SARS Virus May Be Tough to Beat
Body's Immune Response to SARS May Wane Over Time, Researchers Say
Sept. 13, 2007 -- New research shows that SARS (severe acute
respiratory syndrome) may be a
long-term challenge to the immune system.
SARS, which is caused by a virus,
was big news in 2003, when SARS was first reported in Asia.
The 2003 SARS outbreak affected
the Americas, Europe, and Asia, killing 774 people and sickening more than
7,000 others worldwide (including eight people in the U.S.), according to the
World Health Organization and the CDC.
Scientists from China and the
Netherlands studied 56 SARS survivors for three years after the patients
recovered from SARS.
The researchers monitored the SARS
survivors' antibodies to a virus linked to SARS.
Over time, levels of those
antibodies declined in the former SARS patients. By the end of the three-year
study, up to a quarter of the patients' blood samples had undetectable
levels of the antibodies.
"Our data suggest that immune protection [against the SARS virus] may
wane over time," write the scientists, who included Wu-Chun Cao, MD, PhD,
of the State Key Laboratory of Pathogen and Biosecurity in Beijing.
Cao's team doesn't know whether those patients would be capable of fending
off SARS a second time, based on their current level of antibodies.
Cao and colleagues report their findings in a letter published in today's
edition of The New England Journal of Medicine.