Hygiene and barrier methods should be a higher priority in plans for national flu pandemic preparation, according to a study published on www.bmj.com.

The study found methods such as hand washing, wearing masks and isolating infected patients to be highly effective in preventing the spread of viral infections.

This study updates a 2007 study by Professor Tom Jefferson and colleagues, which showed that physical interventions are highly effective in preventing the spread of respiratory viruses.

However, the current mainstay of pandemic interventions appears to be vaccines and antiviral drugs, despite the lack of evidence supporting their widespread use. The team therefore set out to analyse the results of 59 published studies on the effectiveness of physical measures.

The results show that frequent hand washing (more than 10 times a day) and wearing masks, gloves and gowns are effective individually against acute infectious respiratory diseases, and are still more effective when combined.

The team found limited evidence that N95 masks are superior to simple surgical masks - and the former can also cause skin irritation. The effect of adding antiseptics to normal hand washing also remains uncertain. Global measures such as screening at airports were not thoroughly evaluated.

Many simple and low-cost measures can be effective in reducing the transmission of respiratory viruses when used in combination within a structured programme, the authors say.

Where there is high risk of infection, barrier measures such as gloves, gowns, and masks with filtration apparatus and isolation of likely cases should also be implemented.

The report concludes that cost-effective means to reduce the impact of acute respiratory infections through physical interventions should be sought, and ways found to facilitate their introduction.