"There are a lot of issues about face masks that tend to increase their usefulness. One is training. The second is proper fitting. The third is a new generation of face masks which have fibers that are treated with anti-viral and anti-microbial particles that increase killing. Those three important issues weren't properly factored in in this study," he said.
"In our study we used surgical masks, which should be available over the counter in drugstores," Cowling said. "Another less common type of mask is the N95-style respirator, which has a much tighter seal on the face and is only really recommended for use in health-care settings in some situations. These masks work best if they are fit-tested."
The authors of the second study reviewed all available research on Tamiflu and Relenza, and concluded that healthy adults who took the drugs for four weeks or longer were less likely to be stricken with symptoms of flu, although the drugs did not prevent people from actually becoming infected with the virus.
"They prevent the newly formed viruses from leaving the infected cells but they don't prevent initial virus from getting into the body," said study author Dr. Nayer Khazeni, an instructor of medicine in the division of pulmonary and critical care medicine at Stanford University Medical Center.
The two drugs appeared to be equally effective, although patients taking Tamiflu experienced more nausea and vomiting, especially if given in higher-than-recommended doses.
Also, the authors noted, many groups have just never been studied in this context, including children under the age of 12, immune-compromised individuals and people who have received the nasal flu vaccine.
"Another finding was that all of the studies were sponsored by makers of the drugs, which is not surprising," Khazeni said. "They were good quality, but it's always nice to see an independent evaluation."
Although governments have stockpiled these two drugs to use during a pandemic, it's unclear what role the drugs play currently in the swine flu pandemic.
"It's not clear if there's a role for extended use of prophylactic medications," Khazeni said. "Some groups are targeted for extended-duration antiviral prophylaxis, such as high-risk groups and first-line health-care workers."
But these plans are for a more severe pandemic setting, she added.
Also, cases of seasonal flu and swine flu that are resistant to Tamiflu have been seen.
The guidelines for face masks can be viewed at the CDC.
SOURCES: Benjamin Cowling, Ph.D., assistant professor, School of Public Health, The University of Hong Kong; Artealia Gilliard, spokeswoman, U.S. Centers for Disease Control and Prevention, Atlanta; Nayer Khazeni, M.D., instructor, medicine, division of pulmonary and critical care medicine, Stanford University Medical Center, Stanford, Calif.; Scott R. Lillibridge, M.D., assistant dean, Texas A&M Health Science Center School of Rural Public Health, Houston, and executive director, National Center for Emergency Medical Preparedness & Response; Aug. 4, 2009, Annals of Internal Medicine