TABLE 4.

General characteristics and roles of fomites in viral transmission

VirusOptimal environmental conditions for survival (reference[s])Viral transfer via fomite (reference[s])Minimally infectious dose of virus (reference[s])Evidence of transmission by fomite (reference[s])
Respiratory syncytial virusComposition of surface more important than humidity and temp (3, 24)From porous (tissues, gloves) and nonporous (countertops) fomites (33)Intranasal inoculation, humans, 100-640 TCID (54, 55)Proven (3, 22)
RhinovirusSurvived well in high humidity but poorly under dry conditions (64)Clean hands pick up virus when handling contaminated fomites (5, 52); 70% of virus on hands transferred to recipients' fingers (30)Intranasal inoculation, humans, 0.032-0.4 TCID50 (55); reported elsewhere as 1-10 TCID50 (7, 28, 39)Proven, considered minor (3, 22)
Influenza virusSurvival at lab temp of 28°C and 40% humidity for 48 h on dry surface; 72 h for avian influenza virus on dry surface (73); 72 h forinfluenza A virus on wet surface (9)Virus transferred from contaminated surface to hands for up to 24 h after inoculation (9)Intranasal inoculation, humans, 2-790 TCID50 (54, 55)Proven, considered secondary or minor (38)
Parainfluenza virusSurvival decreases above 37°C; stable at 4°C, pH 7.4 to 8.0, and low humidity; recovered after freezing for 26 yrs (37)Stainless steel surfaces to clean fingers (5)Intranasal inoculation, humans, 1.5-80 TCID50 (parainfluenza virus 1) (7, 38, 54)Not proven, indirect evidence supports (3, 22)
CoronavirusHumidity 55-77% and temp 21°C remained infective up to 6 days in PBS (50); remains infective 1-2 days in feces (68)Theoretically possible but not studied (68)Not foundNot proven but suspected (3, 38, 58)
Feline calicivirusSurvived at 4°C when dried on coverslip for 56 days; survival decreased with temp (21); sensitive to humidity in 30-70% range (19, 61)From gloved hands to kitchen utensils and doorknob and vice versa (53); from contaminated surface to clean hands to phone, door handle, or water tap handle (8)Estimated to be as few as 10-100 particles (7, 8, 17, 39)Not proven, indirect evidence supports, CDC lists surface contamination (17, 41)
RotavirusRemained infective for 32 mos at 10°C and 2&12frac; mos at 30°C when stored in feces (25)16% viral transfer from contaminated fingertips to steel disc after 20 min (4)Not found; estimated at 10-100 TCID50 (7, 55)Proven (7, 22)
Hepatitis A virusSurvival inversely proportional to relative humidity and temp, 5°C is optimal temp (1, 48)25% viral transfer from fingers to disc; moisture facilitated transfer (47); 9.2% of virus transferred to lettuce (11)Estimated at 10-100 TCID50 (55, 59)Accepted (food and fecally contaminated surfaces) (1, 41)
AdenovirusSurvived shorter periods in presence of feces and at lower humidity (1, 42, 46, 61)Not foundIntranasal, 150 TCID50; oral, 1,000 TCID50 (capsule form of serotypes 4 and 7) (54)Widely accepted, contaminated surfaces (1)
AstrovirusSurvived 4°C on china for 60 days and paper for 90 days; faster decay at higher temp (2, 61)Not foundNot foundMay play an important role in secondary transmission (2, 61)