Result for
Topic: Transmission
May 11, 2021
Asymptomatic Individuals Positive for Anti-SARS-CoV-2 Antibodies Negative on Molecular Swab
Only 1% (n=212) of over 16,000 frontline workers developed detectable anti-SARS-CoV-2 antibodies during screening in Italy from May to June 2020. Among antibody-positive individuals, only one tested positive for SARS-CoV-2 RNA under a protocol that required antibody-positive participants to be given a PCR test. The authors suggest that performing a PCR test on antibody-positive participants…
May 10, 2021
Viable Virus Shedding during SARS-CoV-2 Reinfection
Additional follow-up data from a prior prospective cohort study of young adults (18-20 years) reinfected with SARS-CoV-2 after testing negative on three nasal swab PCR tests over a 2-week quarantine period found that viable virus was detected in 4 of 16 participants, and only once in each, with titers ranging from 1.7 to 5.5 log10 plaque-forming…
May 4, 2021
Clinical Characteristics and Transmission of COVID-19 in Children and Youths During 3 Waves of Outbreaks in Hong Kong
Among 397 individuals aged ≤18 years with confirmed COVID-19 during the first 3 waves in Hong Kong (January to December 2020), imported infections comprised 79% and 93% of all cases during the first and second wave, respectively, but domestic infections comprised 73% of all cases during the third wave. Overall among domestic infections, 91% had…
May 3, 2021
Lower Household Transmission Rates of SARS-CoV-2 from Children Compared to Adults
The household secondary attack rate (SAR = 0.15) among pediatric index cases under age 18 (n = 17) was significantly lower than the rate among 126 adult (SAR = 0.38) index cases, according to findings from a seroprevalence study among 150 households in Germany with at least one confirmed case of SARS-CoV-2 since June 2020….
Household Clustering of SARS-CoV-2 Variant of Concern B.1.1.7 (VOC-202012-01) in England
In a study in England of all sequenced positive SARS-CoV-2 test results between October 1 – December 15, 2020, odds of household clustering with the SARS-CoV-2 B.1.1.7 variant was 1.9-fold higher than with wildtype virus, after adjusting for Index of Multiple Deprivation, region of residence, time of testing, age group, sex, race, and ethnicity of…
April 30, 2021
Large University with High COVID-19 Incidence Did Not Increase Risk to Non-Student Population
[Pre-print, not peer-reviewed] The COVID-19 incidence among non-student residents of Centre County, PA (home to Penn State University) was lower than among non-student residents of neighboring counties after students returned to classes in fall 2020. However, the rate of COVID-19 among student residents of Centre County was higher than among non-residents in all surrounding counties….
April 29, 2021
COVID-19 Outbreak Among Farmworkers — Okanogan County, Washington, May–August 2020
Investigation of a large SARS-CoV-2 outbreak among employees of a fruit grower in Okanogan County in Washington State between May and August 2020 found that cumulative incidence of SARS-CoV-2 infection was higher among employees living in the community than those living in congregate temporary housing (12% vs 4%). Cumulative incidence was highest among employees packing…
Detecting In-School Transmission of SARS-CoV-2 from Case Ratios and Documented Clusters
[Pre-print, not peer-reviewed] A SARS-CoV-2 transmission model that accounts for a lower probability of symptomatic infection among children (21%) than adults (70%) found that only roughly 4% of in-school child-to-child transmission would be detectable with symptom-based contact tracing, even if all symptomatic cases are detected. The authors suggest that low in-school detection rates do not…
Impact of Vaccination on Household Transmission of SARS-COV-2 in England
[Pre-print, not peer-reviewed] Vaccinated individuals who became infected with SARS-CoV-2 had a lower rate of secondary household transmission compared to unvaccinated index individuals. Among over 550,000 residential households in the UK between January to March 2021, the overall SARS-CoV-2 secondary attack rate was 5.7% in household where the index case had received at least one…
Linked Clusters of SARS-CoV-2 Variant B.1.351 — Maryland, January–February 2021
A contact tracing investigation in January 2021 initiated after a Maryland resident was confirmed to have SARS-CoV-2 infection with the B.1.351 variant, first described in South Africa, identified two clusters comprised of 17 total patients not linked to travel. Sequencing of samples from the index case and three other patients from both clusters confirmed B.1.351…
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