Re-positive testing, clinical evolution and clearance of infection: results from COVID-19 cases in isolation in Viet Nam

Ngoc-anh Hoang; Thai Quang Pham; Ha-linh Quach; Khanh Cong Nguyen; Samantha Colquhoun; Stephen Lambert; Huy Luong Duong; Dai Quang Tran; Cong Dinh Phung; Nhu Duong Tran; Duy Nghia Ngu; Anh Tu Tran; Hue Bich Thi Nguyen; Duc-anh Dang; Florian Vogt

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Re-positive testing, clinical evolution and clearance of infection: results from COVID-19 cases in isolation in Viet Nam

Author: Ngoc-Anh Hoang ^{1
,

2} ; Thai Quang Pham ^{1
,

3} ; Ha-Linh Quach ^{1
,

2} ; Khanh Cong Nguyen ^{1
,

2} ; Samantha Colquhoun ⁴ ; Stephen Lambert ⁴ ; Huy Luong Duong ¹ ; Dai Quang Tran ⁵ ; Cong Dinh Phung ⁶ ; Nhu Duong Tran ⁷ ; Duy Nghia Ngu ¹ ; Anh Tu Tran ¹ ; Hue Bich Thi Nguyen ⁸ ; Duc-Anh Dang ⁷ ; Florian Vogt ^{4
,

9}
Author Information

1. Department of Epidemiology, National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
2. National Centre for Epidemiology and Population Health, Research School of Population Health, College of Health and Medicine, Australian National University, Canberra, Australia
3. School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Viet Nam
4. National Centre for Epidemiology and Population Health, Research School of Population Health, College of Health and Medicine, Australian National University, Canberra, Australia
5. General Department of Preventive Medicine, Ministry of Health, Hanoi, Viet Nam
6. National Agency for Science and Technology Information, Ministry of Science and Technology, Viet Nam
7. National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
8. National Hospital of Tropical Diseases, Hanoi, Viet Nam
9. The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
Publication Type:Journal Article
From: Western Pacific Surveillance and Response 2021;12(4):82-92
CountryWHO-WPRO
Language:English
Abstract: Objectives:Asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and test re-positivity after a negative test have raised concerns about the ability to effectively control the coronavirus disease 2019 (COVID-19) pandemic. We aimed to investigate the prevalence of COVID-19 asymptomatic and pre-symptomatic infections during the second wave of COVID-19 in Viet Nam, and to better understand the duration of SARS-CoV-2 infection and the dynamics between the evolution of clinical symptoms and SARS-CoV-2 test positivity among confirmed COVID-19 cases.
Methods:We conducted a cohort analysis on the first 50 confirmed cases during the second COVID-19 wave in Viet Nam using clinical, laboratory and epidemiological data collected from 9 March to 30 April 2020. Kaplan-Meier estimates were used to assess time to clearance of SARS-CoV-2 infection, and log-rank tests were used to explore factors related to time to SARS-CoV-2 infection clearance.
Results:Most cases (58%) had no typical signs or symptoms of COVID-19 at the time of diagnosis. Ten cases (20%) were re-positive for SARS-CoV-2 during infection. Eight cases (16%) experienced COVID-19 symptoms after testing negative for SARS-CoV-2. The median duration from symptom onset until clearance of infection was 14 days (range: 6–31); it was longer in re-positive and older patients and those with pre-existing conditions.
Conclusion:Asymptomatic and pre-symptomatic infections were common during the second wave of COVID-19 in Viet Nam. Re-positivity was frequent during hospitalization and led to a long duration of SARS-CoV-2 infection.
Full text:wpsar.2021.12.4.857 Hoang FINAL.pdf