The Natural History and Transmission Potential of Asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infection. (4th June 2020)

• Record Type: Journal Article
• Authors: Van Vinh Chau, Nguyen; Lam, Vo Thanh; Dung, Nguyen Thanh; Yen, Lam Minh; Minh, Ngo Ngoc Quang; Hung, Le Manh; Ngoc, Nghiem My; Dung, Nguyen Tri; Man, Dinh Nguyen Huy; Nguyet, Lam Anh; Nhat, Le Thanh Hoang; Nhu, Le Nguyen Truc; Ny, Nguyen Thi Han; Hong, Nguyen Thi Thu; Kestelyn, Evelyne; Dung, Nguyen Thi Phuong; Xuan, Tran Chanh; Hien, Tran Tinh; Phong, Nguyen Thanh; Tu, Tran Nguyen Hoang; Geskus, Ronald B; Thanh, Tran Tan; Truong, Nguyen Thanh; Binh, Nguyen Tan; Thuong, Tang Chi; Thwaites, Guy; Van Tan, Le
• Is Part Of: Clinical infectious diseases. Volume 71:Number 10(2020)
• Page Start: 2679
• Page End: 2687
• Publication Date: 2020-06-04
• Subjects: COVID-19 -- SARS-CoV-2 -- coronaviruses -- pandemic -- Vietnam; Communicable diseases -- Periodicals; 616.905
• DOI: 10.1093/cid/ciaa711
• Languages: English
• ISSNs: 1058-4838

Abstract

Abstract: Background: Little is known about the natural history of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Methods: We conducted a prospective study at a quarantine center for coronavirus disease 2019 in Ho Chi Minh City, Vietnam. We enrolled quarantined people with reverse-transcription polymerase chain reaction (RT-PCR)–confirmed SARS-CoV-2 infection, collecting clinical data, travel and contact history, and saliva at enrollment and daily nasopharyngeal/throat swabs (NTSs) for RT-PCR testing. We compared the natural history and transmission potential of asymptomatic and symptomatic individuals. Results: Between 10 March and 4 April 2020, 14 000 quarantined people were tested for SARS-CoV-2; 49 were positive. Of these, 30 participated in the study: 13 (43%) never had symptoms and 17 (57%) were symptomatic. Seventeen (57%) participants imported cases. Compared with symptomatic individuals, asymptomatic people were less likely to have detectable SARS-CoV-2 in NTS collected at enrollment (8/13 [62%] vs 17/17 [100%]; P = .02). SARS-CoV-2 RNA was detected in 20 of 27 (74%) available saliva samples (7 of 11 [64%] in the asymptomatic group and 13 of 16 [81%] in the symptomatic group; P = .56). Analysis of RT-PCR positivity probability showed that asymptomatic participants had faster viral clearance than symptomatic participants ( P < .001 for difference over the first 19 days). This difference was most pronounced during the first week of follow-up. Two of the asymptomatic individuals appeared to transmit SARS-CoV-2 to 4 contacts. Conclusions: Asymptomatic SARS-CoV-2 infection is common and can be detected by analysis of saliva or NTSs. The NTS viral loads fall faster in asymptomatic individuals, but these individuals appear able to transmit the virus to others. Abstract : Forty-three percent (13/30) of confirmed SARS-CoV-2–infected individuals were asymptomatic, with the virus detected in both saliva and nasopharyngeal/throat swabs. Viral clearance was faster in asymptomatic individuals, but they still appeared able to pass the infection to others.