Surgical Masks Likely to Protect Against SARS

Laurie Barclay, MD

May 01, 2003

May 1, 2003 -- Severe acute respiratory syndrome (SARS) is spread by droplet infection, and surgical masks provide the best protection for exposed healthcare workers, according to the results of a case-control study published in the May 3 issue of The Lancet. Gloves, gowns, and hand-washing together are not as effective as masks.

"Masks seem to be essential for protection.... The other three measures (without the mask) add no significant protection," lead author W. H. Seto, from Queen Mary Hospital in Hong Kong, says in a news release. "This finding fits well with droplets transmission because droplets are generated at the face level making the mask crucial for protection."

Dr. Seto's group compared the protective measures used by 13 staff members infected with SARS and 241 uninfected staff members who had been exposed to 11 index patients with SARS. None of 69 staff members who reported use of all four measures were infected, whereas all infected staff had omitted at least one measure ( P = .0224).

Without the surgical mask, the other measures together did not offer full protection against SARS infection. Although infection occurred in fewer staff who wore masks ( P = .0001) or gowns ( P = .006), and in those who washed their hands ( P =.047), stepwise logistic regression was significant only for masks.

Despite the potential recall bias inherent in a survey, the authors concluded that "masks seem to be essential for protection."

An accompanying editorial discusses the financial and public health impact of SARS on China, which has the fifth largest economy in the world, and the impact on other economies.

In an accompanying commentary, Brian Tomlinson and Clive Cockram, from the Chinese University of Hong Kong, review their experience with SARS at the Prince of Wales Hospital.

"Lack of knowledge of SARS' natural history adds to the difficulty of determining the effectiveness of therapy," they write. "Some patients have a protracted clinical course with potential for relapses continuing into the second or third week or beyond.... Continued viral shedding and the possible development of long-term sequelae, such as pulmonary fibrosis or late post-viral complications, means that patients will require careful surveillance."

Lancet. 2003;361:1519-1520

Reviewed by Gary D. Vogin, MD

Severe Acute Respiratory Syndrome (SARS) Collection on Medscape


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