Health & Wellbeing

Study finds COVID-19 spread in China fueled by “stealth transmission”

Study finds COVID-19 spread in...
This transmission electron microscope image shows SARS-CoV-2 colorized with different tones to better highlight the crown-like spikes protruding from the surface of the virus
This transmission electron microscope image shows SARS-CoV-2 colorized with different tones to better highlight the crown-like spikes protruding from the surface of the virus
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This transmission electron microscope image shows SARS-CoV-2 colorized with different tones to better highlight the crown-like spikes protruding from the surface of the virus
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This transmission electron microscope image shows SARS-CoV-2 colorized with different tones to better highlight the crown-like spikes protruding from the surface of the virus

A new study published in the journal Science has tracked the spread of the novel coronavirus, SARS-CoV2, across China in January concluding 86 percent of early infections were undocumented. The researchers suggest a “radical increase” in identification of undocumented cases is vital to slow the spread.

The study, from scientists at Columbia University, Imperial College London, UC Davis and the University of Hong Kong, used a computer model to simulate the spatiotemporal spread of the virus based on reported cases in 375 Chinese cites between January 10 and 23. The model ultimately showed the total spread of the virus throughout China in January could not be explained by just accounting for confirmed cases. In fact, the model suggests 86 percent of infections across that period of time went undocumented.

“The explosion of COVID-19 cases in China was largely driven by individuals with mild, limited, or no symptoms who went undetected,” says Jeffrey Shaman, from Columbia University Mailman School and co-author on the new study. “Depending on their contagiousness and numbers, undetected cases can expose a far greater portion of the population to virus than would otherwise occur. We find for COVID-19 in China these undetected infected individuals are numerous and contagious. These stealth transmissions will continue to present a major challenge to the containment of this outbreak going forward.”

The study found these undocumented cases were not as contagious as confirmed cases, with estimates suggesting they were only around half as contagious. However, the study did report these milder undocumented cases were most likely responsible for causing 79 percent of the subsequent documented cases.

A secondary simulation tracking infections from the 24th of January to the 8th of February, following China’s implementation of strict control measures, showed a significant reduction in undocumented cases. This affirms the importance of social distancing and broad testing across the entire community.

“Heightened awareness of the outbreak, increased use of personal protective measures, and travel restriction have helped reduce the overall force of infection; however, it is unclear whether this reduction will be sufficient to fully stem the virus spread,” says Shaman.

This is not the first study to suggest a large volume of COVID-19 cases have gone undetected. An Imperial College London study from February estimated two-thirds of all cases worldwide may have gone undetected. And, although this does imply a large number of people may contract COVID-19 and only suffer mild, or even imperceptible symptoms, it also makes the virus’ spread incredibly difficult to control and track.

In the latest media briefing from the World Health Organization, WHO Director General Tedros Adhanom Ghebreyesus reiterates the two most important things right now are for every individual to practice social distancing, and for countries to expand testing as widely as possible. Testing broadly was the key message from Director General Tedros in this briefing, and on two occasions he repeated the mantra, "test, test, test!"

“… the most effective way to prevent infections & save lives is breaking the chains of COVID-19 transmission,” said the Director General. “To do that, you must test & isolate. You cannot fight a fire blindfolded. And we cannot stop this pandemic if we don’t know who is infected.”

The WHO currently recommends testing of those who have been in close contact with confirmed cases even if they are not showing symptoms.

The new study was published in the journal Science.

Source: Columbia Mailman School of Public Health

10 comments
Rusty Harris
I just wish they would stop calling it covid-19. Most of the other corona virus problems, were called by names similar to where they started. Ebola, named for the "black river". MERS Mid East Respiratory Syndrome, etc. This one should be called Wuhan virus or CARS, Chinese Acute Respiratory Syndrome. They are all variations of the corona virus.
KeithW
Rusty. Ebola is not a coronavirus.
akarp
I agree with providing accurate information. NOT providing a naming convention for political reasons. "Chinese Acute Respiratory Syndrome" does that mean only people of Chinese ethnicity will be impacted? How does this name help? Think it through: if COV-19 mutates in some other part of the world...what do we call it? Give it some other region or country name? Say we pick a random name: a new 'Brazil Virus'...everyone would be starting from uncertainty again. VS. if COV-20 was the proper name, then people would have a starting point for symptoms and treatment. Please stop with misinformation and xenophobia. We are a globally integrated system and we ALL need to start acting as such.
Expanded Viewpoint
You're right, KW, but a virus by any other name can be just as deadly. The REAL story here, is that the fiat paper currency/electronic bookkeeping entry financial system the entire world runs on is almost at it's end, so Covid-19 or whatever someone wants to call it is being hyped up to run a smoke screen and distract our attention from the actual reason for this financial collapse. NOTHING in the physical universe can be stretched out to infinity, which is what the Fed is trying to do with its "quantitative easing" 4.0 and zero interest rates. Not even diamonds are strong enough to take that kind of stress and strain without shattering into trillions of "dollars" of pieces! If people would read my treatise What is Money?, from 1996, they would be able to see all of this for what it really is. Randy
Karmudjun
OMG there is so much to address in these four previous comments. Covid-19 is the disease we all understand to cause a mild cold to an extreme pneumonia, and for medical professionals it is important to know what we are treating. Now everyone on this forum can call it what you want to, but don't come to me and say you have Chinese Ebola or some bullshit like that. Now Randy, sorry about your wishes. The virus is known among researchers as SARS-CoV-2 or SARS-CoV2. Why? So we don't mince words or "wish people were on the same page". Either you are, or you are not and are wishing people were more like you. Now, for the tin foil hat folks, you are absolutely right that fiat money is part of the issue. Everything that touches our hands can spread the corona viruses. Of which SARS-CoV-2 is only one type, and not the most serious type. Some meager statisticians (that would be bloggers with a calculator) have declared Covid-19 to be deadlier than most influenza. Okay, I guess if you only count the tested positive patients of interest, yes the death rate is high. If you add 80% to the infected number you find it is about the same or lower than your AVERAGE influenza. Stay with me here since I am not saying the 69+ population has nothing to worry about. Transmission modeling has theorized a massive insidious spread among those with mild "allergy" symptoms to NO symptoms who are the probable transmission route to the more susceptible population. The younger folks seem to experience mild symptoms, the middle aged folks seem to get hit the hardest after a 3+ days to even a week or more incubation period, and the oldsters suffer the consequences. Listen to the news about community acquired: "No known contact with a traveler or a positive case" is what the health departments are saying. So yes - send your co-workers home if they seem to have symptoms but know that you have already been exposed for several days! That goes for fiat money as well, paper or coin that has a representative value rather than an intrinsic value in and of itself. We don't know how long SARS-CoV-2 can exist on coins or folding papers - we do know it can last on hard surfaces (coins are usually hard) for up to 3 days. Just practice decent hygiene - wash your hands, cover your mouth when you cough, and practice social or physical distancing. For my grandparents sake!
Karmudjun
OMG - you people are all over this forum spreading tin-foil suppositions! I agree - the xenophobia does nothing to promote a community wide health initiative. This is not a "Chinese" virus. It is a global virus that developed in a community setting rather than in the wild, and we can blame the Chinese for allowing 'wet markets' to continue nonstop after the SARS epidemic was traced back to similar wet markets which were supposed to have been outlawed in China. Yep, sure enough, they outlawed them. But traditions die hard and they will be around in other countries in the future even if China does manage to eliminate wet markets from within their borders. They say they do, but they don't and they say others are the cause of the issue rather than take responsibility. Xi will sleep just fine at night with that knowledge while his minions try to blame the virus on the world. Look at how long it took to find patient zero - the hunt is still on and they have concluded the virus was in human population in mid November. In China. And they took action first to squash the spread of information, and then by the end of December alerted WHO to the international crisis. So good of them. And then they established strict quarantine after hundreds of thousands fled the city and province. How disingenuous to say they have a handle on it! When it hit Iran and Italy, no one was ready and the insidious spread (silent, 80% showed mild to no symptoms but transmitted the virus anyway) slowly let the populations know there was a problem illness on the rise. Many of the survivors will blame anyone other than their families or communities, but who they associated with the previous 5-10 days are where they got the illness, not China, not a wet market, not from Bats. But from their community of friends. Worry about fiat money, worry about what the virus is called and why the illness isn't the same as the virus name. Just distance yourself and wash your hands, disinfect your house, your car, your phone, your keyboard, everything! Keep others safe even if you suspect they are not keeping you safe!
ljaques
Rusty, it's the incontestable will of (those who must not be named) which proclaimed that the virus be renamed lest the poor folks from China or Mexico get plexed about the (ahem) horribly raycis? name. // The good news is that I can't get the Coronavirus because I don't drink Mexican beer! // The good news is that many sources of the test kits are starting to come online and they are being distrubuted. And some of the vaccines (which couldn't be made for the past 100+ years) are now coming out in just weeks. // Color me: Not a guinea pig.
NW
A few things to say on this but would like to put a few sets of facts out there courtesy of Public Health England... In 2018 28,000 died of complications arising from flu. Not cases - but deaths. Flu is of course very similar. Question...where was the "Hoo Har" then? Where were the lock downs and concern for those loved ones then? Press headlines? Panic? 2013 -2019 on average, 17,000 people annually DIED from complications arising from flu. No one even raised an eyebrow. Italy have the oldest population in Europe. 23% are over 65. Many in their 80s and 90s [so very susceptible - as well as all smoking like chimneys]. Their annual rate for deaths from flu since 2013 is about 11,000 annually. Where were their lock downs then? Figures for death rate from Covid 19 will be WAY off. Many many more people will have it and are not on the stats. Advisors for Boris Johnson are scientists. They will advise on the best way to stop a virus like this spreading through the population - NOT economic implications. The current solution will only result in the complete unravelling of society and the economy. If the economy goes down the pan, no one will be in a position to help anyone. Deaths are still going on at a far greater rate for flu and of course other conditions like sepsis and the usual raft of conditions. I genuinely think this path the government and governments of other countries are running down is wrong. The population has crucial differences. To some it is life and death [as it was in previous years anyway for flu] and to some it is a mild inconvenience. Under 60s with no underlying health issues should go on as normal. Go to work, restaurants, pubs, on holiday etc. Over 65s should self quarantine and society should protect them with food supplies and regular sanitized contact. They should also be prioritised with fast tracked vaccines. But the under 60s should go on as normal - they will only get mild symptoms if they get it anyway. I just think if the economy goes down the tubes, there will be fare more serious implications for everyone than Covid 19 alone.
akarp
Regarding our financial system. As 'Expanded Viewpoint' has mentioned and 'NW' has raised a related question... it's not that people transmit the virus through money, its that our fiat money system is broken and companies are able to use Covid-19 as an 'excuss'. "quantitative easing", 0% interest, Tax cuts...keeping the bubble inflated is getting harder and harder...as 'Expanded Viewpoint' said it can't last forever.
windykites
How many positive testers had no symptoms? There should be a record of this.