Detection of Severe Acute Respiratory Syndrome Coronavirus 2 RNA on Surfaces in Quarantine Rooms

Fa-Chun Jiang; Xiao-Lin Jiang; Zhao-Guo Wang; Zhao-Hai Meng; Shou-Feng Shao; Benjamin D. Anderson; Mai-Juan Ma


Emerging Infectious Diseases. 2020;26(9):2162-2164. 

In This Article

The Study

Two Chinese students studying overseas returned to China on March 19 (patient A) and March 20 (patient B), 2020 (Table 1). On the day of their arrival in China, neither had fever or clinical symptoms, and they were transferred to a hotel for a 14-day quarantine. They had normal body temperatures (patient A, 36.3°C; patient B, 36.5°C) and no symptoms when they checked into the hotel. During the quarantine period, local medical staff were to monitor their body temperature and symptoms each morning and afternoon. On the morning of the second day of quarantine, they had no fever (patient A, 36.2°C; patient B, 36.7°C) or symptoms. At the same time their temperatures were taken, throat swab samples were collected; both tested positive for SARS-CoV-2 RNA by real-time reverse transcription PCR (rRT-PCR). The students were transferred to a local hospital for treatment. At admission, they remained presymptomatic, but nasopharyngeal swab, sputum, and fecal samples were positive for SARS-CoV-2 RNA with high viral loads (Table 1). In patient A, fever (37.5°C) and cough developed on day 2 of hospitalization, but his chest computed tomography images showed no significant abnormality during hospitalization. In patient B, fever (37.9°C) and cough developed on day 6 of hospitalization, and her computed tomography images showed ground-glass opacities.

Approximately 3 hours after the 2 patients were identified as positive for SARS-CoV-2 RNA, we sampled the environmental surfaces of the 2 rooms in the centralized quarantine hotel in which they had stayed. Because of the SARS-CoV-2 outbreak in China, the hotel had been closed during January 24–March 18, 2020. Therefore, only these 2 persons had stayed in the rooms. We used a sterile polyester-tipped applicator, premoistened in viral transport medium, to sample the surfaces of the door handle, light switch, faucet handle, thermometer, television remote, pillow cover, duvet cover, sheet, towel, bathroom door handle, and toilet seat and flushing button. We also collected control swab samples from 1 unoccupied room. We collected each sample by swabbing each individual surface. We tested the samples with an rRT-PCR test kit (DAAN GENE Ltd, targeting the open reading frame 1ab (ORF1ab) and N genes of SARS-CoV-2. We interpreted cycle threshold (Ct) <40 as positive for SARS-CoV-2 RNA and Ct ≥40 as negative.

We collected a total of 22 samples from the 2 rooms of the quarantine hotel (Table 2). Eight (36%) samples were positive for SARS-CoV-2 RNA. Ct values ranged from 28.75 to 37.59 (median 35.64). Six (55%) of 11 samples collected from the room of patient A were positive for SARS-CoV-2 RNA. Surface samples collected from the sheet, duvet cover, pillow cover, and towel tested positive for SARS-CoV-2 RNA, and surface samples collected from the pillow cover and sheet had a high viral load; Ct for ORF1ab gene from the pillow cover was 28.97 and from the sheet, 30.58. Moreover, the Ct values of these 2 samples correlated with those of patient A's nasopharyngeal (24.73) and fecal (33.12) swab samples at hospital admission. One surface sample from the faucet in patient B's room was positive for SARS-CoV-2 RNA; the Ct was 28.75 for the ORF1ab gene. Again, we detected SARS-CoV-2 RNA from the surface samples of the pillow cover; Ct was 34.57. All control swab samples were negative for SARS-CoV-2 RNA.