Coronavirus Science

The effect of control strategies to reduce social mixing on outcomes of the COVID-19 epidemic in Wuhan, China: a modelling study


Background
In December, 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus, emerged in Wuhan, China. Since then, the city of Wuhan has taken unprecedented measures in response to the outbreak, including extended school and workplace closures. We aimed to estimate the effects of physical distancing measures on the progression of the COVID-19 epidemic, hoping to provide some insights for the rest of the world.
Methods
To examine how changes in population mixing have affected outbreak progression in Wuhan, we used synthetic location-specific contact patterns in Wuhan and adapted these in the presence of school closures, extended workplace closures, and a reduction in mixing in the general community. Using these matrices and the latest estimates of the epidemiological parameters of the Wuhan outbreak, we simulated the ongoing trajectory of an outbreak in Wuhan using an age-structured susceptible-exposed-infected-removed (SEIR) model for several physical distancing measures. We fitted the latest estimates of epidemic parameters from a transmission model to data on local and internationally exported cases from Wuhan in an age-structured epidemic framework and investigated the age distribution of cases. We also simulated lifting of the control measures by allowing people to return to work in a phased-in way and looked at the effects of returning to work at different stages of the underlying outbreak (at the beginning of March or April).
Findings
Our projections show that physical distancing measures were most effective if the staggered return to work was at the beginning of April; this reduced the median number of infections by more than 92% (IQR 66–97) and 24% (13–90) in mid-2020 and end-2020, respectively. There are benefits to sustaining these measures until April in terms of delaying and reducing the height of the peak, median epidemic size at end-2020, and affording health-care systems more time to expand and respond. However, the modelled effects of physical distancing measures vary by the duration of infectiousness and the role school children have in the epidemic.
Interpretation
Restrictions on activities in Wuhan, if maintained until April, would probably help to delay the epidemic peak. Our projections suggest that premature and sudden lifting of interventions could lead to an earlier secondary peak, which could be flattened by relaxing the interventions gradually. However, there are limitations to our analysis, including large uncertainties around estimates of R0 and the duration of infectiousness.
Funding
Bill & Melinda Gates Foundation, National Institute for Health Research, Wellcome Trust, and Health Data Research UK.
 
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Characteristics of pediatric SARS-CoV-2 infection and potential evidence for persistent fecal viral shedding
We report epidemiological and clinical investigations on ten pediatric SARS-CoV-2 infection cases confirmed by real-time reverse transcription PCR assay of SARS-CoV-2 RNA. Symptoms in these cases were nonspecific and no children required respiratory support or intensive care. Chest X-rays lacked definite signs of pneumonia, a defining feature of the infection in adult cases. Notably, eight children persistently tested positive on rectal swabs even after nasopharyngeal testing was negative, raising the possibility of fecal–oral transmission.
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Under eleven year olds have very few deaths from the virus. But beware the shiats of the pediatric patients :unsure:
 
Techne said:
www.nature.com

How sewage could reveal true scale of coronavirus outbreak

Wastewater testing could also be used as an early-warning sign if the virus returns.
www.nature.com www.nature.com

Maybe a good idea for South Africa.
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I know a few waste water sites in SA have digital PCR systems.
www.the-scientist.com

New Studies Find Bio-Rad’s QX200 Droplet Digital PCR System Can Detect COVID-19 With Greater Sensitivity and Precision Than Other Existing Molecular Tests

Bio-Rad Laboratories, Inc. (NYSE: BIO and BIOb), a global leader of life science research and clinical diagnostic products, today announced that in two studies published this month, ahead of peer-review, researchers in China reported that Bio-Rad’s QX200 Droplet Digital PCR (ddPCR) System showed...
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Sugary Camouflage on Coronavirus Offers Vaccine Clues
Cells are furry. That might come as a surprise, since textbook illustrations so often represent a cell as smooth — “something like a balloon full of water,” said Elisa Fadda, a computational chemist at Maynooth University in Ireland. “But that is absolutely not true.” In reality, the surface of a cell is adorned with a forest canopy of sugars, intricate and diverse clusters of carbohydrates that extend like branches and leaves from protein tree trunks. And because that canopy is the face that a cell shows to the world, these complex carbohydrates, or glycans, play a critical role in its encounters and interactions with other cells or molecules.
Click to expand...

www.quantamagazine.org

Sugary Camouflage on Coronavirus Offers Vaccine Clues

In the fight against viruses and other pathogens, scientists are looking beyond genes and proteins to the complex sugars, or glycans, on cell surfaces.
www.quantamagazine.org www.quantamagazine.org
 
There are two versions of the coronavirus. One’s not more dangerous than the other


Differences among patients, not the genetic makeup of the coronavirus, determines how severe COVID-19 will be, a study finds.

Factors such as a person’s age and white blood cell counts are associated with disease severity, an analysis of 326 COVID-19 patients from Shanghai shows. Older people and people with low levels of certain immune cells known as T cells and high levels of an immune chemical called IL-6 tended to be sicker. But the version of the coronavirus that people were infected with made no difference in how sick they got, the team reports May 20 in Nature.

IL-6 is a protein known as a cytokine, one of many proteins that signal the immune system to rev up defenses. Overactive immune, known as cytokine storms, are a problem for people with severe cases of COVID-19.
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