Position statement of the German STI Society on the prophylactic use of doxycycline to prevent STIs (Doxy-PEP, Doxy-PrEP).

Over the past two decades, there has been a rise in the incidence of syphilis, particularly among men who have sex with men (MSM). This has sparked interest in studying the prophylactic use of doxycycline to prevent syphilis and other sexually transmitted infections (STIs), commonly referred to as Doxycycline Pre- or Post-Exposure Prophylaxis (Doxy-PrEP, Doxy-PEP). At the same time, demand from potential users for this preventive measure is increasing. Several randomized controlled trials have demonstrated that the prophylactic use of doxycycline in MSM and trans women using HIV pre-exposure prophylaxis (HIV-PrEP) or living with an HIV infection effectively reduces the risk of syphilis and chlamydia infections. At present, however, unresolved questions remain, particularly regarding implications of a broad implementation of prophylactic doxycycline to prevent STIs on tetracycline and other antimicrobial resistance in bacterial STIs, non-STI-related bacterial pathogens, and the microbiome. In response to the increasing demand and the challenge of balancing effectiveness, safety, and the risk of promoting antibiotic resistance, the German STI Society (DSTIG) has issued a position statement, providing specific recommendations regarding potential indications, criteria, and occasions for the use of doxycycline in STI prevention. These recommendations are based on current evidence and expert opinion.

Cholesterol-conjugated siRNAs silence gene expression in mucosal dendritic cells in cervicovaginal tissue in mice.

BACKGROUND: RNA interference (RNAi) provides a powerful way to investigate the role of genes in disease pathogenesis and modulate gene expression to treat disease. In 2018, the FDA approved patisiran, the first RNAi-based drug, hence paving the way for a novel class of RNAi therapeutics. Harnessing RNAi to inhibit vaginal HIV transmission requires effective gene silencing in immune cells, which remains difficult. Knockdown in accessible mucosal tissues may be easier than systemic gene silencing. Vaginally applied cholesterol-conjugated small interfering RNAs (chol-siRNAs) blocked herpes simplex virus transmission in mice without tissue damage or immunostimulation. OBJECTIVES AND METHODS: To investigate using flow cytometry, confocal microscopy, and quantitative imaging if chol-siRNAs silence gene expression in vaginal immune cells in mice. RESULTS: Although chol-siRNAs and lipoplexed-siRNAs silence gene expression in dendritic cells (DCs) in vitro, most internalized siRNAs concentrate within multivesicular bodies, where they are inaccessible to the cellular RNAi machinery. When applied intravaginally in vivo, chol-siRNAs penetrate the vaginal mucosa, including the lamina propria, and are efficiently internalized by intraepithelial (IE) and lamina propria (LP) DCs, and CD11b+ CD45+ cells, but not by T cells. Chol-siRNAs induce partial gene silencing in IE and LP DCs throughout the genital mucosa in vivo but are inactive in F4/80+ CD11b+ macrophages and T cells. CONCLUSION: As mucosal DCs play an essential role for mucosal viral entry and dissemination, chol-siRNAs could be harnessed to target various host factors that are critical for viral uptake, DC migration and trans-infection of virions to T cells, hence allowing the development of a preventive vaginal HIV microbicide. Furthermore, chol-siRNAs could help elucidate the pathways of HIV transmission and understand the immunologic function of DCs in the genital tract.

HIV pre-exposure prophylaxis was associated with no impact on sexually transmitted infection prevalence in a high-prevalence population of predominantly men who have sex with men, Germany, 2018 to 2019.

IntroductionDespite increased use of pre-exposure prophylaxis (PrEP) in Germany, HIV infection rates are not declining and little is known about how this prevention method affects the prevalence of sexually transmitted infections (STI) among men who have sex with men (MSM).AimWe studied, in a large multicentre cohort, STI point prevalence, co-infection rates, anatomical location and influence of PrEP.MethodsThe BRAHMS study was a prospective cohort study conducted at 10 sites in seven major German cities that enrolled MSM reporting increased sexual risk behaviour. At screening visits, MSM were tested for Mycoplasma genitalium (MG), Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT) and Treponema pallidum (TP), and given a behavioural questionnaire. With binomial regression, we estimated prevalence ratios (PR) and 95% confidence intervals (CI) for the association of PrEP and STI.ResultsWe screened 1,043 MSM in 2018 and 2019, with 53.0% currently using PrEP. At screening, 370 participants (35.5%) had an STI. The most common pathogen was MG in 198 (19.0%) participants, followed by CT (n = 133; 12.8%), NG (n = 105; 10.1%) and TP (n = 37; 3.5%). Among the 370 participants with at least one STI, 14.6% (n = 54) reported STI-related symptoms. Infection prevalence was highest at anorectal site (13.4% MG, 6.5% NG, 10.2% CT). PrEP use was not statistically significant in adjusted models for STI (PR: 1.10; 95% CI: 0.91-1.32), NG/CT, only NG or only CT.ConclusionsPrevalence of asymptomatic STI was high, and PrEP use did not influence STI prevalence in MSM eligible for PrEP according to national guidelines.

Online HIV/STI Risk Test (ORT): A prospective cross-sectional study among sexually active individuals in Germany.

BACKGROUND: Our goal was to develop and evaluate an anonymous self-administrable web-based test to determine risk for HIV/STI. METHODS: The Online HIV/STI Risk Test was developed and hosted since 12/2017. 11,529 participants completed the test and 10,668 were analyzed. The test included multiple choice questions about sociodemographic data, sexuality, sexual risk behavior, HIV/STI testing. Participant data was stratified by gender and sexuality and analyzed. RESULTS: 84.5 % were aged 18-39, 7.5 % < 18 and 8.1 % > 40. Males were 53.1 %, female 46.3 % and trans 0.6 %. 12.5 % were men who have sex with men (MSM). 59.1 % and 66.0 % of participants were vaccinated for hepatitis A and B respectively, but 75.1 % unvaccinated for HPV. Prior and repeated instances of HIV or other STI were higher among MSM. Yet, 61.4 % females, 70 % males and 55.4 % MSM had never tested for an STI. Although prevalence of > 3 sexual partners in the last twelve months was highest among MSM, condomless sex was greater among women. 34.5 % of males, 25.6 % of females, and 75 % of MSM engaged in anal sex respectively. CONCLUSIONS: The online HIV/STI Risk Test is a useful tool to acquire data on STI risk-behavior for strategizing STI prevention, testing, and vaccination, thus improving sexual health.

S1 Guidelines for the Kaposi Sarcoma.

Kaposi's sarcoma (KS) is a rare, malignant, multilocular vascular disease originating from lymphatic endothelial cells that can primarily affect the skin and mucous membranes, but also the lymphatic system and internal organs such as the gastrointestinal tract, lungs or liver. Five epidemiological subtypes of KS with variable clinical course and prognosis are distinguished, with increased incidence in specific populations: (1) Classical KS, (2) Iatrogenic KS in immunosuppression, (3) Endemic (African) lymphadenopathic KS, (4) Epidemic, HIV-associated KS and KS associated with immune reconstitution inflammatory syndrome (IRIS), and (5) KS in men who have sex with men (MSM) without HIV infection. This interdisciplinary guideline summarizes current practice-relevant recommendations on diangostics and therapy of the different forms of KS. The recommendations mentioned in this short guideline are elaborated in more detail in the extended version of the guideline (online format of the JDDG).

S1-Leitlinie: Kaposi-Sarkom.

Das Kaposi-Sarkom (KS) ist eine seltene, maligne, von lymphatischen Endothelzellen ausgehende, multilokuläre Gefäßerkrankung, die vor allem Haut und Schleimhäute, aber auch das lymphatische System und innere Organe wie den Gastrointestinaltrakt, die Lunge oder die Leber befallen kann. Fünf epidemiologische Subtypen des KS mit variablem klinischem Verlauf und unterschiedlicher Prognose werden unterschieden, die in spezifischen Populationen vermehrt auftreten: (1) klassisches KS, (2) iatrogenes KS bei Immunsuppression, (3) endemisches (afrikanisches) lymphadenopathisches KS, (4) epidemisches, HIV-assoziiertes KS und mit einem Immunrekonstitutions-Inflammations-Syndrom (IRIS) assoziiertes KS und (5) KS bei Männern, die Sex mit Männern haben (MSM) ohne HIV-Infektion. Diese interdisziplinäre Leitlinie fasst aktuelle praxisrelevante Empfehlungen zu Diagnostik und Therapie der verschiedenen Formen des KS zusammen. Die in dieser Kurzleitlinie genannten Empfehlungen werden in der Langfassung der Leitlinie (Online-Version des JDDG) detaillierter ausgeführt.

Factors associated with testing for HIV and hepatitis C among behaviorally vulnerable men in Germany: a cross-sectional analysis upon enrollment into an observational cohort.

BACKGROUND: HIV and hepatitis C virus (HCV) have shared routes of transmission among men who have sex with men (MSM). Routine testing facilitates early diagnosis and treatment, thereby preventing morbidity and onward transmission. We evaluated factors associated with HIV and HCV testing in a behaviorally vulnerable cohort of predominantly MSM. METHODS: From June 2018 through June 2019, the BRAHMS study enrolled adults at ten German outpatient clinics that serve gender and sexual minority populations. Participants completed behavioral questionnaires that captured prior experience with HIV and HCV testing. Multivariable robust Poisson regression was used to evaluate factors potentially associated with testing in the previous 6 months. RESULTS: Among 1017 participants with median age 33 (interquartile range 28-39) years, 1001 (98.4%) reported any lifetime history of HIV testing and 787 (77.4%) reported any HCV testing, including 16 (1.6%) known to be living with HCV. Testing within the last 6 months was reported by 921 (90.6%) and 513 (50.4%) for HIV and HCV, respectively. Recent HIV testing was more common among participants with higher education level and recent HCV testing. Recent HCV testing was more common among participants with non-cisgender identity, lifetime history of illicit drug use, hepatitis B immunity or infection, and recent HIV testing. CONCLUSION: Prior testing for HIV was common in this cohort, but interventions are needed to improve HCV risk stratification and access to testing. HIV testing infrastructure can be successfully leveraged to support HCV testing, but differentiated preventive care delivery is needed for some vulnerable populations.

German evidence and consensus-based (S3) guideline: Vaccination recommendations for the prevention of HPV-associated lesions.

Anogenital and oropharyngeal infections with human papilloma viruses (HPV) are common. Clinically manifest disease may significantly impact quality of life; the treatment of HPV-associated lesions is associated with a high rate of recurrence and invasive neoplasms, such as cervical, anal, vulvar, penile, and oropharyngeal cancers, which are characterized by significant morbidity and mortality. Vaccination against HPV is an effective and safe measure for the primary prevention of HPV-associated lesions, but immunization rates are still low in Germany. The present publication is an abridged version of the German evidence and consensus-based guideline "Vaccination recommendations for the prevention of HPV-associated lesions", which is available on the website of the German Association of the Scientific Medical Societies (AWMF). On the basis of a systematic review with meta-analyses, a representative panel developed and agreed upon recommendations for the vaccination of different populations against HPV. In addition, consensus-based recommendations were developed for specific issues relevant to everyday practice. Based on current evidence and a representative expert consensus, these recommendations are intended to provide guidance in a field in which there is often uncertainty and in which both patients and health care providers are sometimes confronted with controversial and emotionally charged points of view.

[Sexual health and medicine at the WIR-Walk In Ruhr: presentation of the center and results of the evaluation]. / Sexuelle Gesundheit und Medizin im WIR ­ Walk In Ruhr: Vorstellung des Zentrums und Ergebnisse der Evaluation.

BACKGROUND: Holistic sexual healthcare factors in diversity of social habitat and aims to improvise client outreach for prevention, testing, counseling, and treatment of STIs. Towards this goal, the immunology outpatient clinic, the public health department of Bochum, the AIDS Service Organization Bochum e. v., and other community-driven NGOs mutually cooperate under the umbrella of WIR - Walk In Ruhr, Centre for Sexual Health and Medicine. OBJECTIVES: WIR is an innovative concept for multi-professional in-house ambulatory healthcare with cross-sectoral and cross-legal reach. It has successfully improved accessibility, testing and treatment rates, and HIV/STI self-assessment. We present the results achieved at WIR. METHODS: A mixed-method design of qualitative and quantitative surveys. RESULTS: The WIR reaches more women (27.7%) and heterosexuals (56.4%) than other counseling/test centers. The rate of positive test results at the WIR increased from 9.3% in 2017 to 12.6% in 2018 and progress from prevention to medical care is a significant aspect of WIR. The Federal Ministry of Health has externally evaluated WIR for over three years. DISCUSSION: The integrative care model of WIR allows for early outreach and treatment of individuals with HIV/ST infections. Health advisors remain an important instrument facilitating outreach and psychosocial/psychotherapeutic counseling is administered frequently. Such a multi-layered approach in prevention, testing, and consultation, leads to improvement in both medical outcomes and the self-responsible attitude of patients towards their sexual health. Hence, expansion of integrative care models like WIR on a wider scale could arguably contribute to better health service and sexual health.

[Sexual behavior and prevention of sexually transmitted infections taking the SARS-CoV-2 pandemic into account. Data from a sexual healthcare and medicine center-WIR]. / Sexualverhalten und Prävention sexuell übertragbarer Infektionen unter Berücksichtigung der SARS-CoV-2-Pandemie. Daten aus einem Versorgungszentrum für sexuelle Gesundheit und Medizin ­ WIR.

BACKGROUND: Application-based data regarding sexual health and sexual behavior in various sexually active populations are scarce but at the same time relevant with regards to prevention and healthcare supply strategies. Given the structure of its attendees, the Walk In Ruhr (WIR) Center for Sexual Health and Medicine is able to obtain data from diverse living environments. OBJECTIVES: Based on the online HIV/STI risk test, questionnaires, and attendee data from the WIR, this study aims to deduce population-related findings with regards to age, gender, sexual orientation, and sexual and risk behavior as well as the respective needs for prevention. The influence of the SARS-CoV-19 pandemic on sexual behavior is examined by comparing various phases. METHODS: The analyzed data sources are the online HIV/STI risk test, the COWIR, and the PrEP study as well as the immunological outpatient clinic and the public health department at the WIR. RESULTS: Notwithstanding contact restrictions, sexually transmitted infections (STIs) have increased from 2019 to 2020. Apart from men having sex with men and females having sex with females, young people also have an increased risk of STIs based on sexual practices and the number of sexual contacts. A large number of bisexual and transsexual contacts was found. SARS-CoV­2 led to a decrease in sexual contacts; sexual practices continued. There was a growing proportion of STI tests and the treatment rate including partner treatment rose. DISCUSSION: Data from the WIR center show that young attendees with an active sexual life are being reached. The results from questionnaires and the online HIV/STI risk test are mirrored in increased positive STI test results. These results vary depending on sexual behavior and sexual preferences such that specific strategies for sexual education, prevention, testing, and therapy are required.

Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER): final results of a multicentre, prospective, observational study.

BACKGROUND: The level of evidence for HIV transmission risk through condomless sex in serodifferent gay couples with the HIV-positive partner taking virally suppressive antiretroviral therapy (ART) is limited compared with the evidence available for transmission risk in heterosexual couples. The aim of the second phase of the PARTNER study (PARTNER2) was to provide precise estimates of transmission risk in gay serodifferent partnerships. METHODS: The PARTNER study was a prospective observational study done at 75 sites in 14 European countries. The first phase of the study (PARTNER1; Sept 15, 2010, to May 31, 2014) recruited and followed up both heterosexual and gay serodifferent couples (HIV-positive partner taking suppressive ART) who reported condomless sex, whereas the PARTNER2 extension (to April 30, 2018) recruited and followed up gay couples only. At study visits, data collection included sexual behaviour questionnaires, HIV testing (HIV-negative partner), and HIV-1 viral load testing (HIV-positive partner). If a seroconversion occurred in the HIV-negative partner, anonymised phylogenetic analysis was done to compare HIV-1 pol and env sequences in both partners to identify linked transmissions. Couple-years of follow-up were eligible for inclusion if condomless sex was reported, use of pre-exposure prophylaxis or post-exposure prophylaxis was not reported by the HIV-negative partner, and the HIV-positive partner was virally suppressed (plasma HIV-1 RNA <200 copies per mL) at the most recent visit (within the past year). Incidence rate of HIV transmission was calculated as the number of phylogenetically linked HIV infections that occurred during eligible couple-years of follow-up divided by eligible couple-years of follow-up. Two-sided 95% CIs for the incidence rate of transmission were calculated using exact Poisson methods. FINDINGS: Between Sept 15, 2010, and July 31, 2017, 972 gay couples were enrolled, of which 782 provided 1593 eligible couple-years of follow-up with a median follow-up of 2·0 years (IQR 1·1-3·5). At baseline, median age for HIV-positive partners was 40 years (IQR 33-46) and couples reported condomless sex for a median of 1·0 years (IQR 0·4-2·9). During eligible couple-years of follow-up, couples reported condomless anal sex a total of 76 088 times. 288 (37%) of 777 HIV-negative men reported condomless sex with other partners. 15 new HIV infections occurred during eligible couple-years of follow-up, but none were phylogenetically linked within-couple transmissions, resulting in an HIV transmission rate of zero (upper 95% CI 0·23 per 100 couple-years of follow-up). INTERPRETATION: Our results provide a similar level of evidence on viral suppression and HIV transmission risk for gay men to that previously generated for heterosexual couples and suggest that the risk of HIV transmission in gay couples through condomless sex when HIV viral load is suppressed is effectively zero. Our findings support the message of the U=U (undetectable equals untransmittable) campaign, and the benefits of early testing and treatment for HIV. FUNDING: National Institute for Health Research.

[HIV pre-exposure prophylaxis care in intersectoral collaboration : Interim analysis of a monocentric, prospective study in Germany]. / HIV-Präexpositionsprophylaxe-Versorgung in intersektoraler Zusammenarbeit : Interimsanalyse einer monozentrischen, prospektiven Studie in Deutschland.

BACKGROUND: HIV pre-exposure prophylaxis (PrEP), a further opportunity to prevent HIV, is available at the WIR-Walk In Ruhr, Centre for Sexual Health and Medicine, as part of an innovative model project for intersectoral PrEP care. RESEARCH OBJECTIVES: The present study describes the collective of persons provided with PrEP and how PrEP use influences sexual risk behaviour, the incidence of sexually transmitted diseases (STD) and adverse drug reactions. METHODS: A total of 139 men who started PrEP between 10/2017 and 12/2018 have been included in the study. During a period of 13 months of PrEP treatment, all PrEP users received questionnaires; side effects, HIV and other STI were also monitored via clinical laboratory examinations. RESULTS: The participants' average age was 38 years and 98.6% of them were men who had sex with men (MSM). Most of them had a high educational background; the unemployment rate was low. The average number of sexual partners within the last 6 months increased significantly, while the use of condoms decreased. In all, 44 STI were found in 34 participants within the first 4 months. No one was infected with HIV. Within the first 4 weeks of PrEP, 38.8% of the participants suffered from side effects, mainly gastrointestinal symptoms. CONCLUSION: Most of the participants were working in a job or a vocational training. The sexual risk behaviour increased in the course of using PrEP resulting in a high incidence of STD. Side effects appeared most frequently in the first few weeks after starting PrEP.

[Rapid diagnosis of sexually transmitted infections : Joint statement of DSTIG, RKI, and PEI, as well as the reference centers for HIV, HBV, and HCV and consulting laboratories for Chlamydia, gonococci, and Treponema pallidum]. / Schnelltestdiagnostik sexuell übertragbarer Infektionen : Gemeinsame Stellungnahme von DSTIG, RKI, PEI sowie den Referenzzentren für HIV, HBV und HCV und Konsiliarlaboren für Chlamydien, Gonokokken und Treponema pallidum.

In February 2019, the fourth expert meeting on rapid diagnostic tests (RDTs) for sexually transmitted infections (STI) was held at the Robert Koch Institute (RKI) in Berlin. Novel technical developments and new aspects of RDT applications were discussed by representatives from the German STI Society (DSTIG); RKI; the Paul Ehrlich Institute; national reference centers for HIV, HBV, and HCV; and reference laboratories for Chlamydia, gonococci, and Treponema pallidum.As a result of this meeting, we present a revision of the joint statement on STI diagnostics with RDTs from 2017. The Regulation (EU) 2017/746 of the European Parliament and of the Council on in vitro diagnostic medical devices became effective in May 2017 and includes more stringent regulatory requirements for RDTs, mainly concerning conformity of manufacturing processes and performance characteristics of class D in vitro diagnostics (detection of HIV, HBV, HCV, and T. pallidum). Some RDTs for HIV, HCV, and T. pallidum have been evaluated in clinical studies and/or were WHO prequalified and may be used in low-threshold services. Among them are some HIV RDTs available and approved for self-testing. In addition, some HBV RDTs based on detection of HBs antigen (HBsAg) received WHO prequalification. However, false negative results may occur in samples with low HBsAg levels, as for instance in HIV-coinfected patients receiving antiretroviral therapy. For Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG), antigen-based RDTs still do not allow reliable detection of infection. Only PCR-based CT/NG RDTs possess sufficient diagnostic accuracy to be used as point-of-care tests. Rapid PCR tests for NG, however, do not provide any information about antimicrobial resistance.

Bakterielle sexuell übertragbare Infektionen.

Bakterielle sexuell übertragbare Infektionen (STI) zeigen seit Jahren weltweit eine deutliche Zunahme. In Deutschland wird diese Tatsache durch steigende Meldezahlen für Syphilis bestätigt. Auch für die nicht meldepflichtigen STI Gonorrhoe, Chlamydia-trachomatis- und Mycoplasma-genitalium-Infektionen wird eine zunehmende Inzidenz beobachtet. Entscheidend für die Weiterverbreitung ist, dass das breite klinische Spektrum, welches neben Urogenitalsitus auch Pharynx und Rektum einbezieht, durch eine hohe Zahl asymptomatischer Verläufe ergänzt wird. Neue Real-Time-Multiplex-Diagnostikverfahren ermöglichen einen schnellen und gezielten Nachweis von STI-Erregern. Die häufigste bakterielle STI ist die urogenitale Chlamydieninfektion mit den Serovaren D-K, die besonders bei jungen Erwachsenen auftritt. Einer Chlamydien-Proktitis kann eine Infektion mit L-Serovaren und damit eine Lymphogranuloma-venereum (LGV)-Infektion zugrunde liegen. Neisseria (N.) gonorrhoeae zeigte in den letzten Jahren eine starke Resistenzentwicklung mit Ausbildung von Einzel- und Multiresistenzen gegenüber bisher gängigen Antibiotika. Daher ist für N. gonorrhoeae zusätzlich zum nucleic acid amplification test (NAAT) eine kulturelle Empfindlichkeitstestung durchzuführen. Auch für Mycoplasma genitalium sind Resistenzentwicklungen bekannt, die eine Therapie erschweren können.

Bacterial sexually transmitted infections.

Worldwide, the incidence of bacterial sexually transmitted infections (STIs) has shown a significant increase in recent years. In Germany, this circumstance is reflected by a rise in the number of reported syphilis cases. There has also been an uptick in the incidence of non-notifiable STIs such as gonorrhea and infections caused by Chlamydia trachomatis and Mycoplasma genitalium. A key factor in the spread of these infections is their varied clinical presentation, which includes urogenital, pharyngeal and rectal involvement as well as a large number of asymptomatic cases. New real-time multiplex PCR methods allow for rapid and targeted detection of STI pathogens. The most common bacterial STI is urogenital chlamydial infection caused by serovars D-K, which affects young adults in particular. Lymphogranuloma venereum (LGV) caused by L serovars often presents as chlamydial proctitis. In recent years, Neisseria (N.) gonorrhoeae has shown a significant development of resistance, with high-level monoresistance and multiresistance to antibiotics commonly used for treatment. It is therefore imperative that sensitivity testing of N. gonorrhoeae be performed in addition to nucleic acid amplification tests (NAATs). Increased drug resistance has also been observed for Mycoplasma genitalium, a fact that complicates treatment.

CD4 cell count response to first-line combination ART in HIV-2+ patients compared with HIV-1+ patients: a multinational, multicohort European study.

Background: CD4 cell recovery following first-line combination ART (cART) is poorer in HIV-2+ than in HIV-1+ patients. Only large comparisons may allow adjustments for demographic and pretreatment plasma viral load (pVL). Methods: ART-naive HIV+ adults from two European multicohort collaborations, COHERE (HIV-1 alone) and ACHIeV2e (HIV-2 alone), were included, if they started first-line cART (without NNRTIs or fusion inhibitors) between 1997 and 2011. Patients without at least one CD4 cell count before start of cART, without a pretreatment pVL and with missing a priori-defined covariables were excluded. Evolution of CD4 cell count was studied using adjusted linear mixed models. Results: We included 185 HIV-2+ and 30321 HIV-1+ patients with median age of 46 years (IQR 36-52) and 37 years (IQR 31-44), respectively. Median observed pretreatment CD4 cell counts/mm3 were 203 (95% CI 100-290) in HIV-2+ patients and 223 (95% CI 100-353) in HIV-1+ patients. Mean observed CD4 cell count changes from start of cART to 12 months were +105 (95% CI 77-134) in HIV-2+ patients and +202 (95% CI 199-205) in HIV-1+ patients, an observed difference of 97 cells/mm3 in 1 year. In adjusted analysis, the mean CD4 cell increase was overall 25 CD4 cells/mm3/year lower (95% CI 5-44; P = 0.0127) in HIV-2+ patients compared with HIV-1+ patients. Conclusions: A poorer CD4 cell increase during first-line cART was observed in HIV-2+ patients, even after adjusting for pretreatment pVL and other potential confounders. Our results underline the need to identify more potent therapeutic regimens or strategies against HIV-2.