BEIJING - China has started treating severely infected swine flu patients with blood plasma donated by survivors - a therapy not yet proven to work but one that has shown potential to save lives.
In many parts of China, government-run blood collection stations have been harvesting plasma from people who have high levels of swine flu-fighting antibodies in their blood, because they recently recovered from or were vaccinated against the virus. The plasma is being stored in preparation for transfusions for severely or critically ill patients.
The treatment is based on the principle that transferring antibodies, the immune system's search-and-destroy force, can help a patient fight the virus and recover faster. Because the approach is still being evaluated for safety and effectiveness, the World Health Organization has not recommended it.
Any therapy involving blood transfusions risks introducing new infections of blood-borne diseases such as HIV, hepatitis and syphilis. Some patients could also develop allergic reactions.
Evidence from cases of bird flu and the 2002-03 severe acute respiratory syndrome outbreak have shown promising results using plasma from recovered patients.
Plasma therapy is also used to treat hepatitis B, rabies, and other infectious diseases. Concerns about resistance to antiviral drugs like Tamiflu have also driven interest in additional therapies, particularly in pandemic situations where hospital intensive care units come under strain from severe cases.
It is not clear how many Chinese have received the treatment. Media in recent weeks have reported at least 10 patients have been treated this way, including a baby and a pregnant woman.
Some health experts support China's approach. Microbiologist Guan Yi of the University of Hong Kong co-authored a paper in the New England Journal of Medicine in 2007 about a bird flu patient who recovered quickly after being treated this way.
"I think it's a good strategy," Guan said. In severe cases, the virus penetrates deep into the lungs and replicates in great amounts, which Tamiflu is ineffective in limiting, he said.
"The best way to treat the severe patients is with neutralized antibodies, which are only found in people who have accepted vaccination or in convalescent plasma," said Guan.
Dr. Xu Zhenqiu, who has used the therapy, said plasma treatment offers some hope. "It provides us with an alternative treatment when saving patients, which gives us more hope of saving lives," Xu said in a telephone interview.
The health ministry was cautious in stating its position on the therapy, saying more research was required. Other experts are not fully convinced of the treatment's effectiveness.
"I think it needs careful study," said Dr. Frederick Hayden, a virus expert at the University of Virginia and a World Health Organization flu consultant. "I think it's a very potentially important intervention, but there is insufficient information ... to make a routine recommendation for care in seriously ill patients."
Chinese health authorities have appealed for donations of plasma and hundreds, if not thousands, of people have already done so, according to news reports.
Blood supply safety is a perennial concern in China, where worries still persist despite strengthened controls in recent years on blood collection centres. China also banned blood sales in 2003 after it was discovered unclean blood-buying businesses had passed the HIV/AIDS virus to thousands of people in the 1990s.
Guan said though he supports China's treatment strategy, he has urged the government to strictly regulate plasma donations.
"My concern is they have no standard protocol. Different regions and different hospitals may be screening the blood differently," he said. "I urge them to standardize the whole procedure."
