Doctors led by Tom Jefferson, a professor in the Acute Respiratory Infections Group at the Cochrane Collaboration in Rome, carried out an overview of 59 published trials into protective measures against these microbes.
The pathogens included the ordinary cold virus, the Severe Acute Respiratory Syndrome (SARS) virus and the influenza virus, but not the current H1N1 pandemic strain.
The trials had widely-ranging formats but essentially looked at the number of people who were infected when protective measures were implemented, as compared to the number who fell sick when there was no such protection.
Vaccines and antiviral drugs were not included in these studies.
In hospital settings, regular hand-washing, more than 10 times a day, and the use of masks, gloves and surgical gowns were each effective against spreading respiratory virus, but were especially useful when combined, according to the paper.
Hygiene measures in the home, targeted particularly at younger children, also helped prevent transmission.
"Perhaps this is because younger children are least capable of hygienic behaviour and have longer-lived infections and greater social contact, thereby acting as portals of infection into the household," the authors said.
Two studies found that isolating potentially infected individuals was also effective.
But the review uncovered only limited evidence that much-touted "N95" surgical masks are better than simple face masks.
N95 masks are more uncomfortable and more expensive and can also cause skin irritation, it found.
The team admitted it was hard in some cases to draw a generalised picture, given the diversity of the studies and frequent sketchiness of the data.
Even so, some simple measures have high potential for reducing the toll from a viral respiratory epidemic, it said.
"Vaccines work best in those who are universally considered least to need them, namely, healthy adults. Antivirals may be harmful and their benefits depend on the identification of the agent," it said.
"But physical interventions are effective, safe, flexible, universally applicable and relatively cheap."
The paper is published online by the British Medical Journal (bmj.com).