Medical Disorders
Resources
Basic InformationLookupsLatest News
AHA News: Understanding the Basics of 'Herd Immunity'Multiple Measures of Social Distancing Required to Slow Coronavirus: StudyCough, Fever, Fatigue? Head to CDC's Online Coronavirus Symptom CheckerThree Countries Have Kept Coronavirus in Check; Here's How They Did ItTrial Finds Acupuncture May Help Prevent MigrainesSevere COVID-19 Might Injure the HeartWhy Are Teens, Millennials Ignoring Coronavirus Warnings?An Expert's Guide to Fact-Checking Coronavirus Info OnlineLivestock, Poultry Safe From Coronavirus: ExpertU.S. Hospital Beds Were Already Maxed Out Before Coronavirus PandemicFDA Warns of Defective EpiPen DangersPoll Finds High Anxiety in the Time of CoronavirusCould Robots Be Deployed to Front Line in Fighting COVID-19?COVID-19 May Force Some Cancer Patients to Delay TreatmentWhat People With Parkinson's Need to Know About COVID-19How to Weather Social Isolation During Coronavirus PandemicCOVID-19 Infection Likely Worse for Vapers, SmokersWhen Arteries Narrow, Chest Pain Can Come Earlier for Women Than MenLoss of Sense of Smell Could Be Early Sign of Coronavirus InfectionMany Drugs Already Approved by FDA May Have Promise Against COVID-19The Other Side of COVID-19: Milder Cases, Healthy RecoveryAs Coronavirus Myths Multiply, Experts Sort Fact From FictionA Third of Americans Ordered to Stay at Home; Summer Olympics Postponed for One YearFDA Warns Americans to Beware of Fake COVID-19 Test KitsTaking Steroids for Rheumatoid Arthritis, IBD? Your Odds for Hypertension May RiseWhat Does a Self-Quarantine Look Like?National Guard Activated in 3 States as U.S. Coronavirus Cases Top 34,000U.S. Coronavirus Cases Pass 26,000, With 1 in 4 Americans Under 'Shelter-in-Place' OrdersRaking Your Leaves to the Edge of Your Yard an Invitation to TicksNew Drug Helps Shrink Inoperable Tumors in KidsCoronavirus Crisis Should Put Elective Surgeries on Hold, Doctors' Group SaysAlmost Half of Coronavirus Patients Have Digestive SymptomsNearly 40% of Hospitalizations in U.S. COVID-19 Cases Involve Adults Under 55Healthy Living at Home to Ward Off CoronavirusWhat You Need to Know About Coronavirus If You Have AsthmaStudy Suggests COVID-19 Might Follow Seasonal PatternTrump Signs Massive Relief Package Into Law as U.S. Coronavirus Cases Reach 10,000AHA News: A Look at Allergies and Heart Health, With Tips to Endure Pollen Season Amid Coronavirus FearsNew Coronavirus Wasn't Made in a Lab, Genomic Study ShowsWho's Most at Risk From Coronavirus?The Most Effective Ways to Kill Coronavirus in Your HomeCoronavirus Cases Hit All 50 States, as U.S. Death Toll Tops 100AHA News: Working Out While Staying Safe During the Coronavirus OutbreakMedical Groups Say Heart Meds Don't Worsen COVID-19 SymptomsBelly Fat Can Lead to a Sudden Attack of Pancreatitis: StudyWith New Boost From Medicare, 'Telemedicine' Steps Up to Fight CoronavirusAnother Study Finds COVID-19 Typically Mild for KidsKeeping Coronavirus Anxiety at BayThink You Have COVID-19 Symptoms? Here's What to DoUndetected Cases May Be Driving Coronavirus Spread, Study Finds
Questions and AnswersVideosLinksBook Reviews
Related Topics

Cancer
Men's Health
Women's Health

Undetected Cases May Be Driving Coronavirus Spread, Study Finds

HealthDay News
by By Dennis Thompson
HealthDay Reporter
Updated: Mar 17th 2020

new article illustration

TUESDAY, March 17, 2020 (HealthDay News) -- You're a little feverish, but you feel good enough to get your shopping done and a quick workout at the gym.

If you do, you could become part of the exponential spread of the coronavirus, a new study concludes.

About 86% of COVID-19 cases in China were milder and went undetected during the two-week ramp-up of the epidemic in January, prior to the country imposing travel restrictions, researchers conclude in the March 16 issue of Science.

These undocumented cases of infection were "about half as infectious per person as a documented case who has more severe symptoms and may be shedding more," said senior researcher Jeffrey Shaman. He's a professor of environmental health sciences at Columbia University Mailman School of Public Health, in New York City.

However, "because there are many more of these undocumented cases, it's the undocumented infections that are driving the spread and growth of the outbreak," Shaman said.

The continued and widening lockdown of the United States is therefore the right move to limit the COVID-19 epidemic as much as possible, the researchers said.

On Monday, President Donald Trump announced during a media briefing that the U.S. Centers for Disease Control and Prevention now advises all Americans to avoid all gatherings of more than 10 people, avoid eating and drinking at restaurants, bars and food courts, and avoid discretionary travel for 15 days.

Coronavirus Task Force coordinator Dr. Deborah Birx said during the briefing that the latest step was taken because new modeling shows that a significant amount of the coronavirus' spread is fueled by "silent transmission."

Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, was blunt about the coming weeks. "The worst is yet ahead for us," he said during the briefing. "It's how we respond to that challenge that will determine what the ultimate endpoint is going to be."

Across the country, many shops, schools, restaurants, bars and gyms have already closed in an effort to promote social distancing and keep people from infecting each other with coronavirus.

Another much-touted policy aimed at limiting the spread of COVID-19 -- travel bans -- is not nearly as effective, a second study published recently in Science found.

Travel bans implemented inside China only delayed the spread of the epidemic by three to five days, while international bans halted the spread of coronavirus by about a few weeks, said senior researcher Alessandro Vespignani, director of the Network Science Institute at Northeastern University, in Boston.

"Travel restrictions alone do not really do much but delay the spread of the disease," said study co-author Elizabeth Halloran, a professor of biostatistics at the University of Washington School of Public Health, in Seattle. "Delaying is good because it slows things down, but the idea is that transmissibility really is key."

Reducing transmissibility includes detecting and isolating infected people, social distancing, school closures, increased hygiene, and overall improved awareness of the virus, Halloran said.

"Reduced travel and transmissibility does produce a synergistic effect, but it's the transmissibility that's more important," she concluded.

Trump has floated the idea of restricting domestic travel to California and Washington, but the two studies show this would be little more than a delaying tactic, experts said.

"The epidemic now is already seeded in the United States," Vespignani said. "We see ongoing local transmission in many states, and probably it's just the tip of the iceberg. Closing travel might delay the progression of the epidemic in some places and provide some time for preparation."

In the first study, Shaman and his colleagues created a computer model that tracked observations of reported infection and spread within China, as well as human movement within the country as revealed by mobile phone data.

The research team suspected that mild cases of COVID-19 were likely behind the ferocious spread of the virus in China, given human nature.

"If somebody is experiencing mild symptoms, and I think most of us can relate to this, we're still going to go about our day," Shaman said. "We'll still send the kids to school. We'll still go to work. If we have a little bit of a headache or slight fever, we might take some ibuprofen and still go out shopping and whatnot. It's that sort of continued contact with people that allows the silent transmission of many respiratory viruses."

To make sure the model was accurate, the researchers tested it by shutting off the infectiousness of undocumented COVID-19 cases, Shaman said -- essentially assuming that no people with mild symptoms could infect others.

"When we do that, we see nearly an 80% reduction in the number of documented confirmed cases," Shaman said. "These people are the major driver of it. They're the ones who facilitated the spread. The undocumented infections which tend to be milder are distributing the virus broadly."

For the other study, Vespignani and his colleagues used computer modeling to compare travel between transportation hubs with the onward march of the novel coronavirus both inside China and to other countries.

Vespignani's team found that travel bans within a country are of limited use, but that international travel bans did have a substantial effect in slowing the virus' spread to other nations. Case importations were reduced by nearly 80% until mid-February, when the dam broke and the virus started reaching epidemic levels in other countries.

But the model also concluded that even with 90% travel reductions into and out of China, the number of imported cases in other countries still went up significantly in a matter of weeks. The only thing that halted that spread was a 50% or greater reduction of person-to-person transmission worldwide.

More information

The U.S. Centers for Disease Control and Prevention has more about COVID-19.




Facebook

Amazon Smile

 

Children and Adult services are available now with no wait time.  

Please contact HBH at 860-548-0101, option 2.

 


powered by centersite dot net