Global News Updates
16 January 2008 through 23 January 2008
Topics in this issue:
Food Safety Studies
Avian Influenza
Food Safety Policy Issues
Simple handwashing can reduce diarrhea: studies
23 Jan 2008
Reuters UK
Researchers were cited as saying on Wednesday that encouraging people to wash their hands properly can reduce the rate of diarrhea by 30 percent, potentially saving lives. Their review of 14 different studies showed that in rich and poor countries alike, and in schools, hospitals and elsewhere, hand washing is a simple way to stop infections that cause diarrhea.
Dr. Regina Ejemot of the University of Calabar in Nigeria, who led the study, was quoted as saying in a statement, "This is a huge benefit. For people in low-income areas this effect is comparable to providing clean water. The challenge is to find ways of promoting handwashing, as well as to set up long-term trials that test whether good practice has become part of a person's way of life."
Ejemot and colleagues reviewed the various studies for the Cochrane Collaboration, a journal that specializes in reviewing important scientific and medical studies to get a bigger picture of an issue.
Diarrhea kills around 2.2 million people a year, the World Health Organization estimates. Most are young children in middle- or low-income countries.
"Hand washing can reduce diarrhea episodes by about 30 percent," they wrote. "This significant reduction is comparable to the effect of providing clean water. Some of the studies provided soap, while others involved leaflets or other written materials. The challenge is to find effective ways of getting people to wash their hands appropriately."
Avian Influenza – WHO Review
16 Jan 2008
CIDRAP (Center for Infectious Disease Research & Policy) News [edited]
This 2008 update is published in the 17 Jan 2008 issue of the New England Journal of Medicine (Volume 358(3): 261-273, (http://content.nejm.org/cgi/content/full/358/3/261) and is entitled "Update on Avian Influenza A (H5N1) Virus Infection in Humans," by the Writing Committee of the "Second World Health Organization Consultation on Clinical Aspects of Human Infection with Avian Influenza A (H5N1) Virus."
Exposure source unclear in 25 percent of human H5N1 cases
In at least 25 percent of human infections with the H5N1 avian influenza virus, just how the person was exposed to the virus remains a mystery, according to a report by an expert panel set up by the World Health Organization (WHO). "In one quarter or more of patients with influenza A (H5N1) infection virus infection, the source of exposure is unclear, and environment-to-human transmission remains possible," says the report, which appears today [16 Jan 2008] in the New England Journal of Medicine
The predominant source of exposure in H5N1 cases is contact with infected poultry in the week before onset of illness, the article notes. But in cases involving no such contact, patients might have touched contaminated objects (fomites) or fertilizer containing poultry feces, or have inhaled aerosolized infectious material. The only known risk factor for some patients was visiting a live-poultry market, the article says. The discussion of exposure sources is part of a review of all aspects of human H5N1 cases, including epidemiology, clinical features, diagnosis, treatment, and prevention. The report is based on the WHO's "Second Consultation on Clinical Aspects of Human Infection with Avian Influenza A (H5N1) Virus," a meeting held in Antalya, Turkey, in March 2007.
About a quarter of all human cases have occurred in clusters of 2 or more that were epidemiologically linked, the report says. More than 90 percent of the clusters have involved blood relatives, suggesting a possible genetic susceptibility to the infection. Most people in the clusters probably were infected through common exposure to poultry, "but limited, non-sustained human-to-human transmission has probably occurred during very close, unprotected contact with a severely ill patient," the article states.
Regarding the virus's evolution, the report has a chart that shows a total of 10 different clades (including the original 1997 strain from Hong Kong), or lineages, plus 5 subclades in clade 2. "Changes in multiple viral genes" — not just the surface protein known as hemagglutinin — "are probably required to generate a potentially pandemic influenza A (H5N1) virus," the article says. So far, the virus is not transmissible among ferrets or swine, and reassortment (hybridization) between an H5N1 virus and an H3N2 (human-adapted) virus did not produce a virus transmissible among ferrets.
Concerning host responses, the report does not fully endorse the "cytokine storm" theory: the proposition that the severe disease in H5N1 cases is a result of an overly intense immune response. The tissue damage "probably results from the combined effects of unrestrained viral infection and inflammatory responses" induced by the infection, it says. Further, the current understanding of the immune response to the infection is not adequate to guide efforts to treat the disease by modifying the immune response, the panel says.
In line with that, the report repeats previous WHO advice against the routine use of corticosteroids in H5N1 patients. Corticosteroid therapy has not been effective, and prolonged or high-dose corticosteroids can lead to serious adverse events. As for antiviral drugs, the panel says that clade 1 viruses and most clade 2 viruses from Indonesia are fully resistant to M2 inhibitors (amantadine and rimantadine), but the other clade 2 viruses from other parts of Eurasia and Africa are usually susceptible to these older drugs. The article repeats the standard recommendation for early treatment with oseltamivir, a neuraminidase inhibitor. The panel also reiterates previous WHO statements that doubling the standard oseltamivir dose and duration of treatment may be reasonable. Resistance to the drug has been seen in a few patients, and clade 1 viruses seem to be more susceptible than some clade 2 viruses, though the clinical relevance of this difference is unclear.
Concerning H5N1 vaccines, the panel writes that certain proprietary adjuvants seem to be highly effective in antigen sparing (reducing the amount of antigen needed to generate an immune response) and inducing cross-reactive antibody responses. However, the antibody levels needed for protection against the virus are unknown. The report stops short of endorsing prepandemic vaccination — giving an existing H5N1 vaccine before a pandemic in the hope that it will yield some protection against a later H5N1-based pandemic strain or will at least prime the immune system so that just one dose of a specific pandemic vaccine would be necessary.
Decisions about prepandemic vaccination require complex risk-benefit and cost-benefit analyses because of likely effects on seasonal vaccine production and the chance that mass vaccinations would trigger adverse events, the article says.
Some other observations in the report: - The median age of H5N1 case-patients is about 18, and 90 percent of patients have been 40 years or younger. - While the disease typically leads to severe pneumonia, febrile upper respiratory illnesses without pneumonia have been seen in children, particularly since 2005.- About 15 percent to 20 percent of older adults have some antibodies to H5N1 and might respond to a single dose of vaccine.
WHO tracing system announced
22 Jan 2008
CIDRAP News, corrected version 23 Jan 2009 [edited]
WHO catalogs H5N1 viruses, launches tracking system
Countries affected by H5N1 avian influenza have sent material containing 734 H5N1 virus isolates to the World Health Organization (WHO) over the past 5 years, and from now on the public will be able to track particular isolates that have been submitted and what is being done with them, according to WHO.
An online chart published by WHO yesterday [21 Jan 2008] shows that countries submitted 8763 samples from humans and animals from 2003 through 2007, and 734 H5N1 viruses were isolated from those samples. WHO needs the isolates so it can monitor the virus's evolution, potential for human transmissibility, and susceptibility to antiviral drugs.
Viet Nam contributed the most H5N1 isolates: 375, derived from 1199 samples. But Indonesia provided the second most: 171 isolates derived from 4774 submitted samples. This, despite the fact that the country stopped sending H5N1 samples for several months last year [2007] because of concern that vaccines derived from such samples are too expensive for developing countries. In 2007 Indonesia sent WHO 92 clinical samples, from which 20 viruses were isolated, the WHO chart shows. The country had withheld H5N1 samples from the WHO for about 5 months starting at the beginning of the year, according to previous reports.
Tracking system announced
On the heels of the report on H5N1 specimens submitted, the WHO today unveiled an online system to provide information on H5N1 specimens shared with the WHO through its Global Influenza Surveillance Network. The system permits anyone to search for particular isolates by date of submission, source country, host species, and several other variables. The system provides a page of detailed information for each isolate, including a list of all the laboratories to which the virus has been distributed, including pharmaceutical companies.
WHO describes the current system as an interim version. At this point it contains most of the viruses and clinical specimens that have been submitted to WHO since 24 Nov 2007, plus all H5N1 viruses that have been developed into vaccine viruses, according to a WHO statement. Information on the remaining viruses submitted since 24 Nov 2007 is being added to the system.
Both the tracking system and the country-by-country report are results, at least in part, of Indonesia's concerns about the fairness and openness of the WHO system for the sharing, monitoring, and use of influenza viruses.
A WHO statement today [22 Jan 2008] said the tracking system was developed following the intergovernmental meeting on flu virus sharing that was held 21-23 Nov 2007 in Geneva. At the meeting, a WHO working group tried unsuccessfully to resolve Indonesia's concerns about sending H5N1 specimens to WHO. The country pushed for rules forbidding the commercial use of H5N1 samples, such as for vaccine development, without the source country's permission. But no agreement was reached. The November meeting and other discussions in 2007 were held in response to a resolution passed at WHO's World Health Assembly last May [2007]. The resolution called on the WHO director-general to come up with a system for equitable sharing of the benefits of flu-virus sharing, to set up an international stockpile of vaccines for H5N1 and other potential pandemic viruses, and to revise the "terms of reference" for international sharing of flu viruses.
Viruses chosen for vaccines
The WHO chart of H5N1 viruses submitted in the past 5 years says 13 isolates were selected for development into vaccines. So far, 8 engineered viruses derived from these isolates, "suitable for vaccine development and production, are available for distribution," WHO reports.
The agency says 292 institutions have received one or more copies of the 8 engineered viruses, and 46 institutions have received "wild-type" vaccine viruses.
Numerous other countries besides Viet Nam and Indonesia have submitted samples that yielded H5N1 isolates over the years, according to WHO. For example, Hong Kong submitted 380 specimens that yielded 4 isolates, China (other than Hong Kong) submitted 26 samples with 22 isolates, Egypt sent 758 specimens with 26 isolates, and Turkey provided 335 specimens with 6 isolates.
Global News Updates from 2007 more>>
