Saturday, September 09, 2006

Blood Plasma From Bird Flu Survivors May Fight Virus

Blood Plasma From Bird Flu Survivors May Fight Virus (Update2)

By Jason Gale and Vesna Poljak

Sept. 5 (Bloomberg) -- An infusion of blood products from bird flu survivors may help fight the virus, according to doctors who studied such treatments used during the 1918 Spanish influenza pandemic that killed 50 million people.

Treating patients in 1918 with blood, plasma or serum obtained from people who recovered from Spanish flu cut mortality of seriously ill patients by 50 percent, the doctors said a report in the online edition of next month's Annals of Internal Medicine. The finding is based on an analysis of studies conducted more than 86 years ago.

Disease trackers are searching for ways to treat the H5N1 avian flue strain, which has infected at least 241 people in 10 countries, killing 141 of them, since 2003. The virus may kill millions if it sparks a global outbreak, especially since vaccines and antiviral drugs won't be widely available in the first months.

``Passively delivered anti-influenza antibodies in convalescent human plasma obtained from H5N1 survivors may offer a novel treatment approach and possible solution to these problems,'' said authors Edward Kilbane, Jeffrey Jackson and Thomas Luke, from the Uniformed Services University in Bethesda, Maryland, and retired Navy physician, Stephen Hoffman.

Scientists are seeking clues from the 1918 outbreak, the deadliest of the 20th century's three major pandemics, about how to treat H5N1 patients and how to prepare for a new contagion. Similar disease patterns and a tendency to kill younger people have been observed in both Spanish flu and H5N1.

CSL's Plans

CSL Ltd., the world's second-largest maker of blood plasma products, hasn't considered bringing on new treatments for avian and pandemic flu beyond a candidate vaccine that it's developing, Mark Dehring, a spokesman for the Melbourne-based company said in a telephone interview today.

``It's probably something we'd have a look at more so at the end of this year,'' when clinical trials on the vaccine are concluded, he said.

Producing blood products for flu is ``well within our capabilities,'' Dehring said. ``We're certainly keeping our eye on it.''

Antibody infusions have been used to prevent and treat diseases such as rabies, measles, hepatitis B, cytomegalovirus, and respiratory syncytial virus, and human plasma may be effective in the treatment of severe acute respiratory syndrome, or SARS, the authors said.

Blood collection centers at many hospitals produce large volumes of plasma for treating blood-clotting disorders and other conditions. The same infrastructure, personnel, and regulatory framework could produce plasma for the treatment of H5N1 influenza, they said.

`Immediately Effective'

``A single H5N1 convalescent donor could provide a weekly volume of plasma sufficient to treat multiple patients with H5N1,'' the authors said. Locally produced plasma from survivors or early vaccine recipients ``could be immediately effective,'' they said. Blood products could also be processed into a frozen form and shipped to other regions for use during a pandemic.

``While these may be interesting ideas, and they may have biologic plausibility, they have very little supply chain and logistic possibility,'' said Michael Osterholm, head of the University of Minnesota's Center for Infectious Disease Research and Policy in Minneapolis.

Needles, syringes, reagents and other equipment needed for blood collection and screening might be difficult to source, as supply chains ``around the world will quickly collapse during a pandemic,'' Osterholm said in a telephone interview today.

`Formidable' Hurdles

``Formidable logistical hurdles would complicate the ability to obtain, characterize, and prepare these materials for use in the midst of an outbreak,'' John Treanor, professor of medicine at the University of Rochester Medical Center in Rochester, New York, wrote in a review of the study, also appearing in October's Annals of Internal Medicine.

``We lack sufficient understanding of the immune response to H5N1 infection in humans,'' including whether patients who recover from infection develop high levels of antibody, Treanor said. ``We don't know the level of antibody that needs to be achieved to confer protection or the appropriate dose of serum needed to achieve useful antibody levels in recipients.''

`Extremely Expensive'

The volume of plasma from recovered H5N1 patients that has been screened for diseases such as HIV and hepatitis would be ``miniscule'' and ``extremely expensive'' to collect, said Donald Kaye, a professor of medicine at Drexel University, in Gladwyne, Pennsylvania.

Collecting plasma from people immunized against the pandemic flu strain would also be difficult because there will be inadequate supplies of vaccine, Kaye said in an e-mail.

``It probably would be effective if given early or prophylactically, but again this is impractical as huge amounts would be necessary,'' he said. ``If given once severe disease occurs, it remains to be seen if it would be effective.''

The concept is important and it should be explored further, especially given the lack of proven interventions to prevent or treat illness due to H5N1 influenza, Treanor said.

``We can, should, and must explore these issues'' in advance of the pandemic, he said. ``Although many logistical hurdles exist, controlled clinical studies done now will probably pay a considerable dividend when the pandemic begins.''

To contact the reporters on this story: Jason Gale in Singapore at at j.gale@bloomberg.net ; Vesna Poljak in Sydney at vpoljak@bloomberg.net
Last Updated: September 5, 2006 04:49 EDT

0 Comments:

Post a Comment

Links to this post:

Create a Link

<< Home