Result for
Topic: Transmission
June 23, 2020
Persistence of SARS-CoV-2 in the Environment and COVID-19 Transmission Risk from Environmental Matrices and Surfaces
Carraturo et al. reviewed the survival of SARS-CoV-2 in the environment and found that survival of the virus is likely to be very low in contaminated food, on inanimate surfaces, and in water, wastewater, sludge, or bio-solid waste contaminated by feces. They note that while transmission risks may be higher for some occupational groups (e.g., wastewater treatment workers), with appropriate PPE use and disinfection protocols this…
June 22, 2020
Reconstruction of Transmission Pairs for Novel Coronavirus Disease 2019 (COVID-19) in Mainland China: Estimation of Super-Spreading Events, Serial Interval, and Hazard of Infection
Xu et al. analyzed 643 transmission clusters from 1,407 transmission pairs in mainland China and identified 34 primary cases as super-spreaders and 5 super-spreading events that occurred within households. The median duration between symptom onset of primary and secondary cases was 5.0 days (IQR 1.5-8.5) for household transmissions and 5.2 days (1.6-8.8) for non-household transmissions. The risk of being infected outside of households was higher for those age 18 to 64 years, whereas the risk…
High-Density Amplicon Sequencing Identifies Community Spread and Ongoing Evolution of SARS-CoV-2 in the Southern United States
[pre-print, not peer reviewed] McNamara et al. demonstrated SARS-CoV-2 evolution in a suburban Southern US region using high-density amplicon sequencing of 175 symptomatic cases. The presence of spike D614G variant, a mutation implicated in higher pathogenicity of the virus, was observed among 57% of strains and was associated with a higher genome copy number (p<0.002). The single nucleotide variant pattern…
Clinical and Immunological Assessment of Asymptomatic SARS-CoV-2 Infections
There was a longer duration of viral shedding among a group of 37 asymptomatic patients with SARS-CoV-2 infection in the Wanzhou District, China, compared to a paired symptomatic group (HR 1.69, 95%CI 1.06, 2.70). Asymptomatic individuals had significantly lower virus-specific IgG levels (median 3.4, IQR 1.6-10.7 vs. 20.5, 5.8-38.2; p = 0.005) in the acute phase of infection. Asymptomatic individuals were more likely to have a reduction in neutralizing antibody…
Asymptomatic Patients as a Source of COVID-19 Infections: A Systematic Review and Meta-Analysis
Kronbichler et al. conducted a meta-analysis with 34 studies that included 506 asymptomatic patients with COVID-19 and reported that 62% had abnormalities visible in computed tomography (CT) scans, with ground glass opacities in the lungs most frequently observed (43%). Patients with normal CT results were younger than patients with abnormal CT findings (mean 20 years vs. 39 Years; p = 0.013). Kronbichler et al. (June 13, 2020). Asymptomatic Patients as a Source of COVID-19 Infections: A Systematic Review and…
June 18, 2020
Asymptomatic SARS-CoV-2 Infection and COVID-19 Mortality during an Outbreak Investigation in a Skilled Nursing Facility
Patel et al. conducted an outbreak investigation at a skilled nurse facility in Illinois on March 15 and followed 126 residents tested for COVID-19 for 30 days. Of the 33 confirmed cases at the beginning, 58% were symptomatic, 39% remained asymptomatic, and 3% developed symptoms over follow-up. The 30-day probability of death among cases was…
June 17, 2020
Environmental Surface Testing for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) during Prolonged Isolation of an Asymptomatic Carrier
Testing of high-touch surfaces (e.g. mobile phone, door handle) in an isolation room of an asymptomatic pediatric patient positive for SARS-CoV-2 found no evidence of environmental contamination. The patient had been diagnosed 41 days prior to sampling, but remained PCR positive without decrease in viral titer. The most recent cleaning of the environment was 4 days prior. These results give some indication…
The Assessment of Transmission Efficiency and Latent Infection Period on Asymptomatic Carriers of SARS-CoV-2 Infection
Of 147 initially asymptomatic individuals with SARS-CoV-2 infection in Anhui Province, China, 11% developed illness during a 14 day isolation period. The secondary attack rate was 10% for the pre-symptomatic carriers, versus 3% for the asymptomatic carriers. Liu et al. (June 2020). The Assessment of Transmission Efficiency and Latent Infection Period on Asymptomatic Carriers of SARS-CoV-2 Infection. International Journal of Infectious Diseases. https://doi.org/10.1016/j.ijid.2020.06.036
Epidemiological Features and Viral Shedding in Children with SARS-CoV-2 Infection
An analysis of all children (n=314) from families with SARS-CoV-2 infected members in Zhejiang Province, China found incidence in children who were close contacts was significantly lower than in adults who were close contacts (13% vs 21%). Among 43 pediatric cases, the mean age was 8.2 years and mean incubation was 9.1 days, 77% had mild pneumonia and the remainder were asymptomatic. While SARS-CoV-2 RNA could…
SARS-CoV-2 Community Transmission During Shelter-in-Place in San Francisco
[pre-print, not peer reviewed] All residents and non-residents who work in a densely-populated, majority Latinx San Francisco community were offered SARS-CoV-2 RT-PCR testing (2,598 of 5,174 residents and 1,355 non-resident workers were tested). The estimated SARS-CoV-2 prevalence among residents was 4% among Latinx vs 0.2% among non-Latinx, while estimated prevalence among workers was 10% for Latinx and 0% for non-Latinx workers. Twenty-nine percent of PCR–positive participants remained asymptomatic after two weeks of follow-up. The estimated seroprevalence of SARS-CoV-2 antibodies was…
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