At-risk Contacts Research Articles

Prospective Evaluation of Routine Statewide Integration of Molecular Epidemiology and Contact Tracing to Disrupt Human Immunodeficiency Virus Transmission.

Human immunodeficiency virus (HIV) remains a global challenge and novel measures for transmission disruption are needed. Contact tracing is limited by reluctance or inability of newly diagnosed individuals to name at-risk contacts. Molecular cluster analysis is mostly used for outbreak investigations, and its role in routine public health activities remains uncertain. We conducted a 2-year prospective statewide study in Rhode Island to evaluate integration of HIV cluster analyses into routine contact tracing, by attempting to reinterview all new diagnoses who clustered, notifying them of clustering, and evaluating benefits of this strategy. Clustering was compared between a phylogenetic ensemble versus distance-based HIV-TRACE. Of 100 new diagnoses during 2021-2022, 52 individuals clustered, of whom only 31% were reinterviewed. Reinterviewing did not improve contact tracing beyond initial interviews, and the study was stopped early for futility. Clustering concordance within the phylogenetic ensemble was high (88%-89%), but lower (74%) for HIV-TRACE. Despite hypothesis rejection, we established a public health-academic partnership, developed a bioinformatics pipeline enabling near real-time cluster analysis, and identified gaps and unique opportunities for intervention. Attempting to reinterview all statewide new HIV diagnoses in molecular clusters showed no evidence of improving contact tracing. However, a strong academic-public health partnership enabled near real-time, longitudinal integration of molecular cluster analysis into routine public health activities, and identified barriers and opportunities tailoring data-driven approaches to unique individual and community characteristics, guiding future work on optimal use of molecular epidemiology to disrupt HIV transmission.

Mpox in children and adolescents and contact follow-up in school settings in greater Paris, France, May 2022 to July 2023.

BackgroundDuring the 2022 mpox outbreak in Europe, primarily affecting men who have sex with men, a limited number of cases among children and adolescents were identified. Paediatric cases from outbreaks in endemic countries have been associated with a higher likelihood of severe illness. Detailed clinical case descriptions and interventions in school settings before 2022 are limited.AimTo describe clinical characteristics of mpox cases among children (< 15 years) and adolescents (15-17 years) in the greater Paris area in France, and infection control measures in schools.MethodsWe describe all notified laboratory-confirmed and non-laboratory-confirmed cases among children and adolescents identified from May 2022 to July 2023, including demographic and clinical characterisation and infection control measures in school settings, i.e. contact tracing, contact vaccination, secondary attack rate and post-exposure vaccination uptake.ResultsNineteen cases were notified (13 children, 6 adolescents). Four adolescent cases reported sexual contact before symptom onset. Ten child cases were secondary cases of adult patients; three cases were cryptic, with vesicles on hands, arms and/or legs and one case additionally presented with genitoanal lesions. Five cases attended school during their infectious period, with 160 at-risk contacts identified, and one secondary case. Five at-risk contacts were vaccinated following exposure.ConclusionCases among children and adolescents are infrequent but require a careful approach to identify the source of infection and ensure infection control measures. We advocate a 'contact warning' strategy vs 'contact tracing' in order to prevent alarm and stigma. Low post-exposure vaccination rates are expected.

Examining the feasibility of assisted index case testing for HIV case-finding: a qualitative analysis of barriers and facilitators to implementation in Malawi

BackgroundAssisted index case testing (ICT), in which health care workers take an active role in referring at-risk contacts of people living with HIV for HIV testing services, has been widely recognized as an evidence-based intervention with high potential to increase status awareness in people living with HIV. While the available evidence from eastern and southern Africa suggests that assisted ICT can be an effective, efficient, cost-effective, acceptable, and low-risk strategy to implement in the region, it reveals that feasibility barriers to implementation exist. This study aims to inform the design of implementation strategies to mitigate these feasibility barriers by examining “assisting” health care workers’ experiences of how barriers manifest throughout the assisted ICT process, as well as their perceptions of potential opportunities to facilitate feasibility.MethodsIn-depth interviews were conducted with 26 lay health care workers delivering assisted ICT in Malawian health facilities. Interviews explored health care workers’ experiences counseling index clients and tracing these clients’ contacts, aiming to inform development of a blended learning implementation package. Transcripts were inductively analyzed using Dedoose coding software to identify and describe key factors influencing feasibility of assisted ICT. Analysis included multiple rounds of coding and iteration with the data collection team.ResultsParticipants reported a variety of barriers to feasibility of assisted index case testing implementation, including sensitivities around discussing ICT with clients, privacy concerns, limited time for assisted index case testing amid high workloads, poor quality contact information, and logistical obstacles to tracing. Participants also reported several health care worker characteristics that facilitate feasibility (knowledge, interpersonal skills, non-stigmatizing attitudes and behaviors, and a sense of purpose), as well as identified process improvements with the potential to mitigate barriers.ConclusionsMaximizing assisted ICT’s potential to increase status awareness in people living with HIV requires equipping health care workers with effective training and support to address and overcome the many feasibility barriers that they face in implementation. Findings demonstrate the need for, as well as inform the development of, implementation strategies to mitigate barriers and promote facilitators to feasibility of assisted ICT.Trial registrationNCT05343390. Date of registration: April 25, 2022.

Variability in Occult Injury Screening Among Siblings/Household Contacts of Physical Abuse Victims.

The objective of this study is to examine radiologic occult injury screening performance/yield among contacts presenting for precautionary medical assessments and assess factors associated with deferred screening. Data were collected retrospectively from charts of contacts younger than 8 years presenting for precautionary evaluation to a level 1 pediatric emergency department January 1, 2018 to March 31, 2023. Demographics, radiologic performance/yield, physical examination, social work-based psychosocial assessment, reasons for deferred imaging, and diagnostic codes were abstracted. Descriptive statistics and χ 2 analysis are reported. Three hundred ninety contacts were identified; 364 (93.3%) were biological siblings. Most (276, 70.8%) were 2 to 8 years old. Statistically significant relationships were identified with age, insurance, and hospital social work assessment and screening. Thirty-four infants (54%) underwent neuroimaging; no studies were abnormal. Of 114 contacts, <2 years old, 97 (85%) underwent skeletal survey (SS); 9 (9%) SS were abnormal. Twenty-seven (24%) returned for follow-up SS; 4 (14.8%) were abnormal. For 2 contacts, an abnormal initial SS was refuted by follow-up imaging. Physical examinations were abnormal for 11% of contacts. Reasons for deferred imaging included contact well appearance, caregiver concerns, and clinician disagreement with indications. Encounter International Classification of Diseases codes varied, commonly reflecting nonspecific screening assessments. Despite national clinical practice guidelines, studies of abusive injury prevalence and radiologic yield among at-risk contacts exposed to unsafe environments are few. Screening evaluations inclusive of physical examination and radiologic studies identify abuse concerns among at-risk contacts. Further study of factors impacting radiologic screening decisions is needed. Considerations to advance epidemiologic research include standardized diagnostic coding and prospective assessment of radiologic yield.

Single dose ivermectin for scabies pre-emptive therapy among healthcare workers in Careggi University Hospital, Florence, Italy.

Scabies is a neglected disease that cause outbreaks in facilities such as hospitals and prisons. In Europe, treatment with 2 doses of ivermectin 200 mcg/kg, 7 days apart, is authorised and recommended especially in population mass treatment. We describe the management of a mass pre-emptive therapy of primary contacts of a confirmed case of classic scabies among health care workers. Hospital personnel were evaluated, and at-risk contacts were treated with oral ivermectin 200 mcg/kg single dose if asymptomatic. Hospital staff were called after 7, 30, and 60 days after the first visit to assess presence of adverse drug reactions (ADRs) or symptoms compatible with scabies. Among 27 patients evaluated, 19/27 (70.4%) received single dose ivermectin for scabies pre-emptive therapy. A total of 11/13 patients were nurses, and 8/14 were healthcare assistants. A total of 87 tablets of ivermectin were administered, with a total cost of 423.69 euros. Two people reported ADRs at 7 days; one and two patients reported possible ADRs at 30 and 60 days, respectively. The efficacy in preventing scabies was 100%. To our knowledge, this is the first Italian experience in which a single dose of ivermectin has been implemented for mass pre-emptive therapy in asymptomatic primary contacts of classical scabies, showing excellent efficacy of the drug even when used as a single dose.

The Effectiveness of Health Education Using Media Booklets and WhatsApp on Tuberculosis Patients at the Linggang Bigung Health Center, West Kutai Regency

The main obstacle to controlling tuberculosis is knowledge and behavior to prevent transmission among at-risk contacts. Health education is needed to increase public knowledge. The purpose of this study was to analyze the effectiveness of health education using Booklet and WhatsApp media among tuberculosis sufferers. This type of research was quasi-experimental with a control group pre- and post-test approach, samples were taken from 41 tuberculosis patients who were currently being treated. Knowledge measurements were carried out before and after health education was carried out using Booklet and WhatsApp media. The analysis to test the effectiveness of the booklet and WhatsApp media used the Wilcoxon test. The Wilcoxon test results obtained a p-value of 0.046 (booklet) and a p-value of 0.014 (WhatsApp) lower than α = 0.05, meaning that both are effective in increasing knowledge, but Whatsapp media is more effective than booklet media.

Dynamics of non-household contacts during the COVID-19 pandemic in 2020 and 2021 in the Netherlands

The COVID-19 pandemic was in 2020 and 2021 for a large part mitigated by reducing contacts in the general population. To monitor how these contacts changed over the course of the pandemic in the Netherlands, a longitudinal survey was conducted where participants reported on their at-risk contacts every two weeks, as part of the European CoMix survey. The survey included 1659 participants from April to August 2020 and 2514 participants from December 2020 to September 2021. We categorized the number of unique contacted persons excluding household members, reported per participant per day into six activity levels, defined as 0, 1, 2, 3–4, 5–9 and 10 or more reported contacts. After correcting for age, vaccination status, risk status for severe outcome of infection, and frequency of participation, activity levels increased over time, coinciding with relaxation of COVID-19 control measures.

SG-APSIC1113: Descriptive study on COVID-19 exposures in Singapore General Hospital

Objectives: The highly transmissible SARS-CoV-2 has swept across the globe, causing large swaths of COVID-19, displacing medical resources and attention from patients with other life-threatening illnesses, and overwhelming healthcare institutions. Shifting toward endemicity, the Singapore Ministry of Health ceased issuing quarantine orders to close contacts of infected cases on October 11, 2021. However, contact tracing and exposure management within SGH continued with the same risk criteria. We have examined COVID-19 exposures in different hospital locations to determine the effectiveness of surveillance in breaking the chain of transmission. Methods: Contact tracing of COVID-19 exposures among Singapore General Hospital (SGH) staff and patients has been conducted since the first COVID-19 diagnosis in January 2020. The information collected is used to identify those at higher risk of infection for enhanced surveillance or isolation. The data analyzed in this study were collected during later periods of the SARS-CoV-2 δ (delta) pandemic wave between August 1, 2021, and December 31, 2021. Results: During the 4-month study period, there were 1,686 SARS-CoV-2 exposures in SGH. Among these 1,686 exposures, 1,157 (69%) were contacts with an infected patient. Among these infected source patients, 915 were emergency department patients, 210 were ward inpatients, and 32 were clinic outpatients. The remaining 524 exposure events (31%) were contacts with infected staff, of whom 441 were SGH employees and 83 were employees from other SingHealth institutions. The remaining 5 index cases were visitors to SGH. Of the 1,686 exposure events, 330 had associated at-risk contacts requiring exposure management. Among 330 patient index cases, 213 (64.5%) resulted in 699 exposed contacts (patients vs staff), whereas 117 staff index cases resulted in 435 exposed contacts (patients vs staff). For 434 exposed contacts who were staff, 204 (47%) of their exposures occurred in inpatient ward settings, followed by 153 (35.3%) that occurred in outpatient clinics, 36 (8%) that occurred common lounging areas, 16 (3.6%) that occurred in office sites, 15 (3.4%) that occurred in the community, 8 (1.8%) that occurred in occupation therapy, and 2 (0.5%) that occurred in the emergency department. For 688 exposed contacts who were patients, 579 (84.1%) exposures occurred in inpatient wards, 70 (10.2%) occurred in DEM, 19 (2.7%) occurred in other SingHealth institutions, 16 (2.3%) were exposures to roving porters, and 3 (0.4%) occurred in the community. During the study period, 3 hospital clusters were identified and investigated, one of which included secondary cases. Conclusions: Most SARS-CoV-2 exposures in SGH occurred in inpatient settings where patients were index cases. Despite intensive contact tracing and stringent surveillance and isolation measures, inpatient clusters could not be prevented.

Integration of Epidemiological and Genomic Data to Investigate H5N1 HPAI Outbreaks in Northern Italy in 2021-2022.

Between October 2021 and April 2022, 317 outbreaks caused by highly pathogenic avian influenza (HPAI) H5N1 viruses were notified in poultry farms in the northeastern Italian regions. The complete genomes of 214 strains were used to estimate the genetic network based on the similarity of the viruses. An exponential random graph model (ERGM) was used to assess the effect of 'at-risk contacts', 'same owners', 'in-bound/out-bound risk windows overlap', 'genetic differences', 'geographic distances', 'same species', and 'poultry company' on the probability of observing a link within the genetic network, which can be interpreted as the potential propagation of the epidemic via lateral spread or a common source of infection. The variables 'same poultry company' (Est. = 0.548, C.I. = [0.179; 0.918]) and 'risk windows overlap' (Est. = 0.339, C.I. = [0.309; 0.368]) were associated with a higher probability of link formation, while the 'genetic differences' (Est. = -0.563, C.I. = [-0.640; -0.486]) and 'geographic distances' (Est. = -0.058, C.I. = [-0.078; -0.038]) indicated a reduced probability. The integration of epidemiological data with genomic analyses allows us to monitor the epidemic evolution and helps to explain the dynamics of lateral spreads casting light on the potential diffusion routes. The 2021-2022 epidemic stresses the need to further strengthen the biosecurity measures, and to encourage the reorganization of the poultry production sector to minimize the impact of future epidemics.

392. 3D-DOSS – Using Digital Twins and Spatiotemporal Data Mapping for Infectious Disease Surveillance and Outbreak Investigations

BackgroundThe COVID-19 pandemic has brought to light the importance of contact tracing in outbreak management. Digital technologies have been leveraged to enhance contact tracing in community settings. However, within complex hospital environments, where patient and staff movement and interpersonal interactions are central to care delivery, tools for contact tracing and cluster detection remain limited. We aimed to develop a system to promptly, identify contacts in infectious disease exposures and detect infectious disease clusters. MethodsWe prototyped a 3D mapping tool 3-Dimensional Disease Outbreak Surveillance System (3D-DOSS), to have a spatial representation of patients in the hospital inpatient locations. Based on the AutoCAD drawings, the hospital physical spaces are built within a game-development software to obtain accurate digital replicas. This concept borrows from the way gamers interact with the virtual world/space, to mimic the interactions in physical space, like the SIMS franchise. Clinical, laboratory and patient movement data is then integrated into the virtual map to develop syndromic and disease surveillance systems. Risk assignment to individuals exposed is through mathematical modeling based on distance coordinates, room type and ventilation parameters and whether the disease is transmitted via contact, droplet or airborne route. ResultsWe have mapped acute respiratory illness (ARI) data for the period September to December 2018. We identified an influenza cluster of 10 patients in November 2018. In a COVID-19 exposure involving a healthcare worker (HCW), we identified 44 primary and 162 secondary contacts who were then managed as per our standard exposure management protocols. MDRO outbreaks could also be mapped.ConclusionThrough early identification of at-risk contacts and detection of infectious disease clusters, the system can potentially facilitate interventions to prevent onward transmission. The system can also support security, environmental cleaning, bed assignment and other operational processes. Simulations of novel diseases outbreaks can enhance preparedness planning as health systems that had been better prepared have been more resilient in this current pandemic. Disclosures All Authors: No reported disclosures

Mycobacterium caprae in a dairy farm in Northeast Italy.

Veneto region, Northeast Italy, has been declared officially free from bovine tuberculosis since 2008, although the disease is sporadically detected in association with cattle trade. In September 2015, bovine tuberculosis was detected in a dairy cattle farm of the region, in a holding with 69 animals. The herd underwent single intradermal tuberculin testing as part of the regional surveillance plan, and 24 animals resulted positive. Mycobacterium caprae was evidenced in 22 samples, further genotyped by PCR-based assays, as Allgäu type. Epidemiological investigation reported that sixteen animals were introduced from an officially tuberculosis free Member State in previous years. Nevertheless, spoligotyping and multilocus variable tandem repeat analysis (MLVA) indicated that M. caprae was strictly related to the strain circulating in 2007-2009 in Trento province, although no at-risk contacts were described. M. caprae is a zoonotic pathogen and further analyses are warranted in order to control its spread and impact on public health and animal trade.

Drop-out from the tuberculosis contact investigation cascade in a routine public health setting in urban Uganda: A prospective, multi-center study.

SettingSeven public tuberculosis (TB) units in Kampala, Uganda, where Uganda’s national TB program recently introduced household contact investigation, as recommended by 2012 guidelines from WHO.ObjectiveTo apply a cascade analysis to implementation of household contact investigation in a programmatic setting.DesignProspective, multi-center observational study.MethodsWe constructed a cascade for household contact investigation to describe the proportions of: 1) index patient households recruited; 2) index patient households visited; 3) contacts screened for TB; and 4) contacts completing evaluation for, and diagnosed with, active TB.Results338 (33%) of 1022 consecutive index TB patients were eligible for contact investigation. Lay health workers scheduled home visits for 207 (61%) index patients and completed 104 (50%). Among 287 eligible contacts, they screened 256 (89%) for symptoms or risk factors for TB. 131 (51%) had an indication for further TB evaluation. These included 59 (45%) with symptoms alone, 58 (44%) children <5, and 14 (11%) with HIV. Among 131 contacts found to be symptomatic or at risk, 26 (20%) contacts completed evaluation, including five (19%) diagnosed with and treated for active TB, for an overall yield of 1.7%. The cumulative conditional probability of completing the entire cascade was 5%.ConclusionMajor opportunities exist for improving the effectiveness and yield of TB contact investigation by increasing the proportion of index households completing screening visits by lay health workers and the proportion of at-risk contacts completing TB evaluation.

Identifying barriers to and facilitators of tuberculosis contact investigation in Kampala, Uganda: a behavioral approach

BackgroundThe World Health Organization recommends routine household tuberculosis contact investigation in high-burden countries but adoption has been limited. We sought to identify barriers to and facilitators of TB contact investigation during its introduction in Kampala, Uganda.MethodsWe collected cross-sectional qualitative data through focus group discussions and interviews with stakeholders, addressing three core activities of contact investigation: arranging household screening visits through index TB patients, visiting households to screen contacts and refer them to clinics, and evaluating at-risk contacts coming to clinics. We analyzed the data using a validated theory of behavior change, the Capability, Opportunity, and Motivation determine Behavior (COM-B) model, and sought to identify targeted interventions using the related Behavior Change Wheel implementation framework.ResultsWe led seven focus-group discussions with 61 health-care workers, two with 21 lay health workers (LHWs), and one with four household contacts of newly diagnosed TB patients. We, in addition, performed 32 interviews with household contacts from 14 households of newly diagnosed TB patients. Commonly noted barriers included stigma, limited knowledge about TB among contacts, insufficient time and space in clinics for counselling, mistrust of health-center staff among index patients and contacts, and high travel costs for LHWs and contacts. The most important facilitators identified were the personalized and enabling services provided by LHWs. We identified education, persuasion, enablement, modeling of health-positive behaviors, incentivization, and restructuring of the service environment as relevant intervention functions with potential to alleviate barriers to and enhance facilitators of TB contact investigation.ConclusionsThe use of a behavioral theory and a validated implementation framework provided a comprehensive approach for systematically identifying barriers to and facilitators of TB contact investigation. The behavioral determinants identified here may be useful in tailoring interventions to improve implementation of contact investigation in Kampala and other similar urban settings.

Editorial Commentary: More Evidence to Support Screening of Child Contacts of Tuberculosis Cases: If Not Now, Then When?

Evidence Q2 that informs the rationale for 10 screening of children who are close contacts of a case of tuberculosis and for providing preventive therapy for this high-risk group has been available for >50 years [1, 2]. The policy is almost universally accepted, being 15 included in global and almost all national tuberculosis control program guidelines [3]. However, in practice it is rarely implemented except in low-tuberculosis-burden, resource-rich settings [4]. Contact screening 20 has 2 main roles. One is to identify at-risk contacts such as young or human immunodeficiency virus (HIV)–infected children who require preventive therapy. The other is to identify contacts of any age who have 25 tuberculosis, that is, active, case finding. In this issue of Clinical Infectious Diseases, Jaganath et al [5] provide additional compelling evidence from a well-conducted study of the potential of contact investiga30 tion as a public health intervention in a tuberculosis-endemic and resource-limited setting. Although the findings are largely consistent with previous studies, there are features worth highlighting that make this an important study. It is a large prospective study reporting 761 Ugandan children who were household contacts of an adult with tuberculosis, and half of the contacts were young children (aged <5 years). Case definitions were clearly defined, and contacts were carefully evaluated, including samples for culture taken from those with symptoms or suggestive radiological findings, thereby strengthening diagnostic certainty. Furthermore, the cohort was followed for 2 years, providing important outcome data that are not available from the many previous cross-sectional studies that have reported a high prevalence of infection with Mycobacterium tuberculosis in child contacts [6, 7]. Tuberculosis was diagnosed in 10% of child contacts. This represents a higher prevalence than is usually reported [6, 7] but cannot be dismissed as simply overdiagnosis given that the majority (71%) of cases were culture confirmed. Diagnostic yield from culture was 4-fold higher than from smear and, as expected, tuberculosis was significantly more common in the young children. The prevalence of disease in the young child contacts was extremely high, equivalent to 16 400 per 100 000 young child contacts. Active case finding identified 79 children with tuberculosis who had not been diagnosed previously. These data provide strong support for case finding in this high-risk age group. 35 Moreover, this age group is still poorly represented by recording and reporting practices in many endemic settings. A tuberculin test was positive at baseline in 63% of child contacts without disease, 40 at the upper range of infection prevalence reported previously [6, 7]. Isoniazid preventive therapy (IPT) is very effective in preventing disease in these children [1, 8] but is rarely implemented in tuberculosis45 endemic settings, and, when implemented, uptake and adherence are often poor. In this study, 74% of eligible contacts completed at least 6 months of IPT. Only 2 (<1%) children developed tuberculosis 50 while receiving IPT and 1 after completion. This is a very positive outcome and an important observation strengthened by the 2 years of follow-up. The efficacy of IPT in this population cannot be deter55 mined from this study, but this finding supports the benefit of IPT for child contacts. The main characteristics that were identified for disease were young age, HIV 60 infection, and lack of a BCG scar. The increased risk for HIV-infected children is well established, and IPT is recommended for HIV-infected contacts irrespective of age once disease is excluded [3]. A recent 65 study from Tanzania reported an additional protective effect of antiretroviral therapy Received 22 August 2013; accepted 23 August 2013. Correspondence: Stephen M. Graham, PhD, FRACP, Centre for International Child Health, The University of Melbourne Department of Paediatrics, Royal Children’s Hospital, Flemington Road, Parkville, VIC 3052, Australia (steve.graham@rch. org.au). Clinical Infectious Diseases © The Author 2013. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals. permissions@oup.com. DOI: 10.1093/cid/cit647

Measles transmission by ‘fly‐in fly‐out’ workers in Australia

To describe the outbreak investigation and control measures for a cluster of measles cases involving 'fly-in fly-out' (FIFO) workers on an off-shore industrial vessel. Following Australian guidelines, measles cases were interviewed and at-risk contacts on the Australian mainland received measles vaccine, immunoglobulin or health advice. For the industrial vessel: (i) exposed FIFO workers who had already left the vessel received health advice through their employer; (ii) workers remaining on the vessel were offered measles vaccine; and (iii) FIFO workers joining the vessel for 21 days following the prodrome onset of the last case of measles on the vessel were offered measles vaccine. Measles virus isolates were sent for genotype determination. Four measles cases from two Australian jurisdictions were epidemiologically linked to the retrospectively identified index case, a New Zealand FIFO worker. No further cases were detected following the institution of outbreak control measures. FIFO workers congregating on large industrial projects are a discrete risk group with the potential to spread infectious diseases over large distances, both domestically and internationally. FIFO workers' immunisation history should be reviewed prior to deployment. Catch-up vaccination, where appropriate, would minimise transmission of vaccine-preventable diseases such as measles and help maintain a healthy, productive workforce.

Contact screening in tuberculosis: can we identify those with higher risk?: Table 1–

To the Editor: Contact screening, as a strategy to identify recently infected individuals, is part of the tuberculosis (TB) elimination strategy. It follows risk stratification concerning the infectiousness of the index patient, the duration and proximity of exposure, and the susceptibility of the contact [1, 2]. For its optimisation it is important to know which risk factors are associated with Mycobacterium tuberculosis transmission in order to not over screen or lose at-risk contacts. In view of that, this study aims to identify potential risk factors for M. tuberculosis transmission among contacts of pulmonary TB patients, in a Portuguese TB reference centre. From January to December of 2011, all contacts of confirmed pulmonary TB patients, screened in the TB centre, were questioned about their exposure to the index patient through a questionnaire completed during the medical appointment. Both household and casual contacts were screened, independent of their cumulative exposure. Contacts excluded: those with exposure outdoors ( e.g. in the street); those with incomplete characterisation of exposure ( e.g. index patients for whom we did not know the symptomatic period); those non-compliant with screening ( e.g. contacts who failed tuberculin skin test (TST) reading); and those with a past history of M. tuberculosis infection or TB disease ( e.g. contact´s verbal report of previous TB disease, contact with a pulmonary TB patient or treatment for latent tuberculosis infection (LTBI)). Contacts of patients with a diagnosis of pulmonary TB were identified for screening at the moment of the index patient diagnosis. The index patient was asked to identify contacts within the family, social and work spheres. Furthermore, some other …

Pertussis and Persistent Cough: Practical, Clinical and Epidemiologic Issues

BackgroundEpidemiologic issues of testing, treatment, prevention, immunization, mandated reporting, and post-exposure prophylaxis do not often intrude on the Emergency Department management of the well-appearing adolescent or adult with a couple of weeks of cough. ObjectivesConsidering that waning immunity to pertussis, the only vaccine-preventable disease with increasing cases and deaths in the United States, is responsible for 12–35% of such illness, such issues need to be considered. DiscussionMostly self-limited in adults, transmission of pertussis to infants places them at risk for hospitalization and death. Pertussis is highly contagious (80% transmission), and atypical presentations are the rule in adults (cough alone) and infants (apnea, bradycardia, poor feeding). Treatment in the first few weeks can impact the clinical course, and later treatment can still prevent transmission. Clinical features like paroxysmal cough, inspiratory “whoop,” and post-tussive emesis have mildly increased predictive values and may be absent in adults. Testing is unreliable after 3 weeks of cough. Treatment reduces communicability within 5 days and is suggested without regard to test results within 3 weeks of cough onset for those aged > 1 year (within 6 weeks of cough for < 1 year). Reporting requirements are based on the clinical case definition: ([Cough ≥2 weeks] + [paroxysms OR whoop OR post-tussive emesis]). Lower reporting thresholds are appropriate during an outbreak or when vulnerable populations are at risk. Post-exposure prophylaxis is recommended for at-risk contacts. Tdap is encouraged for all adults. ConclusionPractical recommendations consistent with the most current guidelines are offered.

Improving tuberculosis contact tracing: the role of evaluations in the home and workplace

In 2004, the tuberculosis (TB) contact screening strategy in Vila Nova de Gaia, Portugal, was changed from targeting only close contacts identified by interviews with the index patient (reflecting national policy) to include visits to the patient?s home and workplace. To find out 1) whether the new strategy increased adherence to TB screening procedures, 2) whether the strategy identified more at-risk contacts and 3) whether the strategy increased prevention of TB. We compared TB contact tracing during the periods 2001-2003 and 2004-2006. The numbers of identified and screened contacts and the results of screening procedures (number of patients with active TB and latent TB infection [LTBI] detected per index case) were analysed. The number of instances of active TB prevented and the numbers of contacts that had to be screened to prevent one such instance were calculated and compared for both screening strategies. Home and workplace visits helped to identify more at-risk contacts (8.4 per index patient) than interview (2.5 per index patient), and improved adherence (87.3% of identified contacts were screened compared to 67.6% previously). More patients with active TB and LTBI were detected (1.4 per index patient compared with 0.75 per index patient previously), and more TB cases were prevented. The newly implemented contact screening programme, featuring home and workplace evaluation of TB patient contacts, improved adherence to screening procedures, identified more at-risk contacts and should prevent more TB cases in the future.

Evaluation of various cytokines elicited during antigen-specific recall as potential risk indicators for the differential development of leprosy

Leprosy is a dermato-neurological disease caused by Mycobacterium leprae infection that manifests across a wide range of clinical and immunological outcomes. Diagnosis is still currently based on clinical manifestations and simple tests are needed. This study investigated whether biomarkers induced by defined M. leprae proteins in 24-h whole blood assays (WBA) could discriminate active leprosy patients from at-risk contacts. Newly diagnosed, untreated paucibacillary (PB; tuberculoid leprosy/borderline tuberculoid [TT/BT]) and multibacillary (MB; borderline lepromatous/lepromatous leprosy [BL/LL]) leprosy patients, as well as healthy household contacts (HHC) of MB patients, were recruited in central western Brazil (Goiânia/Goiás). Cell-based responses to the ML0276, ML1623, ML0405, ML1632, 92f, and ML1011 antigens were measured by Luminex 14-plex assays detecting eotaxin, IFNγ, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-15, IL-17A, IL-23, IL-31, IP-10, and TNFα. Our data reinforce that IFNγ is currently the best indicator of the antigen-specific cellular immune response of TT/BT leprosy and demonstrate that the same antigens promote the secretion of IL-4 in blood from BL/LL leprosy patients. While none of the biomarkers tested could discriminate leprosy patients from HHC, our data indicate that, although most HHC antigen-specific responses are qualitatively similar to TT/BT patients, some HHC can respond similarly to BL/LL patients.

Prophylaxie autour d'un cas index d'hépatite A : immunoglobulines ou vaccination ?

France has changed from a country where hepatitis A is endemic to one where residents are at risk of hepatitis A infection: in 20 years, the seroprevalence in 20-year-olds has fallen from 50% to less than 10%. Prophylaxis for close contacts of an index case has therefore become a major problem because their risk of hepatitis A is high. Polyvalent immunoglobulins are recommended in several countries, but no immunoglobulins are approved for this indication in France. Immunoglobulins are also expensive and only slightly efficacious. A vaccine against hepatitis A administered to young children or adolescents can break the epidemic chain and protect adults very effectively by limiting virus circulation. Many countries propose early vaccination to at-risk contacts, with vaccination generally advised within a week of the initial infectious contact. Although more specific and more plentiful data are still necessary before this recommendation can be generalized, it must be taken into account. This medical decision should thus be made on an individualized basis after discussion between the physician and family about the risk.