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Ivy Altomare,1 Karynsa Cetin,2 Sally Wetten,3 Jeffrey S Wasser4 1Department of Medicine, Duke University School of Medicine, Durham, NC, 2Center for Observational Research, Amgen Inc., Cambridge, MA, USA; 3Centre for Observational Research, Amgen Ltd., Uxbridge, UK; 4Carole and Ray Neag Comprehensive Cancer Center, University of Connecticut School of Medicine, Farmington, CT, USA Background: Immune thrombocytopenia (ITP) is a rare disorder characterized by low platelet counts and an increased tendency to bleed. The goal of ITP therapy is to treat or prevent bleeding. Actual rates of bleeding are unknown. Clinical trial data may not reflect real-world bleeding rates because of the inclusion of highly refractory patients and more frequent use of rescue therapy. Methods: We used administrative medical claims data in the US to examine the occurrence of bleeding-related episodes (BREs) – a composite end point including bleeding and/or rescue therapy use – in adults diagnosed with primary ITP (2008–2012). BRE rates were calculated overall and by ITP phase and splenectomy status. Patients were followed from ITP diagnosis until death, disenrollment from the health plan, or June 30, 2013, whichever came first. Results: We identified 6,651 adults diagnosed with primary ITP over the study period (median age: 53 years; 59% female). During 13,064 patient-years of follow-up, 3,768 patients (57%) experienced ≥1 BRE (1.08 BREs per patient-year; 95% confidence interval: 1.06–1.10). The majority (58%) of BREs consisted of rescue therapy use only. Common bleeding types were gastrointestinal hemorrhage, hematuria, ecchymosis, and epistaxis. Intracranial hemorrhage was reported in 74 patients (1%). Just over 7% of patients underwent splenectomy. Newly diagnosed and splenectomized patients had elevated BRE rates. Conclusion: We provide current real-world estimates of BRE rates in adults with primary ITP. The majority of ITP patients experienced ≥1 BRE, and over half were defined by rescue therapy use alone. This demonstrates the importance of examining both bleeding and rescue therapy use to fully assess disease burden. Keywords: immune thrombocytopenia, bleeding, cohort study, epidemiology

The article answers a question on whether encouraging influenza vaccination for nursing home staff reduces mortality and influenza-like illness in hospital residents. A cost effectiveness analysis of the policy to vaccinate healthcare workers against influenza found that in the base case, vaccination was cost saving. Several measures seem to improve uptake, such as educational campaigns, special vaccination clinics and gift incentives.

Clinical trials have demonstrated the efficacy and safety of carfilzomib in patients with relapsed/refractory multiple myeloma (RRMM); however, prospective real-world data are limited. This real-world, prospective, observational study evaluated carfilzomib use, effectiveness and safety in adults with RRMM. Data are presented for a subset of patients ( n  = 383) who received carfilzomib in combination with lenalidomide and dexamethasone (KRd). The overall response rate (ORR) was 83.6% among 360 evaluable patients. Treatment responses were better when KRd was administered at earlier therapy lines than at later lines of therapy (ORR: second line, 85.3%; third line or later, 81.0%). In patients with the anti-CD38 antibody-refractory disease, ORR was higher when KRd was administered earlier than at later therapy lines (second line/third line, 75.0%; fourth line or later, 60.0%). An ORR of 68.1% and 82.0% was achieved in the lenalidomide-refractory and not lenalidomide-refractory subgroups, respectively. KRd was consistently administered per the European label (twice weekly dose of 27 mg/m 2 ) and the median time to discontinuation was 14.6 months. The safety profile of KRd was consistent with previous studies. These real-world data highlight the effectiveness of KRd as a treatment for patients with RRMM, including those with disease refractory to lenalidomide or anti-CD38 antibodies., Competing Interests: Xavier Leleu received honoraria from Amgen, BMS, CARsgen Therapeutics, Celgene, Gilead, Janssen, Karyopharm Therapeutics, Merck, Oncopeptides, Roche and Takeda. Eirini Katodritou received honoraria and research funding from Amgen and Janssen‐Cilag; held membership on boards of directors or advisory committees for Amgen and Janssen‐Cilag; received expenses and research funding from Genesis Pharma and Takeda; and received research funding from AbbVie and Karyopharm Therapeutics. Thomas Kuehr received consultancy fees and honoraria from Incyte and Janssen; received honoraria and fees to cover travel, accommodation and expenses from Bayer and Lilly; and received honoraria from AbbVie, Amgen, Celgene, Merck, Novartis, Roche and Takeda. Evangelos Terpos received grants, personal fees and non‐financial support from Amgen regarding this work; received grants, personal fees and non‐financial support from Amgen, Celgene/Genesis Pharma, Janssen and Takeda; and received personal fees from AbbVie, BMS, GSK and Novartis, outside the submitted work. Jo Caers received honoraria from Amgen, Celgene, Janssen and Takeda; held membership on boards of directors or advisory committees for Amgen, Celgene, Janssen and Takeda. Renato Zambello held membership on boards of directors or advisory committees for Celgene and Janssen. Alessandra Brescianini is an employee of Amgen and an equity holder. Tony Liang is an employee of Parexel and received funding from Amgen. Sally Wetten was an employee of Amgen and an equity holder at the time of this work. Sorina N. Badelita received consultancy fees, fees to cover travel, accommodation and expenses from Amgen, Janssen and Takeda; and consultancy fees and honoraria from Novartis., (© 2022 The Authors. eJHaem published by British Society for Haematology and John Wiley & Sons Ltd.)

This prospective, observational study examined the real-world use of carfilzomib across 11 European countries in adults with relapsed/refractory multiple myeloma (RRMM) who received at least one prior line of therapy. Carfilzomib and dexamethasone (Kd) use, effectiveness and safety were analyzed. In total, 271 patients received Kd among 701 adults enrolled. The median relative dose intensity of carfilzomib was 82.7% (20/56 mg/m 2 , twice weekly). The overall response rate (ORR) to Kd was 68.8% (95% confidence interval [CI], 62.7-74.5): 79.2% in second line (2L), 71.6% in third line (3L) and 63.1% in fourth line or later (4L+). The ORR was 59.9% (95% CI, 51.1-68.1) in the lenalidomide-refractory subgroup and 67.7% (95% CI, 48.6-83.3) in the not lenalidomide-refractory subgroup. In the anti-CD38 refractory subgroup, the ORR was 51.6% (95% CI, 38.6-64.5); ORRs were higher when Kd was received at 2L/3L (66.7%) than at 4L+ (49.1%). Overall, patients were treated for a median time of 7.7 months. One-fifth of patients reported treatment-related treatment-emergent adverse events (≥grade 3), with a safety profile consistent with previous clinical trials. This study demonstrated the real-world use, effectiveness and safety of Kd in patients with RRMM. Despite the increasing number of new therapeutic strategies to treat RRMM, Kd remains a safe and effective option, even for older, frail and lenalidomide- or anti-CD38 mAb-refractory patients.

The COVID-19-pandemic forced many countries to close schools abruptly in the spring of 2020. These school closures and the subsequent period of distance learning has led to concerns about increasing inequality in education, as children from lower-educated and poorer families have less access to (additional) resources at home. This study analyzes differences in declines in learning gains in primary education in the Netherlands for reading, spelling and math, using rich data on standardized test scores and register data on student and parental background for almost 300,000 unique students. The results show large inequalities in the learning loss based on parental education and parental income, on top of already existing inequalities. The results call for a national focus on interventions specifically targeting vulnerable students., Competing Interests: The authors have declared that no competing interests exist.

Minimal (or 'measurable') residual disease in acute lymphoblastic leukemia appears to be a prognostic indicator, with potential value in informing individualized treatment decisions. Complete understanding of the strength of the association between minimal residual disease and long-term outcomes is, however, lacking. A systematic literature review and meta-analysis were performed to elucidate the clinical significance of minimal residual disease with respect to relapse-free survival and overall survival in precursor B-cell acute lymphoblastic leukemia. A total of 23 articles and abstracts, most published between 2012 and 2016, were identified for inclusion in the primary meta-analysis. Typically, patients were in their first complete remission at the time of minimal residual disease assessment; in two studies, all patients were in their second, or later, complete remission. The primary analysis revealed improved relapse-free survival across all studies for patients who achieved minimal residual disease negativity (random effects hazard ratio, 2.34; 95% confidence interval, 1.91-2.86). Improved overall survival for patients who achieved minimal residual disease negativity was also observed (hazard ratio, 2.19; 95% confidence interval, 1.63-2.94). There was no observed difference in the impact of minimal residual disease status in subgroups based on disease stage, minimal residual disease sensitivity threshold level, Philadelphia chromosome status, histological phenotype, risk group, minimal residual disease testing location, minimal residual disease timing after induction, or minimal residual disease detection method. Despite heterogeneity in study design and patient populations between the contributing studies, these data provide a compelling argument for minimal residual disease as a clinical tool for assessing prognosis and guiding treatment decisions in precursor B-cell acute lymphoblastic leukemia., (Copyright© 2019 Ferrata Storti Foundation.)

Hematopoietic stem cell transplantation (HSCT) is considered an effective way to prevent relapse in adults with acute lymphoblastic leukemia (ALL). This study aimed to assess general trends in the use of various types of HSCTs performed between 2001 and 2015 in Europe, based on data reported to the European Society for Blood and Marrow Transplantation registry. We also evaluated HSCT rates with respect to ALL incidence in selected countries. Altogether, 15,346 first allogeneic (n = 13,460) or autologous (n = 1886) HSCTs were performed in the study period. Comparing 2013-2015 and 2001-2003, the number of allogeneic HSCTs performed in first complete remission increased by 136%, most prominently for transplantations from unrelated (272%) and mismatched related donors (339%). The number of HSCTs from matched sibling donors increased by 42%, while the total number of autologous HSCTs decreased by 70%. Increased use of allogeneic HSCT was stronger for Philadelphia chromosome (Ph)-positive (166%) than for Ph-negative ALL (38%) and for patients aged > 55 years (599%) than for younger adults (59%). The proportion of allogeneic HSCT with reduced-intensity conditioning (RIC) increased from 6 to 27%. The age-standardized rates of allogeneic HSCT per ALL incidence varied strongly among countries. Our analysis showed a continued trend toward increased allogeneic HSCT use for adults with ALL, which may be attributed to increasing availability of unrelated donors, wider use of RIC regimens, and improving efficacy of pretransplant therapy, including tyrosine kinase inhibitors for Ph-positive ALL. Allogeneic HSCT remains a major tool in the fight against ALL in adults.

Background: Romiplostim is a thrombopoietin-mimetic peptibody for adult refractory chronic immune thrombocytopenia (ITP). We aimed to describe ITP patients receiving romiplostim, platelet counts and romiplostim usage in UK clinical practice., Methods: This was a retrospective cohort study of patients in the UKITP Registry who received romiplostim between October 2009 and January 2015, including data up to 6 months before romiplostim initiation through follow-up., Results: Of 1440 patients in the UKITP Registry, 118 adults with primary ITP were eligible. Before romiplostim, 22% had splenectomy, 12% received platelet transfusion, 97% received ≥ 1 different ITP medication and 77% received ≥ 3. Most patients (73%) initiated romiplostim ≥ 1 year after ITP diagnosis (chronic phase). The mean duration of romiplostim treatment was 5.7 (SE 0.9) months, and the median was 1.4 months (IQR: 0.2, 6.5). Mean platelet count before romiplostim was 38 × 10 9 /L, rising to 103 × 10 9 /L within 1 month, and remaining 50-150 × 10 9 /L through up to 3 years of follow-up. After romiplostim, 4% of patients had splenectomy, 6% received platelet transfusion, and 57% received just one ITP medication other than romiplostim., Conclusion: The study provides valuable insights into the real-world use of romiplostim in primary ITP in routine practice and highlighted the timing of romiplostim initiation at different ITP disease phases., (© 2019 The Authors. European Journal of Haematology Published by John Wiley & Sons Ltd.)

Purpose: Prophylaxis for febrile neutropenia (FN) is recommended for the duration of myelosuppressive chemotherapy in high-risk patients; yet, granulocyte-colony-stimulating factor (G-CSF) discontinuation occurs frequently in clinical practice. The objective of this study was to investigate the incidence of FN in real-world settings and the extent and impact of early pegfilgrastim discontinuation., Methods: This prospective, observational study enrolled patients with any-stage non-Hodgkin's lymphoma (NHL) or breast cancer initiating a new chemotherapy course with a high (> 20%) FN risk, with pegfilgrastim in cycle 1. During routine clinical visits, data were collected on FN events, discontinuation of pegfilgrastim (defined as administration of G-CSF other than pegfilgrastim for ≥ 1 cycle) and all G-CSF (and reasons), neutropenic complications and adverse drug reactions (ADRs)., Results: Overall, 943 patients were enrolled; 844 met the eligibility criteria (full analysis set) and 814 (86%) completed the study. Twenty-eight patients (3%) had 31 FN events (NHL, n = 17; breast cancer, n = 11). Twenty-six patients (3%) discontinued pegfilgrastim. Forty-four patients (5%) discontinued G-CSF. The most common reason for pegfilgrastim discontinuation was physician preference for daily G-CSF (n = 14 [2%]), and for discontinuation of all G-CSFs was reduced FN risk (n = 14 [2%]). Patients who continued G-CSF prophylaxis were less likely to experience neutropenic complications (odds ratio [95% confidence interval]: 0.26 [0.09-0.80]). Suspected ADRs to pegfilgrastim occurred in 43 patients (5%) and serious ADRs in 5 (1%)., Conclusions: FN rates were consistent with previous reports with pegfilgrastim in clinical practice. No new ADRs were observed. G-CSF discontinuation was uncommon but appeared to increase the likelihood of neutropenic complications.

Introduction: Romiplostim is a subcutaneously administered thrombopoietin-receptor agonist approved in the European Union for self-administration (or administration by a caregiver) in selected adult patients with chronic primary immune thrombocytopenia refractory to other treatments. To mitigate the risk of medication errors due to self-administration, the manufacturer has implemented additional risk minimisation measures (RMM) in the form of a Home Administration Training (HAT) pack to support the training of both healthcare professionals (HCPs) (guide and checklist for patient selection and training) and patients (a preparation mat, quick guide booklet, step-by-step guide, self-administration diary and DVD/video)., Objective: The primary objective was to estimate the proportion of patients/caregivers who administered romiplostim correctly after HAT pack training., Methods: A multicentre observational study was conducted to evaluate the effectiveness of the HAT pack by recording data on a standardised collection form during direct observation of patients/caregivers in the act of administering romiplostim at the first standard-of-care visit 4 weeks after training with the HAT pack., Results: Among the 40 patients/caregivers enrolled across 12 study centres in eight European countries, 35 [87.5%; 95% confidence interval (CI) 73.9-94.5] administered romiplostim correctly, and five (12.5%; 95% CI 5.5-26.1) did not., Conclusion: The correct administration of romiplostim by most patients/caregivers supports the effectiveness of the HAT pack as an additional risk minimisation tool in the population and setting of this study.

Treatment of non-Hodgkin lymphoma (NHL) requires chemotherapy regimens with significant risk of febrile neutropenia (FN). For patients at ≥20% FN risk, guidelines recommend primary prophylaxis (PP) with granulocyte-colony stimulating factor (G-CSF). This study assessed whether G-CSF use in NHL was in line with recommendations in routine practice. This was a retrospective, observational study of adult NHL patients receiving first-line (R)CHOP-like chemotherapy and G-CSF support between June 2010 and 2012, in Italy. The primary outcome was whether G-CSF was provided as PP, which was defined as G-CSF initiation on days 1-3 after chemotherapy, ≥3 days' use for daily G-CSFs and continued prophylaxis from cycle 1 across all cycles. Secondary prophylaxis was defined as continued prophylaxis from cycle 2 or later, and all other use was defined as Suboptimal. The analysis included 199 patients, 61% of whom had diffuse large B cell lymphoma and 21% follicular lymphoma. (R)CHOP-21 was given to 52% of patients and (R)CHOP-14 to 32%. Overall, 29% of patients received PP, while two-thirds received Suboptimal G-CSF. Of patients receiving daily G-CSF, 3% received PP and 94% received Suboptimal use; with pegfilgrastim, 65% received PP and 26% Suboptimal use. FN occurred in 13 patients (7%) and grade 3/4 neutropenia in 43%. Chemotherapy dose delays occurred in 22% and dose reductions in 18% of patients. Delivery of G-CSF, particularly daily G-CSFs, was not in accordance with guideline or product label recommendations in a large proportion of NHL patients receiving chemotherapy in Italy.

Background: Diagnoses of genital warts (GW) in genitourinary medicine (GUM) clinics have been increasing in England for many years. In 2008, an HPV immunization program began with a bivalent vaccine (Cervarix). This was expected to markedly reduce infections and disease due to human papillomavirus (HPV) 16/18 but not HPV 6/11 infections or disease. However, from 2009 to 2011 there were decreases in reported diagnoses of GW in young females at GUM clinics., Methods: Using data from GUM clinics and a sample of general practices (GPs) throughout England, we analyzed rates of GW diagnoses by age, year of diagnosis, and estimated immunization coverage., Results: The overall reduction in GW diagnoses at GUM clinics between 2008 and 2011 was 13.3% among 16- to 19-year-old females, with the greatest decline of 20.8% in 17-year-olds. Declines were positively associated with estimated immunization coverage. A similar pattern was seen in GP diagnoses, but not among older women, and for other GUM consultations., Conclusions: Several factors might contribute to declines in GW. However, the size and pattern of the declines strongly suggest that we are observing an unexpected, moderately protective effect of HPV 16/18 vaccination against GW.

Aims: To investigate the effects of two single nucleotide polymorphisms (SNPs) in the human P2X₇ receptor gene (P2RX7)--1068G>A (A348T) and 1513A>C (E496A)--on P2X₇ receptor function, using a specific receptor antagonist (GSK1370319A) and prospective genetic stratification., Methods: Lipopolysaccharide- and ATP-stimulated interleukin-1β production was determined in the presence or absence of GSK1370319A in blood culture from 32 prospectively genotyped subjects., Results: There was approximately 6.7-fold difference (P < 0.0001) in IC₅₀ for inhibition of ATP-stimulated interleukin-1β release by GSK1370319A between individuals with the homozygous gain--(1068A) and loss-of-function (1513C) genotypes (expressing the 348T, 496E and 348A, 496A alleles, respectively)., Conclusions: Leukocyte P2X₇ receptors had significantly altered pharmacodynamic responses to a specific antagonist (GSK1370319A), directly related to SNP genotype., (© 2012 GlaxoSmithKline. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.)

Replications of the association between APOE-ε4 allele load and regional brain atrophy in Alzheimer's disease (AD) patients hold promise for future studies testing relationships between other disease risk gene variants and brain structure. A polymorphism, rs10868366, in the Golgi phosphoprotein 2 gene, GOLM1, was recently identified as an AD risk factor in a genome-wide association study. In a subset of the same AD cohort, we used voxel-based morphometry to test for association between the disease risk genotype and reduced regional gray matter (GM) volume in AD patients (n = 72). A mean 14% reduction in GM volume was observed in the left frontal gyrus with the higher risk GG genotype. A similar association was observed in an independent, dataset of nondemented subjects (n = 278), although with a smaller effect (1%). This replicated association with GM structural variation suggests that GOLM1 polymorphisms may be related to cognitive phenotypes. The greater effect size in AD patients also suggests that the GG genotype could be a risk factor for the expression of cognitive deficits in AD., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Heterogeneity is observed in the patterns of cognition in Alzheimer's disease (AD). Such heterogeneity might suggest the involvement of different etiological pathways or different host responses to pathology. A total of 627 subjects with mild/moderate AD underwent cognitive assessment with the Mini-Mental State Examination (MMSE) and the Dementia Rating Scale-2 (DRS-2). Latent class analysis (LCA) was performed on cognition subscale data to identify and characterize cognitive subgroups. Clinical, demographic, and genetic factors were explored for association with class membership. LCA suggested the existence of four subgroups; one group with mild and another with severe global impairment across the cognitive domains, one group with primary impairments in attention and construction, and another group with primary deficits in memory and orientation. Education, disease duration, age, Apolipoprotein E-epsilon4 (APOE epsilon4) status, gender, presence of grasp reflex, white matter changes, and early or prominent visuospatial impairment were all associated with class membership. Our results support the existence of heterogeneity in patterns of cognitive impairment in AD. Our observation of classes characterized by predominant deficits in attention/construction and memory respectively deserves further exploration as does the association between membership in the attention/construction class and APOE epsilon4 negative status.

APOE epsilon4 is the best-established genetic risk factor for sporadic Alzheimer's disease (AD). However, while homozygotes show greater disease susceptibility and earlier age of onset than heterozygotes, they may not show faster rates of clinical progression. We hypothesize that there are differential APOE epsilon4 allele-load dependent influences on neuropathology across the brain. Our aim was to define the relationship between APOE epsilon4 allele load and regionally-specific brain cortical atrophy in Alzheimer's Disease (AD). For this reason voxel-based morphometry (VBM) was performed using T1-weighted MR images from 83 AD patients, contrasting regional cortical grey matter by APOE epsilon4 load according to either dominant or genotypic models. Patients fulfilled NINCDS-ADRDA criteria and were genotyped for APOE epsilon4 (15 epsilon4/epsilon4, 39 epsilon4/- and 29-/-). We observed that grey matter volume (GMV) decreased additively with increasing allele load in the medial (MTL) and anterior temporal lobes bilaterally. By contrast, a 2 degree-of-freedom genotypic model suggested a dominant effect of the APOE epsilon4 allele in the left temporal lobe. Brain regions showing a significant APOE epsilon4 allele load effect on GMV in AD included only some of those typically described as having greatest amyloid plaque deposition and atrophy. Temporal regions appeared to show a dominant effect of APOE epsilon4 allele load instead of the additive effect previously strongly associated with age of onset. Regional variations with allele load may be related to different mechanisms for effects of APOE epsilon4 load on susceptibility and disease progression.

Objective: To identify single-nucleotide polymorphisms (SNPs) associated with risk and age at onset of Alzheimer disease (AD) in a genomewide association study of 469 438 SNPs., Design: Case-control study with replication., Setting: Memory referral clinics in Canada and the United Kingdom., Participants: The hypothesis-generating data set consisted of 753 individuals with AD by National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association criteria recruited from 9 memory referral clinics in Canada and 736 ethnically matched control subjects; control subjects were recruited from nonbiological relatives, friends, or spouses of the patients and did not exhibit cognitive impairment by history or cognitive testing. The follow-up data set consisted of 418 AD cases and 249 nondemented control cases from the United Kingdom Medical Research Council Genetic Resource for Late-Onset AD recruited from clinics at Cardiff University, Cardiff, Wales, and King's College London, London, England., Main Outcome Measures: Odds ratios and 95% confidence intervals for association of SNPs with AD by logistic regression adjusted for age, sex, education, study site, and French Canadian ancestry (for the Canadian data set). Hazard ratios and 95% confidence intervals from Cox proportional hazards regression for age at onset with similar covariate adjustments., Results: Unadjusted, SNP RS4420638 within APOC1 was strongly associated with AD due entirely to linkage disequilibrium with APOE. In the multivariable adjusted analyses, 3 SNPs within the top 120 by P value in the logistic analysis and 1 in the Cox analysis of the Canadian data set provided additional evidence for association at P< .05 within the United Kingdom Medical Research Council data set: RS7019241 (GOLPH2), RS10868366 (GOLPH2), RS9886784 (chromosome 9), and RS10519262 (intergenic between ATP8B4 and SLC27A2)., Conclusions: Our genomewide association analysis again identified the APOE linkage disequilibrium region as the strongest genetic risk factor for AD. This could be a consequence of the coevolution of more than 1 susceptibility allele, such as APOC1, in this region. We also provide new evidence for additional candidate genetic risk factors for AD that can be tested in further studies.

Although Simulium exiguum Roubaud s.l. is present in all South American onchocerciasis foci, it is a significant vector only in Colombia and Ecuador. This variable vectorial role has been attributed to sibling forms that differ in their ability to allow Onchocerca volvulus larval development and their preferred bloodmeal hosts. Here we evaluate the relationship between parasite availability in human skin and infective larval output measured as (a) number of L3 larvae and (b) proportion of surviving flies with L3s in the Cayapa form of S. exiguum s.l. from Ecuador, taking into account the variation in counts of microfilariae (mf) from 6skin snips/patient. Comparisons with other cytoforms (Aguarico, Bucay and Quevedo, absent in the main Ecuadorean onchocerciasis foci) are made to suggest the relative roles of intrinsic susceptibility or co-adaptation versus density-dependent parasite uptake. A nonlinear (limitation) relationship, characterised by an initial rapid increase in infective larvae with increasing mf skin density was confirmed for the Cayapa cytoform. The proportion of infective Cayapa flies increased and saturated rapidly (reaching 80% for >/= 20mf/mg skin). After adjusting for density dependence, non-Cayapa cytoforms exhibited significantly lower L3 loads and proportions of infective flies for a given mf skin density than Cayapa flies, indicating that the susceptibility of those cytoforms is intrinsically lower than that of the Cayapa cytoform and that the differences observed are not due to density-dependent effects.

Objective: To determine whether vaccination of care home staff against influenza indirectly protects residents., Design: Pair matched cluster randomised controlled trial., Setting: Large private chain of UK care homes during the winters of 2003-4 and 2004-5., Participants: Nursing home staff (n=1703) and residents (n=2604) in 44 care homes (22 intervention homes and 22 matched control homes)., Interventions: Vaccination offered to staff in intervention homes but not in control homes., Main Outcome Measures: The primary outcome was all cause mortality of residents. Secondary outcomes were influenza-like illness and health service use in residents., Results: In 2003-4 vaccine coverage in full time staff was 48.2% (407/884) in intervention homes and 5.9% (51/859) in control homes. In 2004-5 uptake rates were 43.2% (365/844) and 3.5% (28/800). National influenza rates were substantially below average in 2004-5. In the 2003-4 period of influenza activity significant decreases were found in mortality of residents in intervention homes compared with control homes (rate difference -5.0 per 100 residents, 95% confidence interval -7.0 to -2.0) and in influenza-like illness (P=0.004), consultations with general practitioners for influenza-like illness (P=0.008), and admissions to hospital with influenza-like illness (P=0.009). No significant differences were found in 2004-5 or during periods of no influenza activity in 2003-4., Conclusions: Vaccinating care home staff against influenza can prevent deaths, health service use, and influenza-like illness in residents during periods of moderate influenza activity., Trial Registration: National Research Register N0530147256.