SARS Virus May Be Tough To Beat

Patients May Not Keep Their Immune Protection Against SARS In The Long Run, Chinese Doctors Say

(CBS)  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 United States), according to the World Health Organization and the Centers for Disease Control and Prevention.

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.