Wagering contingent on a previous decision, or post-decision wagering,
has recently been proposed to measure conscious awareness. Whilst intuitively
appealing, it remains unclear whether economic context interacts with subjective
confidence and how such interactions might impact on the measurement of awareness.
Here we propose a signal detection model which predicts that advantageous wagers
placed on the identity of preceding stimuli are affected by loss aversion, despite
stimulus visibility remaining constant. This pattern of predicted results was evident
in a psychophysical task where we independently manipulated perceptual and economic
factors. Changes in wagering behaviour induced by changes in wager size were largely
driven by changes in criterion, consistent with the model. However, for
near-threshold stimuli, a reduction in wagering efficiency was also evident,
consistent with an apparent but potentially illusory decrease in awareness of the
stimulus. These findings challenge an assertion that post-decision wagering provides
a direct index of subjective awareness.
Post-decision wagering; Perception; Economics; Signal detection theory; Reward; Awareness; Metacognition; Psychophysics
Superstitious behaviours, which arise through the incorrect assignment of cause and effect, receive considerable attention in psychology and popular culture. Perhaps owing to their seeming irrationality, however, they receive little attention in evolutionary biology. Here we develop a simple model to define the condition under which natural selection will favour assigning causality between two events. This leads to an intuitive inequality—akin to an amalgam of Hamilton's rule and Pascal's wager—-that shows that natural selection can favour strategies that lead to frequent errors in assessment as long as the occasional correct response carries a large fitness benefit. It follows that incorrect responses are the most common when the probability that two events are really associated is low to moderate: very strong associations are rarely incorrect, while natural selection will rarely favour making very weak associations. Extending the model to include multiple events identifies conditions under which natural selection can favour associating events that are never causally related. Specifically, limitations on assigning causal probabilities to pairs of events can favour strategies that lump non-causal associations with causal ones. We conclude that behaviours which are, or appear, superstitious are an inevitable feature of adaptive behaviour in all organisms, including ourselves.
optimality theory; behavioural ecology; animal behaviour
Public wagering was examined in relation to game adjustments during the first 523 draws of Oregon's “Megabucks” lottery and the first 540 draws of Arizona's “The Pick” lottery. Oregon's lottery was modified five times during this period, and Arizona's lottery underwent four modifications. Public wagering was not related to decreases in the odds of winning in either state. Wagering increased in both states following the introduction of a minimum $1 million jackpot. Wagering also increased following a change in game frequency from weekly to semiweekly draws. Sales trends in both states suggest that over the period examined, larger jackpots were required to maintain previous levels of lottery play. These data suggest that public participation in gambling can be manipulated by state lottery commissions through adjustments in lottery contingencies.
wagering; state lotteries; game manipulations; naturalistic observation
Research in competitive games has exclusively focused on how opponent models are developed through previous outcomes and how peoples' decisions relate to normative predictions. Little is known about how rapid impressions of opponents operate and influence behavior in competitive economic situations, although such subjective impressions have been shown to influence cooperative decision-making. This study investigates whether an opponent's face influences players' wagering decisions in a zero-sum game with hidden information. Participants made risky choices in a simplified poker task while being presented opponents whose faces differentially correlated with subjective impressions of trust. Surprisingly, we find that threatening face information has little influence on wagering behavior, but faces relaying positive emotional characteristics impact peoples' decisions. Thus, people took significantly longer and made more mistakes against emotionally positive opponents. Differences in reaction times and percent correct were greatest around the optimal decision boundary, indicating that face information is predominantly used when making decisions during medium-value gambles. Mistakes against emotionally positive opponents resulted from increased folding rates, suggesting that participants may have believed that these opponents were betting with hands of greater value than other opponents. According to these results, the best “poker face” for bluffing may not be a neutral face, but rather a face that contains emotional correlates of trustworthiness. Moreover, it suggests that rapid impressions of an opponent play an important role in competitive games, especially when people have little or no experience with an opponent.
This article examines the influence of the business cycle on expenditures of three major types of legalized gambling activities: Casino gambling, lottery, and pari-mutuel wagering. Empirical results are obtained using monthly aggregated US per capita consumption time series for the period 1959.01–2010.08. Among the three gambling activities only lottery consumption appears to be recession-proof. This series is characterized by a vast and solid growth that exceeds the growth in income and the growth in other gambling sectors. Casino gambling expenditures show a positive growth during expansions and no growth during recessions. Hence, the loss in income during recessions affects casino gambling. However, income shocks which are not directly related to the business cycle do not influence casino gambling expenditures. Pari-mutuel wagering displays an overall negative trend and its average growth rate is smaller than the growth in income, especially during recessions. The findings of this article provide important implications for the gambling industry and for local governments.
Gambling; Business cycle; Time series analysis; Cointegration
Background: The goal of this study is to identify betting patterns displayed during the first month of actual Internet gambling on a betting site that can serve as behavioural markers to predict the development of gambling-related problems. Methods: Using longitudinal data, k-means clustering analysis identified a small subgroup of high-risk gamblers. Results: Seventy-three percent of the members of this subgroup eventually closed their account due to gambling-related problems. The characteristics of this high-risk subgroup were as follows: (i) frequent and (ii) intensive betting combined with (iii) high variability across wager amount and (iv) an increasing wager size during the first month of betting. Conclusion: This analysis provides important information that can help to identify potentially problematic gamblers during the early stages of gambling-related problems. Public health workers can use these results to develop early interventions that target high-risk Internet gamblers for prevention efforts. However, one study limitation is that the results distinguish only a small proportion of the total sample; therefore, additional research will be necessary to identify markers that can classify larger segments of high-risk gamblers.
About half of patients with gastroesophageal reflux disease (GERD) have a normal endoscopy, so symptom assessment is the only appropriate outcome measure for these persons. Symptom assessment is also of great importance in persons with erosive esophagitis. There is currently no fully validated questionnaire to compare symptom response to treatment of patients with GERD. The aim of this review is to consider ReQuest™ assessment tool to evaluate esophageal, supra-esophageal, and infra-esophageal symptoms, as well as any modification of the patient’s quality of life. The ReQuest™ may be combined with the Los Angeles classification of esophagitis (LA A–D), to include the normal endoscopic finding in normal endoscopy reflux disease. The ReQuest™ score declines rapidly towards normal with patient treatment with a proton pump inhibitor. A proportion of patients need more than the usual 8 weeks of therapy. For example, in GERD patients with Los Angeles B–D, the ReQuest™ score falls more with pantoprazole 40 mg than with esomoprazole 40 mg after 12 weeks of therapy. Now that the simplified ReQuest in Practice™ is available, this validated brief questionnaire has potential as an instrument for use in GERD patients seen in everyday clinical practice.
complete healing; dyspepsia; erosive esophagitis; GERD symptoms; pH; ReQuest™
College students experience high rates of problem and pathological gambling, yet little research has investigated methods for reducing gambling in this population. This study sought to examine the efficacy of brief intervention strategies.
117 college student problem and pathological gamblers.
Students were randomly assigned to: an assessment-only control, 10 minutes of Brief Advice, 1 session of motivational enhancement therapy (MET), or 1 session of MET plus 3 sessions of cognitive-behavioral therapy (CBT). The three interventions were designed to reduce gambling.
Gambling was assessed at baseline, week 6, and month 9 using the Addiction Severity Index-Gambling (ASI-G) module, which also assesses days and dollars wagered.
Compared to the assessment-only condition, those receiving any intervention had significant decreases in ASI-G scores and days and dollars wagered over time. The MET condition significantly decreased ASI-G scores and dollars wagered over time, and it increased the odds of a clinically significant reduction in gambling at the 9-month follow-up relative to the assessment-only condition, even after controlling for baseline indices that could impact outcomes. The Brief Advice and MET+CBT conditions had benefits on some, but not all, indices of gambling. None of the interventions differed significantly from one another.
These results suggest the efficacy of brief interventions for reducing gambling problems in college students.
gambling; brief interventions; motivational enhancement therapy; cognitive-behavioral therapy; treatment efficacy
Models of consciousness differ in whether they predict a gradual change or a discontinuous transition between nonconscious and conscious perception. Sergent and Dehaene (Psychological Science, 15, 720–728, 2004) asked subjects to rate on a continuous scale the subjective visibility of target words presented during an attentional blink. They found that these words were either detected as well as targets outside the attentional-blink period or not detected at all, and interpreted these results as support for a discontinuous transition between nonconscious and conscious processing. We present results from 4 attentional-blink experiments showing that this all-or-none rating pattern disappears with the use of an alternative measure of consciousness (post-decision wagering) and a more difficult identification task. Instead, under these circumstances, subjects used the consciousness rating scales in a continuous fashion. These results are more consistent with models that assume a gradual change between nonconscious and conscious perception during the attentional blink.
Electronic supplementary material
The online version of this article (doi:10.3758/s13414-010-0026-1) contains supplementary material, which is available to authorized users.
Attentional blink; Consciousness; Post-decision wagering; Awareness; Subjective ratings
Concurrent drinking and gambling is prevalent among young adults and may increase negative consequences associated with each behavior. The effects of alcohol, initial gambling outcomes, gambling-related cognitions, and impulsivity on gambling behavior were evaluated. Initial gambling outcomes, gambling-related cognitions, and impulsivity were also assessed as potential moderators of the relation between alcohol and gambling behavior. Participants (N = 130) were randomly assigned to receive active placebo or alcohol (0.84 g/kg and 0.76 g/kg for men and women, respectively) and were invited to wager on a simulated slot machine programmed to produce 1 of 3 initial outcomes (win, breakeven, or loss) before beginning a progressive loss schedule. Alcohol consumption was associated with larger average bets and more rapid loss of all available funds, though no evidence was found for predicted main effects and interactions for gambling persistence. The effect of impulsivity was moderated by beverage condition, such that higher levels of impulsivity were associated with larger average bets for participants in the placebo but not the alcohol group. Results have direct implications for individual-focused and public-health interventions.
alcohol; gambling; persistence; betting behavior; impulsivity
Prize-based contingency management (CM) is efficacious in treating cocaine abuse, and the chance-based procedures of prize CM may be appealing to those who gamble. Using data from three randomized trials, we evaluated whether cocaine abusers who had wagered in the month before treatment (n = 62) responded more favorably to prize CM than those who had not (n = 278). Participants were randomized to standard care (SC) or SC plus prize CM. Although prize CM was related to better outcomes overall, recent gambling was not associated with outcomes across or within treatment conditions. Gambling participation before treatment entry was associated with reductions in gambling over time, and this effect was more pronounced among those assigned to CM. These data suggest that prize CM is equally efficacious for substance abusers who do and do not gamble, and they extend prior studies indicating that prize CM does not increase gambling.
treatment outcome; contingency management; cocaine dependence; gambling
Nicholas Agar has recently argued that it would be irrational for future human beings to choose to radically enhance themselves by uploading their minds onto computers. Utilizing Searle’s argument that machines cannot think, he claims that uploading might entail death. He grants that Searle’s argument is controversial, but he claims, so long as there is a non-zero probability that uploading entails death, uploading is irrational. I argue that Agar’s argument, like Pascal’s wager on which it is modelled, fails, because the principle that we (or future agents) ought to avoid actions that might entail death is not action guiding. Too many actions fall under its scope for the principle to be plausible. I also argue that the probability that uploading entails death is likely to be lower than Agar recognizes.
Agar; Searle; Consciousness; Radical enhancement; Uploading; Probability
Confidence judgements, self-assessments about the quality of a subject's knowledge, are considered a central example of metacognition. Prima facie, introspection and self-report appear the only way to access the subjective sense of confidence or uncertainty. Contrary to this notion, overt behavioural measures can be used to study confidence judgements by animals trained in decision-making tasks with perceptual or mnemonic uncertainty. Here, we suggest that a computational approach can clarify the issues involved in interpreting these tasks and provide a much needed springboard for advancing the scientific understanding of confidence. We first review relevant theories of probabilistic inference and decision-making. We then critically discuss behavioural tasks employed to measure confidence in animals and show how quantitative models can help to constrain the computational strategies underlying confidence-reporting behaviours. In our view, post-decision wagering tasks with continuous measures of confidence appear to offer the best available metrics of confidence. Since behavioural reports alone provide a limited window into mechanism, we argue that progress calls for measuring the neural representations and identifying the computations underlying confidence reports. We present a case study using such a computational approach to study the neural correlates of decision confidence in rats. This work shows that confidence assessments may be considered higher order, but can be generated using elementary neural computations that are available to a wide range of species. Finally, we discuss the relationship of confidence judgements to the wider behavioural uses of confidence and uncertainty.
metacognition; uncertainty; Bayesian; psychophysics; model-based; post-decision wagering
Individuals with addictive disorders, including substance abusers and pathological gamblers, discount or devalue rewards delayed in time more than controls. Theoretically, preference for probabilistic rewards is directly related to gambling, but limited empirical research has examined probabilistic discounting in individuals with pathological gambling. This study evaluated probability and delay discounting in treatment-seeking pathological gamblers and their association with gambling treatment outcomes during and following treatment. At time of treatment entry, 226 pathological gamblers completed probability and delay discounting tasks. They were then randomized to one of three treatment conditions, and gambling behavior was measured throughout treatment and at a one-year follow-up assessment. After controlling for possibly confounding variables and treatment condition, more shallow probability discounting was associated with greater reductions in amounts wagered during treatment and likelihood of gambling abstinence at the end of treatment and throughout the follow-up period. No associations were noted between delay discounting and gambling treatment outcomes. These data suggest that probability discounting may be an important construct in understanding pathological gambling and its treatment.
probability discounting; pathological gambling; treatment
Twelve doctors with special training in hepatology independently reviewed two to five cases each from a group of seven cases of complicated hepatobiliary problems. A doctor's willingness to take risks to improve his patients' health was quantified by a wagering technique based on the probability of achieving a successful intervention. These probabilities were then used to calculate "utilities," which represented the average opinion of the doctors about the relative worth of each of six predefined states of health. The results showed that, in the context of risky decisions for severely ill patients, a year of life was considered by the doctors to be worth 44% of a full recovery; being mobile for that year increased this value to 57%. Survival for up to five years with restricted mobility was considered to be worth 70% of a full recovery and the ability to work during that period increased this value to 85%. It is concluded that in clinical decision making the uncertainty and preferences implicit in a course of action can be quantified and thus made explicit.
The distinction between processes used to perceive and understand the self and others has received considerable attention in psychology and neuroscience. Brain findings highlight a role for various regions, in particular the medial prefrontal cortex (mPFC), in supporting judgments about both the self and others. We performed a meta-analysis of 107 neuroimaging studies of self- and other-related judgments using Multilevel Kernel Density Analysis (MKDA; Kober & Wager, 2010). We sought to determine what brain regions are reliably involved in each judgment type, and in particular, what the spatial and functional organization of mPFC is with respect to them. Relative to non-mentalizing judgments, both self and other judgments were associated with activity in mPFC, ranging from ventral to dorsal extents, as well as common activation of the left temporoparietal junction (TPJ) and posterior cingulate. A direct comparison between self and other judgments revealed that ventral mPFC (vmPFC), as well as left ventrolateral PFC and left insula, were more frequently activated by self-related judgments, whereas dorsal mPFC (dmPFC), in addition to bilateral TPJ and cuneus, were more frequently activated by other-related judgments. Logistic regression analyses revealed that ventral and dorsal mPFC lay at opposite ends of a functional gradient: the z-coordinates reported in individual studies predicted whether the study involved self- or other-related judgments, which were associated with increasingly ventral or dorsal portions of mPFC, respectively. These results argue for a distributed rather than localizationist account of mPFC organization and support an emerging view on the functional heterogeneity of mPFC.
IMGT/V-QUEST is the highly customized and integrated system for the standardized analysis of the immunoglobulin (IG) and T cell receptor (TR) rearranged nucleotide sequences. IMGT/V-QUEST identifies the variable (V), diversity (D) and joining (J) genes and alleles by alignment with the germline IG and TR gene and allele sequences of the IMGT reference directory. New functionalities were added through a complete rewrite in Java. IMGT/V-QUEST analyses batches of sequences (up to 50) in a single run. IMGT/V-QUEST describes the V-REGION mutations and identifies the hot spot positions in the closest germline V gene. IMGT/V-QUEST can detect insertions and deletions in the submitted sequences by reference to the IMGT unique numbering. IMGT/V-QUEST integrates IMGT/JunctionAnalysis for a detailed analysis of the V-J and V-D-J junctions, and IMGT/Automat for a full V-J- and V-D-J-REGION annotation. IMGT/V-QUEST displays, in ‘Detailed view’, the results and alignments for each submitted sequence individually and, in ‘Synthesis view’, the alignments of the sequences that, in a given run, express the same V gene and allele. The ‘Advanced parameters’ allow to modify default parameters used by IMGT/V-QUEST and IMGT/JunctionAnalysis according to the users’ interest. IMGT/V-QUEST is freely available for academic research at http://imgt.cines.fr
OntoQuest is a physician decision support system that mines the hospital data base for previous decisions made in cases similar to the current one. For example, OntoQuest displays a list of the medications prescribed to similar historical patients from which the physician may compare his choice of medication for the current patient. This information retrieval is accomplished using ontological queries. Unlike a regular database query, an ontological query is able to account for semantic similarity between patients. To implement the ontological query, we propose a method for computing the ontological similarity between patients represented by sets of ICD-9 diagnoses. We have tested the OntoQuest prototype on a pilot data set of 2077 patients. Finally, we compare the OntoQuest performance to conventional database queries. We believe that OntoQuest can be extended to compare services, quality and outcomes among patient and provider groups.
Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008–2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming.
We compared Ixodes ricinus questing density, the infestation of rodents by immature stages, and the diversity of Borrelia burgdorferi sensu lato (sl) in questing ticks and ticks collected from rodents in two Lyme borreliosis (LB)-endemic areas in Switzerland (Portes-Rouges [PR] and Staatswald [SW]) from 2003 to 2005. There were variations in the seasonal pattern of questing tick densities among years. Questing nymphs were globally more abundant at PR than at SW, but the proportion of rodents infested by immature ticks was similar (59.4% and 61%, respectively). Questing tick activity lasted from February to November with a strong decline in June. The seasonal pattern of ticks infesting rodents was different. Ticks infested rodents without decline in summer, suggesting that the risk of being bitten by ticks remains high during the summer. Rodents from SW showed the highest infestation levels (10±21.6 for larvae and 0.54±1.65 for nymphs). The proportion of rodents infested simultaneously by larvae and nymphs (co-feeding ticks) was higher at SW (28%) than at PR (11%). Apodemus flavicollis was the species the most frequently infested by co-feeding ticks, and Myodes glareolus was the most infective rodent species as measured by xenodiagnosis. At PR, the prevalence of B. burgdorferi sl in questing ticks was higher (17.8% for nymphs and 32.4% for adults) than at SW (10.4% for nymphs and 24.8% for adults), with B. afzelii as the dominant species, but B. garinii, B. burgdorferi sensu stricto, and B. valaisiana were also detected. Rodents transmitted only B. afzelii (at PR and at SW) and B. bavariensis (at SW) to ticks, and no mixed infection by additional genospecies was observed in co-feeding ticks. This implies that co-feeding transmission does not contribute to genospecies diversity. However, persistent infections in rodents and co-feeding transmission contribute to the perpetuation of B. afzelii in nature.
Borrelia burgdorferi sensu lato; Co-feeding transmission; Rodents
In the last decades increasing attention is paid to the topic of responsibility in technology development and engineering. The discussion of this topic is often guided by questions related to liability and blameworthiness. Recent discussions in engineering ethics call for a reconsideration of the traditional quest for responsibility. Rather than on alleged wrongdoing and blaming, the focus should shift to more socially responsible engineering, some authors argue. The present paper aims at exploring the different approaches to responsibility in order to see which one is most appropriate to apply to engineering and technology development. Using the example of the development of a new sewage water treatment technology, the paper shows how different approaches for ascribing responsibilities have different implications for engineering practice in general, and R&D or technological design in particular. It was found that there was a tension between the demands that follow from these different approaches, most notably between efficacy and fairness. Although the consequentialist approach with its efficacy criterion turned out to be most powerful, it was also shown that the fairness of responsibility ascriptions should somehow be taken into account. It is proposed to look for alternative, more procedural ways to approach the fairness of responsibility ascriptions.
Responsibility; Liability; Efficacy; Fairness; Informed consent; No harm principle; Technological risk; Engineering practice; Consequentialism
Long-term maintenance of the memory T-cell response is the hallmark of immune protection and, hence, constitutes one of the most important objectives of vaccine-development strategies. Persistent memory T cells, developed after vaccination or microbial infections, ensure the generation of an antimicrobial response upon re-exposure to the pathogen through rapid clonal proliferation and activation of effector functions. However, in the context of many pathogen infections, these memory T cells fail to persist and die. In this review, we will highlight recent exciting findings in studies of memory T cells, their generation, their lineage relationships and their survival pathways; indeed, survival of memory T cells and maintenance of their functionality are key features of the immune response in its quest to control disease progression and in the development of vaccines to persistent microbial infections.
differentiation; FOXO3a; memory; signaling; survival; T cell
Influenza is a vaccine preventable disease that causes severe illness and excess mortality in humans. Licensed influenza vaccines induce humoral immunity and protect against strains that antigenically match the major antigenic components of the vaccine, but much less against antigenically diverse influenza strains. A vaccine that protects against different influenza viruses belonging to the same subtype or even against viruses belonging to more than one subtype would be a major advance in our battle against influenza. Heterosubtypic immunity could be obtained by cytotoxic T-cell (CTL) responses against conserved influenza virus epitopes. The molecular mechanisms involved in inducing protective CTL responses are discussed here. We also focus on CTL vaccine design and point to the importance of immune-related databases and immunoinformatics tools in the quest for new vaccine candidates. Some techniques for analysis of T-cell responses are also highlighted, as they allow estimation of cellular immune responses induced by vaccine preparations and can provide correlates of protection.
Management of patients with gastro-oesophageal reflux disease (GORD) can be assisted by information predicting the likely response to proton pump inhibitor (PPI) treatment. The aim was to undertake a study of GORD patients designed to approximate ordinary clinical practice that would identify patient characteristics predicting symptomatic response to pantoprazole treatment.
1888 patients with symptoms of GORD were enrolled in a multicentre, multinational, prospective, open study of 8 weeks pantoprazole treatment, 40 mg daily. Response was assessed by using the ReQuest™ questionnaire, by the investigator making conventional clinical enquiry and by asking patients about their satisfaction with symptom control. Factors including pre-treatment oesophagitis, gender, age, body mass index (BMI), Helicobacter pylori status, anxiety and depression, and concurrent IBS symptoms were examined using logistic regression to determine if they were related to response, judged from the ReQuest™-GI score.
Poorer treatment responses were associated with non-erosive reflux disease, female gender, lower BMI, anxiety and concurrent irritable bowel syndrome symptoms before treatment. No association was found with age, Helicobacter pylori status or oesophagitis grade. Some reflux-related symptoms were still present in 14% of patients who declared themselves 'well-satisfied' with their symptom control.
Some readily identifiable features help to predict symptomatic responses to a PPI and consequently may help in managing patient expectation. ClinicalTrial.gov identifier: NCT00312806.
Hepatitis B virus (HBV) infection is much more common in hemodialysis patients than the general population. These patients have an impaired immune response to HBV vaccination; to that end there are certain studies that have evaluated levamisole as an immunomodulator agent improving HBV vaccination response rate in hemodialysis patients.
In the current review, we have assembled all of the results to determine whether lavamisole is of value as an adjuvant to HBV vaccination in hemodialysis patients.
Materials and Methods
Science Direct (Elsevier), ProQuest, Springer, MD Consult, BMJ Journals, Pubmed and Wiley were searched for levamisole application to HBV vaccination in hemodialysis patients. All studies revealed a seroconversion response level between levamisole plus HBV vaccine versus HBV vaccine alone.
From 10 relevant studies, 5 studies fulfilled our inclusion criteria. Three of them suggested the significant benefit of adding levamisole to the HBV vaccine to increase augment seroprotection level in hemodialysis patients. Another study reported a decrease in seroprotection level and another study showed no significant difference caused by levamisole administration.
Due to the limited number of studies evaluated, it is challenging to perform a definite decision about routinely administering levamisole in addition to the HBV vaccine for all hemodialysis patients. However, it does seem reasonable to recommend administration of levamisole for impaired immune response patients.
Hepatitis B; Vaccination; Hemodialysis Units, Hospital