Medscape Infectious Diseases Journal Scan

http://www.medscape.com/Medscape/features/JournalScan/ID/2001/js-id0401.html

Medscape Infectious Diseases Journal Scan
Volume 4, Number 1
(Updated January 19, 2001)

Benjamin Davis, MD, Contributing Editor

About the Author: Dr. Davis is Instructor in Medicine, Harvard Medical School, Cambridge, and Assistant Physician, Infectious Disease Unit, Massachusetts General Hospital, Boston.

Journal Scan is the clinician's guide to the latest clinical research findings in J Infect Dis, Clin Infect Dis, Emerging Infectious Diseases, Ann Intern Med, The New England Journal of Medicine, and JAMA. Short summaries of feature articles include links to the article abstracts and full text, when available. [Medscape, 2001. © 2001 Medscape, Inc.]

From
Lancet
October 2000 (Volume 356, Number 9238)

Effectiveness of a Hospital-wide Programme to Improve Compliance With Hand Hygiene. Infection Control Programme.

Pittet D, Hugonnet S, Harbarth S, et al.
Lancet. 2000;356:1307-1312

Handwashing remains the most important measure in preventing nosocomial infections in hospitals. Many infection control departments remain vexed by inexplicably poor compliance with this safe, inexpensive, and effective precaution! Pittet and colleagues report a hospital-wide hand hygiene initiative in Geneva, which is notable for its success as well as its duration.

Because heavy workload was found to be inversely related to handwashing, the investigators promoted an alcohol-based handrub, which was distributed widely in patient care areas. Posters advocating hand hygiene were used, and the program received the active support of senior hospital administrators as well as medical and nursing directors.

Direct observation of hand hygiene "opportunities" was recorded twice yearly between 1994 and 1997. Compliance improved steadily from 48% in 1994 to 66% in 1997. Improvement was highest among nurses and nursing assistants and poorest among physicians, in whom no statistically significant improvement could be demonstrated.

Most importantly, the investigators demonstrated a reduction in nosocomial infection rates in their hospital from 16.9% to 9.9% and a reduction in MRSA transmission as measured by active surveillance on patient care units. MRSA transmission was reduced from 2.16 to 0.93 episodes per 10,000 patient-days. The consumption of the alcohol-based handrub increased from 3.5 to 15.4 liters per 1000 patient-days. The challenge, of course, is to maintain the gains from a program like this after the period of active intervention ends.

Abstract

Variant Creutzfeldt-Jakob Disease in UK Children: A National Surveillance Study

Verity CM, Nicoll A, Will RG, Devereux G, Stellitano L
Lancet. 2000;356:1224-1227

Variant Creutzfeldt-Jakob disease (vCJD) was first described in 10 British patients in 1996. This disease differed from sporadic CJD in that the age of onset was younger, there was a greater likelihood of early psychiatric symptoms, and there was less likelihood of characteristic triphasic spikes being present on EEG. Nevertheless, spongiform encephalopathy with PrP deposition and plaques was still found on pathologic examination. Early on, this variant presentation was thought to be linked to bovine spongiform encephalopathy (BSE). BSE is a disease of cattle first described in 1987 and probably transmitted by feed contaminated with a scrapie-like agent. In 1989, the Bovine Offal Prohibition Regulations were implemented, hopefully removing the source of both BSE and vCJD.

Although most cases of vCJD occur in adults (there have been 82 cases to date), detection of pediatric cases is critically important for public health purposes. Children born after the regulations were put in place should not develop vCJD if contaminated cattle feed is the major mechanism of transmission to humans.

Verity and colleagues report 3 years of active surveillance for pediatric vCJD in the United Kingdom. Six hundred fifty-five children with progressive intellectual and neurologic deterioration were systematically identified. Of these, 360 clearly had another neurodegenerative disease as the cause of their decline. Of undiagnosed cases, the vast majority have no features suggesting vCJD. However, the investigators did find 3 cases of definite or probable vCJD in children, including the youngest case ever reported, in a 12-year-old girl.

This report can be viewed in 2 ways. It is reassuring that only 3 cases were found in 3 years of systematic surveillance. Nonetheless, vCJD has only recently been described, and its incubation period and full clinical manifestations are still unknown. It is therefore possible that more pediatric cases will emerge in the coming years. If this turns out to be the case, we may not see the expected waning of adult cases of vCJD following the cattle feed regulations in Great Britain, and further efforts to discover all important means of transmission will be warranted.

Abstract

From
MMWR Morbidity and Mortality Weekly Report
December 2000 (Volume 49, Number 48)

Outbreak of Poliomyelitis - Dominican Republic and Haiti, 2000

MMWR Morb Mortal Wkly Rep. 2000;49:1094, 1103

and

Lancet
October 2000 (Volume 356, Number 9238)

Characterisation of Vaccine-derived Polioviruses Isolated From Sewage and River Water in Japan

Yoshida H, Horie H, Matsuura K, et al.
Lancet. 2000;356:1461-1463.

There have been no reports of acute flaccid paralysis attributable to wild poliovirus in the Western Hemisphere since 1991. However, oral poliovirus vaccine (OPV)-derived mutants are capable of causing human disease and paralysis. An outbreak of acute flaccid paralysis attributed to neurovirulent OPV-derived strains has recently been reported from the Caribbean island of Hispanola. In all, 20 children and adolescents, 84% of whom were 6 years of age or younger, were afflicted between July and November 2000. All patients were either unvaccinated or undervaccinated. Molecular characterization of the mutant viruses showed that they have 97% homology to the parent OPV strain, and that they have been circulating in the population for approximately 2 years.

In a second report marking the potential for neurovirulence in circulating OPV-derived strains, Yoshida and colleagues reported on 29 poliovirus strains isolated from sewage and river water in Japan immediately following OPV vaccination, which is given twice annually. Fully 55% of these strains were estimated to have increased neurovirulence by virtue of a nucleotide change at codon 472 (472-C revertants). No cases of paralytic polio have been reported from Japan since a wild type-strain case in 1980.

As the world moves toward the goal of global eradication of polio, these 2 reports remind us that continued vigilance remains critical. It should be emphasized that the only reliable protection against OPV-derived paralytic polio is maintenance of high rates of vaccination in a population. OPV remains safe and effective and remains recommended for the eradication of polio in many parts of the world. In fact, high rates of OPV administration are most effective against OPV-derived poliomyelitis outbreaks. Nonetheless, in parts of the world where the risk of polio is growing more and more remote, such as the United States, recommendations to use IPV rather than OPV for primary vaccination of children and adults have been introduced. The transition from OPV to IPV is best made nation by nation according to local conditions.

Abstract (MMWR)
Abstract (Lancet)

From
JAMA
October 2000 (Volume 284, Number 13)

Effectiveness and Cost-Benefit of Influenza Vaccination of Healthy Working Adults

Bridges CB, Thompson WW, Meltzer MI, et al.
JAMA.2000;284:1655-1663

A debate exists about the advisability of routine influenza vaccination for healthy adults younger than 65. For older adults, the risk of serious complications due to influenza, including hospitalization and death, are high enough to warrant routine immunization. The data from randomized trials of influenza vaccination in healthy young adults have been less clear, partly because vaccine efficacy varies from year to year, and partly because influenza is not always virologically defined in clinical trials. Buxton Bridges and colleagues report a randomized trial of influenza vaccination among 2375 healthy adults aged 18-64 years working at the Ford Motor Company during the 1997-8 and 1998-9 influenza seasons.

The most important finding of this trial was that the efficacy of vaccination varied depending on the year. In 1997-8, most clinical illness in the study population was due to influenza A/Sydney/5/97-like (H3N2), a strain that was antigenically distinct from the H3N2 vaccine component. Consequently, vaccine efficacy was not statistically significant that year. By contrast, in 1998-9, most clinical illness was due to either influenza A or B strains that matched the vaccine components administered that year. In this trial, the vaccine efficacy was 86% (P = .001) in 1998-9.

Notably, vaccination of healthy adults did not provide a measurable economic benefit in either year, in terms of days lost from work. It is also worth noting that only 23% of illnesses suspected to be caused by influenza actually were caused by influenza. Only 1% to 10% of all participants experienced laboratory-confirmed influenza (depending on the year and vaccination status) during the study years. Most other studies report influenza incidence in healthy adults of 10% or lower.

Abstract

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