Risk Assessment and Meningococcal A Conjugate Vaccine Introduction in Africa: The District Prioritization Tool.

BACKGROUND: A group A meningococcal (MenA) conjugate vaccine has progressively been introduced in the African meningitis belt since 2010. A country-wide risk assessment tool, the District Prioritization Tool (DPT), was developed to help national stakeholders combine existing data and local expertise to define priority geographical areas where mass vaccination campaigns should be conducted. METHODS: DPT uses an Excel-supported offline tool that was made available to the countries proposed for immunization campaigns. It used quantitative-qualitative methods, relying predominantly on evidence-based risk scores complemented by expert opinion. RESULTS: DPT was used by most of the countries that introduced the group A conjugate vaccine. Surveillance data enabled the computation of severity scores for meningitis at the district level (magnitude, intensity, and frequency). District data were scaled regionally to facilitate phasing decisions. DPT also assessed the country's potential to conduct efficient preventive immunization campaigns while paying close attention to the scope of the geographic extension of the campaigns. The tool generated meningitis district profiles that estimated the number of vaccine doses needed. In each assessment, local meningitis experts contributed their knowledge of local risk factors for meningitis epidemics to refine the final prioritization decisions. CONCLUSIONS: DPT proved to be a useful and flexible tool that codified information and streamlined discussion among stakeholders while facilitating vaccine distribution decisions after 2011. DPT methodology may be tailored to prioritize vaccine interventions for other diseases.

Serogroup W Meningitis Outbreak at the Subdistrict Level, Burkina Faso, 2012.

In 2012, Neisseria meningitidis serogroup W caused a widespread meningitis epidemic in Burkina Faso. We describe the dynamic of the epidemic at the subdistrict level. Disease detection at this scale allows for a timelier response, which is critical in the new epidemiologic landscape created in Africa by the N. meningitidis A conjugate vaccine.

Epidemiological changes in meningococcal meningitis in Niger from 2008 to 2011 and the impact of vaccination.

BACKGROUND: The epidemiology of bacterial meningitis in the African 'meningitis belt' changes periodically. In order to design an effective vaccination strategy, we have examined the epidemiological and microbiological patterns of bacterial meningitis, and especially that of meningococcal meningitis, in Niger during the period 2008-2011. During this period a mass vaccination campaign with the newly developed meningococcal A conjugate vaccine (MenAfriVac®) was undertaken. METHOD: Cerebrospinal fluid samples were collected from health facilities throughout Niger and analysed by culture, seroagglutination and/or speciation polymerase chain reaction, followed by genogrouping PCR for Neisseria meningitidis infections. A sample of strains were analysed by multi-locus sequence typing. RESULTS: N. meningitidis serogroup A cases were prevalent in 2008 and 2009 [98.6% and 97.5% of all N. meningitidis cases respectively]. The prevalence of serogroup A declined in 2010 [26.4%], with the emergence of serogroup W Sequence Type (ST) 11 [72.2% of cases], and the serogroup A meningococcus finally disappeared in 2011. The geographical distribution of cases N. meningitidis serogroups A and W within Niger is described. CONCLUSION: The substantial decline of serogroup A cases that has been observed from 2010 onwards in Niger seems to be due to several factors including a major polysaccharide A/C vaccination campaign in 2009, the introduction of MenAfriVac® in 10 districts at risk in December 2010, the natural dynamics of meningococcal infection and the persistence of serogroup A sequence-type 7 for about 10 years. The emergence of serogroup W strains suggests that there may be a need for serogroup W containing vaccines in Niger in the coming years.

Definition and characterization of localised meningitis epidemics in Burkina Faso: a longitudinal retrospective study.

BACKGROUND: The epidemiology of meningococcal meningitis in the African meningitis belt is characterised by seasonality, localised epidemics and epidemic waves. To facilitate research and surveillance, we aimed to develop a definition for localised epidemics to be used in real-time surveillance based on weekly case reports at the health centre level. METHODS: We used national routine surveillance data on suspected meningitis from January 2004 to December 2008 in six health districts in western and central Burkina Faso. We evaluated eight thresholds composed of weekly incidence rates at health centre level for their performance in predicting annual incidences of 0.4%and 0.8% in health centre areas. The eventually chosen definition was used to describe the spatiotemporal epidemiology and size of localised meningitis epidemics during the included district years. RESULTS: Among eight weekly thresholds evaluated, a weekly incidence rate of 75 cases per 100,000 inhabitants during at least two consecutive weeks with at least 5 cases per week had 100% sensitivity and 98% specificity for predicting an annual incidence of at least 0.8% in health centres. Using this definition, localised epidemics were identified in all but one years during 2004-2008, concerned less than 10% of the districts' population and often were geographically dispersed. Where sufficient laboratory data were available, localised epidemics were exclusively due to meningococci. CONCLUSIONS: This definition of localised epidemics a the health centre level will be useful for risk factor and modelling studies to understand the meningitis belt phenomenon and help documenting vaccine impact against epidemic meningitis where no widespread laboratory surveillance exists for quantifying disease reduction after vaccination.

Feasibility, acceptability, and effectiveness of non-pharmaceutical interventions against infectious diseases among crisis-affected populations: a scoping review.

BACKGROUND: Non-pharmaceutical interventions (NPIs) are a crucial suite of measures to prevent and control infectious disease outbreaks. Despite being particularly important for crisis-affected populations and those living in informal settlements, who typically reside in overcrowded and resource limited settings with inadequate access to healthcare, guidance on NPI implementation rarely takes the specific needs of such populations into account. We therefore conducted a systematic scoping review of the published evidence to describe the landscape of research and identify evidence gaps concerning the acceptability, feasibility, and effectiveness of NPIs among crisis-affected populations and informal settlements. METHODS: We systematically reviewed peer-reviewed articles published between 1970 and 2020 to collate available evidence on the feasibility, acceptability, and effectiveness of NPIs in crisis-affected populations and informal settlements. We performed quality assessments of each study using a standardised questionnaire. We analysed the data to produce descriptive summaries according to a number of categories: date of publication; geographical region of intervention; typology of crisis, shelter, modes of transmission, NPI, research design; study design; and study quality. RESULTS: Our review included 158 studies published in 85 peer-reviewed articles. Most research used low quality study designs. The acceptability, feasibility, and effectiveness of NPIs was highly context dependent. In general, simple and cost-effective interventions such as community-level environmental cleaning and provision of water, sanitation and hygiene services, and distribution of items for personal protection such as insecticide-treated nets, were both highly feasible and acceptable. Logistical, financial, and human resource constraints affected both the implementation and sustainability of measures. Community engagement emerged as a strong factor contributing to the effectiveness of NPIs. Conversely, measures that involve potential restriction on personal liberty such as case isolation and patient care and burial restrictions were found to be less acceptable, despite apparent effectiveness. CONCLUSIONS: Overall, the evidence base was variable, with substantial knowledge gaps which varied between settings and pathogens. Based on the current landscape, robust evidence-based guidance is not possible, and a research agenda is urgently required that focusses on these specific vulnerable populations. Although implementation of NPIs presents unique practical challenges in these settings, it is critical that such an agenda is put in place, and that the lessons learned from historical and present experiences are documented to build a firm evidence base.

Age limit does not replace serologic testing for determination of immune status for measles.

Adults more than 40 years old are not necessarily immune to measles. A measles outbreak that involved healthcare workers occurred after contact with a 44-year-old patient. Results of a hospital-wide program of mass screening revealed that 117 (4.5%) of 2,600 individuals tested seronegative for measles; 31 (26.1%) of these 117 individuals were more than 40 years old.

Staffing level: a determinant of late-onset ventilator-associated pneumonia.

INTRODUCTION: The clinical and economic burden of ventilator-associated pneumonia (VAP) is uncontested. We conducted the present study to determine whether low nurse-to-patient ratio increases the risk for VAP and whether this effect is similar for early-onset and late-onset VAP. METHODS: This prospective, observational, single-centre cohort study was conducted in the medical intensive care unit (ICU) of the University of Geneva Hospitals. All patients who were at risk for ICU-acquired infection admitted from January 1999 to December 2002 were followed from admission to discharge. Collected variables included patient characteristics, admission diagnosis, Acute Physiology and Chronic Health Evaluation II score, co-morbidities, exposure to invasive devices, daily number of patients and nurses on duty, nurse training level and all-site ICU-acquired infections. VAP was diagnosed using standard definitions. RESULTS: Among 2,470 patients followed during their ICU stay, 262 VAP episodes were diagnosed in 209/936 patients (22.3%) who underwent mechanical ventilation. Median duration of mechanical ventilation was 3 days (interquartile range 2 to 6 days) among patients without VAP and 11 days (6 to 19 days) among patients with VAP. Late-onset VAP accounted for 61% of all episodes. The VAP rate was 37.6 episodes per 1,000 days at risk (95% confidence interval 33.2 to 42.4). The median daily nurse-to-patient ratio over the study period was 1.9 (interquartile range 1.8 to 2.2). By multivariate Cox regression analysis, we found that a high nurse-to-patient ratio was associated with a decreased risk for late-onset VAP (hazard ratio 0.42, 95% confidence interval 0.18 to 0.99), but there was no association with early-onset VAP. CONCLUSION: Lower nurse-to-patient ratio is associated with increased risk for late-onset VAP.

Liquid versus gel handrub formulation: a prospective intervention study.

INTRODUCTION: Hand hygiene is one of the cornerstones of the prevention of health care-associated infection, but health care worker (HCW) compliance with good practices remains low. Alcohol-based handrub is the new standard for hand hygiene action worldwide and usually requires a system change for its successful introduction in routine care. Product acceptability by HCWs is a crucial step in this process. METHODS: We conducted a prospective intervention study to compare the impact on HCW compliance of a liquid (study phase I) versus a gel (phase II) handrub formulation of the same product during daily patient care. All staff (102 HCWs) of the medical intensive care unit participated. Compliance with hand hygiene was monitored by a single observer. Skin tolerance and product acceptability were assessed using subjective and objective scoring systems, self-report questionnaires, and biometric measurements. Logistic regression was used to estimate the association between predictors and compliance with the handrub formulation as the main explanatory variable and to adjust for potential risk factors. RESULTS: Overall compliance (phases I and II) with hand hygiene practices among nurses, physicians, nursing assistants, and other HCWs was 39.1%, 27.1%, 31.1%, and 13.9%, respectively (p = 0.027). Easy access to handrub improved compliance (35.3% versus 50.6%, p = 0.035). Nurse status, working on morning shifts, use of the gel formulation, and availability of the alcohol-based handrub in the HCW's pocket were independently associated with higher compliance. Immediate accessibility was the strongest predictor. Based on self-assessment, observer assessment, and the measurement of epidermal water content, the gel performed significantly better than the liquid formulation. CONCLUSION: Facilitated access to an alcohol-based gel formulation leads to improved compliance with hand hygiene and better skin condition in HCWs.

Contact tracing performance during the Ebola virus disease outbreak in Kenema district, Sierra Leone.

Contact tracing in an Ebola virus disease (EVD) outbreak is the process of identifying individuals who may have been exposed to infected persons with the virus, followed by monitoring for 21 days (the maximum incubation period) from the date of the most recent exposure. The goal is to achieve early detection and isolation of any new cases in order to prevent further transmission. We performed a retrospective data analysis of 261 probable and confirmed EVD cases in the national EVD database and 2525 contacts in the Contact Line Lists in Kenema district, Sierra Leone between 27 April and 4 September 2014 to assess the performance of contact tracing during the initial stage of the outbreak. The completion rate of the 21-day monitoring period was 89% among the 2525 contacts. However, only 44% of the EVD cases had contacts registered in the Contact Line List and 6% of probable or confirmed cases had previously been identified as contacts. Touching the body fluids of the case and having direct physical contact with the body of the case conferred a 9- and 20-fold increased risk of EVD status, respectively. Our findings indicate that incompleteness of contact tracing led to considerable unmonitored transmission in the early months of the epidemic. To improve the performance of early outbreak contact tracing in resource poor settings, our results suggest the need for prioritized contact tracing after careful risk assessment and better alignment of Contact Line Listing with case ascertainment and investigation.This article is part of the themed issue 'The 2013-2016 West African Ebola epidemic: data, decision-making and disease control'.

Outbreak of endophthalmitis after cataract surgery: the importance of the quality of the surgical wound.

Postoperative endophthalmitis is a rare but potentially devastating condition. We investigated an outbreak of 8 cases of endophthalmitis in patients who underwent phakectomy performed by a single surgeon from January through September 2004. The outbreak was traced to damaged surgical blades, and it highlights the importance of the quality of the surgical wound.

Learning from imbalanced data in surveillance of nosocomial infection.

OBJECTIVE: An important problem that arises in hospitals is the monitoring and detection of nosocomial or hospital acquired infections (NIs). This paper describes a retrospective analysis of a prevalence survey of NIs done in the Geneva University Hospital. Our goal is to identify patients with one or more NIs on the basis of clinical and other data collected during the survey. METHODS AND MATERIAL: Standard surveillance strategies are time-consuming and cannot be applied hospital-wide; alternative methods are required. In NI detection viewed as a classification task, the main difficulty resides in the significant imbalance between positive or infected (11%) and negative (89%) cases. To remedy class imbalance, we explore two distinct avenues: (1) a new re-sampling approach in which both over-sampling of rare positives and under-sampling of the noninfected majority rely on synthetic cases (prototypes) generated via class-specific sub-clustering, and (2) a support vector algorithm in which asymmetrical margins are tuned to improve recognition of rare positive cases. RESULTS AND CONCLUSION: Experiments have shown both approaches to be effective for the NI detection problem. Our novel re-sampling strategies perform remarkably better than classical random re-sampling. However, they are outperformed by asymmetrical soft margin support vector machines which attained a sensitivity rate of 92%, significantly better than the highest sensitivity (87%) obtained via prototype-based re-sampling.

Knowledge of standard and isolation precautions in a large teaching hospital.

OBJECTIVE: To assess the level of knowledge regarding and attitudes toward standard and isolation precautions among healthcare workers in a hospital. METHOD: A confidential, self-administered questionnaire survey was conducted in a random sample of 1500 nurses and 500 physicians in a large teaching hospital. RESULTS: A total of 1,241 questionnaires were returned (response rate, 62%). The median age of respondents was 39 years; 71.9% were women and 21.2% had senior staff status. One-fourth had previously participated in specific training regarding transmission precautions for pathogens conducted by the infection control team. More than half (55.9%) gave correct answers to 10 or more of the 13 knowledge-type questions. The following reasons for noncompliance with guidelines were judged as "very important": lack of knowledge (47%); lack of time (42%); forgetfulness (39%); and lack of means (28%). For physicians and healthcare workers in a senior position, lack of time and lack of means were significantly less important (P < .0005). On multivariate linear regression, knowledge was independently associated with exposure to training sessions (coefficient, 0.33; 95% confidence interval, 0.08 to 0.57; P = .009) and less professional experience (coefficient per increasing professional experience, -0.024; 95% confidence interval, -0.035 to -0.012; P < .0005). CONCLUSIONS: Despite a training effort targeting opinion leaders, knowledge of transmission precautions for pathogens remained insufficient. Nevertheless, specific training proved to be the major determinant of "good knowledge".

Nosocomial bacteremia: clinical significance of a single blood culture positive for coagulase-negative staphylococci.

OBJECTIVES: To describe the epidemiology of nosocomial coagulase-negative staphylococci (CoNS) bacteremia and to evaluate the clinical significance of a single blood culture positive for CoNS. DESIGN: A 3-year retrospective cohort study based on data prospectively collected through hospital-wide surveillance. Bacteremia was defined according to CDC criteria, except that a single blood culture growing CoNS was not systematically considered as a contaminant. All clinically significant blood cultures positive for CoNS nosocomial bacteremia were considered for analysis. SETTING: A large university teaching hospital in Geneva, Switzerland. RESULTS: A total of 2,660 positive blood cultures were identified. Of these, 1,108 (41.7%) were nosocomial; CoNS were recovered from 411 nosocomial episodes (37.1%). Two hundred thirty-four episodes of CoNS bacteremia in the presence of signs of sepsis were considered clinically relevant and analyzed. Crude mortality and associated mortality were 24.4% and 12.8%, respectively. Associated mortality was similar among patients with one positive blood culture and those with two or more (16.2% vs 10.8%, respectively; P = .3). Mortality rates after bacteremia for patients with a single positive blood culture and for those with two or more were 15.3% and 7.0%, respectively, at day 14 (RR, 2.2; CI95, 0.87-5.46) and 20.8% and 11.3%, respectively, at day 28 (RR, 1.9; CI95, 0.9-3.8). On multivariate analysis, only age and a rapidly fatal disease were independently associated with death. CONCLUSION: CoNS bacteremia harbor a significant mortality and a single positive blood culture in the presence of signs of sepsis should be considered as clinically relevant.

Alcohol-based handrub improves compliance with hand hygiene in intensive care units.

BACKGROUND: Nosocomial infection is a leading complication in intensive care units. Although hand hygiene is the single most efficient preventive measure, compliance with this simple action remains low. OBJECTIVES: To assess the effect of an intervention to promote hand hygiene and to investigate risk factors for noncompliance in intensive care units. METHODS: We performed 7 observational surveys and implemented a promotional campaign after baseline in medical, surgical, and pediatric intensive care units of a teaching hospital. Health care workers were observed during routine patient care. The intervention consisted of a hospitalwide promotional campaign, including observation and performance feedback, posters display, and distribution of individual bottles of alcohol-based handrub. The main outcome measure was compliance with hand hygiene through handwashing or handrubbing. RESULTS: We observed 2743 opportunities for hand hygiene distributed over 248 periods. Overall compliance increased from 38.4% to 54.5% during the study (P<.001). Although recourse to handwashing remained stable at around 30%, handrubbing increased from 5.4% at baseline to 21.7% at the last survey (P<.001). Compliance increased among nurses and nursing assistants, but remained stable among physicians. Handwashing compliance decreased, on average, by 4.7% for an increase of 10 opportunities for hand hygiene per hour of patient care (P<.001), whereas no such association existed for handrubbing. CONCLUSIONS: Our intervention induced a marked and sustained increase in compliance with hand hygiene. In intensive care units, less time-consuming handrubbing might replace standard handwashing and overcome the barrier of time constraints.

Hand hygiene among physicians: performance, beliefs, and perceptions.

BACKGROUND: Physician adherence to hand hygiene remains low in most hospitals. OBJECTIVES: To identify risk factors for nonadherence and assess beliefs and perceptions associated with hand hygiene among physicians. DESIGN: Cross-sectional survey of physician practices, beliefs, and attitudes toward hand hygiene. SETTING: Large university hospital. PARTICIPANTS: 163 physicians. MEASUREMENTS: Individual observation of physician hand hygiene practices during routine patient care with documentation of relevant risk factors; self-report questionnaire to measure beliefs and perceptions. Logistic regression identified variables independently associated with adherence. RESULTS: Adherence averaged 57% and varied markedly across medical specialties. In multivariate analysis, adherence was associated with the awareness of being observed, the belief of being a role model for other colleagues, a positive attitude toward hand hygiene after patient contact, and easy access to hand-rub solution. Conversely, high workload, activities associated with a high risk for cross-transmission, and certain technical medical specialties (surgery, anesthesiology, emergency medicine, and intensive care medicine) were risk factors for nonadherence. LIMITATIONS: Direct observation of physicians may have influenced both adherence to hand hygiene and responses to the self-report questionnaire. Generalizability of study results requires additional testing in other health care settings and physician populations. CONCLUSION: Physician adherence to hand hygiene is associated with work and system constraints, as well as knowledge and cognitive factors. At the individual level, strengthening a positive attitude toward hand hygiene and reinforcing the conviction that each individual can influence the group behavior may improve adherence among physicians. Physicians who work in technical specialties should also be targeted for improvement.

The development of global vaccine stockpiles.

Global vaccine stockpiles, in which vaccines are reserved for use when needed for emergencies or supply shortages, have effectively provided countries with the capacity for rapid response to emergency situations, such as outbreaks of yellow fever and meningococcal meningitis. The high cost and insufficient supply of many vaccines, including oral cholera vaccine and pandemic influenza vaccine, have prompted discussion on expansion of the use of vaccine stockpiles to address a wider range of emerging and re-emerging diseases. However, the decision to establish and maintain a vaccine stockpile is complex and must take account of disease and vaccine characteristics, stockpile management, funding, and ethical concerns, such as equity. Past experience with global vaccine stockpiles provide valuable information about the processes for their establishment and maintenance. In this Review we explored existing literature and stockpile data to discuss the lessons learned and to inform the development of future vaccine stockpiles.

Noma: an "infectious" disease of unknown aetiology.

Noma (cancrum oris) is a devastating gangrenous disease that leads to severe tissue destruction in the face and is associated with high morbidity and mortality. It is seen almost exclusively in young children living in remote areas of less developed countries, particularly in Africa. The exact prevalence of the disease is unknown, but a conservative estimate is that 770000 people are currently affected by noma sequelae. The cause remains unknown, but a combination of several elements of a plausible aetiology has been identified: malnutrition, a compromised immune system, poor oral hygiene and a lesion of the gingival mucosal barrier, and an unidentified bacterial factor acting as a trigger for the disease. This review discusses the epidemiology, clinical features, current understanding of the pathophysiology, and treatment of the acute phase and sequelae requiring reconstructive surgery. Noma may be preventable if recognised at an early stage. Further research is needed to identify more exactly the causative agents.

Cost implications of successful hand hygiene promotion.

We evaluated the costs associated with a sustained and successful campaign for hand hygiene promotion that emphasized alcohol-based handrubs. The total cost of the hand hygiene promotion corresponded to less than 1% of the costs associated with nosocomial infections. Successful hand hygiene promotion is probably cost-saving.