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 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 &lt; .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.

The Natural History of Subarachnoid Haemorrhage with Negative Angiography: A prospective study and 3-year follow-up

1988 ◽  
Vol 2 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Robert M. Redfern ◽  
Stefan Zygmunt ◽  
John D. Pickard ◽  
Patrick M. Foy ◽  
M. D. M. Shaw
Keyword(s):  
Natural History ◽  
Subarachnoid Haemorrhage ◽  
Prospective Study ◽  
Negative Angiography ◽  
History Of ◽  
A Prospective Study

scholarly journals Upper respiratory viral load in asymptomatic individuals and mildly symptomatic patients with SARS-CoV-2 infection

Thorax ◽  
2020 ◽  
Vol 76 (1) ◽  
pp. 61-63 ◽  
Author(s):  
Sang Hyun Ra ◽  
Joon Seo Lim ◽  
Gwang-un Kim ◽  
Min Jae Kim ◽  
Jiwon Jung ◽  
...  
Keyword(s):  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Viral Loads ◽  
Reverse Transcription Pcr ◽  
Laboratory Confirmation ◽  
Upper Respiratory ◽  
Asymptomatic Individuals ◽  
Study Participants ◽  
Pcr Targeting

BackgroundAsymptomatic individuals with SARS-CoV-2 infection have viable viral loads and have been linked to several transmission cases. However, data on the viral loads in such individuals are lacking. We assessed the viral loads in asymptomatic individuals with SARS-CoV-2 infection in comparison with those in symptomatic patients with COVID-19.MethodsStudy participants were recruited from a community facility designated for the isolation of patients with mild COVID-19 in South Korea. The presence of symptoms was evaluated with a questionnaire-based survey. Viral loads in the upper respiratory tract were measured with real-time reverse transcription-PCR (RT-PCR) targeting the E, RdRp and N genes of SARS-CoV-2, with a cycle threshold (Ct) value of 40 for determining positivity.ResultsIn 213 patients with SARS-CoV-2 infection, 41 (19%) had remained asymptomatic from potential exposure to laboratory confirmation and admission; of them, 39 (95%) underwent follow-up RT-PCR testing after a median 13 days. In 172 symptomatic patients, 144 (84%) underwent follow-up RT-PCR testing. Twenty-one (54%) asymptomatic individuals and 92 (64%) symptomatic patients tested positive for SARS-CoV-2 at follow-up. Asymptomatic individuals and symptomatic patients did not show any significant differences in the mean Ct values of the E (31.15 vs 31.43; p>0.99), RdRp (32.26 vs 32.93; p=0.92) and N (33.05 vs 33.28; p>0.99) genes.ConclusionApproximately one-fifth of the individuals without severe symptoms were asymptomatic, and their viral loads were comparable to those in symptomatic patients. A large proportion of mildly symptomatic patients with COVID-19 or asymptomatic individuals with SARS-CoV-2 showed persistent positive upper respiratory RT-PCR results at follow-up.

Natural history of helicobacter pylori infection from infancy to adulthood: A 21-year follow-up cohort study

2001 ◽  
Vol 120 (5) ◽  
pp. A128-A128 ◽  
Author(s):  
H MALATY ◽  
D GRAHAM ◽  
A ELKASABANY ◽  
S REDDY ◽  
S SRINIVASAN ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Cohort Study ◽  
Natural History ◽  
Helicobacter Pylori Infection ◽  
History Of

The natural history of pituitary apoplexy: long term follow-up study

2019 ◽  
Author(s):  
Ayesha Shaikh ◽  
Natasha Shrikrishnapalasuriyar ◽  
Giselle Sharaf ◽  
David Price ◽  
Maneesh Udiawar ◽  
...  
Keyword(s):  
Natural History ◽  
Pituitary Apoplexy ◽  
Follow Up Study ◽  
Long Term Follow Up ◽  
History Of

The natural history of benign thyroid nodules: 10 years follow-up

2020 ◽  
Author(s):  
Valeria Ramundo ◽  
Giorgio Grani ◽  
Rocco Bruno ◽  
Giuseppe Costante ◽  
Domenico Meringolo ◽  
...  
Keyword(s):  
Natural History ◽  
Thyroid Nodules ◽  
History Of ◽  
Benign Thyroid Nodules ◽  
Benign Thyroid

Unruptured intracranial aneurysms in children: 18 years’ experience in a tertiary care pediatric institution

2019 ◽  
Vol 24 (2) ◽  
pp. 184-189 ◽  
Author(s):  
Daniel-Alexandre Bisson ◽  
Peter Dirks ◽  
Afsaneh Amirabadi ◽  
Manohar M. Shroff ◽  
Timo Krings ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Natural History ◽  
Internal Carotid Artery ◽  
Intracranial Aneurysms ◽  
Internal Carotid ◽  
Tertiary Care ◽  
Unruptured Intracranial Aneurysms ◽  
History Of ◽  
Mean Size

OBJECTIVEThere are little data in the literature on the characteristics and natural history of unruptured intracranial aneurysms in children. The authors analyzed their experience with unruptured intracranial aneurysms in the pediatric population at their tertiary care pediatric institution over the last 18 years. The first objective was to assess the imaging characteristics and natural history of these aneurysms in order to help guide management strategies in the future. A second objective was to evaluate the frequency of an underlying condition when an incidental intracranial aneurysm was detected in a child.METHODSThe authors conducted a Research Ethics Board–approved retrospective review of incidental intracranial aneurysms in patients younger than 18 years of age who had been treated at their institution in the period from 1998 to 2016. Clinical (age, sex, syndrome) and radiological (aneurysm location, type, size, thrombus, mass effect) data were recorded. Follow-up imaging was assessed for temporal changes.RESULTSSixty intracranial aneurysms occurred in 51 patients (36 males, 15 females) with a mean age of 10.5 ± 0.5 years (range 9 months–17 years). Forty-five patients (88.2%) had a single aneurysm, while 2 and 3 aneurysms were found in 3 patients each (5.8%). Syndromic association was found in 22 patients (43.1%), most frequently sickle cell disease (10/22 [45.5%]). Aneurysms were saccular in 43 cases (71.7%; mean size 5.0 ± 5.7 mm) and fusiform in the remaining 17 (28.3%; mean size 6.5 ± 2.7 mm). Thirty-one aneurysms (51.7%) arose from the internal carotid artery (right/left 1.4), most commonly in the cavernous segment (10/31 [32.3%]). Mean size change over the entire follow-up of 109 patient-years was a decrease of 0.6 ± 4.2 mm (range −30.0 to +4.0 mm, rate −0.12 ± 9.9 mm/yr). Interval growth (2.0 ± 1.0 mm) was seen in 8 aneurysms (13.3%; 4 saccular, 4 fusiform). An interval decrease in size (8.3 ± 10.7 mm) was seen in 6 aneurysms (10%). There was an inverse relationship between aneurysm size and growth rate (r = −0.82, p < 0.00001). One aneurysm was treated endovascularly with internal carotid artery sacrifice.CONCLUSIONSUnruptured pediatric intracranial aneurysms are most frequently single but can occur in multiples in a syndromic setting. None of the cases from the study period showed clinical or imaging signs of rupture. Growth over time, although unusual and slow, can occur in a proportion of these patients, who should be identified for short-term imaging surveillance.

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