity assay were reclassified as non-recent if CD4 count was
