NEW YORK (Reuters Health) – Early treatment with a long-acting form of interferon, called pegylated interferon-alpha, seems to reduce lung damage caused by the virus that produces SARS, i.e., severe acute respiratory syndrome — at least in macaques. The results suggest that preventive or early post-exposure treatment with interferon may protect health care workers and others exposed to the virus, Dr. Albert D. M. E. Osterhaus and colleagues note in an article in Nature Medicine.
Osterhaus, at Erasmus Medical Centre in Rotterdam, Netherlands, and his team injected macaques with the SARS virus. Treatment with pegylated interferon begun three days before infection substantially reduced virus levels in the lungs four days after infection. The extent and severity of lung damage was reduced by 80 percent. Although less effective than preventive use, interferon administered at one and three days after exposure still reduced lung damage to some extent, compared with that seen in untreated infected animals. The authors theorize that the reduced level of protection was probably because therapy was started too close to the peak of viral infection in the lungs, which occurs at two days after exposure in macaques. However, peak SARS virus infection in humans does not occur until about 16 days post-exposure. Therefore, the team theorizes that “the time interval during which effective postexposure treatment with pegylated interferon-alpha can be initiated may be longer in humans than in experimentally infected macaques.” They conclude that clinical studies with pegylated IFN-alpha are warranted if SARS re-emerges in humans.
Nature Medicine
23 February 2004