How do you become infected with the coronavirus? A chalk drawing in New York City encourages people to take simple steps to slow the spread of the new coronavirus. (Getty Images) By Rong-Gong Lin IIStaff Writer March 22, 2020 3 AM Dr. Robert Redfield, director of the U.S. Centers for Disease Control and Prevention, said at a recent congressional hearing. It also spreads via “sneezing, coughing and hand contamination,” he said. What are these droplets like? Imagine an infected person who coughs or sneezes. He or she sprays tiny drops of infected saliva, which fall to the ground within seconds, like rain. Those drops — scientists call them droplets because they are tiny — are loaded with virus that can infect you. California coronavirus cases: Tracking the outbreak California coronavirus cases: Tracking the outbreak The latest maps and charts on the spread of COVID-19 in California. Advertisement How would the virus get from someone else’s saliva into my body? Getting sneezed at or coughed on by someone who’s infected is probably the most common way, according to the CDC. If that virus-carrying saliva lands on a wet part of your face — your eyes, nose or mouth — you’ll be infected. Droplets from a sneeze or cough can fly about 3 feet before they drop to the ground. If the cough or sneeze is “very forceful,” they can go as far as 6 feet, said Dr. Aruna Subramanian, an infectious diseases specialist at Stanford University. The droplets could also be inhaled directly into the lungs of those nearby. Droplets of saliva remain in the air for only a few seconds before falling to the ground. “What we’re really talking about is droplet spread,” said Dr. George Rutherford, an epidemiologist and infectious disease expert at UC San Francisco. “Droplets fly out ... and you inhale them on the fly.” Can I be infected without even noticing? Yes, you can. This is why officials urge you to not touch your face. A sneeze or cough can deposit droplets of infected saliva onto doorknobs, elevator buttons or your cellphone. Alternately, someone who’s ill could touch these or other objects, depositing the infected saliva that’s already on their hands onto a surface that others will touch. Then, all you have to do is lay a finger on one of these surfaces and touch your nose, your eye or your mouth. How long can the virus survive on surfaces? Scientists ran experiments to find out. In the lab, samples of the new coronavirus remained viable on stainless steel and on plastic for up to three days, according to a study in the New England Journal of Medicine. Tests also found that cardboard could not sustain infectious levels of the virus for 24 hours, and copper couldn’t do it for four hours. Advertisement The amount of virus the researchers used in their experiments was meant to mimic the amounts typically found in the respiratory tracts of COVID-19 patients. However, if the researchers had started out with even more, the virus could have remained viable for a longer period of time. Also, the time periods reported in the study reflect the specific conditions used in the experiment; if variables such as temperature or humidity were different, the results might be different too. How long can it survive in the air? For hours, potentially. However, experts aren’t sure about the chances that virus-infected mist could infect other people, and more research would be needed to determine that answer, said Jamie Lloyd-Smith, an ecology and evolutionary biology professor at UCLA who worked on the new study. How do we know the coronavirus can become airborne? Scientists made it airborne in the study Lloyd-Smith co-wrote. Indeed, they showed just how the virus can survive as an aerosolized particle. Is an aerosolized particle different from a droplet? An aerosolized particle is much smaller than a droplet. It can float and fly in a room for hours, much like an aerosolized air freshener. A droplet, meanwhile, is large enough that it drops to the ground by gravity within seconds. OK, where were we? We were discussing the lab experiment. Scientists put coronaviruses through a machine called a nebulizer, transforming them into a mist in an enclosed space. The researchers found that the coronavirus survived in aerosolized particles for at least three hours. Added bonus: they were still able to infect cells and replicate. Of the original amount of coronavirus sprayed into the mist, half of it remained after roughly one hour. So by the end of the three-hour experiment, roughly one-eighth (or 12.5%) of the initial amount still remained. In real-life conditions where there’s fresh air or ventilation, any virus in a mist will get diluted pretty quickly. But in theory, if you’re in an elevator or a subway car with limited ventilation, the virus could hang out in the air for a while, Lloyd-Smith said. Advertisement He also noted that scientists aren’t sure how much virus it takes for a person to become infected. How does that compare to measles? Measles ranks among the most infectious diseases. One infected person can pass it on to between 12 and 40 others if they haven’t been vaccinated, according to the CDC. For the new coronavirus, by contrast, the World Health Organization estimates that every infected person spreads it to 2 to 2.5 others, on average, at least according to data collected early in the outbreak. That’s still worse than the seasonal flu. Depending on the influenza strain, every infected person passes the virus to 1.2 to 2 others, Lloyd-Smith said. Will I be safe if I wash my hands and stay 6 feet from others? Those are still prudent ways to protect yourself. And certainly, staying away from sick people — and keeping your distance from anyone else, really — will help prevent infections. That’s why a number of states around the nation — including California, New York and Illinois — have issued orders instructing the public to stay at home as much as possible in the coming weeks to help slow the spread of the virus. Can the coronavirus be found in fecal matter? Yes. SARS-CoV-2 can be found in the feces of infected people. But there’s currently no evidence that it’s an efficient way to infect others, Subramanian said. That would make it different from the coronavirus that caused Severe Acute Respiratory Syndrome. Back in 2003, that virus was thought “to have spread via aerosolized fecal matter” through a faulty sewage system in a Hong Kong apartment complex with the help of bathroom exhaust fans. “There’s nothing like that going on” with the new coronavirus, Rutherford said. What are the risks for doctors and nurses? Healthcare workers have a higher risk of infection because they work close to patients and can be exposed to large volumes of virus. Sometimes they perform lifesaving procedures, such as inserting a breathing tube in a patient’s windpipe, that aerosolize infected saliva. How can they protect themselves? Ideally, they would wear tight-fitting N95 masks, or respirators, which are designed to filter out 95% of small airborne particles. They offer more protection than the paper masks you see so often these days, but, even if properly fitted on a face, do not completely eliminate the risk of infection. The problem is, there aren’t enough N95 masks to go around. If the virus spreads only through droplets, conventional face masks — along with gowns, gloves and eye protection — would be sufficient. But if the virus can spread through aerosolized mist, failing to wear an N95 mask puts them at greater risk, particularly if healthcare workers are doing a procedure that aerosolizes the patient’s saliva. Have scientists detected coronavirus in hospital rooms? Yes. A research letter in the Journal of the American Medical Assn. examined the rooms of three COVID-19 patients in Singapore and found genetic evidence of the virus lurking in one of them, on an air outlet fan. That suggests it’s possible “that small virus-laden droplets may be displaced by airflows and deposited on equipment such as vents,” the researchers wrote. The authors also found viral genetic material on the toilet bowl, sink and door handle. (Stool samples from that patient were found to contain the virus.) Routine cleaning was enough to return the hospital room to a virus-free state. The researchers couldn’t find genetic evidence of the coronavirus in the other two hospital rooms. And none of the three rooms contained air that tested positive for viral material. Viral material was also found on a shoe covering worn by a physician. ScienceWorld & NationCaliforniaCoronavirus PandemicMedicine Newsletter Get our free Coronavirus Today newsletter Sign up for the latest news, best stories and what they mean for you, plus answers to your questions. You may occasionally receive promotional content from the Los Angeles Times. Rong-Gong Lin II Follow Us twitter instagram email facebook Rong-Gong Lin II is a metro reporter, specializing in covering statewide earthquake safety issues. The Bay Area native is a graduate of UC Berkeley and started at the Los Angeles Times in 2004. More From the Los Angeles Times California L.A. County strengthens coronavirus bans: Nail and hair salons, drive-in movies among closures View attachment upload_2020-3-22_8-6-19.gif California L.A. County strengthens coronavirus bans: Nail and hair salons, drive-in movies among closures The new county order largely matches the stronger stay-at-home order issued for the city of Los Angeles on Thursday night, just moments before the statewide order was announced. March 22, 2020 Science Coronavirus drugs: Where we are and what we know View attachment upload_2020-3-22_8-6-19.gif Science Coronavirus drugs: Where we are and what we know Medicines designed to treat COVID-19 won’t be available for months, so doctors are looking to drugs already approved for treating other diseases. March 21, 2020 Politics COVID-19 doctors running out of masks? Try a bandanna, the CDC says View attachment upload_2020-3-22_8-6-19.gif Politics COVID-19 doctors running out of masks? Try a bandanna, the CDC says Doctors treating coronavirus patients running out of masks? Try a bandanna, the CDC says March 21, 2020 Science Why is the coronavirus so much more deadly for men than for women? View attachment upload_2020-3-22_8-6-19.gif Science Why is the coronavirus so much more deadly for men than for women? Italy announced that coronavirus deaths of men outnumbered those of women by a factor of 2 to 1. That mirrors the experience of China. What gives? March 21, 2020 Latest Science Science Free coronavirus coverage from the Los Angeles Times View attachment upload_2020-3-22_8-6-19.gif Science Free coronavirus coverage from the Los Angeles Times The Times’ essential coronavirus coverage for nonsubscribers. March 20, 2020 Science How the blood of coronavirus survivors may protect others from COVID-19 View attachment upload_2020-3-22_8-6-19.gif Science How the blood of coronavirus survivors may protect others from COVID-19 Scientists racing to stave off a tidal wave of coronavirus infections show renewed interest in a little-known medicine: convalescent plasma. March 20, 2020 Business Hiltzik: The coronavirus crisis shows what happens when a country puts its workers last View attachment upload_2020-3-22_8-6-19.gif Business Hiltzik: The coronavirus crisis shows what happens when a country puts its workers last In recent days, alarm about the economic impact of the novel coronavirus have turned conservatives who weeks ago were boasting about the shrinking of the U.S. government into raving Keynesians, proclaiming the virtues of deficit-financed economic stimulus. March 20, 2020 California Here is what you can and can’t do under L.A.'s new coronavirus Safe at Home order View attachment upload_2020-3-22_8-6-19.gif California Here is what you can and can’t do under L.A.'s new coronavirus Safe at Home order The city of L.A. ordered residents to stay at home as much as possible, while L.A. County ordered stores that are nonessential to shut down. March 20, 2020 Science Why we should learn to accept the coronavirus craziness View attachment upload_2020-3-22_8-6-19.gif Science Why we should learn to accept the coronavirus craziness Daily life feels very different now that we are living with the coronavirus. Psychologists offer their advice for learning how to get used to it. March 19, 2020