Nguyen Van Vinh Chau, Vo Thanh Lam, N. Dung, L. Yen, Ngo Ngọc Quang Minh, L. Hung, N. M. Ngoc, N. T. Dung, D. N. H. Man, L. A. Nguyet, L. T. H. Nhat, L. Nhu, N. Ny, N. Hong, E. Kestelyn, N. T. Dung, Tran Chanh Xuan, T. Hien, N. Phong, T. N. H. Tu, R. Geskus, T. T. Thanh, N. Truong, N. T. Binh, T. C. Thuong, G. Thwaites, Le Van Tan, Nguyen Nguyen Thanh Le Manh Huynh Thi Nguyen Thanh Nguyen Van Vinh Chau Dung Hung Loan Truong Phong Man Van , Nguyen Van Vinh Chau, N. Dung, L. Hung, H. Loan, N. Truong, N. Phong, D. N. H. Man, N. Van Hao, D. B. Thuy, N. M. Ngoc, N. P. H. Lan, Pham Thi Ngoc Thoa, T. Thảo, T. T. Phuong, Le Thi Tam Uyen, Tran Thi Thanh Tam, B. T. That, Huynh Thi Kim Nhung, Ngo Tan Tai, T. N. H. Tu, V. Vuong, Dinh Thi Bich Ty, L. T. Dung, Thai Lam Uyen, N. T. Tien, Hoang Thu Thao, Nguyen Ngoc Thao, Huynh Ngoc Thien Vuong, P. Thao, P. M. Phuong, D. Tam, E. Kestelyn, D. Joseph, R. Geskus, G. Thwaites, H. V. van Doorn, Hoang Van Hien, Huynh le Anh Huy, Huynh Ngan Ha, Huynh Xuan Yen, Jennifer Ilo van Nuil, J. Day, Joseph Donovan, Katrina J. Lawson, L. A. Nguyet, L. Yen, L. Nhu, L. T. H. Nhat, Le Van Tan, S. Odette, L. Thwaites, M. Rabaa, Marc Choisy, Mary Chambers, Motiur Rahman, N. T. Hoa, Nguyen Thanh Thuy Nhien, N. Ny, Nguyen Thi Kim Tuyen, N. T. Dung, N. Hong, Nguyen Xuân Truong, Phan Nguyen Quoc Khanh, P. L. K. Yen, S. Yacoub, T. Kesteman, N. Thuong, T. T. Thanh, T. Hien, V. Hang, N. T. Dung, L. H. Nga
Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 2020
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.
Cited by 56 publications.
Field of study: Medicine