Hand Hygiene Can Prevent Spread of Respiratory Viruses

ROME, Oct. 17 -- Simple measures -- such as handwashing with soap and water -- could be the best way to reduce the spread of respiratory viruses that cause illnesses like flu and SARS, a new Cochrane review has found.

Better hand hygiene appears to be especially important for children, perhaps because, left to themselves, kids' hygiene is poor, Tom Jefferson, M.D., of the Cochrane Vaccines Field here, and colleagues, reported in the fourth issue for 2007 of the Cochrane Library.

"There is a strong indication that introducing hygienic measures around younger children can be a very powerful way of blocking spread, protecting them and the community they live in," Dr. Jefferson said in a statement.

But the evidence for most interventions -- aside from vaccines and antiviral drugs, which were not part of the analysis -- is spotty and forms a difficult footing for solid conclusions, the investigators said.

They found 49 reports of 51 studies but there were few randomized controlled studies and those were of "poor quality." The observational studies, they said, were of mixed quality.

"The variable quality of the methods of these studies is striking," Dr. Jefferson and colleagues said.

On the basis of the literature, the researchers concluded that:

• The highest quality cluster randomized controlled trials suggest respiratory virus spread can be prevented by hygienic measures around younger children.
• Studies with other designs appear to confirm that hygiene for children has benefits for other members of a household, although the potential for confounding is greater.
• Six case-control studies suggested that implementing barriers to transmission -- such as gloves and gowns -- can be effective at containing respiratory virus epidemics.
• The case-control studies also suggested that isolation and hygienic measures can be beneficial in epidemics.
• Evidence that the uncomfortable and expensive N95 masks are superior to simple surgical masks was limited.
• The benefit of adding virucidals or antiseptics to normal handwashing is uncertain.

There has been no proper evaluation of such global measures as screening at entry ports and social distancing -- limiting or eliminating social contacts among people at risk -- as methods of slowing or stopping an epidemic, the researchers found.

There were also very few studies from low-income countries "where the vast majority of the burden lies, and where cheap interventions are so critical," the researchers said.

Despite the limited evidence, the authors suggest that transmission of viral respiratory disease could be reduced by implementing:

• Frequent handwashing, with or without adding antiseptics.
• Barrier measures such as gloves, gowns, and masks with filtration apparatus.
• Isolation of likely cases.

The greatest effort should be aimed at reducing transmission from young children, they said.

But they also called for more and better research. Noting that "public health measures can be highly effective," the researchers said "there is a clear requirement to carry out further large pragmatic trials to evaluate the best combinations (of interventions)."