There is so much new research about COVID-19 that it’s hard to keep up. As the epidemic expands, so do the investigations — so we’re finally getting data from labs in the U.S., Italy and other affected nations and are no longer dependent solely on the very early observations in China.
Some of these new discoveries offer more precise answers to old questions. Others offer answers to questions that had eluded us. Expect this information to change as we learn more.
Here are some answers from the experts:
Q: How is COVID-19 spread?
A: The most important way it is spread is through droplets coming from the mouth or nose of someone who is infected. Those droplets, because of their weight, usually fall through the air and drop to the ground within about six feet. So we think if you’re within that distance of somebody who’s infected, you have a chance of getting infected.
Those droplets could be expelled just through normal talking. With every person you’re next to — within that six foot radius — you’re taking a risk, because you don’t know whether they’re infected or not. So the most prudent thing to do is to limit your contact.
Another route is touching an object, like a pen, that’s been touched by someone who is infected. The virus can sit on an object and then spread to you if you touch it and then touch your nose, mouth or eyes.
John Swartzberg, clinical professor emeritus of infectious diseases and vaccinology, UC Berkeley
Q: How long does the virus live in the air and on surfaces?
A: The virus remains infectious in the air for up to three hours. It’s on copper for up to four hours and on cardboard for up to 24 hours. On steel or plastic surfaces, it can be detected after three days, although infectivity decreases with time. That’s why it’s important to wash your hands.
National Institute of Allergy and Infectious Diseases
https://www.nejm.org/doi/full/10.1056/NEJMc2004973?query=featured_home
Q: How long is the “incubation period” between exposure and symptoms?
A: The median incubation period is 5.1 days, with most people getting sick between four and six days. About 97.5% of those who develop symptoms will do so within 11.5 days.
The CDC supports the recommended 14-day quarantine or monitoring of people exposed to the virus, although longer monitoring periods might be justified in extreme cases.
Annals of Internal Medicine
Q: What are the most common symptoms?
A: Early on, we identified the classic symptoms as dry cough, fever and severe body aches. But now we’re seeing lots of very different presentations as well.
Some people get very short of breath pretty quickly. But other people may be sick a week before they experience even a little shortness of breath. Some people get upper respiratory congestion; others don’t. A few people get diarrhea. There are a myriad of symptoms.
John Swartzberg, clinical professor emeritus of infectious diseases and vaccinology, UC Berkeley
Q: When do the most severe symptoms hit?
A: Many of the people who get sicker tend to do so in about a week or so into their illness. So that’s a challenging time. At Harvard’s hospitals, about half of all people who are hospitalized need intensive care.
Patients develop acute respiratory distress syndrome, in which fluid builds up in the small air sacs of the lungs. That restricts how much air the lungs can take in, reducing the oxygen supply to vital organs, sometimes fatally.
Paul Biddinger, Director of the Massachusetts General Hospital Center for Disaster Medicine
https://www.facebook.com/Forumhsph
Q: If I don’t have symptoms, or if I recover, can I give it to others?
A: What is disturbing is that virus “shedding,” as detected in the mouth or nose, is very, very common and could be there prior to onset of symptoms in an infected person. That’s why transmission could occur from asymptomatic individuals.
And virus shedding could continue for up to three weeks after a person recovers.
Dr. David Ho, Aaron Diamond AIDS Research Center, Columbia University
https://www.caltech.edu/about/news/tip-iceberg-virologist-david-ho-bs-74-speaks-about-covid-19
Q: What’s the current death rate?
A: The first good analysis of outcomes among patients in the U.S. shows trends that are similar to what’s been seen in other countries: The risk for serious disease and death increases with age. The age-related death risk probably reflects the strength, or weakness, of the respiratory system.
The CDC analyzed data from February 12–March 16 and found that death rates were highest in people age 85 and older, ranging from 10% to 27%. Among people 65 to 84, rates were 3% to 11%; ages 55 to 64, 1 to 3; ages 20 to 55, below 1%. There were no deaths in people under the age of 19.
Overall, 31% of cases, 45% of hospitalizations, 53% of ICU admissions and 80% of deaths were among adults age 65 or older, with the highest percentage of severe outcomes among persons aged age 85 or older.
The overall death rate in Italy (7.2%) is substantially higher than in China (2.3%), reflecting the older population in Italy.
Source: Centers for Disease Control and Prevention
https://www.cdc.gov/mmwr/volumes/69/wr/mm6912e2.htm
Q: What are the risks to children?
A: In the U.S., no ICU admissions or deaths were reported among young people under the age of 19.
Most children stay healthy. When they’re infected with the virus they might not have symptoms. Or they might have very mild symptoms.
But there are still children that are quite vulnerable — children with asthma and other chronic disease. That represents about 15% of all children.
Dr. Jason Wang, associate professor of pediatrics, Stanford University
Q: Once you become infected with the virus, can you get it again?
A: There’s potential immunity — but nobody knows.
Of the seven coronaviruses that infect humans, four cause common colds – which, as we all know, can re-infect us. Antibodies are produced but then the levels slowly decline. So they sicken people again and again.
People infected by the fifth coronavirus, called MERS, show more durable signs of immunity. Antibodies can be detected up to two years after infection.
With the new virus’s closest cousin, SARS, there’s immunity that lasts at least two to three years.
There’s only one study of immunity in the new virus, and it’s not a human study. It’s a macaque study. They infected the primates with this virus, then waited until they recovered and then tried to re-infect them. They could not. That bodes well for human immunity.
Dr. Michele Barry, senior associate Dean of Global Health, Stanford University
http://medicine.stanford.edu/news/updates-covid-19.html
Dr. David Ho, Aaron Diamond AIDS Research Center, Columbia University
https://www.caltech.edu/about/news/tip-iceberg-virologist-david-ho-bs-74-speaks-about-covid-19
