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N Verlander

Publications and source records attributed to N Verlander.

5 recordsLinked to original sources
PubMed2005

Evaluation of syndromic surveillance based on National Health Service Direct derived data--England and Wales.

INTRODUCTION: Syndromic surveillance systems might serve as an early warning to detect outbreaks of infectious diseases and chemical poisoning, including those caused by deliberate release. In England and Wales, data from National Health Service (NHS) Direct, a national telephone health advice service, were used for surveillance of 10 syndromes commonly occurring in the community. OBJECTIVES: The objective of this study was to evaluate NHS Direct syndromic surveillance using the "Framework for Evaluating Public Health Surveillance Systems for Early Detection of Outbreaks", published by CDC. METHODS: Quantitative and qualitative assessments were performed. Examination of daily data flow was used to determine the timeliness and data quality. Validity was determined by comparing NHS Direct surveillance with a well-established clinical-based surveillance system using a time series analysis. Semistructured interviews of main stakeholders were conducted to determine usefulness, flexibility, acceptability, portability, stability, and system costs. RESULTS: NHS Direct syndromic surveillance has representative national coverage, provides near real-time recording and data analysis, and can potentially detect high-risk, large-scale events. Direct costs are low and variable costs are unpredictable. Flexibility depends on urgency of the need for change, and portability relies on the existence of infrastructure similar to NHS Direct. Statistically significant correlation exists between NHS Direct surveillance and a surveillance system based on the Royal College of General Practitioners data for influenza-like illness. CONCLUSION: The CDC framework is a useful tool to standardize the evaluation of syndromic surveillance. NHS Direct syndromic surveillance is timely, representative, useful, and acceptable with low marginal costs and borderline flexibility and portability. Cross-correlation time series modeling might represent an appropriate method in the evaluation of syndromic surveillance validity.

Disease Outbreaks↗
PubMed2004

National symptom surveillance using calls to a telephone health advice service--United Kingdom, December 2001-February 2003.

INTRODUCTION: Recent terrorist activity has highlighted the need to improve surveillance systems for the early detection of chemical or biologic attacks. A new national surveillance system in the United Kingdom (UK) examines symptoms reported to NHS Direct, a telephone health advice service. OBJECTIVES: The aim of the surveillance system is to identify an increase in symptoms indicative of early stages of illness caused either by a deliberate release of a biologic or chemical agent or by common infections. METHODS: Data relating to 10 key syndromes (primarily respiratory and gastrointestinal) are received electronically from 23 call centers covering England and Wales. Data are analyzed daily and statistically significant excesses, termed exceedances, in calls are automatically highlighted and assessed by a multidisciplinary team. RESULTS: During December 2001-February 2003, a total of 1,811 exceedances occurred, of which 126 required further investigation and 16 resulted in alerts to local or national health-protection teams. Examples of these investigations are described. CONCLUSION: Surveillance of call-center data has detected substantial levels of specific syndromes at both national and regional levels. Although no deliberate release of a biologic or chemical agent has been detected thus far by this or any other surveillance system in the UK, the NHS Direct surveillance system continues to be refined.

Bioterrorism↗
PubMed2001

Evaluation of donor arm disinfection techniques.

BACKGROUND AND OBJECTIVE: To validate a standardized optimal national procedure for donor arm disinfection. MATERIALS AND METHODS: A direct swabbing and plating technique was used to enumerate bacteria present on the arm pre- and postdisinfection. Twelve donor arm disinfection techniques were evaluated. RESULTS: The Medi-Flex Adapted method, consisting of a two-stage process with an initial application of isopropyl alcohol followed by tincture of iodine, produced the best arm disinfection. A percentage reduction in bacterial counts of 99.79% (logarithmic reduction of 2.67) was obtained. Postdisinfection, 70% of donors had bacterial counts of zero, and 98% had counts of 10 or less. CONCLUSION: The Medi-Flex disinfection method offers the English National Blood Service a validated, optimal 'best practice' disinfection technique and should contribute significantly to the reduction in risk of transmission of bacteria by transfusion.

2-Propanol↗
PubMed2000

Predictive value of the ultrasensitive HIV viral load assay in clinical practice.

The aim of this study was to determine whether an HIV viral load of <50 copies/ml (c/ml), in the first available plasma sample to have shown a viral load of <400 c/ml, in patients on antiretroviral therapy, is correlated with longer term suppression of viral load (at <400 c/ml) compared to a viral load of 50-399 c/ml, and secondly, to compare the results obtained by ultrasensitive and standard viral load assays carried out on the same sample. A total of 98 HIV-positive patients on antiretroviral therapy with a viral load of <400 c/ml and at least one subsequent viral load measurement, were selected. For each patient, the first available specimen showing a viral load of <400 c/ml was tested using the Roche Amplicor ultrasensitive viral load assay, and patients were followed up subsequently for a median period of 52 weeks. Whether patients achieved an ultrasensitive viral load (USVL) of <50 c/ml or not made very little difference to the proportion of patients in each group showing continued response to treatment (52% vs. 45% respectively). The only variable that was shown to significantly predict longevity of response was the number of antiretroviral drugs used. Secondly, a standard viral load of <400 c/ml but with a detectable signal above background levels, was strongly predictive of a USVL of >50 c/ml. Overall, the findings suggest that the advantage in predictive value of the ultrasensitive over the standard HIV viral load assay, shown previously in clinical trials, may be limited in clinical practice.

Anti-HIV Agents↗