TABLE 4.
General characteristics and roles of fomites in viral transmission
| Virus | Optimal 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 virus | Composition 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) |
| Rhinovirus | Survived 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 virus | Survival 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 virus | Survival 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) |
| Coronavirus | Humidity 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 found | Not proven but suspected (3, 38, 58) |
| Feline calicivirus | Survived 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) |
| Rotavirus | Remained 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 virus | Survival 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) |
| Adenovirus | Survived shorter periods in presence of feces and at lower humidity (1, 42, 46, 61) | Not found | Intranasal, 150 TCID50; oral, 1,000 TCID50 (capsule form of serotypes 4 and 7) (54) | Widely accepted, contaminated surfaces (1) |
| Astrovirus | Survived 4°C on china for 60 days and paper for 90 days; faster decay at higher temp (2, 61) | Not found | Not found | May play an important role in secondary transmission (2, 61) |