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The Amsterdam Cohort Study (ACSresearch.nl) is a prospective observational study initiated in 1984, focusing on HIV/AIDS and other blood-borne and sexually transmitted infections. With over 35 years of multidisciplinary research, the ACS investigates the prevalence, incidence, determinants, and natural course of these infections, contributing significantly to public health knowledge. / The Amsterdam Cohort Studies The Amsterdam Cohort Study (ACS) on HIV/ AIDS and other blood-borne infections (BBI), sexually transmittable infections (STI) and other infections is a prospective observational cohort studie. The ACS among men who have sex with men (MSM) started in 1984. In 1985, the study was expanded to include people who use drugs. Early on, research focused on HIV/AIDS. Later, the study was broadened to include research on hepatitis viruses A,B, and C, Chlamydia, gonorrhoeae, human papillomavirus (HPV), herpesviruses, coronaviruses, etc. From the outset, research within the ACS has taken a multidisciplinary approach. The ACS investigates the prevalence and incidence of infections, associated determinants and the natural course and pathogenesis of these infections. read more » ACS for researchers The ACS is a longitudinal study with >35 years of follow-up. The data and material collection is large and offers many opportunities for research. The ACS team enjoys working with scientists all over the world. On this page you will find how to work together with the ACS and we provide information on our study protocol and data collection. read more » ACS for participants Scientifically, the ACS is a very successful study. This is due to its highly commitment participants who visit the study every 6 months. We are grateful for their commitment. Some participants have been participating since that start of the study. Every year new people join the study and some participants leave. Participation is voluntary and you can stop at any time. The ACS aims to be a good reflection of the MSM community in Amsterdam. read more » ACS Publications The ACS publishes peer-reviewed scientific articles, theses and year reports. Since the start of the ACS, more than XXX articles and XXX theses have been published. read more »

ACS Public data & downloads The Amsterdam Cohort Studies (ACS) publishes data that can can be used publicly. There are several publications, the yearly reports and of course the public data set which you can use for your own research. ACS scientific year reports are published in the HIV monitoring report of the Dutch HIV Monitoring Foundation . Annual reports of the ACS are published in the annual reports of the Dutch HIV Monitoring Foundation Downloads (Dutch) » Downloads (English) » Year reports » ACS theses & articles HIV monitoring report / Publications /

/ About / ACS among PWUD / ACS among people who use drugs (PWUD) As of 31 December 2016, 1,680 PWUD were included in the ACS and contributed 28,194 visits. In 2014, the cohort was closed to new participants. Regular follow up of PWUD continued until February 2016. All PWUD who had ever participated in the ACS were then invited for an end-of-study interview and follow up was successfully ended in July 2016. Research using ACS data on PWUD is still ongoing. Before 2014, participants visited the GGD Amsterdam every four to six months. They completed a standardised questionnaire designed to obtain information regarding medical history, sexual and drug use behaviour, underlying psychosocial determinants, healthcare use, depression, psychological disorders, and demographics. In addition, HIV-positive participants, and in the past also HIV-negative participants, underwent a medical examination. Blood was collected for diagnostic tests and storage. In 2014, the cohort was closed for new participants and PWUD included in the ACS were divided into two groups in line with the advice of the international scientific advisory committee in 2013. Group 1 consisted of PWUD who visited the GGD Amsterdam once a year to complete questionnaires with no testing and blood sampling. Group 2, the focus group, consisted of PWUD who were 1) HIV positive; 2) hepatitis C virus (HCV) seroconverters; 3) multiple-exposed, non-infected with HIV and HCV, and 4) a random control group. This group visited the GGD Amsterdam twice a year for testing and blood sampling and to fill out questionnaires, as in previous years. Regular follow up of drug users continued until February 2016. Finally, all drug users who had ever participated in the ACS were invited for an end-of-study interview. A total of 182 end-of-study interviews were held between February and July 2016, after which the follow up of drug users was successfully ended. Of the 1,680 PWUD, 323 were HIV-positive at entry, and 99 seroconverted during follow up. The figure shows the yearly-observed HIV incidence rate for PWUD and people who injected drugs (PWID) from the start of the ACS through the end of 2012. The HIV incidence declined over time and stabilized after 1999 at almost zero new infections per 100 person years. The last HIV seroconversion was seen in 2012. By 31 December 2016, 576 deaths had been confirmed among PWUD. The median age of the PWUD who visited the ACS in 2016 was 55 (IQR 49-59), 8.1% had attained a high level of education, and 63.4% were born in the Netherlands.

/ About / ACS among MSM / ACS among men who have sex with men (MSM) As of 31 December 2020, 2,901 MSM were included in the ACS. Every three to six months, participants complete a standardised questionnaire designed to obtain data regarding medical history, sexual behaviour and drug use, psychosocial determinants, health care use, signs of depression and other psychological disorders, and demographics. Moreover, blood is collected for diagnostic tests and storage at the ACS biobank. Of the 2,901 MSM, 607 were HIVpositive at entry into the study and 263 seroconverted for HIV during follow up. In total, the GGD Amsterdam has been more than 63,500 times by MSM since 1984. In 1984-85, men who had had sexual contact with a man in the preceding six months were enrolled, independent of their HIV status. In the period 1985-88, HIV-negative men of all age groups were eligible to participate if they lived in, or around Amsterdam, and had had at least two male sexual partners in the preceding six months. In 1988-98, the cohort also included MSM living with HIV. In 1995–2004, only men aged 30 years or younger, with at least one male sexual partner in the previous six months, could be included the study. Since 2005, HIV-negative men of all age groups have been eligible to participate in the ACS if they live in, or are closely connected to the city of Amsterdam, and have had at least one male sexual partner in the preceding six months. In line with the advice issued by the International Scientific Advisory Committee in 2013, the cohort continues additional efforts to recruit young HIV-negative MSM (aged 30 years or younger). HIV-seroconverters within the ACS remained in the cohort until 1999, when follow up of a selection of MSM living with HIV was transferred to the MC Jan van Goyen. In 2003, the HIV Research in Positive Individuals (Hiv Onderzoek onder Positieven, HOP) protocol was initiated. Individuals with a recent HIV infection when entering the study at the GGD Amsterdam, and those who seroconverted for HIV during follow up within the cohort, continue to return for study visits at the GGD Amsterdam, or at an HIV treatment centre. Blood samples from these participants are stored. All behavioural data are collected on a six-monthly basis by questionnaires, coordinated by the GGD Amsterdam, and clinical data are provided by SHM. In 2020, which was affected by the COVID-19 pandemic, 699 HIV-negative and 50 MSM living with HIV were active participants at the GGD Amsterdam; in other words, they visited the cohort at least once in 2019 or 2020. All 50 MSM living with HIV filled out behavioural questionnaires. In 2020, two new HIV-negative MSM, who were 28.7 and 48.4 years of age at inclusion, were recruited. The median age of the total group of MSM in active follow up was 44.5 (interquartile range [IQR] 34.0- 55.9) years at their last cohort visit. The majority were born in the Netherlands and were residents of Amsterdam (83.4% and 88.8%, respectively). In total, 77.2% of the participants had a college degree or higher. HIV incidence The observed HIV incidence rate among MSM participating in the ACS has changed over time. In 1985-93, it declined significantly, it then stabilised in 1993-96, before rising in 1996-2009. From 2009 onwards, the HIV incidence decreased significantly. In 2020, none of the MSM participating in the ACS seroconverted for HIV. The figure shows the yearly-observed HIV incidence rate for MSM from the start of the ACS through 2020. Further information on trends in sexual behavior, other infections such as STI and SARS-CoV-2 can be found in the ACS year report which is published on this website and in our scientific publications.

Submit your Research Proposal Are you planning a research project? Then, you can submit a research proposal to obtain data or material of participants from the Amsterdam Cohort Studies. Please use the following documents for your proposal: application form A application form B If you are affiliated with the ACS, you can send your research proposal to Neeltje Kootstra (n.a.kootstra@amsterdamumc.nl ). You will receive a receipt within 3 days. The project leaders of ACS decide whether the application will be approved, a process that requires sufficient time. If the proposal is approved , we will make an appointment with you to further arrange the sharing of data or materials. If you are not affiliated with the ACS, please contact Neeltje Kootstra (n.a.kootstra@amsterdamumc.nl ) before submitting your full proposal. / Researchers / ACS Study Protocol Inclusiecriteria: Man zijn Seks hebben gehad met een man in de voorafgaande 6 maanden Minimaal 16 jaar oud zijn Bedreven in het lezen/spreken van Nederlands/Engels Woonachtig in de regio Amsterdam of betrokken bij MSM-gerelateerde activiteiten die plaatsvinden in Amsterdam Schriftelijke geïnformeerde toestemming geven Specifieke inclusiecriteria per studiearm: HIV-negatief, bevestigd door de HIV-test die is uitgevoerd bij het basisbezoek > [studiearm 1 en 2] Geen PrEP gebruiken of elders PrEP-zorg ontvangen > [studiearm 1] PrEP gebruiken of PrEP-gebruik starten bij baseline en PrEP-zorg verlenen door onderzoekspersoneel van het cohort > [studiearm 2] HIV-1-positief bij baseline > [studiearm 3] HIV-1-seroconversie tijdens een follow-up > [studiearm 4] Na beoordeling van de inclusiecriteria en het geven van schriftelijke geïnformeerde toestemming, gaat de deelnemer naar de ACS-studiearm 1, 2 of 3 . Onderzoeksarm 1: Deelnemers zijn hiv-negatief en gebruiken geen PrEP of ontvangen elders PrEP-zorg. Onderzoeksarm 2: Deelnemers zijn hiv-negatief, gebruiken PrEP en ontvangen PrEP-zorg bij de GGD Amsterdam. Onderzoeksarm 3: Deelnemers zijn hiv-positief. Onderzoeksbezoeken: 1 Basisbezoek Alle deelnemers aan het onderzoek vullen een door het onderzoekspersoneel ondersteund rapportformulier in over belangrijke demografische kenmerken en medische geschiedenis. Daarnaast vullen deelnemers een online vragenlijst in over andere sociaal-demografische kenmerken, gezondheid, welzijn, seksueel gedrag en bijbehorende factoren. Er worden hiv-/soa-testen uitgevoerd en er wordt bloed verzameld voor opslag. 6-maandelijkse vervolgbezoeken Halfjaarlijks ontvangen alle deelnemers een online vragenlijst over gezondheid, welzijn, seksueel gedrag en bijbehorende factoren. Er worden hiv-/soa-testen uitgevoerd en er wordt bloed verzameld voor opslag. 3-maandelijkse tussenbezoeken Deelnemers aan studiearm 2 hebben 2 extra tussenbezoeken voor PrEP-zorg. Er worden hiv/soa-testen uitgevoerd. Voorafgaand aan dit bezoek vullen deelnemers een korte gezondheidsvragenlijst in. HIV-positieve deelnemers aan studiearm 3 krijgen de mogelijkheid om zich elke 3 maanden te laten testen op soa's. Als ze de voorkeur geven aan bezoeken om de 3 maanden, vullen ze ook de aanvullende gezondheidsvragenlijst in. Onderzoeksarm 4: Deelnemers krijgen tijdens de follow-up een nieuwe diagnose van hiv. Extra studiebezoek De deelnemer wordt uitgenodigd voor een extra studiebezoek (het seroconversiebezoek) waarin hij het door het studiepersoneel ondersteunde seroconversierapportformulier invult en wordt gevraagd deel te nemen aan studiearm 4. Gedurende de eerste 6 maanden na het seroconversiebezoek bezoeken deelnemers het cohort elke maand om bloed af te nemen en een korte gezondheidsvragenlijst in te vullen. Na deze periode wordt de follow-up vergelijkbaar met studiearm 3. Guidelines for using ACS data The ACS collects data from study participants. They have given informed consent to conduct research within the scope of the study. This is one of the criteria that is considered when a research proposal is submitted. It is not allowed to use data for other reasons than the approved research proposal. In addition, you must comply with laws and regulations such as the GDPR. A data or material sharing agreement must be signed in advance. Data dictionary Participants complete online questionnaires prior to their study visits. During the study visits, additional data will be collected and samples will be taken for HIV/STI testing and storage. data dictionairy ACS for researchers The ACS is a longitudinal study with >35 years of follow-up. The data and material collection is large and offers many opportunities for research. The ACS team enjoys working with scientists all over the world. On this page, we share our study protocol, information on our data collection, and recent questionnaires. We also explain how to submit a research proposal to collaborate with the ACS and obtain data.

/ About / About the Amsterdam Cohort Studies The Amsterdam Cohort Studies (ACS) on HIV infection and AIDS started shortly after the first cases of AIDS were diagnosed in the Netherlands. Since October 1984, men who have sex with men (MSM) have been enrolled in a prospective cohort study. A second cohort involving people who use/used (injecting) drugs (PWUD/PWID) was initiated in 1985 and discontinued in 2016. From the outset, research in the ACS has taken a multidisciplinary approach, integrating epidemiology, social science, virology, immunology, and clinical medicine in one study team. This unique collaboration has been highly productive, significantly contributing to the knowledge and understanding of many different aspects of HIV-1 infection, as well as other infections including STI (e.g., chlamydia, gonorrhea, syphilis, viral hepatitis B and C [HBV and HCV] and human papillomavirus [HPV]) and (re-)emerging infectious diseases (COVID-19, mpox). This expertise, in turn, has contributed directly to advances in prevention, diagnosis, and management of these infections. ACS among people who use or inject drugs (PWUD/PWID) Between 1984-2016, a total of 1,661 PWUD had been included in the ACS of whom 1,303 had at least two cohort visits (maximum 78 visits). Study enrolment and data collection continued until 2014 and February 2016, respectively. Data and samples from these participants of this cohort are still being used for research. read more » ACS among men who have sex with men (MSM) As of 31 December 2020, 2,901 MSM were included in the ACS. Every three to six months, participants complete a standardised questionnaire designed to obtain data regarding medical history, sexual behaviour and drug use, psychosocial determinants, health care use, signs of depression and other psychological disorders, and demographics. Moreover, blood is collected for diagnostic tests and storage at the ACS biobank. read more » Collaborating institutes and financing Within the ACS, the following different institutes collaborate to bring together data and biological sample collections and to conduct research. These include: In previous years, Sanquin Blood Supply Foundation, Medical Center Jan van Goyen, and the HIV Focus Center of the DC-Clinics also contributed to sample and data collection, still being used in current research projects. In addition, there are numerous collaborations between the ACS and other research groups, both within and outside the Netherlands. The ACS is financially supported by the Centre for Infectious Disease Control Netherlands of the National Institute for Public Health and the Environment (Centrum voor Infectieziektenbestrijding - Rijksinstituut voor Volksgezondheid en Milieu, RIVM-CIb). ACS Project team The ACS team consists of scientists with different background, PhD students, study nurses, medical doctors and data managers. Data collection takes place at the GGD Amsterdam and additional lab tests are performed at the UMC Amsterdam, location Meibergdreef. The study is directed by the steering committee. The advisory board advices on the scientific direction of the study. read more »

The Amsterdam Cohort Study (ACS) is a prospective observational study initiated in 1984, focusing on HIV/AIDS and other blood-borne and sexually transmitted infections. With over 35 years of multidisciplinary research, the ACS investigates the prevalence, incidence, determinants, and natural course of these infections, contributing significantly to public health knowledge. ACS Publications The ACS publishes peer-reviewed scientific articles, theses and year reports. Since the start of the ACS, more than XXX articles and XXX theses have been published. Open-access data is available for educational purposes. read more » De Amsterdamse Cohort Studie De Amsterdam Cohort Study (ACSresearch.nl) onderzoekt hiv/aids en andere door bloed overgedragen infecties (BBI), seksueel overdraagbare infecties (SOA) en andere infecties is een prospectieve observationele cohortstudie. De ACS onder mannen die seks hebben met mannen (MSM) begon in 1984. In 1985 werd de studie uitgebreid met mensen die drugs gebruiken. In de beginfase lag de focus van het onderzoek op hiv/aids. Later werd de studie verbreed en omvatte onderzoek naar hepatitisvirussen A, B en C, Chlamydia, gonorroe, humaan papillomavirus (HPV), herpesvirussen, coronavirussen, enzovoort. Vanaf het begin heeft onderzoek binnen de ACS een multidisciplinaire aanpak gevolgd. De ACS onderzoekt de prevalentie en incidentie van infecties, de bijbehorende determinanten en het natuurlijke verloop en de pathogenese van deze infecties. read more » ACS for researchers The ACS is a longitudinal study with >35 years of follow-up. The data and material collection is large and offers many opportunities for research. The ACS team enjoys working with scientists all over the world. On this page you will find how to work together with the ACS and we provide information on our study protocol and data collection. read more » ACS for participants Scientifically, the ACS is a very successful study. This is due to its highly commitment participants who visit the study every 6 months. We are grateful for their commitment. Some participants have been participating since that start of the study. Every year new people join the study and some participants leave. Participation is voluntary and you can stop at any time. The ACS aims to be a good reflection of the MSM community in Amsterdam. read more » Collaborating Institutes and Funding Within the ACS, different institutes collaborate to bring together data and biological sample collections, and to conduct research. These include: From the start, Sanquin Blood Supply Foundation has been involved in the ACS and, since 2007, has provided financial support for the biobank of viable peripheral blood mononuclear cells (PBMC) at the AMC’s Department of Experimental Immunology. In addition, there are numerous collaborations between the ACS and other research groups, both within and outside the Netherlands. The ACS is financially supported by the Centre for Infectious Disease Control Netherlands of the National Institute for Public Health and the Environment (Centrum voor Infectieziektenbestrijding-Rijksinstituut voor Volksgezondheid en Milieu, RIVM-CIb). Data dictionairy Participants complete online questionnaires prior to their study visits. During the study visits, additional data are collected and samples are taken for HIV/STI testing and storage. Currently, the following questionnaires are used: data dictionairy » Interested in participating? Would you like to contribute to the Amsterdam Cohort Studies by participating in this ongoing study? We are happy to have you join our research group. You can join if you: are at least 18 years old live in Amsterdam or have a tight connection with the city have had at least 1 male sexual partner in the past 6 months and are willing to participate registration form ACS publications The ACS publishes peer-reviewed scientific articles, theses and year reports. Since the start of the ACS, more than XXX articles and XXX theses have been published. Open-access data is available for educational purposes. read more » / Publications / Test Page /

Interested in participating? Would you like to contribute to the Amsterdam Cohort Studies by participating in this ongoing study? We are happy to have you join our research group. You can join if you: - Are at least 18 years old - Live in Amsterdam or have a tight connection with the city - You have had at least 1 male sexual partner in the past 6 months - and are willing to participate in this research Registration form / Participants / ACS for participants The ACS is a very scientifically successful study, which is due to the participants who are willing to visit the study every 6 months. We are grateful for their commitment. Some participants have been participating since the start of the study. Each year new people join the study and some participants leave. Participation is voluntary and you can stop at any time. The ACS strives to be a good representation of the MSM community in Amsterdam.

ACS Team members Short text introducing all team members and what tey have in common / dedication to.... Payton Hillman GGD Amsterdam James Wilson Affiliates Jessica Davis Affiliates Chloe Williams Affiliates ACS Advisory board Short text introducing all team members and what tey have in common / dedication to.... Payton Hillman GGD Amsterdam James Wilson Affiliates Jessica Davis Affiliates Chloe Williams Affiliates / ACS People /