purple peril. a new vaccine stimulates an immune response that blocks the virus SARS from attaching to cells.
a growl of a new nasal spray vaccine may soon keep severe acute respiratory syndrome (SARS) at bay. The new vaccine, a hybrid of SARS and a human respiratory virus, prevented infection in monkeys and may soon lead to a new nasal spray in people.
Since SARS emerged in China in 02, the virus has infected 8,000 people, causing pneumonia in many of them and killing 774. The outbreak was controlled in 03 and health authorities have contained recent epidemics, including an outbreak in China in April, isolating patients. But the disease still lurks, and new strains could emerge and start another epidemic, says virologist Peter Collins of the National Institute of Allergy and Infectious Diseases.
No vaccine against SARS has not been proven in clinical trials, but researchers have developed several prototypes, including a virus of SARS and died a DNA vaccine, both of which have to be injected. Since the laboratory Collins makes genetically nasal spray vaccine against childhood respiratory diseases and SARS is a respiratory virus, "it seemed natural," Collins said, to make a hybrid strain of vaccinia virus to ward off SARS.
The researchers spliced the gene encoding the spike protein of SARS, which is on the surface of the virus and allows it to invade human cells, in an attenuated variant of human parainfluenza virus 3. This strain was designed as a nasal spray vaccine to protect children against pneumonia. After the growth and isolation of the hybrid virus were administered to a group of African green monkeys. A month later, the researchers infected each monkey with SARS. Then they stamped nose and throat each day and tested hardware. A group of vaccinated false green monkeys remained infected by SARS up to 8 days, while the vaccinated animals showed no signs of infection, according to the results to be published Saturday The Lancet . Because parainfluenza vaccine strain has already tested safe in a clinical trial, the hybrid vaccine is ready for clinical trials in children and, with modifications, for adults, Collins said.
"It is a very smart job," said Ruth Foxwell mucosal immunologist at the University of Canberra in Australia. The new vaccine could protect infants and children, although the immune system in adults can neutralize the vaccine, she said. But to develop a vaccine just a year after the virus was discovered "is fantastic compared to what is normal."
related Site
WHO RAD page
CDC SARS FAQ
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