scholarly journals The Natural History and Transmission Potential of Asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infection

2020 ◽  
Vol 71 (10) ◽  
pp. 2679-2687 ◽  
Author(s):  
Nguyen Van Vinh Chau ◽  
Vo Thanh Lam ◽  
Nguyen Thanh Dung ◽  
Lam Minh Yen ◽  
Ngo Ngoc Quang Minh ◽  
...  
Keyword(s):  
Natural History ◽  
Severe Acute Respiratory Syndrome ◽  
Rt Pcr ◽  
Asymptomatic Group ◽  
Transmission Potential ◽  
Viral Loads ◽  
Imported Cases ◽  
History Of ◽  
Asymptomatic Individuals ◽  
A Prospective Study

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.

scholarly journals The natural history and transmission potential of asymptomatic SARS-CoV-2 infection

2020 ◽  
Author(s):  
Nguyen Van Vinh Chau ◽  
Vo Thanh Lam ◽  
Nguyen Thanh Dung ◽  
Lam Minh Yen ◽  
Ngo Ngoc Quang Minh ◽  
...  
Keyword(s):  
Natural History ◽  
Ho Chi Minh City ◽  
Rt Pcr ◽  
Transmission Potential ◽  
Viral Loads ◽  
Symptomatic Group ◽  
History Of ◽  
Asymptomatic Individuals ◽  
A Prospective Study

ABSTRACTBackgroundLittle is known about the natural history of asymptomatic SARS-CoV-2 infection or its contribution to infection transmission.MethodsWe conducted a prospective study at a quarantine centre for COVID-19 in Ho Chi Minh City, Vietnam. We enrolled quarantined people with RT-PCR-confirmed SARS-CoV-2 infection, collecting clinical data, travel and contact history, and saliva at enrolment and daily nasopharyngeal throat swabs (NTS) for RT-PCR testing. We compared the natural history and transmission potential of asymptomatic and symptomatic individuals.ResultsBetween March 10th and April 4th, 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. 17(57%) participants acquired their infection outside Vietnam. Compared with symptomatic individuals, asymptomatic people were less likely to have detectable SARS-CoV-2 in NTS samples collected at enrolment (8/13 (62%) vs. 17/17 (100%) P=0.02). SARS-CoV-2 RNA was detected in 20/27 (74%) available saliva; 7/11 (64%) in the asymptomatic and 13/16 (81%) in the symptomatic group (P=0.56). Analysis of the probability of RT-PCR positivity showed asymptomatic participants had faster viral clearance than symptomatic participants (P<0.001 for difference over first 19 days). This difference was most pronounced during the first week of follow-up. Two of the asymptomatic individuals appeared to transmit the infection to up to four contacts.ConclusionsAsymptomatic SARS-CoV-2 infection is common and can be detected by analysis of saliva or NTS. NTS viral loads fall faster in asymptomatic individuals, but they appear able to transmit the virus to others.

scholarly journals Clinical features of imported cases of coronavirus disease 2019 in Tibetan patients in the Plateau area

2020 ◽  
Author(s):  
Yu Lei ◽  
Xiaobo Huang ◽  
Bamu SiLang ◽  
YunPing Lan ◽  
Jianli Lu ◽  
...  
Keyword(s):  
Clinical Laboratory ◽  
Clinical Symptoms ◽  
Asymptomatic Group ◽  
Asymptomatic Patients ◽  
Abnormal Chest ◽  
Plateau Area ◽  
Imported Cases ◽  
High Altitude Area ◽  
History Of ◽  
The Mean

AbstractCoronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, has rapidly spread throughout China, but the clinical characteristics of Tibetan patients living in the Qinghai-Tibetan plateau are unknown. We aimed to investigate the epidemiological, clinical, laboratory and radiological characteristics of these patients. We included 67 Tibetan patients with confirmed SARS-CoV-2 infection. The patients were divided into two groups based on the presence of clinical symptoms at admission, with 31 and 36 patients in the symptomatic and asymptomatic groups, respectively. The epidemiological, clinical, laboratory and radiological characteristics were extracted and analysed. No patient had a history of exposure to COVID-19 patients from Wuhan or had travelled to Wuhan. The mean age of Tibetan patients was 39.3 years and 59% of the patients were male. Seven patients presented with fever on admission and lymphocytopenia was present in 20 patients. 47 patients had abnormal chest CTs at admission instead of stating that 20 were unchanged. Lactate dehydrogenase levels were increased in 31 patients. Seven patients progressed to severe COVID-19; however, after treatment, their condition was stable. No patients died. Of the 36 asymptomatic patients, the mean age was younger than the symptomatic group (34.4±17.3vs 44.9±18.1 years, P=0.02). Lymphocyte count and prealbumin levels were higher in the asymptomatic group than the group with clinical symptoms (1.6±0.5 vs 1.3±0.6 and 241.8±68.2 vs 191.9±60.3, respectively; P<0.05). Imported cases of COVID-19 in Tibetan patients were generally mild in this high-altitude area. Absence of fever or radiologic abnormalities on initial presentation were common.

scholarly journals The Natural History of Appendicitis in Adults A Prospective Study

1995 ◽  
Vol 221 (3) ◽  
pp. 278-281 ◽  
Author(s):  
Claire L. Temple ◽  
Shirley A. Huchcroft ◽  
Walley J. Temple
Keyword(s):  
Natural History ◽  
Prospective Study ◽  
History Of ◽  
A Prospective Study

scholarly journals A primary care approach to the COVID-19 pandemic: clinical features and natural history of 2,073 suspected cases in the Corona São Caetano programme, São Paulo, Brazil

2020 ◽  
Author(s):  
Fabio E Leal ◽  
Maria C Mendes-Correa ◽  
Lewis F Buss ◽  
Silvia F Costa ◽  
Joao CS Bizario ◽  
...  
Keyword(s):  
Primary Care ◽  
Natural History ◽  
Clinical Features ◽  
Older Patients ◽  
Population Based ◽  
Rt Pcr ◽  
Community Based ◽  
Care Approach ◽  
History Of ◽  
At Home

ABSTRACTBackgroundDespite most cases not requiring hospital care, there are limited community-based clinical data on COVID-19.Methods and findingsThe Corona São Caetano program is a primary care initiative offering COVID-19 care to all residents of São Caetano do Sul, Brazil. After triage of potentially severe cases, consecutive patients presenting between 13th April and 13th May 2020 were tested at home with SARS-CoV-2 reverse transcriptase (RT) PCR; positive patients were followed up for 14 days. RT-PCR-negative patients were offered SARS-CoV-2 serology. We describe the clinical features, virology and natural history of this prospective population-based cohort. Of 2,073 suspected COVID-19 cases, 1,583 (76·4%) were tested by RT-PCR, of whom 444 (28·0%, 95%CI: 25·9% - 30·3%) were positive; 604/1,136 (53%) RT-PCR-negative patients underwent serology, of whom 52 (8·6%) tested SARS-CoV-2 seropositive. The most common symptoms of COVID-19 were cough, fatigue, myalgia and headache; whereas self-reported fever, anosmia, and ageusia were most associated with a positive COVID-19 diagnosis. RT-PCR cycle thresholds were lower in men, older patients, those with fever and arthralgia, and around symptom onset. The rates of hospitalization and death among 444 RT-PCR-positive cases were 6·7% and 0·7%, respectively, with older age and obesity more frequent in the hospitalized group.ConclusionsCOVID-19 presents similarly to other mild respiratory disease in primary care. Some symptoms assist the differential diagnosis. Most patients can be managed at home.

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