• Nguyen Van Vinh Chau, Lam Vo Thanh VT Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam., Dung Nguyen Thanh NT Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam., Lam Minh Yen, Ngo Ngoc Quang Minh, Le Manh Hung, Nghiem My Ngoc, Nguyen Tri Dung, Man Dinh Nguyen Huy DNH Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam., Lam Anh Nguyet, Le Thanh Hoang Nhat, Le Nguyen Truc Nhu, Nguyen Thi Han Ny, Nguyen Thi Thu Hong, Evelyne Kestelyn, Nguyen Thi Phuong Dung, Tran Chanh Xuan, Tran Tinh Hien, Phong Nguyen Thanh NT Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam., Tran Nguyen Hoang Tu, Ronald B Geskus, Tran Tan Thanh, Truong Nguyen Thanh NT Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam., Nguyen Tan Binh, Tang Chi Thuong, Guy Thwaites, Van Tan Le L Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam., and Oxford University Clinical Research Unit COVID-19 Research Group.
• Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.
• Clin. Infect. Dis. 2020 Dec 17; 71 (10): 2679-2687.

BackgroundLittle is known about the natural history of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.MethodsWe 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.ResultsBetween 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.ConclusionsAsymptomatic 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.© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America.

11 keywords...

hide…