Community Transmission of SARS-CoV-2 Omicron Variant, South Korea, 2021

Kim, Eun Young; Choe, Young June; Park, Hanul; Jeong, Hyoseon; Chung, Jae-Hwa; Yu, Jeong-Hee; Ko, Hwa-Pyeong; Ahn, Hyun Jeong; Go, Mi-Young; Lee, Ju-Hyung; Kim, Won Ick; Lee, Bu Sim; Kim, Soo-Yeon; Yu, Mi; Kim, Jia; Lee, Hye Ryeon; Jang, Eun Jung; Lee, Ji Joo; Lee, Hye Young; Kim, Jong Mu; Choi, Ji Hyun; Lee, Sang Eun; Kim, Il-Hwan; Park, Ae Kyung; Rhee, Jee Eun; Kim, Eun Jin; Lee, Sang‐Won; Park, Young-Joon

doi:10.3201/eid2804.220006

Cited by 27 publications

(26 citation statements)

References 6 publications

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“…For studies with participants who received booster vaccines, the pooled proportion of asymptomatic infection reached 67.2%, significantly higher than participants who were unvaccinated and received a primary vaccination series, 15,18 urging border vaccination of the third and even the fourth dose of COVID-19 vaccine. However, only slight difference was observed between studies with <65% fully vaccinated individuals and ≥65% fully vaccinated individuals, [20][21][22][23][24][25][26][27][28][29][30] making broad coverage of vaccination seem to be meaningless. This is probably due to decreased pathogenicity of Omicron itself.…”

Section: High Proportion Of Asymptomatic Infection Observed In Childrenmentioning

confidence: 99%

Proportion of asymptomatic infection and nonsevere disease caused by SARS‐CoV‐2 Omicron variant: A systematic review and analysis

Guo

Zhang

et al. 2022

Journal of Medical Virology

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SARS‐CoV‐2 Omicron variant seemed to cause milder disease compared to previous predominated variants. We aimed to conduct a meta‐analysis to assess the pooled proportion of nonsevere disease and asymptomatic infection among COVID‐19 patients infected with Omicron and Delta. We searched PubMed, Embase, Web of Science, and China National Knowledge Infrastructure (CNKI) databases. We included studies of SARS‐CoV‐2 Omicron infection from November 1, 2021, to April 18, 2022, and studies of Delta infection from October 1, 2020, to June 30, 2022. Studies without corresponding data, with less than 50 patients, or obviously biased concerning main outcome were excluded. Meta‐analysis was performed in R 4.2.0 with the “meta” package. Subgroup analyses were conducted by study group and vaccination status. The pooled proportion of asymptomatic infection and nonsevere disease with Omicron were 25.5% (95% confidence interval [CI] 17.0%–38.2%) and 97.9% (95% CI 97.1%–98.7%), significantly higher than those of Delta with 8.4% (95% CI 4.4%–16.2%) and 91.4% (95% CI 87.0%–96.0%). During Omicron wave, children and adolescents had higher proportion of asymptomatic infection, SOTR and the elderly had lower proportion of nonsevere disease, vaccination of a booster dose contributed to higher proportion of both asymptomatic infection and nonsevere disease. This study estimates the pooled proportion of asymptomatic infection and nonsevere disease caused by SARS‐CoV‐2 Omicron compared to other predominant variants. The result has important implications for future policy making.

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Section: High Proportion Of Asymptomatic Infection Observed In Childrenmentioning

confidence: 99%

Proportion of asymptomatic infection and nonsevere disease caused by SARS‐CoV‐2 Omicron variant: A systematic review and analysis

Guo

Zhang

et al. 2022

Journal of Medical Virology

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“…His main research addresses the quantification and understanding of the mechanisms by which immunization programs affect public health. T he COVID-19 pandemic has severely affected skilled nursing facility (SNF) residents and healthcare personnel (HCP) (1,2). HCP are at high risk for SARS-CoV-2 exposure during patient care (3,4), and were among the earliest groups prioritized for COV-ID-19 vaccination starting in mid-December 2020 (5).…”

Section: About the Authorsmentioning

confidence: 99%

“…S ince its initial detection in November 2021, the SARS-CoV-2 B.1.1.529 (Omicron) variant has become the dominant strain in South Korea. Its emergence led to a large increase in the number of COV-ID-19 cases, mainly through household transmission (1,2). In this study, we sought to estimate the effect of booster vaccinations on reducing the household transmission of COVID-19 to guide current COV-ID-19 mitigation strategy.…”

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confidence: 99%

Household Secondary Attack Rates of SARS-CoV-2 Omicron Variant, South Korea, February 2022

Lim¹,

Choe²,

Kim³

et al. 2022

Emerg. Infect. Dis.

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“…Multiple previous studies have indicated that asymptomatic or minimally symptomatic SARS-CoV-2 infections are likely triggers of outbreaks as well as ongoing rapid person-to-person transmission across communities. [7][8][9] Although rapid antigen testing kits, which were distributed to facilitate self-diagnosis, are now widely available throughout the US, the extent to which some individuals with Omicron variant infection are unaware of their infection while it is actively transmissible is unknown.…”

Section: Introductionmentioning

confidence: 99%

Awareness of SARS-CoV-2 Omicron Variant Infection Among Adults With Recent COVID-19 Seropositivity

et al. 2022

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ImportanceSome individuals who were infected by the SARS-CoV-2 Omicron variant may have been completely unaware of their infectious status while the virus was actively transmissible.ObjectiveTo examine awareness of infectious status among individuals during the recent Omicron variant surge in a diverse and populous urban region of Los Angeles County.Design, Setting, and ParticipantsThis cohort study analyzed the records of adult employees and patients of an academic medical center who were enrolled in a longitudinal COVID-19 serological study in Los Angeles County, California. These participants had 2 or more serial anti-nucleocapsid IgG (IgG-N) antibody measurements at least 1 month apart, with the first occurring after the end of a regional Delta variant surge (September 15, 2021) and a subsequent one occurring after the start of a regional Omicron variant surge (December 15, 2021). Adults with evidence of new SARS-CoV-2 infection occurring during the Omicron variant surge period through May 4, 2022, were included in the present study sample.ExposuresRecent Omicron variant infection as evidenced by SARS-CoV-2 seroconversion.Main Outcomes and MeasuresAwareness of recent SARS-CoV-2 infection was ascertained from review of self-reported health updates, medical records, and COVID-19 testing data.ResultsOf the 210 participants (median [range] age, 51 (23-84) years; 136 women [65%]) with serological evidence of recent Omicron variant infection, 44% (92) demonstrated awareness of any recent Omicron variant infection and 56% (118) reported being unaware of their infectious status. Among those who were unaware, 10% (12 of 118) reported having had any symptoms, which they attributed to a common cold or other non–SARS-CoV-2 infection. In multivariable analyses that accounted for demographic and clinical characteristics, participants who were health care employees of the medical center were more likely than nonemployees to be aware of their recent Omicron variant infection (adjusted odds ratio, 2.46; 95% CI, 1.30-4.65).Conclusions and RelevanceResults of this study suggest that more than half of adults with recent Omicron variant infection were unaware of their infectious status and that awareness was higher among health care employees than nonemployees, yet still low overall. Unawareness may be a highly prevalent factor associated with rapid person-to-person transmission within communities.

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Community Transmission of SARS-CoV-2 Omicron Variant, South Korea, 2021

Abstract: et al. Mutation-specific SARS-CoV-2 PCR screen: rapid and accurate detection of variants of concern and the identification of a newly emerging variant with spike L452R mutation.

Cited by 27 publications

References 6 publications

Proportion of asymptomatic infection and nonsevere disease caused by SARS‐CoV‐2 Omicron variant: A systematic review and analysis

Proportion of asymptomatic infection and nonsevere disease caused by SARS‐CoV‐2 Omicron variant: A systematic review and analysis

Household Secondary Attack Rates of SARS-CoV-2 Omicron Variant, South Korea, February 2022

Awareness of SARS-CoV-2 Omicron Variant Infection Among Adults With Recent COVID-19 Seropositivity

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