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Dive into the research topics where Maarten F. Schim van der Loeff is active.

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Featured researches published by Maarten F. Schim van der Loeff.


Lancet Infectious Diseases | 2008

Tuberculosis-associated immune reconstitution inflammatory syndrome: case definitions for use in resource-limited settings

Graeme Meintjes; Stephen D. Lawn; Fabio Scano; Gary Maartens; Martyn A. French; William Worodria; Julian Elliott; David M. Murdoch; Robert J. Wilkinson; Catherine Seyler; Laurence John; Maarten F. Schim van der Loeff; Peter Reiss; Lut Lynen; Edward N. Janoff; Charles F. Gilks; Robert Colebunders

The immune reconstitution inflammatory syndrome (IRIS) has emerged as an important early complication of antiretroviral therapy (ART) in resource-limited settings, especially in patients with tuberculosis. However, there are no consensus case definitions for IRIS or tuberculosis-associated IRIS. Moreover, previously proposed case definitions are not readily applicable in settings where laboratory resources are limited. As a result, existing studies on tuberculosis-associated IRIS have used a variety of non-standardised general case definitions. To rectify this problem, around 100 researchers, including microbiologists, immunologists, clinicians, epidemiologists, clinical trialists, and public-health specialists from 16 countries met in Kampala, Uganda, in November, 2006. At this meeting, consensus case definitions for paradoxical tuberculosis-associated IRIS, ART-associated tuberculosis, and unmasking tuberculosis-associated IRIS were derived, which can be used in high-income and resource-limited settings. It is envisaged that these definitions could be used by clinicians and researchers in a variety of settings to promote standardisation and comparability of data.


Lancet Infectious Diseases | 2010

Virological follow-up of adult patients in antiretroviral treatment programmes in sub-Saharan Africa: a systematic review

Roos E. Barth; Maarten F. Schim van der Loeff; Rob Schuurman; Andy I. M. Hoepelman; Annemarie M. J. Wensing

Following large-scale roll-out of antiretroviral therapy in sub-Saharan Africa, the non-clinical efficacy of antiretroviral therapy has received little attention. We aimed to systematically review virological efficacy and drug-resistance outcomes of programmes of antiretroviral therapy in sub-Saharan Africa. 89 studies with heterogeneous design, definitions, and methods were identified. Overall, in on-treatment analysis, 10 351 (78%) of 13 288 patients showed virological suppression after 6 months of antiretroviral therapy, 7413 (76%) of 9794 after 12 months, and 3840 (67%) of 5690 after 24 months. Long-term virological data are scarce. Genotyping results were available for patients with virological failure (HIV-1 RNA greater than 1000 copies per mL). Most patients (839 of 849; 99%) were infected with a non-B HIV-1 subtype. However, drug-resistance patterns were largely similar to those in subtype B. Resistance profiles were associated with the antiretroviral drugs commonly used: the lamivudine-associated M184V mutation was most common, followed by K103N which is associated with non-nucleoside reverse transcriptase inhibitors. Thymidine-analogue mutations and the K65R mutation were less common. First-line antiretroviral therapy regimens used in sub-Saharan Africa are effective. Profiles of drug resistance suggest that a second-line treatment regimen based on protease inhibitors, with a backbone of nucleoside reverse transcriptase inhibitors, is a reasonable option for patients with HIV in sub-Saharan Africa who experience first-line treatment failure.


Hepatology | 2014

The effects of female sex, viral genotype, and IL28B genotype on spontaneous clearance of acute hepatitis C virus infection.

Jason Grebely; Kimberly Page; Rachel Sacks-Davis; Maarten F. Schim van der Loeff; Thomas M. Rice; Julie Bruneau; Meghan D. Morris; Behzad Hajarizadeh; Janaki Amin; Andrea L. Cox; Arthur Y. Kim; Barbara H. McGovern; Janke Schinkel; Jacob George; Naglaa H. Shoukry; Georg M. Lauer; Lisa Maher; Andrew Lloyd; Margaret Hellard; Gregory J. Dore; Maria Prins

Although 20%‐40% of persons with acute hepatitis C virus (HCV) infection demonstrate spontaneous clearance, the time course and factors associated with clearance remain poorly understood. We investigated the time to spontaneous clearance and predictors among participants with acute HCV using Cox proportional hazards analyses. Data for this analysis were drawn from an international collaboration of nine prospective cohorts evaluating outcomes after acute HCV infection. Among 632 participants with acute HCV, 35% were female, 82% were Caucasian, 49% had interleukin‐28 (IL28)B CC genotype (rs12979860), 96% had injected drugs ever, 47% were infected with HCV genotype 1, and 7% had human immunodeficiency virus (HIV) coinfection. Twenty‐eight percent were HCV antibody negative/RNA positive at the time of acute HCV detection (early acute HCV). During follow‐up, spontaneous clearance occurred in 173 of 632, and at 1 year after infection, 25% (95% confidence interval [CI]: 21, 29) had cleared virus. Among those with clearance, the median time to clearance was 16.5 weeks (IQR: 10.5, 33.4), with 34%, 67%, and 83% demonstrating clearance at 3, 6, and 12 months. Adjusting for age, factors independently associated with time to spontaneous clearance included female sex (adjusted hazards ratio [AHR]: 2.16; 95% CI: 1.48, 3.18), IL28B CC genotype (versus CT/TT; AHR, 2.26; 95% CI: 1.52, 3.34), and HCV genotype 1 (versus non‐genotype 1; AHR: 1.56; 95% CI: 1.06, 2.30). The effect of IL28B genotype and HCV genotype on spontaneous clearance was greater among females, compared to males. Conclusions: Female sex, favorable IL28B genotype, and HCV genotype 1 are independent predictors of spontaneous clearance. Further research is required to elucidate the observed sex‐based differences in HCV control. (Hepatology 2014;58:109–120)


Journal of Acquired Immune Deficiency Syndromes | 2004

Body Mass Index at Time of Hiv Diagnosis: A Strong and Independent Predictor of Survival

Marianne A. B. van der Sande; Maarten F. Schim van der Loeff; Akum A. Aveika; Saihou Sabally; Toyin Togun; Ramu Sarge-Njie; Abraham Alabi; Assan Jaye; Tumani Corrah; Hilton Whittle

BackgroundIdentification of basic prognostic indicators of HIV infection is essential before widespread antiretroviral therapy can be implemented in low-technology settings. This study assessed how well body mass index (BMI:kg/m2) predicts survival. MethodsBMI within 3 months of HIV diagnosis was obtained from 1657 patients aged ≥15 years, recruited in a seroprevalent clinical cohort in The Gambia since 1992 and followed up at least once. Baseline CD4+ counts and clinical assessment at time of diagnosis were done. ResultsThe mortality hazard ratio (HR) of those with a baseline BMI <18 compared with those with a baseline BMI ≥18 was 3.4 (95% CI, 3.0–3.9). The median survival time of those presenting with a BMI <16 was 0.8 years, in contrast to a median survival of 8.9 years for those with a baseline BMI ≥22. Baseline BMI <18 remained a highly significant independent predictor of mortality after adjustment for age, sex, co-trimoxazole prophylaxis, tuberculosis, reported wasting at diagnosis, and baseline CD4+ cell count (adjusted HR = 2.5, 95% CI 2.0–3.0). Sensitivity and specificity of baseline BMI <18 was comparable to that of a CD4+ count <200 in predicting mortality within 6 months of diagnosis. DiscussionBMI at diagnosis is a strong, independent predictor of survival in HIV-infected patients in West Africa. In the absence of sophisticated clinical and laboratory support, BMI may also prove a useful guide for deciding when to initiate antiretroviral therapy.


AIDS | 2002

Mortality of HIV-1, HIV-2 and HIV-1/HIV-2 dually infected patients in a clinic-based cohort in The Gambia.

Maarten F. Schim van der Loeff; Shabbar Jaffar; Akum A. Aveika; Saihou Sabally; Tumani Corrah; Elizabeth Harding; Abraham Alabi; Alhajie Bayang; Koya Ariyoshi; Hilton Whittle

ObjectiveTo assess and compare the mortality rates of patients with HIV-1, HIV-2 or both infections (HIV-D) in the same population. DesignClinic-based cohort study. MethodsHIV-seropositive patients aged 15 years and older who attended the Medical Research Council clinics in Fajara between May 1986 and September 1997 were recruited. Clinical assessment using the Karnofsky score, CDC cell staging, WHO staging, and CD4 cell counts was performed at baseline. Patients attended clinic every 3 months; if they did not attend, they were visited at home by field workers to ascertain survival status. No patient was on antiretroviral therapy during the study period. ResultsData from 1519 HIV-positive adult patients were analysed. A total of 746 patients had HIV-1, 666 HIV-2, and 107 patients had HIV-D. A total of 828 patients (55%) died, and 161 (11%) were lost to follow-up. The median follow-up was 12 months (range 0–128). CD4 cell counts were available for 894 patients. Compared with HIV-1, the adjusted hazards ratio for mortality in the CD4 cell count category 500 cells/μl or greater was 0.50 for HIV-2 (95% CI 0.28–0.88) and 1.27 (95% CI 0.51–3.7) for HIV-D. Among those with CD4 cell counts less than 500 cells/μl the mortality rates in HIV-2 and HIV-D were similar to those in HIV-1. DiscussionHIV-2-infected patients with CD4 cell counts of 500 cells/μl and greater had a significantly lower mortality rate than HIV-1-infected patients. HIV-2-infected patients with advanced disease had the same poor prognosis as patients with HIV-1. Dually infected patients had mortality rates similar to HIV-1.


Transactions of The Royal Society of Tropical Medicine and Hygiene | 2003

The effect of mass administration of sulfadoxine-pyrimethamine combined with artesunate on malaria incidence: a double-blind, community-randomized, placebo-controlled trial in The Gambia

Lorenz von Seidlein; Gijs Walraven; Paul Milligan; Neal Alexander; Fandingding Manneh; Jacqueline L. Deen; Roz Coleman; Musa Jawara; Steve W. Lindsay; Chris Drakeley; Sarah De Martin; Piero Olliaro; Steve Bennett; Maarten F. Schim van der Loeff; Kunle Okunoye; Geoff Targett; Keith P. W. J. McAdam; Justin F. Doherty; Brian Greenwood; Margaret Pinder

A double-blind, community-randomized, placebo-controlled trial was conducted in a rural area of The Gambia between June and December 1999 to test whether a reduction in the infectious reservoir can reduce malaria transmission. Overall 14,017 (85%) individuals living in the study area were treated with either placebo or sulfadoxine-pyrimethamine (SP) combined with a single dose of artesunate (AS). Following the mass drug administration (MDA) 1375 children aged 6 months to 10 years were kept under surveillance for clinical malaria in 18 villages throughout the 1999 malaria transmission season. During a 20-week surveillance period 637 episodes of malaria were detected. The mean incidence rate was 2.5/100 child-weeks in the placebo villages, and 2.3/100 child-weeks in villages that received SP + AS. The mean rate ratio, adjusted for individual and village-level covariates, was 0.91 (95% CI 0.68-1.22, P = 0.49). During the first 2 months of surveillance, the malaria incidence was lower in treated villages. After 2 months the incidence was slightly higher in the MDA group but this was not statistically significant. Overall, no benefit of the MDA could be detected. The reason for the absence of an impact on malaria transmission is probably the very high basic reproductive number of malaria, and the persistence of mature gametocytes, which are not affected by AS treatment.


AIDS Research and Human Retroviruses | 2002

Low level viremia and high CD4% predict normal survival in a cohort of HIV type-2-infected villagers

Neil G. Berry; Shabbar Jaffar; Maarten F. Schim van der Loeff; Koya Ariyoshi; Elizabeth Harding; Pa Tamba Ngom; Francisco Dias; Andrew Wilkins; Dominic Ricard; Peter Aaby; Richard S. Tedder; Hilton Whittle

A community-based study of human immunodeficiency virus type 2 (HIV-2) infection was conducted in a rural village in northern Guinea Bissau, West Africa to assess the relationship between plasma HIV-2 RNA levels, CD4 lymphocyte percentage, and survival over an 8-year period. The cohort of 133 HIV-2-infected individuals and 160 HIV-uninfected controls enrolled in 1991 were followed up at home until 1998. Thirty-one (23%) HIV-2-infected and 24 (16%) HIV-uninfected individuals died over the follow-up period (mortality hazard ratio 1.7, 95% CI 1.0, 2.9; p= 0.06). In HIV-2-infected individuals, the median HIV-2 RNA level was 347 copies/ml and the mean CD4% was 28.6. Both plasma viremia and CD4% were independent predictors of survival, with hazard ratios increasing by 1.6 (95% CI, 1.1, 2.3) for each log(10) increase of plasma viremia and 1.7 (1.1, 2.6) for each 10% decrease of CD4%. Infected subjects with a plasma viral load >or= the median (347 copies/ml) and a CD4% <or= the mean (28.6%) had a mortality hazard ratio of 3.1 (95% CI 1.7, 5.8) compared to uninfected controls, whereas the remaining infected subjects had a mortality rate similar to uninfected controls, the mortality hazard ratio being 1.0 (95% CI, 0.5, 2.1.) In those who survived between 1991 and 1996, HIV-2 RNA levels were unchanged overall and CD4 lymphocyte counts remained high. In conclusion, baseline HIV-2 RNA levels predicted a normal survival for the majority, with low and stable levels of plasma viremia characterizing HIV-2 infections in this rural West African community.


Sexually Transmitted Infections | 2013

Anorectal and inguinal lymphogranuloma venereum among men who have sex with men in Amsterdam, the Netherlands: trends over time, symptomatology and concurrent infections

Nynke Hesselina Neeltje de Vrieze; Martijn S. van Rooijen; Maarten F. Schim van der Loeff; Henry J. C. de Vries

Objectives To examine lymphogranuloma venereum (LGV) trends over time among men who have sex with men (MSM) visiting the Amsterdam sexually transmitted infection (STI) clinic; to investigate anal LGV symptomatology; and to examine the positivity and characteristics of anorectal and inguinal LGV. Methods We included MSM consultations from whom a swab (from anorectum, bubo or an genital ulcer) was taken for Chlamydia trachomatis (Ct) screening. Anorectal swabs were taken from all MSM who reported receptive anorectal intercourse in the preceding 6 months. Ct positive samples were further tested with a pmpH PCR to identify L-genovars. Patient symptoms, clinical and anoscopic inflammatory signs, and STI co-infections were noted; Gram-stained anorectal mucosal smears were examined. Results Between January 2005 and June 2012, 48 570 consultations among MSM were conducted. In 3628/35 650 visits, anorectal Ct infections were diagnosed, including 411 anal LGV (1.2%). Moreover, 65/1649 genital ulcer swabs were Ct positive; 10 were inguinal LGV (0.6%) Since January 2011 a significant increase in the positivity of LGV occurred (p<0.0001). 89 (27.2%) anorectal LGV cases were asymptomatic. HIV prevalence among anorectal LGV cases was significantly higher (p=0.008) than among inguinal LGV cases. STI co-morbidity in anorectal LGV cases remained invariably high during the study period. Conclusions Since January 2011, LGV positivity in MSM consultations in Amsterdam has risen significantly. The great majority comprise anal LGV; inguinal LGV is rare. Anal LGV is asymptomatic in a quarter of cases. In all MSM with anal Ct infections LGV should be excluded, irrespective of symptoms or inflammatory signs.


Journal of Acquired Immune Deficiency Syndromes | 2007

Elevated iron status strongly predicts mortality in West African adults with HIV infection

Joann M. McDermid; Assan Jaye; Maarten F. Schim van der Loeff; Jim Todd; C. J. Bates; Steve Austin; David Jeffries; Akum Aveika Awasana; Hilton Whittle; Andrew M. Prentice

Objective:To comprehensively assess iron status and determine whether elevated iron status, like anemia, predicts mortality. Methods:We followed 1362 Gambian adults (53% female) in an HIV-seroprevalent clinic-based cohort over 11.5 years to ascertain all-cause mortality. Baseline iron status (iron, soluble transferrin receptor [sTfR], transferrin, ferritin, transferrin saturation, log [transferrin receptor: ferritin]), age, gender, ethnicity, hemoglobin, body mass index, HIV type, absolute CD4 count, malaria status, and α-1-antichymotrypsin were measured. Results:The mortality rate was 25.9/100 person-years. Elevated iron universally predicted greater mortality compared to normal iron status for all iron status indices, with the exception of sTfR in unadjusted models. In fully adjusted models, transferrin (elevated vs. normal, hazard ratio [HR]: 1.77; 95% confidence interval [CI]: 1.30 to 2.42; P < 0.001), ferritin (elevated vs. normal, HR: 1.40; 95% CI: 1.07 to 1.83; P = 0.014), and the combined iron status index (highly elevated vs. normal, HR: 2.20; 95% CI: 1.16 to 4.18; P = 0.016) remained significant predictors. As expected, hemoglobin (Hb) concentration and absolute CD4 counts were each inversely associated with mortality. Conclusions:Elevated iron status predicts mortality in HIV infection, even after adjustment for immunosuppression and other confounders. This finding has implications in the clinical monitoring of disease progression and for iron-supplementation practices in areas of high HIV prevalence.


American Journal of Respiratory and Critical Care Medicine | 2014

Risk of Tuberculosis after Recent Exposure. A 10-Year Follow-up Study of Contacts in Amsterdam

Rosa Sloot; Maarten F. Schim van der Loeff; Peter M. Kouw; Martien W. Borgdorff

RATIONALE The lifetime risk of tuberculosis (TB) for infected contacts is often mentioned to be 5-10%, but these estimates are based on studies conducted decades ago, and thus may not reflect current epidemiologic conditions. OBJECTIVES To estimate the risk of TB among contacts with evidence of infection and to compare this with estimates often stated in the literature. METHODS A retrospective cohort study was performed using records on contacts of pulmonary TB patients at the Public Health Service Amsterdam, 2002-2011. The Public Health Service Amsterdam TB electronic registration system identified TB cases during follow-up until October 2012; these were defined as coprevalent if diagnosed less than or equal to 180 days and incident if diagnosed greater than 180 days after TB diagnosis of index patient. Cumulative TB risk was estimated with Kaplan-Meier curves. MEASUREMENTS AND MAIN RESULTS Of 9,332 contacts of pulmonary TB patients, 4,774 were screened for latent TB infection (LTBI) of whom 739 (16%) had evidence of infection. Among these the 5-year Kaplan-Meier TB cumulative risk was 9.5% (95% confidence interval, 7.5-11.9). This varied by age: 33.3% of 36 contacts aged less than 5 years, 19.1% of 84 contacts aged 5-14 years, and 6.7% of 619 contacts aged greater than or equal to 15 years (log rank, P < 0.001). Of 739 contacts with evidence of infection, 57 had coprevalent TB and 14 developed incident TB. Of patients without coprevalent TB but with LTBI diagnosis, 45% received preventive therapy. Five-year risk of incident TB was 2.4% (95% confidence interval, 1.2-4.7) among contacts with LTBI who did not start preventive therapy. CONCLUSIONS Five-year risk of TB among contacts with evidence of infection was higher compared with older estimates, and differed considerably by age. Incidence of TB among contacts with LTBI was low, suggesting limited impact may be expected of expanding preventive therapy.

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Maria Prins

University of Amsterdam

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Assan Jaye

Medical Research Council

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Peter Aaby

Statens Serum Institut

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Carla van Tienen

Erasmus University Rotterdam

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