Effect of a serogroup A meningococcal conjugate vaccine (PsA-TT) on serogroup A meningococcal meningitis and carriage in Chad: a community study [corrected].

BACKGROUND: A serogroup A meningococcal polysaccharide-tetanus toxoid conjugate vaccine (PsA-TT, MenAfriVac) was licensed in India in 2009, and pre-qualified by WHO in 2010, on the basis of its safety and immunogenicity. This vaccine is now being deployed across the African meningitis belt. We studied the effect of PsA-TT on meningococcal meningitis and carriage in Chad during a serogroup A meningococcal meningitis epidemic. METHODS: We obtained data for the incidence of meningitis before and after vaccination from national records between January, 2009, and June, 2012. In 2012, surveillance was enhanced in regions where vaccination with PsA-TT had been undertaken in 2011, and in one district where a reactive vaccination campaign in response to an outbreak of meningitis was undertaken. Meningococcal carriage was studied in an age-stratified sample of residents aged 1-29 years of a rural area roughly 13-15 and 2-4 months before and 4-6 months after vaccination. Meningococci obtained from cerebrospinal fluid or oropharyngeal swabs were characterised by conventional microbiological and molecular methods. FINDINGS: Roughly 1·8 million individuals aged 1-29 years received one dose of PsA-TT during a vaccination campaign in three regions of Chad in and around the capital N'Djamena during 10 days in December, 2011. The incidence of meningitis during the 2012 meningitis season in these three regions was 2·48 per 100,000 (57 cases in the 2·3 million population), whereas in regions without mass vaccination, incidence was 43·8 per 100,000 (3809 cases per 8·7 million population), a 94% difference in crude incidence (p<0·0001), and an incidence rate ratio of 0·096 (95% CI 0·046-0·198). Despite enhanced surveillance, no case of serogroup A meningococcal meningitis was reported in the three vaccinated regions. 32 serogroup A carriers were identified in 4278 age-stratified individuals (0·75%) living in a rural area near the capital 2-4 months before vaccination, whereas only one serogroup A meningococcus was isolated in 5001 people living in the same community 4-6 months after vaccination (adjusted odds ratio 0·019, 95% CI 0·002-0·138; p<0·0001). INTERPRETATION: PSA-TT was highly effective at prevention of serogroup A invasive meningococcal disease and carriage in Chad. How long this protection will persist needs to be established. FUNDING: The Bill & Melinda Gates Foundation, the Wellcome Trust, and Médecins Sans Frontères.

A Bayesian network approach to the study of historical epidemiological databases: modelling meningitis outbreaks in the Niger.

OBJECTIVE: To develop a tool for evaluating the risk that an outbreak of meningitis will occur in a particular district of the Niger after outbreaks have been reported in other, specified districts of the country. METHODS: A Bayesian network was represented by a graph composed of 38 nodes (one for each district in the Niger) connected by arrows. In the graph, each node directly influenced each of the "child" nodes that lay at the ends of the arrows arising from that node, according to conditional probabilities. The probabilities between "influencing" and "influenced" districts were estimated by analysis of databases that held weekly records of meningitis outbreaks in the Niger between 1986 and 2005. For each week of interest, each district was given a Boolean-variable score of 1 (if meningitis incidence in the district reached an epidemic threshold in that week) or 0. FINDINGS: The Bayesian network approach provided important and original information, allowing the identification of the districts that influence meningitis risk in other districts (and the districts that are influenced by any particular district) and the evaluation of the level of influence between each pair of districts. CONCLUSION: Bayesian networks offer a promising approach to understanding the dynamics of epidemics, estimating the risk of outbreaks in particular areas and allowing control interventions to be targeted at high-risk areas.

[Consequences of an unsufficient range of immunity in "pediatric" infectious diseases--example with measles]. / Die Folgen einer ungenügenden Herdimmunität bei "pädiatrischen" Infektionskrankheiten--Beispiel einer Masernepidemie.

From January to February 2005, the healthcare authorities of the Canton of Geneva were alerted to 15 cases of measles, in contrast to one single case in 2004. The adult status (17-44 years) of the affected persons years was unusual. Four were health care workers at the same hospital who were infected after contact with a 44-year-old patient in a single night during his stay in the emergency room. The presumption that measles are only a paediatric disease had made the diagnosis difficult. None of all these adults was immune according to the actual recommendations. Despite a federal vaccine policy, repetition of recommendations, good results of available vaccines and reimbursement of the cost by health insurance companies, voluntary vaccination prevalence is too small in Switzerland to prevent the outbreak of epidemics. In contrast to the goals of the World Health Organization (WHO) and the Swiss Federal Office of Public Health, the country is unfortunately far from displaying a sufficiently high herd immunity to prevent health care-associated and economic damage by sporadic epidemics.

Variation in nosocomial infection prevalence according to patient care setting:a hospital-wide survey.

A study was performed to estimate the prevalence of nosocomial infections (NI) and assess differences between medical care settings in one hospital complex. A seven-day period-prevalence survey was conducted in May 1998 in a large primary and tertiary healthcare centre in Geneva, Switzerland, that included all patients in acute, sub-acute and chronic care settings. Variables included demography, exposure to invasive devices and antibiotics, surgical history, and patients' localization. Overall prevalence of NI was 11.3% (acute, 8.4%; sub-acute, 11.4%; chronic care setting, 16.4%) in the 1928 patients studied, and ranged from 0% in ophthalmology to 23% in critical care units. Odds of infection in sub-acute and chronic care settings were significantly higher than in the acute care setting even after adjustment for case-mix [OR, 2.59; 95% confidence interval (CI(95)) 1.53-4.41; and OR, 2.34; Cl(95)1.38-3.95, respectively]. As a distinct group, patients in the geriatric location (belonging to the sub-acute care setting) showed a significant proportion of urinary (39%) and respiratory (21%) tract infections, contrasting with a relatively low exposure to urinary catheters (6.1%) and orotracheal intubation (0%). In conclusion, sub-acute and chronic care settings are associated with high infection prevalence even after case-mix adjustment. Prevalence studies are an easy surveillance tool that can be exploited further by analysing data according to hospital care settings to identify high-risk areas.

Effectiveness of a hospital-wide programme to improve compliance with hand hygiene. Infection Control Programme.

BACKGROUND: Hand hygiene prevents cross infection in hospitals, but compliance with recommended instructions is commonly poor. We attempted to promote hand hygiene by implementing a hospital-wide programme, with special emphasis on bedside, alcohol-based hand disinfection. We measured nosocomial infections in parallel. METHODS: We monitored the overall compliance with hand hygiene during routine patient care in a teaching hospital in Geneva, Switzerland, before and during implementation of a hand-hygiene campaign. Seven hospital-wide observational surveys were done twice yearly from December, 1994, to December, 1997. Secondary outcome measures were nosocomial infection rates, attack rates of methicillin-resistant Staphylococcus aureus (MRSA), and consumption of handrub disinfectant. FINDINGS: We observed more than 20,000 opportunities for hand hygiene. Compliance improved progressively from 48% in 1994, to 66% in 1997 (p<0.001). Although recourse to handwashing with soap and water remained stable, frequency of hand disinfection substantially increased during the study period (p<0.001). This result was unchanged after adjustment for known risk factors of poor adherence. Hand hygiene improved significantly among nurses and nursing assistants, but remained poor among doctors. During the same period, overall nosocomial infection decreased (prevalence of 16.9% in 1994 to 9.9% in 1998; p=0.04), MRSA transmission rates decreased (2.16 to 0.93 episodes per 10,000 patient-days; p<0.001), and the consumption of alcohol-based handrub solution increased from 3.5 to 15.4 L per 1000 patient-days between 1993 and 1998 (p<0.001). INTERPRETATION: The campaign produced a sustained improvement in compliance with hand hygiene, coinciding with a reduction of nosocomial infections and MRSA transmission. The promotion of bedside, antiseptic handrubs largely contributed to the increase in compliance.

Hand Hygiene Revisited: Lessons from the Past and Present.

Hand hygiene is the most effective measure to prevent cross-transmission of microorganisms. Adequate hand hygiene can be achieved by standard handwashing--with water alone or with soap--or by the use of an alcohol-based hand-rub solution. Despite considerable efforts, compliance with this simple infection-control measure remains low. Factors predicting non-compliance have been extensively studied, and include physician status, procedures associated with a high risk of cross-transmission, and an important workload. Future interventions to improve compliance should consider complex behavioral theories and the use of multimodal and multidisciplinary strategies. We believe that one of the key components of these interventions should be the wide use of alcohol-based hand-rub, which is microbiologically effective and less time-consuming than standard handwashing.

Improvement of pain and function after arthroscopy and arthrocentesis of the temporomandibular joint: a comparative study.

In 1993 and 1994, 720 patients with pain in the temporo-mandibular joint area were examined and treated. The authors describe their therapeutic protocol. Sixty-two patients were not relieved by conservative nonsurgical therapy and were treated by arthroscopy or arthrocentesis. In both groups the differences in functional result and in pain control were analysed. Results show that both arthroscopy and lavage are useful in improving function and diminishing pain. Arthroscopy shows better results for functional treatment whereas arthrocentesis and arthroscopy show similar results in pain control.

Hand hygiene-beliefs or science?

Over a century has passed since Ignaz P. Semmelweis demonstrated the association between hand hygiene and nosocomial infections, but this simple procedure is still not recognized by many healthcare workers as one of the most important measures to prevent cross-transmission of microorganisms. A relatively large amount of research has been done, in particular to try to understand why compliance remains so low, in order to implement successful promotion campaigns. This research has generated a fair amount of strong scientific data which are sometimes misunderstood and misused because of myths or certain beliefs. Observational or intervention studies have consistently shown a number of risk factors associated with non-compliance, such as high workload, professional category, or type of ward. Others are thought to be barriers to adequate compliance but have not yet been properly assessed. These include skin irritation due to hand hygiene agents, lack of knowledge of hand hygiene recommendations, or lack of institutional policy. Future interventions to promote hand hygiene will need to address these risk factors, and target the individual healthcare worker, as well as the group or institution if a significant degree of success is to be achieved.