The causative agent involved in the current outbreaks of coronavirus disease 2019 (COVID-19), SARS-CoV-2 (genus: Betacoronavirus), belongs to the family of Coronaviridae, a large family of enveloped, positive-sense single-stranded RNA viruses.
Coronaviruses are transmitted in most instances through large respiratory droplets and contact transmission, but other modes of transmission have also been proposed.
The time of survival and the conditions affecting SARS-CoV-2 viability in the environment are currently unknown.
Persistence of coronavirus on inanimate surfaces
On different types of materials it can remain infectious for from 2 hours up to 9 days. A higher temperature such as 30°C or 40°C reduced the duration of persistence of highly pathogenic MERS-CoV, TGEV and MHV.
However, at 4°C persistence of TGEV and MHV can be increased to ≥ 28 days.
Few comparative data obtained with SARS-CoV indicate that persistence was longer with higher inocula (Table I).
In addition it was shown at room temperature that HCoV-229E persists better at 50% compared to 30% relative humidity – [Ijaz, M.K., Brunner, A.H., Sattar, S.A., Nair, R.C., and Johnson-Lussenburg, C.M. Survival characteristics of airborne human coronavirus 229E. J Gen Virol. 1985; 66: 2743–2748].
Table I – Persistence of coronaviruses on different types of inanimate surfaces
| Type of surface | Virus | Strain / isolate | Inoculum (viral titer) | Temp. | Persistence | Reference | |
| Steel | MERS-CoV | Isolate HCoV-EMC/2012 | 105 |
20°C 30°C |
48
h 8–24 h | [21] | |
| TGEV | Unknown | 106 |
4°C 20°C 40°C |
≥
28 d 3–28 d 4–96 h | [22] | ||
| MHV | Unknown | 106 |
4°C 20°C 40°C |
≥
28 d 4–28 d 4–96 h | [22] | ||
| HCoV | Strain 229E | 103 | 21°C | 5 d | [23] | ||
| Aluminium | HCoV | Strains 229E and OC43 | 5 x 103 | 21°C | 2–8 h | [24] | |
| Metal | SARS-CoV | Strain P9 | 105 | RT | 5 d | [25] | |
| Wood | SARS-CoV | Strain P9 | 105 | RT | 4 d | [25] | |
| Paper | SARS-CoV | Strain P9 | 105 | RT | 4–5 d | [25] | |
| SARS-CoV | Strain GVU6109 |
106 105 104 | RT |
24
h 3 h < 5 min | [26] | ||
| Glass | SARS-CoV | Strain P9 | 105 | RT | 4 d | [25] | |
| HCoV | Strain 229E | 103 | 21°C | 5 d | [23] | ||
| Plastic | SARS-CoV | Strain HKU39849 | 105 | 22°-25°C | ≤ 5 d | [27] | |
| MERS-CoV | Isolate HCoV-EMC/2012 | 105 |
20°C 30°C |
48
h 8–24 h | [21] | ||
| SARS-CoV | Strain P9 | 105 | RT | 4 d | [25] | ||
| SARS-CoV | Strain FFM1 | 107 | RT | 6–9 d | [28] | ||
| HCoV | Strain 229E | 107 | RT | 2–6 d | [28] | ||
| PVC | HCoV | Strain 229E | 103 | 21°C | 5 d | [23] | |
| Silicon rubber | HCoV | Strain 229E | 103 | 21°C | 5 d | [23] | |
| Surgical glove (latex) | HCoV | Strains 229E and OC43 | 5 x 103 | 21°C | ≤ 8 h | [24] | |
| Disposable gown | SARS-CoV | Strain GVU6109 |
106 105 104 | RT |
2
d 24 h 1 h | [26] | |
| Ceramic | HCoV | Strain 229E | 103 | 21°C | 5 d | [23] | |
| Teflon | HCoV | Strain 229E | 103 | 21°C | 5 d | [23] | |
MERS = Middle East Respiratory Syndrome; HCoV = human coronavirus; TGEV = transmissible gastroenteritis virus; MHV = mouse hepatitis virus; SARS = Severe Acute Respiratory Syndrome; RT = room temperature.
Environmental cleaning options
Due to the potential survival of the virus in the environment for several days, the premises and areas potentially contaminated with SARS-CoV-2 should be cleaned before their re-use, using products containing antimicrobial agents known to be effective against coronaviruses.
Although there is lack of specific evidence for their effectiveness against SARS-CoV-2, cleaning with water and household detergents and use of common disinfectant products should be sufficient for general precautionary cleaning.
A recent paper which compared different healthcare germicides [4] found that those with 70% concentration ethanol had a stronger effect on two different coronaviruses (mouse hepatitis virus and transmissible gastroenteritis virus) after one minute contact time on hard surfaces when compared with 0.06% sodium hypochlorite.
Tests carried out using SARS-CoV showed that sodium hypochlorite is effective at a concentration of 0.05 and 0.1% after five minutes when it is mixed to a solution containing SARS-CoV [5].
Similar results were obtained using household detergents containing sodium lauryl ether sulphate, alkyl polyglycosides and coco-fatty acid diethanolamide [5].
Table 2. Antimicrobial agents effective against different coronaviruses: human coronavirus 229E (HCoV-229E), mouse hepatitis virus (MHV-2 and MHV-N), canine coronavirus (CCV), transmissible gastroenteritis virus (TGEV), and severe acute respiratory syndrome coronavirus (SARS-CoV)1
| Antimicrobial agent | Concentration | Coronaviruses tested | References |
| Ethanol | 70% | HCoV-229E, MHV-2, MHV-N, CCV, TGEV | [4,6,7] |
| Sodium hypochlorite | 0.1–0.5% 0.05–0.1% | HCoV-229E SARS-CoV | [6] [5] |
| Povidone-iodine | 10% (1% iodine) | HCoV-229E | [6] |
| Glutaraldehyde | 2% | HCoV-229E | [6] |
| Isopropanol | 50% | MHV-2, MHV-N, CCV | [7] |
| Benzalkonium chloride | 0.05% | MHV-2, MHV-N, CCV | [7] |
| Sodium chlorite | 0.23% | MHV-2, MHV-N, CCV | [7] |
| Formaldehyde | 0.7% | MHV-2, MHV-N, CCV | [7] |
Inactivation of coronaviruses by biocidal agents in suspension tests
- Ethanol (78–95%), 2-propanol (70–100%), the combination of 45% 2-propanol with 30% 1-propanol, glutardialdehyde (0.5–2.5%), formaldehyde (0.7–1%) and povidone iodine (0.23–7.5%) readily inactivated coronavirus infectivity by approximately 4 log10 or more. (Table II).
- Sodium hypochlorite required a minimal concentration of at least 0.21% to be effective.
- Hydrogen peroxide was effective with a concentration of 0.5% and an incubation time of 1 min.
- Data obtained with benzalkonium chloride at reasonable contact times were conflicting. Within 10 min a concentration of 0.2% revealed no efficacy against coronavirus whereas a concentration of 0.05% was quite effective. 0.02% chlorhexidine digluconate was basically ineffective (Table II).
Table II – Inactivation of coronaviruses by different types of biocidal agents in suspension tests
| Biocidal agent | Concentration | Virus | Strain / isolate | Exposure time | Reduction of viral infectivity (log10) | Reference |
| Ethanol | 95% | SARS-CoV | Isolate FFM-1 | 30 s | ≥ 5.5 | [29] |
| 85% | SARS-CoV | Isolate FFM-1 | 30 s | ≥ 5.5 | [29] | |
| 80% | SARS-CoV | Isolate FFM-1 | 30 s | ≥ 4.3 | [29] | |
| 80% | MERS-CoV | Strain EMC | 30 s | > 4.0 | [14] | |
| 78% | SARS-CoV | Isolate FFM-1 | 30 s | ≥ 5.0 | [28] | |
| 70% | MHV | Strains MHV-2 and MHV-N | 10 min | > 3.9 | [30] | |
| 70% | CCV | Strain I-71 | 10 min | > 3.3 | [30] | |
| 2-Propanol | 100% | SARS-CoV | Isolate FFM-1 | 30 s | ≥ 3.3 | [28] |
| 75% | SARS-CoV | Isolate FFM-1 | 30 s | ≥ 4.0 | [14] | |
| 75% | MERS-CoV | Strain EMC | 30 s | ≥ 4.0 | [14] | |
| 70% | SARS-CoV | Isolate FFM-1 | 30 s | ≥ 3.3 | [28] | |
| 50% | MHV | Strains MHV-2 and MHV-N | 10 min | > 3.7 | [30] | |
| 50% | CCV | Strain I-71 | 10 min | > 3.7 | [30] | |
| 2-Propanol and 1-propanol | 45% and 30% | SARS-CoV | Isolate FFM-1 | 30 s | ≥ 4.3 | [29] |
| SARS-CoV | Isolate FFM-1 | 30 s | ≥ 2.8 | [28] | ||
| Benzalkonium chloride | 0.2% | HCoV | ATCC VR-759 (strain OC43) | 10 min | 0.0 | [31] |
| 0.05% | MHV | Strains MHV-2 and MHV-N | 10 min | > 3.7 | [30] | |
| 0.05% | CCV | Strain I-71 | 10 min | > 3.7 | [30] | |
| 0.00175% | CCV | Strain S378 | 3 d | 3.0 | [32] | |
| Didecyldimethyl ammonium chloride | 0.0025% | CCV | Strain S378 | 3 d | > 4.0 | [32] |
| Chlorhexidine digluconate | 0.02% | MHV | Strains MHV-2 and MHV-N | 10 min | 0.7–0.8 | [30] |
| 0.02% | CCV | Strain I-71 | 10 min | 0.3 | [30] | |
| Sodium hypochlorite | 0.21% | MHV | Strain MHV-1 | 30 s | ≥ 4.0 | [33] |
| 0.01% | MHV | Strains MHV-2 and MHV-N | 10 min | 2.3–2.8 | [30] | |
| 0.01% | CCV | Strain I-71 | 10 min | 1.1 | [30] | |
| 0.001% | MHV | Strains MHV-2 and MHV-N | 10 min | 0.3–0.6 | [30] | |
| 0.001% | CCV | Strain I-71 | 10 min | 0.9 | [30] | |
| Hydrogen peroxide | 0.5% | HCoV | Strain 229E | 1 min | > 4.0 | [34] |
| Formaldehyde | 1% | SARS-CoV | Isolate FFM-1 | 2 min | > 3.0 | [28] |
| 0.7% | SARS-CoV | Isolate FFM-1 | 2 min | > 3.0 | [28] | |
| 0.7% | MHV | 10 min | > 3.5 | [30] | ||
| 0.7% | CCV | Strain I-71 | 10 min | > 3.7 | [30] | |
| 0.009% | CCV | 24 h | > 4.0 | [35] | ||
| Glutardialdehyde | 2.5% | SARS-CoV | Hanoi strain | 5 min | > 4.0 | [36] |
| 0.5% | SARS-CoV | Isolate FFM-1 | 2 min | > 4.0 | [28] | |
| Povidone iodine | 7.5% | MERS-CoV | Isolate HCoV-EMC/2012 | 15 s | 4.6 | [37] |
| 4% | MERS-CoV | Isolate HCoV-EMC/2012 | 15 s | 5.0 | [37] | |
| 1% | SARS-CoV | Hanoi strain | 1 min | > 4.0 | [36] | |
| 1% | MERS-CoV | Isolate HCoV-EMC/2012 | 15 s | 4.3 | [37] | |
| 0.47% | SARS-CoV | Hanoi strain | 1 min | 3.8 | [36] | |
| 0.25% | SARS-CoV | Hanoi strain | 1 min | > 4.0 | [36] | |
| 0.23% | SARS-CoV | Hanoi strain | 1 min | > 4.0 | [36] | |
| 0.23% | SARS-CoV | Isolate FFM-1 | 15 s | ≥ 4.4 | [38] | |
| 0.23% | MERS-CoV | Isolate HCoV-EMC/2012 | 15 s | ≥ 4.4 | [38] |
Inactivation of coronaviruses by biocidal agents in carrier tests
Ethanol at concentrations between 62% and 71% reduced coronavirus infectivity within 1 min exposure time by 2.0–4.0 log10.
Concentrations of 0.1–0.5% sodium hypochlorite and 2% glutardialdehyde were also quite effective with > 3.0 log10 reduction in viral titre.
In contrast, 0.04% benzalkonium chloride, 0.06% sodium hypochlorite and 0.55% ortho-phtalaldehyde were less effective (Table III).
Table III – Inactivation of coronaviruses by different types of biocidal agents in carrier tests
| Biocidal agent | Concentration | Virus | Strain / isolate | Volume / material | Organic load | Exposure time | Reduction of viral infectivity (log10) | Reference |
| Ethanol | 71% | TGEV | Unknown | 50 μl / stainless steel | None | 1 min | 3.5 | [39] |
| 71% | MHV | Unknown | 50 μl / stainless steel | None | 1 min | 2.0 | [39] | |
| 70% | TGEV | Unknown | 50 μl / stainless steel | None | 1 min | 3.2 | [39] | |
| 70% | MHV | Unknown | 50 μl / stainless steel | None | 1 min | 3.9 | [39] | |
| 70% | HCoV | Strain 229E | 20 μl / stainless steel | 5% serum | 1 min | > 3.0 | [40] | |
| 62% | TGEV | Unknown | 50 μl / stainless steel | None | 1 min | 4.0 | [39] | |
| 62% | MHV | Unknown | 50 μl / stainless steel | None | 1 min | 2.7 | [39] | |
| Benzalkoniumchloride | 0.04% | HCoV | Strain 229E | 20 μl / stainless steel | 5% serum | 1 min | < 3.0 | [40] |
| Sodium hypochlorite | 0.5% | HCoV | Strain 229E | 20 μl / stainless steel | 5% serum | 1 min | > 3.0 | [40] |
| 0.1% | HCoV | Strain 229E | 20 μl / stainless steel | 5% serum | 1 min | > 3.0 | [40] | |
| 0.06% | TGEV | Unknown | 50 μl / stainless steel | None | 1 min | 0.4 | [39] | |
| 0.06% | MHV | Unknown | 50 μl / stainless steel | None | 1 min | 0.6 | [39] | |
| 0.01% | HCoV | Strain 229E | 20 μl / stainless steel | 5% serum | 1 min | < 3.0 | [40] | |
| Glutardialdehyde | 2% | HCoV | Strain 229E | 20 μl / stainless steel | 5% serum | 1 min | > 3.0 | [40] |
| Ortho-phtalaldehyde | 0.55% | TGEV | Unknown | 50 μl / stainless steel | None | 1 min | 2.3 | [39] |
| 0.55% | MHV | Unknown | 50 μl / stainless steel | None | 1 min | 1.7 | [39] | |
| Hydrogen peroxide | Vapor of unknown concentration | TGEV | Purdue strain type 1 | 20 μl / stainless steel | None | 2–3 h | 4.9–5.3* | [41] |
TGEV = transmissible gastroenteritis virus; MHV = mouse hepatitis virus; HCoV = human coronavirus; *depending on the volume of injected hydrogen peroxide.
Cleaning approaches
Cleaning should be performed using the proper personal protective equipment (PPE). The correct donning and doffing of PPE should be followed; further information on the donning and doffing procedures can be found in the ECDC Technical Document ‘Safe use of personal protective equipment in the treatment of infectious diseases of high consequence’ [8].
Disposable PPE should be treated as potentially infectious material and disposed in accordance with national rules.
The use of disposable or dedicated cleaning equipment is recommended; non-single use PPE should be decontaminated using the available products (e.g. 0.1% sodium hypochlorite or 70% ethanol).
When other chemical products are used, the manufacturer’s recommendation should be followed and the products prepared and applied according to them.
When using chemical products for cleaning, it is important to keep the facility ventilated (e.g. by opening the windows) in order to protect the health of cleaning personnel.
The following PPE items are suggested for use when cleaning facilities likely to be contaminated by SARS-CoV-2:
- Filtering face pieces (FFP) respirators class 2 or 3 (FFP2 or FFP3)
- Goggles or face shield
- Disposable long-sleeved water-resistant gown
- Disposable gloves.
All frequently touched areas, such as all accessible surfaces of walls and windows, the toilet bowl and bathroom surfaces, should be also carefully cleaned.
All textiles (e.g. bed linens, curtains, etc.) should be washed using a hot-water cycle (90 °C) and adding laundry detergent.
If a hot-water cycle cannot be used due to the characteristics of the tissues, specific chemicals should be added when washing the textiles (e.g. bleach or laundry products containing sodium hypochlorite, or decontamination products specifically developed for use on textiles).
References
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