Table II.
Sampling, hygiene procedures and CT test results
| Study ID | Timing of sample collection | Hygiene procedures | No. of fomite samples | No. of SARS-CoV-2-positive samples | Sites of positive samples | Comments |
|---|---|---|---|---|---|---|
| Adenaiye 2021 [11] | Phone/tablet swab done at each visit | Surgical masks | 74 | 42/80 (52.5%) | Mobile phone | 6/6 of alpha variant and 36/74 of other variant positive. |
| Ahn 2020 [12] | Patient 1: hospital day 7 when patient was febrile with poor oxygenation, and on that day, chest imaging demonstrated severe ARDS. Patient 2: hospital day 4 when patient had a sustained fever with rapid deterioration to severe ARDS. Patient 3: hospital day 13 when patient had a persistent cough with sputum and shortness of breath and spat out sputum frequently. |
Nurses performed daily routine cleaning, but disinfection was performed only after the patients were discharged. | 76 Patients 1 and 2: 48 Patient 3: 28 |
15/76 (19.7%) Patients 1 and 2: 2/48 (4.2%) Patient 3: 13/28 (46.4%) |
Patients 1 and 2: outside surface of the endotracheal tubes in the area connected to the ventilator circuit. Patient 3: thermometer, restraints, bedsheets, cup, nasal prongs, NIV mask, high-flow oxygen generator, telephone, remote control, and fixed structures including bedrails, floor, and the grill of an air outlet fan in the ceiling. |
All patients were symptomatic, and immunocompromised by virtue of their critical care stay or underlying cancer. Respiratory specimens persistently tested positive for SARS-CoV-2 by rRT–PCR up to the time of environmental sampling, which varied between 9 and 22 days post symptom onset. CT of sputum samples: 13.32 to 40.0 between hospital days 1–14 and CT of environmental samples 28.85 to 31.78 for positive PCR samples that were culture positive. CT of positive samples: 22.31 to 29.65. |
| Alvis-Chirinos 2021 [13] | The frequency of sample collection was once a week and four times during a month from Nov–Dec 2020 | Not specified | 2055 960 food surfaces 1095 inert surfaces |
1/2055 (0.1%) Food surfaces: 0/960 Inert surfaces: 1/1095 (0.1%) |
ATM | Non-probabilistic convenience sampling was applied to select the samples. Prior to sample collection, authorization for the entry of field personnel was coordinated with those responsible authorities. CT of positive samples: 35.01–37.08. |
| Ang 2021 [14] | Samples were collected once during the last campaign of air sampling in the same wards. The chosen swab sites were not cleaned for at least 8 h prior to swabbing. The timing for sample collection and analysis were subject to the availability of the trained medical staff, consent of patients, and the capacity of the BSL-3 processing laboratory. |
All patients were masked with regular surgical mask whenever possible. | 73 | 7/73 (9.6%) | Toilets, patient bedside table | Surface samples were collected from one isolation ward and two open-cohort wards. A portion of some swab sites, e.g. the bedside table in the patient care areas and ledge in the toilet, were covered with a sieve one day before swabbing to avoid direct contact from the patient. The LOD of the RT–qPCR assay was 3.9 copies per reaction. |
| Bartlett 2021 [15] | Before and after encounters between the patients and HCP | In all clinical encounters, the HCP wore hair bouffant, surgical mask, contact gown, and gloves. Pre-exposure samples were collected prior to donning of PPE, while post-exposure samples were collected following PPE doffing and upon exiting the patient's room. |
82 | 2/82 (2.4%) | Patient's room on the door threshold following the encounter with the HCP. Door handle leading to a physician's workroom in the emergency department. |
70 samples from clinical encounters; 12 samples from high-touch surface areas from heavy traffic COVID-19 hospital care areas. Samples were collected from skin around the nose and mouth. Samples were also collected from the HCP's exposed skin at the temples, cheeks, and neck. Additional samples were taken from the sides of the HCP's footwear. CT for positive samples: 30.6, 37.2. |
| Ben-Shmuel 2020 [16] | Not specified | Routine cleaning and decontamination were done once daily at best only in communal areas. Staff routinely used gowns, masks, shoe covers, face shields, and disposable surgical caps. |
55 | 29/55 (51%) | Outside the patient's room on the door threshold following the encounter with the HCP door handle leading to a physician's workroom in the emergency department. | Patients had mild to moderate disease. No patients on ventilation. CT for positive samples: 34 to 37.9. |
| Binder 2020 [17] | Not specified | No scheduled cleaning of rooms while COVID-19 patients were occupying them. Deep cleaning of the rooms and sanitation procedures such as disinfecting floors and surfaces with bleach solution and UV light emitter treatment for 45 min were performed between patients. | 112 | 7/112 (6.3%) | TV remote, bedrails, tray, toilet bowl, cell phone. | Fomite sampling was conducted in an empty hospital room (no patient contact for four days) in the Duke University Hospital COVID-19 ward which had been disinfected by bleach solution wipe downs and UV light treatment for 45 min. CT for positive samples: 36.4–39.8. |
| Coil 2021 [18] | Not specified | Improved cleaning protocols with a change in the frequency/duration/composition of cleaning material in the hospital between April and August 2020. | 224 56 in April 2020 168 in Jul/Aug 2020 |
11/224 (4.9%) 6/56 (11%) for Apr 2020 5/168 (3%) for Jul/Aug 20 |
Telemetry screen, soiled linen, endotracheal tube strap, computer station. | Changes to hygiene procedures were instituted after collection of the first samples in Apr 2020. CT for positive samples: 32–44. |
| Colaneri 2020 [19] | Swabs were performed around 12 noon, ∼4 h after cleaning. | Ward surfaces were routinely cleaned twice daily (morning and early afternoon). HCWs wore PPE comprising liquid-repelling gowns, double gloves, class 2 filtering face-piece respirators and eye protection. | 26 | 2/26 (7.7%) | External surface of the CPAP helmet. | In the sub-intensive care ward, swabs were performed in a double room where two patients with CPAP helmets were allocated. In the emergency room, samples were collected from two different rooms. Each room accommodated three patients, one of them with a CPAP helmet. CT for two patients in sampling area was 23 and 26 respectively. |
| da Silva 2021 [20] | Between 09:00 and 13:00 | Qualified technicians wore PPE. | 400 Transport terminals 84 Healthcare units 84 Beach areas 21 Public parks 105 Supply centre 21 Public markets 81 |
97/400 (24.2%) | Toilets, ATMs, handrails, playground and outdoor gym. | SARS-CoV-2 RNA was found most frequently on rock (10/22, 45.4%), followed by plastic (18/50, 36%), wood (12/47, 25.5%), metal (45/179, 25.1%), glass (2/10, 20%), concrete (8/55, 14.5%) and others (ceramic and rubber) (2/37, 5.4%). CT for positive samples: 31.0 to 38.7. |
| Dumont-Leblond 2021 [21] | Rooms were sampled from 8 to 30 days after the patient was diagnosed and from 9 to 48 days since of the first confirmed case in the corresponding long-term care facility. | Standard infection control practices instituted. The swabbed surfaces were out of reach and unfrequently cleaned. | 62 | 20/62 (32%) | Shelving units, door frames. | Positive tests: Shelving units: median 761.5 genome equivalents/surface (1st quartile = 74.6, 3rd quartile = 2615.6). Door frames: median 830.8 genome equivalents/surface (1st quartile = 391, 3rd quartile = 2772). |
| Espinoza 2021 [22] | Not specified | HCWs wore lab coats, N95 face masks and surgical caps inside the unit, and a surgical gown, face shield and gloves when entering the patient room. | 51 | 2/51 (3.9%) | Mobile phones | An educational campaign on SARS-CoV-2 cross-transmission, its permanence on fomites, and the proper use and disinfection of mobile phones was performed. CT of positive samples: 34,36. |
| Kowta 2021 [23] | At enrolment and every three days | Not specified | 474 | 125/474 (25%) | Bathroom door, bed and switch, phone, table and chair, toilet and sink. | Median CT value of surface samples testing positive for SARS-CoV-2 was 35.1 (IQR: 32.8–36.9). Factors significantly associated with positive environmental samples: hypoxia on admission, PCR-positive nasopharyngeal swab with CT ≤30 on or after the environmental sampling date, higher Charlson Comorbidity Index, and shorter time from onset of illness to environmental sample date. |
| Lin 2021 [24] | Not specified | No data were collected on the frequency of cleaning of fomites. | 21 Used tissues 5 Nasal prongs 4 Dentures 2 Phone/call bell 10 |
10/21 (47.6%) Used tissues 4/5 (80%) Nasal prongs 3/4 (75%) Dentures 1/2 (50%) Phone/call bell 2/10 (20%) |
Used tissues, nasal prongs, face cloth, dentures, phone/call bell, bedrail. | They found the ability to detect culturable virus was within the first 7 days after symptom onset and then declined dramatically with the exception of immunocompromised patients. Positive results also identified in specimens also collected from a patient's two hands after one hand had been coughed on, kiss samples inside of the polyethylene bag touched by a patient's lip, and dried saliva on a Petri dish (post 2 h). Duration of infectiousness on fomites was assessed by placing a respiratory clinical sample from an infected patient on fomites such as a call bell, computer keyboard, stethoscope diaphragm and an N95 respirator and demonstrating minimal reduction in quantitative burden of SARS-C0V-2 from baseline after 4 h and in dried saliva on a plastic surface for 2 h with no reduction. |
| Ma 2021 [25] | Not specified | Not specified | 919 Stage 1: 420 Stage 2: 499 |
102/919 (11.1%) Stage 1: 51/420 (12.1%) Stage 2: 51/499 (10.2%) |
Outer surface of cold-chain containers. | |
| Ma 2021 [26] | Not specified | Not specified | 5370 Processing workplace: 39 Cold-chain seafood: 4963 Cold-chain pollock packaging: 368 |
148/5370 (2.8%) Processing workplace: 14/39 (35.9%) Cold-chain seafood: 0/4963 Cold-chain pollock packaging: 134/368 (36.4%) |
Cold-chain containers | Surface swab samples of the inner and outer packaging of the cold-chain imported seafood that were suspected to be contaminated by COVID-19 virus were carefully smeared and collected. Imported cold-chain seafood by Company K; all other imported cold-chain seafood products from the two cargo ships that were temporarily stored at Company K were sampled and tested. |
| Marcenac 2021 [27] | Four households on enrolment visit (day 0). Five households on median 7 days (range: 4–9). One household on day 20. |
Not specified. Two households reported using disinfecting wipes and sprays on high-touch surfaces after someone became ill with COVID-19. | 150 | 23/150 (15%) | Nightstands (4/6 samples, 67%), pillows (4/23, 17%), and light switches (3/21, 14%). Also, on doorknobs (2/17, 12%); kitchen surfaces and appliances, including a sink handle (1/5, 20%), countertop (1/9, 11%), table (1/4, 25%), refrigerator handle (1/11, 9%), microwave (1/7, 14%), and trash can lid (1/1, 100%); and electronic items, including a phone (1/3, 33%), computer (1/4, 25%), and TV remote control (1/7, 14%). |
15 surfaces were sampled in each household. CT for positive samples: Median 33.8 (26.4–37.2). Positive culture from a nightstand sample (CT = 26.4) was found in a 35-year-old man) with respiratory symptoms whose nasopharyngeal swab was positive for SARS-CoV-2 (CT = 15.5) on the environmental sampling date. This man first tested positive for SARS-CoV-2 two days prior to environmental sampling. |
| Nannu Shankar 2021 [28] | Surface samples collected from volunteer A's room on days 5 and 6 after positive test. Surface samples collected from volunteer B's room on days 2 and 6 after positive test. |
Self-isolation | 7 Volunteer A: 3 Volunteer B: 4 |
2/7 (28.6%) Volunteer A: 0/3 Volunteer B: 2/4 (50%) |
Mobile phone (front screen and back cover). | Both positive samples for Volunteer B were collected Oct 2nd, 2020; negative samples collected Oct 6th, 2020. CT for positive samples: 35.91 and 36.4 |
| Newey 2021 [29] | Fresh environmental samples were obtained from surfaces of bank notes and coins from local restaurants and assayed within 1 h | Not specified | 813 Money cards and ID cards 279 Bank notes 429 Coins 105 |
17/813 (2.1%) Money cards and ID cards: 17/279 (6.1%) Bank notes: 0/429 Coins: 0/105 |
Bank notes | |
| Oksanen 2021 [30] | Not specified | Hand hygiene, universal masking for staff (FFP2/3 for ICU and surgical masks for the COVID ward), guidance on social distancing (2 m), and PPE following droplet precautions. The room was cleaned twice a day. | 252 Hospital 182 Homes 70 |
25/252 (9.9%) | High touch surfaces: bed remote, cell phone, drinking glass, computer, door handle. Low touch surfaces: hospital equipment, floor, table, bedrail. Toilet surfaces: toilet seat, toilet flush button. |
Positive surface samples were detected more often when there were multiple COVID-19 patients in the ward/house during the sampling (P = 0.02). |
| Rajendiran 2021 [31] | In the morning before cleaning | Investigators wore PPE and complied with the respective hospital protocol on donning and doffing procedures. | 124 Stage 1: 104 samples from high-touch surfaces and areas used by patients and HCWs. Stage 2: 20 samples from general wards. |
6/124 (4.8%) Stage 1: 3/104 (2.9%) Stage 2: 3/20 (15%) |
Cardiac table, sink in an isolation room and open ward in stage 1. Floor, sink and toilet bowl in stage 2. |
2 stage sample collection: In stage 1, sampling was performed on random days in the intensive care unit (ICU) and general wards. In stage 2, samples were collected serially on alternate days for 7 days in two selected general wards. CT for positive samples: 33.49 to 37.52. |
| Winslow 2021 [32] | 0–15 days in hospital with illness | Not specified | 90 | 6/90 (7%) | Floor (5), high-object surface (1) | Environmental samples varied according to clinical and operational needs. Participants in the HFNO group were sampled significantly later in their illness compared to those receiving only supplemental oxygen: mean 16 days (95% CI: 13 to 19) vs mean 9 days (95% CI: 5 to 13), from symptom onset, respectively. Clinical surfaces were more contaminated with viral RNA than the air samples. CT for positive samples: 35–40. |
| Zhou 2020 [33] | Not specified | All areas were disinfected daily with an additional twice-daily disinfection of high-touch surfaces. | 218 | 23/218 (10.6%) | Computer keyboards/mice, alcohol gel dispensers, and chairs, and >50% of toilet seats, sink taps, and patient bedrails. |
ARDS, acute respiratory distress syndrome; CT, cycle threshold; CPAP, continuous positive airway pressure; HCP, healthcare professional; HCW, healthcare worker; HFNO, high-flow nasal oxygen; ID, identity cards; PPE, personal protective equipment.