Covid-19 in South Korea — Challenges of Subclinical Manifestations

Song, Joon Young; Yun, Jin Gu; Noh, Ji Yun; Cheong, Hee Jin; Kim, Woo Joo

doi:10.1056/nejmc2001801

Cited by 120 publications

(112 citation statements)

References 4 publications

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“…This effect was again demonstrated for people in SK under the age of 40. The lower rates of CSM in SK might represent BCG vaccination, the efforts of the public health department, or an unknown/unmeasured variable [30]. Similarly, in cluster 2, Ireland was the only country with an active BCG vaccination program, though with decreases in vaccination rates starting in 2005, but with higher levels of CSM which might more closely represent delay in taking COVID-19 measures [31].…”

Section: Discussionmentioning

confidence: 99%

The association of Coronavirus Disease-19 mortality and prior bacille Calmette-Guerin vaccination: a robust ecological evaluation using unsupervised machine learning

Brooks

Puri

Garg

et al. 2020

Preprint

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Population-level data have suggested that bacille Calmette-Guerin (BCG) vaccination may lessen the severity of Coronavirus Disease-19 (COVID-19) prompting clinical trials in this area. Some reports have demonstrated conflicting results. We performed a robust, ecologic analysis comparing COVID-19 related mortality (CSM) between strictly selected countries based on BCG vaccination program status utilizing publicly available databases and machine learning to define the association between active BCG vaccination programs and CSM. Validation was performed using linear regression and country-specific modeling. CSM was lower for 80% of similarly clustered countries with a BCG vaccination policy for at least the preceding 15 years (BCG15). CSM increased significantly for each increase in the percent population over age 65. The total population of a country and BCG15 were significantly associated with improved CSM. There was a consistent association between countries with a BCG vaccination for the preceding 15 years, but not other vaccination programs, and CSM.

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Section: Discussionmentioning

confidence: 99%

The association of Coronavirus Disease-19 mortality and prior bacille Calmette-Guerin vaccination: a robust ecological evaluation using unsupervised machine learning

Brooks

Puri

Garg

et al. 2020

Preprint

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“…Infection may remain asymptomatic or pass with only minor symptoms, making a clinical diagnosis impossible in many cases. [2][3][4] High viral titers in the upper airways during the first week of symptoms 5,6 and presymptomatic transmission 7 likely contributes to the difficulty containing the pandemic. In the struggle against the pandemic, the WHO recently urged nations to "test, test, test".…”

Section: Introductionmentioning

confidence: 99%

FACT- Frankfurt adjusted COVID-19 testing- a novel method enables high-throughput SARS-CoV-2 screening without loss of sensitivity

Schmidt

Hoehl

Berger

et al. 2020

Preprint

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Background: In the pandemic, testing for SARS-CoV-2 by RT-PCR in one of the pillars on which countermeasures are based. Factors limiting the output of laboratories interfere with the effectiveness of public health measures. Conserving reagents by pooling samples in low-probability settings is proposed, but may cause dilution and loss of sensitivity. Methods: We tested an alternate approach (FACT) by simultaneously incubating multiple respiratory swabs in a single tube. This protocol was evaluated by serial incubation of a respiratory swab in up to 10 tubes. The analytics validity of this concept was demonstrated in a five-sample mini pool set-up. It was consequently applied in the testing of 50 symptomatic patients (five-sample pools) as well as 100 asymptomatic residents of a nursing home (ten-sample pools).Results: Serial incubation of a respiratory swab in up to 10 tubes did not lead to a significant decline in viral concentration. The novel FACT-protocol did not cause a false negative result in a five-sample mini-pool setup, with non-significantly differing Ct values between single sample and mini-pool NAT. In two routine applications, all mini pools containing positive patient samples were correctly identified.Conclusions: Our proposed FACT-protocol did not cause a significant loss in analytic or diagnostic sensitivity compared to single sample testing in multiple setups. It reduced the amount of reagents needed by up to 40%, and also reduced hands-on time. This method could enhance testing efficiency, especially in groups with a low pretest-probability, such as systemically relevant professional groups.

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“…Infection may remain asymptomatic or pass with only minor symptoms, making a clinical diagnosis impossible in many cases. [2][3][4] High viral titers in the upper airways during the first week of symptoms 5,6 and presymptomatic transmission 7 likely contributes to the difficulty containing the pandemic. In the struggle against the pandemic, the World Health Organization (WHO) recently urged nations to "test, test, test."…”

Section: Introductionmentioning

confidence: 99%

Novel multiple swab method enables high efficiency in SARS‐CoV‐2 screenings without loss of sensitivity for screening of a complete population

et al. 2020

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Background: In the pandemic, testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by real-time polymerase chain reaction is one of the pillars on which countermeasures are based. Factors limiting the output of laboratories interfere with the effectiveness of public health measures. Conserving reagents by pooling samples in low-probability settings is proposed but may cause dilution and loss of sensitivity. Blood transfusion services had experience in performance of high throughput nucleic acid testing (NAT) analysis and can support the national health system by screening of the inhabitants for SARS-COV-2. Methods: We evaluated a new approach of a multiple-swab method by simultaneously incubating multiple respiratory swabs in a single tube. Analytical sensitivity was constant up to a total number of 50 swabs. It was consequently applied in the testing of 50 symptomatic patients (5-sample pools) as well as 100 asymptomatic residents of a nursing home (10-sample pools). Results: The novel method did not cause false-negative results with nonsignificantly differing cycle threshold values between single-swab and multiple-swab NAT. In two routine applications, all minipools containing positive patient samples were correctly identified. Conclusions: The new method enables countries to increase the total number of testing significantly. The multiple-swab method is able to screen system relevant groups of employees frequently. The example in Germany shows that blood transfusion services can support general health systems with their experience in NAT and their high-throughput instruments. Screening of a huge number of inhabitants is currently the only option to prevent a second infection wave and enable exit strategies in many countries.

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Covid-19 in South Korea — Challenges of Subclinical Manifestations

Cited by 120 publications

References 4 publications

The association of Coronavirus Disease-19 mortality and prior bacille Calmette-Guerin vaccination: a robust ecological evaluation using unsupervised machine learning

The association of Coronavirus Disease-19 mortality and prior bacille Calmette-Guerin vaccination: a robust ecological evaluation using unsupervised machine learning

FACT- Frankfurt adjusted COVID-19 testing- a novel method enables high-throughput SARS-CoV-2 screening without loss of sensitivity

Novel multiple swab method enables high efficiency in SARS‐CoV‐2 screenings without loss of sensitivity for screening of a complete population

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