Thread by @andreaprinzi

Hey, friends. Here's what's up in the world of #COVID19 literature from the last 24 hours (7/23). Simple summaries provided, as always, follow the link for original manuscripts. BE WELL! #IDtwitter #MedED #MedTwitter #Microbiology #InfectiousDiseases

1. Title: Addendum to: Children are not COVID-19 super spreaders: time to go back to school
Link: adc.bmj.com/content/archdi…
Brief Study Design: This is a letter (addendum) to the author’s original research paper (cited in the letter and can be accessed from it).

Simple Summary: Contact-tracing studies have demonstrated that children have a significantly lower attack rate of COVID-19 compared to adults.

Household studies in New York, Israel and the Netherlands used rt-PCR and serology to demonstrate that children became infected at about half the rate of adults within the same household.

Studies from Iceland and the Netherlands have shown that infection rates child->child and child->adults are low. Seroprevalence studies from around the world have shown increases in infection with age.

Vigilance will need to increase as the age of students increases. Implementation of track+trace systems is key to safe re-opening. The authors state that risks of severe illness/widespread transmission are greatly reduced, and the potential for control of an outbreak is better.

2. Title Seroprevalence of Antibodies to SARS-CoV-2 in 10 Sites in the United States, March 23-May 12, 2020
Link: jamanetwork.com/journals/jamai…

Brief Study Design: This was a cross-sectional study of a convenience sample. The researchers collected residual blood samples (from standard lab testing like cholesterol, glucose, etc.), from patients in Washington, NYC, FL, PA, SF Bay area, Minneapolis St. Paul, Missouri,

Connecticut and Louisiana. The patients varied in age. Sera were tested at CDC in a 2-step process using a CDC-validated ELISA serology test, which is described in a separate paper. 16,025 samples from 10 sites collected between 3/23 and 5/12 were tested for SARS-CoV-2 antibodies

Simple Summary: Seroprevalence estimates varied from 1.0% in the San Francisco Bay area in late April to 6.9% in the NYC metro area in late March. The authors conclude that the number of infections was much greater than the number of reported cases throughout the study period,

likely because these were mild infections where people did not get tested or seek care. Using population estimates and statistical analysis, the authors estimated that there were from 6 times as many SARS-CoV-2 infections as reported cases in CT...

to 24 times the number of infections as reported cases in MO. From March to early May, a large majority of people in 10 sites in the US had not been infected with SARSCoV-2. However, the estimated # of infections was much greater than the number of reported cases in all sites.

Key limitations to consider: This was a convenience sample, so no data on recent symptomatic illness, underlying conditions, or possible COVID-19 exposures were available.

The people sampled may be more likely to seek+receive medical care, which may not be representative of the larger population. There were few samples from people <18, so seroprevalence in children could not be estimated.

It is possible that the serology test may exhibit cross-reactivity with antibodies to other common human coronaviruses and some results may represent a false-positive result for SARS-CoV-2, especially in areas where disease prevalence is low.

3. Title Proportion of asymptomatic coronavirus disease 2019 (COVID-19): a systematic review and meta-analysis of asymptomatic COVID-19
Link: onlinelibrary.wiley.com/doi/epdf/10.10…

Simple Summary: The researchers reviewed 41 studies that included a total of 50,155 patients. The pooled % of asymptomatic infection is 15.6% (95% CI: 10.1%-23.0%). The pooled % of pre-symptomatic infection among 180 initially asymptomatic patients is 48.9% (95% CI: 31.6-66.2%).

The pooled proportion of asymptomatic infection among 1152 COVID-19 children from 11 studies is 27.7% (95% CI: 16.4-42.7%), which is much higher than patients from all aged groups. Abnormal CT scan features are common in asymptomatic COVID-19 infection.

Nearly half of the patients with no symptoms at the time of detection will develop symptoms later. Children are more likely to have asymptomatic infection than adults.

4. Title Using statistics and mathematical modelling to understand infectious disease outbreaks: COVID-19 as an example.
Link sciencedirect.com/science/articl…
Brief Study Design: Serves as a toolkit containing various statistical models that can be used to predict various things.

Simple Summary: While this article is very stats heavy, it is helpful if you want to gain some understanding of how complex tracking and predicting outbreaks is. The use of analytics is fascinating and an increasingly useful tool for pandemics like COVID-19.

5. Title Serosurveillance and the COVID-19 Epidemic in the USUndetected, Uncertain, and Out of Control
Link jamanetwork.com/journals/jama/…
Brief Study Design: This is a peer-reviewed editorial article through the Journal of the American Medical Association

Simple Summary: Key points:
-As of July 15, 2020, there have been 3.4 million confirmed cases in the United States, but this is only a fraction of all infections.
-Approximately 40% of all SARS-CoV-2 infections are thought to be asymptomatic.

-The authors discuss the findings from the Seroprevalence study by Havers et al (mentioned above), including limitations and strengths. Be sure to read this editorial for a shorter (but informative) summary of that study.

The study shows us that so-called herd immunity is not realistic for the US right now. These data show that dangerous practices like “COVID parties” are not a smart or safe way to promote herd-immunty.
-Acquired immunity may be short-lived. We don’t know how long it lasts yet.

6. Title COVID-19 and Inequity: a Comparative Spatial Analysis of New York City and Chicago Hot Spots
Link link.springer.com/content/pdf/10…

Brief Study Design: The goal of this ecological cross-sectional study was to examine the spatial and demographic nature of reported SARS-CoV-2 diagnoses in New York City (NYC) and Chicago (CHI) as of April 13, 2020.

The researchers identified SARS-CoV-2 diagnosis rates per ZIP code tabulation area (ZCTA) and compared sociodemographic/economic characteristics between hot spots and cold spots. The characteristics of the NYC and CHI spots were compared to reveal differences and similarities.

Simple Summary: In both Chicago and New York City, cold spots (less disease) had a higher prevalence of social determinants of health characteristics typically associated with better health outcomes and the ability to maintain physical distance.

These neighborhoods tended to be wealthier, have higher educational attainment, higher proportions of non-Hispanic white residents, and more workers in managerial occupations.

The NYC hot spots can generally be characterized as working-class and middle-income communities, higher concentration of service workers and other occupations (including those classified as “essential services” during the pandemic).

Chicago’s hot spot neighborhoods are among the city’s most vulnerable, low-income neighborhoods with extremely high rates of poverty, unemployment, and Non-Hispanic Black residents.

Important limitations: This represents an ecological analysis, not individual-level data, the goal of this project is not to infer causation but to describe SARSCoV-2 hot and cold spots in 2 large US cities, there is potential bias, limited testing/reporting and false pos/negs

7. Title Potential Repurposed Therapeutics and New Vaccines against COVID-19 and Their Clinical Status

Link journals.sagepub.com/doi/10.1177/24…

Brief Study Design: Summary of major drug and vaccine candidates for treatment of COVID-19 disease

Simple Summary: All the details pertaining to the clinical status of each therapeutic candidate have been updated as of June 12, 2020.

8. Title Coronavirus Disease 2019 and Stroke: Clinical Manifestations and Pathophysiological Insights

Link strokejournal.org/article/S1052-…

Brief Study Design: Review article

Simple Summary: This article reviews major findings in several different categories.

-Markedly elevated D-dimer levels and fibrin degradation products have been associated with high mortality rates among COVID-19 patients

- In a study of 198 patients with COVID-19, the overall incidence of venous thromboembolism (VTE) was 17%.

- COVID-19 patients can develop a more severe coagulopathy defined as COVID19-associated coagulopathy (CAC).

- SARS-CoV-2 can lead to severe inflammation, including an inflammatory cytokine storm which in turn leads to CAC or thrombosis.

- There is preliminary evidence for an association between COVID-19 and stroke, but causality has not been established (more well-designed studies are needed to determine if COVID-19 is causing strokes, especially in younger people).

-Some COVID-19 patients develop strokes, seizures, confusion, and brain inflammation.
- The EPI data on stroke incidence during the COVID-19 pandemic are not published yet, but anecdotal observations suggest an increase of thromboembolic stroke among younger adults.

Further studies are needed to understand the true incidence.

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