Advice about the control of Norovirus seems to centre around hand washing / Universal Precautions. All very good,however as this virus,once called Winter Vomiting Virus,can be airborne,what good is waving clean hands at the 1000s of airborne viral particles?(about 20 required for infection) I have seen occasional reference to bleach on hard surfaces & laundering,but next to nothing about the airborne threat.So please advise: 1:Should RPE be worn,type,when attending infected clients/closed wards etc? 2/ How long does an infected particle remain active / airborne? (activity? / settling velocity?) 3/ Should fogging the atmosphere be considered or is bleach adequate? Regards,Paul

It is a sensible idea but is rarely practical. Fogging, using H2O2 vapour, is likely to be helpful but the tests to prove activity against Norovirus have not been done and its use would be entirely speculative. Remember also that this is used for terminal decontamination only. It is a hazardous procedure that requires the area to be vacated and sealed during treatment - what do you do with patients in the meantime?

Studies show massive contamination of air in the vicity of a patient with projectile vomiting but the numbers of virus particles fall off rapidly with distance from the source. Not a nice thing to think about, but I suppose the consistency of vomitus does not lend itself to aerosolisation! Fogging can be done anywhere, and is frequently used on ships. Wherever it happens, the same neds apply. vacate and seal the area. This means closing a hospital ward or a series of rooms on a ship. That places those area out of use for at least 4 hours, and with cleaning probably 24 hours. Since you cant decant the occupants to another area without them contaminating that area, its value in acute outbreak management falls far below cohort management and isolation, together with scrupulous hygiene management procedures. As the outbrake wanes and numbers of affected cases become small, the areas used for cohort management become fewer and as they are vacated then can be fogged and part of, but not the only, terminal hygiene procedure. H2O2 fogging may decontaminate clean surfaces. The evidence for penetration of sterilant into fabrics and heavily soiled surfaces, or into recesses and other voids where free circulation of air cannot be guaranteed, is not proven and probably poor. Effective cleaning with a suitable detergent disinffectant product remains essential.

Different viruses, different routes of elimination. Vomiting and coughs/sneezes are completely different in their aibility to generate fine droplets that become and remain airborne

Forget the virus, they are too small to make a diffeence, and concentrate on the droplet in which it is bound. How fast it that droplet moving? What is its viscosity, relative humidity and air temp (evaporation with reduce larger droplets to smaller lighter droplet nuclei that stay suspended for longer)? How turbulent is the air in general? Lots of factors, and many more beside, make rules of thumb totally unreliable. Ther have been quite a few studies each of a different situation and each offering figures for fall-out zones. Some might be reasonable as an average but that is no comfort if you are exposed at a point beyond that average. Personally, I dont thing such data are of particular value - there are just too many variables. It still comes down to personal hygiene to prevent unnecessary release (ie, coughing/sneezing). But from any other orifice, there isnt that much that the average patient can do about it. Now. almost time for lunch!