Background: Severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) is suspected to be spread from an infected person to a susceptible host primarily via droplet and possibly direct contact (1). The roles of transmission by indirect contact (fomites) or by long-range airborne route are uncertain. Currently, there are no data on the risk for transmission from infants or young children with coronavirus disease 2019 (COVID-19) who may be asymptomatic or pauci-symptomatic.

A 6-month-old infant was admitted for isolation in our hospital because both parents were in the isolation units of other hospitals for confirmed COVID-19. On admission, the infant was asymptomatic, but nasopharyngeal swabs confirmed COVID-19 infection with very high viral load. The cycle threshold (Ct) values for N gene and Orf1ab gene polymerase chain reaction (PCR) assay were 15.6 and 13.7, respectively, on the day of admission (2). The infant was generally well throughout admission, with only a single measured temperature of 38.5 °C on day 2 of admission. There were no respiratory symptoms, results of physical examination were normal, and no other abnormal vital signs were noted throughout the infant's stay.

Objective: To investigate environmental contamination and potential for transmission from an infant with COVID-19.

Methods and Findings: On day 2 of admission, we sampled the infant's isolation environment and the personal protective equipment (PPE) of a health care worker (HCW) who was looking after the infant. On that day, the Ct values on real-time PCR for the N gene and Orf1ab gene were 18.8 and 18.6, respectively, while urine and stool samples remained negative (2). No one apart from HCWs with full PPE had contact with the infant during the admission. Synthetic fiber flocked swabs with Universal Transport Medium were used to sample the infant's bedding; the cot rail; a table situated 1 meter away from the infant's bed; and the HCW's face shield, N95 mask, and waterproof gown (6 swabs in total) (Figure). Each swab was run over nearly 100% of the item or area. The PPE of the HCW was sampled after the HCW carried and fed the infant. Total time spent in the room was about 15 minutes. The environmental samples were tested with PCR, using a published protocol (3) for the E and RdRp genes. Ct values less than 36 were considered positive. Lower Ct values represent higher viral load, and vice versa.

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The infant's bedding, the cot rail, and a table situated 1 meter away (all 3 environment samples) were found to be positive for SARS-CoV-2. The SARS-CoV-2 RdRp gene Ct values for the bedding, cot, and table were 28.7, 33.3, and 29.7, respectively. Similar SARS-CoV-2 E gene Ct trend values were detected from the environment in terms of distance from the infant (Figure). All 3 samples from the HCW's PPE were found to be negative for SARS-CoV-2.

Discussion: Our investigation confirmed that a generally well infant with COVID-19 can contaminate the environment with PCR-detectable virus. Although we cannot be certain of virus viability, other coronaviruses have been reported to remain viable on surfaces for up to 9 days (4). Despite close physical contact with the infant during feeding, we did not detect any evidence of SARS-CoV-2 on the gown of the HCW.

A study of mobile adults with COVID-19 who had symptoms found widespread environmental contamination but negative PPE swabs (5). Although our infant had no respiratory symptoms, the nearby environment could have been contaminated with SARS-CoV-2 through crying or drooling. There was a downward trend of viral load with increasing distance from the infant (from bedding to cot rail). However, the Ct values at the table 1 meter away from the cot indicated higher viral load. For droplet transmission, one would expect the viral load in the environment to fall with increasing distance from the immobile infant. However, baby formula and other items, such as baby wipes, were placed on it. Therefore, it seems more likely that the contamination was due to indirect contact via HCW hands between baby and table. These findings suggests that even generally well infants positive for SARS-CoV-2 with no respiratory symptoms can easily contaminate nearby environments. Our data also reaffirm the importance of hand hygiene when caring for infants with COVID-19 and potentially in helping to reduce environmental virus contamination.

References

• 1. Centers for Disease Control and Prevention. How COVID-19 spreads. 28 February 2020. Accessed at www.cdc.gov/coronavirus/2019-ncov/about/transmission.html on 27 March 2020. Google Scholar
• 2. Kam KQ, Yung CF, Cui L, et al. A well infant with coronavirus disease 2019 (COVID-19) with high viral load. Clin Infect Dis. 2020. [PMID: 32112082] doi:10.1093/cid/ciaa201 Google Scholar
• 3. Corman VM, Landt O, Kaiser M, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. Euro Surveill. 2020;25. [PMID: 31992387] doi:10.2807/1560-7917.ES.2020.25.3.2000045 Google Scholar
• 4. Kampf G, Todt D, Pfaender S, et al. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. J Hosp Infect. 2020;104:246-251. [PMID: 32035997] doi:10.1016/j.jhin.2020.01.022 Google Scholar
• 5. Ong SWX, Tan YK, Chia PY, et al. Air, surface environmental, and personal protective equipment contamination by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a symptomatic patient. JAMA. 2020. [PMID: 32129805] doi:10.1001/jama.2020.3227 Google Scholar

This article was published at Annals.org on 1 April 2020.

中文翻译：

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在感染婴儿的隔离室中进行 SARS-CoV-2 环境和个人防护设备测试。

背景：严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 被怀疑主要通过飞沫和可能的直接接触从感染者传播到易感宿主 (1)。通过间接接触（污染物）或通过远程空气传播途径传播的作用尚不确定。目前，尚无关于可能无症状或仅有少数症状的 2019 年冠状病毒病 (COVID-19) 婴儿或幼儿传播风险的数据。

一名 6 个月大的婴儿因父母双方均因确诊的 COVID-19 入住其他医院的隔离病房而被收治入院隔离。入院时，婴儿没有症状，但鼻咽拭子证实感染了 COVID-19，且病毒载量非常高。入院当天N基因和Orf1ab基因聚合酶链式反应 (PCR) 检测的循环阈值 (Ct) 分别为 15.6 和 13.7 (2)。婴儿在入院期间总体状况良好，入院第 2 天仅测得一次体温 38.5 °C。婴儿在整个住院期间没有出现呼吸道症状，体检结果正常，也没有发现其他异常生命体征。

目的：调查环境污染和感染 COVID-19 的婴儿传播的可能性。

方法和结果：在入院第二天，我们对婴儿的隔离环境和照顾婴儿的医护人员 (HCW) 的个人防护装备 (PPE) 进行了采样。当天， N基因和Orf1ab基因的实时PCR Ct值分别为18.8和18.6，而尿液和粪便样本仍呈阴性（2）。在入院期间，除了配备全套个人防护装备的医护人员外，没有人与婴儿接触过。使用带有通用传输介质的合成纤维植绒拭子对婴儿的床上用品进行取样；婴儿床栏杆；距离婴儿床1米的桌子；以及医护人员的面罩、N95 口罩和防水服（共 6 个棉签）（图）。每个拭子几乎覆盖了 100% 的物品或区域。在医护人员抱起并喂养婴儿后，对医护人员的个人防护装备进行了采样。在房间里度过的总时间约为15分钟。使用已发布的E和RdRp基因方案 (3) 通过 PCR 测试环境样本。 Ct 值小于 36 被认为是阳性。较低的 Ct 值代表较高的病毒载量，反之亦然。

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婴儿的床上用品、婴儿床栏杆和 1 米外的桌子（所有 3 个环境样本）均被发现 SARS-CoV-2 呈阳性。床上用品、婴儿床和桌子的 SARS-CoV-2 RdRp基因 Ct 值分别为 28.7、33.3 和 29.7。在与婴儿的距离方面，从环境中检测到了类似的 SARS-CoV-2 E基因 Ct 趋势值（图）。医护人员的个人防护装备中的所有 3 个样本均呈 SARS-CoV-2 阴性。

讨论：我们的调查证实，总体健康的感染 COVID-19 的婴儿可能会被 PCR 可检测到的病毒污染环境。尽管我们无法确定病毒的生存能力，但据报道，其他冠状病毒在表面上可存活长达 9 天 (4)。尽管在喂养过程中与婴儿有密切的身体接触，但我们没有在医护人员的长袍上发现任何 SARS-CoV-2 的证据。

一项针对患有 COVID-19、有症状的流动成人的研究发现，环境污染广泛，但个人防护装备拭子呈阴性 (5)。尽管我们的婴儿没有呼吸道症状，但附近的环境可能通过哭泣或流口水而被 SARS-CoV-2 污染。随着与婴儿的距离（从床上用品到婴儿床栏杆）的增加，病毒载量呈下降趋势。然而，距离婴儿床 1 米的桌子上的 Ct 值表明病毒载量较高。对于飞沫传播，人们预计环境中的病毒载量会随着与不动婴儿的距离的增加而下降。然而，上面放置了婴儿配方奶粉和其他物品，例如婴儿湿巾。因此，污染似乎更有可能是由于医护人员的手与婴儿和桌子之间的间接接触造成的。这些发现表明，即使是健康状况良好、SARS-CoV-2 呈阳性且没有呼吸道症状的婴儿也很容易污染附近的环境。我们的数据还重申了护理感染 COVID-19 婴儿时手部卫生的重要性，并可能有助于减少环境病毒污染。

 参考

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  1.疾病控制和预防中心。 COVID-19 如何传播。 2020 年 2 月 28 日。2020 年 3 月 27 日访问 www.cdc.gov/coronavirus/2019-ncov/about/transmission.html 。谷歌学术
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  3. Corman VM、Landt O、Kaiser M 等人。通过实时 RT-PCR 检测 2019 新型冠状病毒（2019-nCoV）。欧元监视。 2020;25。 [PMID：31992387] doi：10.2807/1560-7917.ES.2020.25.3.2000045谷歌学术

本文于 2020 年 4 月 1 日发表于 Annals.org。