With so much discussion about the new coronavirus, a few questions are especially top of mind right now. How does the new coronavirus spread? Why is it spreading so quickly? And how, if possible, can you reduce your risk of infection—or transmission?
Now that so much of the public health focus is on “flattening the curve,” or avoiding a surge of cases that makes the illness harder to manage, it’s more important than ever to understand how the new coronavirus spreads. The thing is, the situation is constantly changing, and experts are learning more and more every day. As of now, here’s what we know about the new coronavirus transmission. (You can also see all of our coverage thus far here.)
What is the new coronavirus?
A virus called SARS-CoV-2 is behind the infectious disease now known as COVID-19, the CDC explains. SARS-CoV-2 is part of a family of viruses referred to as coronaviruses. Some coronaviruses cause the common cold. Others cause more serious infections like severe acute respiratory syndrome (SARS) and Middle Eastern respiratory syndrome (MERS).
“[SARS-CoV-2 is] different from all of those in that it causes more severe disease, especially in older adults, than the seasonal coronavirus, and less severe disease than SARS and MERS,” Marc Lipsitch, D.Phil., professor of epidemiology at Harvard University T.H. Chan School of Public Health, tells SELF. He adds that it also seems to be more transmissible than SARS and MERS. Lipsitch says the combination—easy transmission and potentially severe cases—make the illness a concern for epidemiologists and the rest of us alike.
If this all sounds overwhelming, keep in mind that around 80% of people with the illness are thought to get well without needing special treatment, according to the WHO. There’s some confusion surrounding what exactly this number means, though, because “mild” cases can still include people with new coronavirus-induced pneumonia who don’t need treatment like supplemental oxygen.
The most common symptoms of COVID-19 include fever, fatigue, and a cough, the WHO explains. Additionally, the WHO says some people get aches and pains, nasal congestion, runny nose, a sore throat, and diarrhea. In the less likely event that someone gets a more severe form of the disease, they can experience issues like trouble breathing. This is most likely to happen if you’re 60 or older and/or have underlying conditions like heart disease, diabetes, and cancer, the WHO explains.
The overwhelming concern with COVID-19 is that, unlike the seasonal flu, there aren’t any vaccines or antiviral treatments available yet. So, even if you get the new coronavirus and fall into the 80% of people who don’t develop a severe case, you can still pass it to older people and immunocompromised people at greater risk of complications. Plus, the sheer number of cases has the potential to overwhelm a health care system, as we’ve seen happen in Italy. This is why prevention tactics for slowing the spread have become our first line of defense—but more on that in a bit.
How does the new coronavirus spread?
Many coronaviruses cycle between animals like camels, cattle, cats, and bats, but they don’t typically jump from animals to humans, the CDC explains. When they do, this is called a spillover event, according to the National Institute of Allergies and Infectious Diseases (NIAID). Experts believe that the new coronavirus, like several other coronaviruses that have moved from animals to people, was originally prevalent in bats, the CDC says.
How it spreads from human to human, however, is a bit clearer. Most cases of the new coronavirus spread through respiratory droplets, Lipsitch explains. This means that the virus can spread if someone with the illness coughs or sneezes (or even talks), and droplets containing SARS-CoV-2 then land in mouths and on the noses of people nearby (usually within about six feet), the CDC explains.
In addition to those close encounters, it’s possible that people can get the new coronavirus from touching surfaces that have the virus on it, then touching their nose, mouth, or possibly eyes, but this seems less common, the CDC says. There’s a lot we still don’t know about how the virus functions, but based on other coronaviruses, the new coronavirus might live on surfaces for between a few hours and several days, the WHO says. Researchers, including those from the NIAID, just published a new study that suggests the virus can potentially live on copper surfaces for up to four hours, on cardboard for around 24 hours, and on plastic and stainless steel for up to three to four days. It’s worth noting that this research hasn’t yet been peer-reviewed, but it’s of interest since this is something we’re trying to navigate right this second. Experts will need more time to determine for sure how long the virus can live on surfaces and how we might best protect ourselves with that knowledge in mind.
People are thought to be most contagious when they’re showing the most symptoms, the CDC says, but there is also some evidence that people who don’t yet show symptoms of the new coronavirus can pass it on to other people. “Either people are really without symptoms, or they have symptoms that they can't tell from just a bad day or a cold,” Lipsitch posits. Lipsitch does say that, even though researchers know this happens, they aren’t yet sure how common this asymptomatic transmission actually is.
Finally, there is emerging research that suggests the new coronavirus might exist in other bodily fluids like fecal matter. “It's unclear whether you can transmit the infection through feces,” Lipsitch says. So it’s best to focus on the bottom line: The vast majority of cases spread from human contact, which is why limiting human contact with people who are showing any symptoms or may have been exposed to someone who was is incredibly important.
How do we prevent spreading the new coronavirus?
Okay, so it’s clear that the new coronavirus spreads pretty easily from one person to another, and that someone can catch COVID-19 without being able to pinpoint the source, the CDC says. That’s called community spread. When community spread is a factor, limiting opportunities for transmission becomes a big part of containing and managing the illness. “We distinguish between interventions that depend on knowing who is sick—which we call case-based interventions—and interventions that are generally trying to keep people from contacting each other,” Lipsitch says, adding that the latter methods are known as social distancing measures.
Case-based interventions include quarantines and monitoring people who are exhibiting symptoms or have tested positive for COVID-19. Social distancing practices are larger measures that communities use to keep transmission opportunities low. You’ve probably noticed them in your own life: school closures, event cancellations, and work-from-home recommendations.
We hate to be a bummer, but limiting travel as much as possible, even domestically, is probably a good idea right now. This becomes especially true when you think about how closely you’re packed in with other people on airplanes, buses, and similar travel methods—that makes it easier to become exposed to the virus or spread it to someone else, even if you don’t have symptoms.
When it comes to international travel, however, the advice is even clearer. The U.S. Department of State Consular Affairs Bureau has issued a level-three travel warning for all travel abroad, which boils down to: Please reconsider international travel. (Even if you didn’t get the new coronavirus or spread it to anyone else, you could become stranded based on how travel restrictions change in the future.) And, if you have any symptoms at all, you should definitely stay home.
Social distancing, while crucial to flattening the curve of infections, isn’t always possible. That’s why proper handwashing (with soap and water, y’all) is also incredibly important. Wash your hands often, but especially before you eat and before you touch your face so that, if you pick up the virus, you aren’t then transferring it to your eyes, nose, or mouth. On that note, try as best as you can to stop touching your face so much (here are some tips for that). And know that in a pinch, hand sanitizer is better than nothing (here’s how to make sure yours is up for the job).
Even if you pride yourself on your cleaning prowess (this writer does not), hearing that the new coronavirus may be able to live on various surfaces for hours to days might make you a little nervous. So, first, a (hopefully comforting) disclaimer: “Your house is not necessarily a hotbed of coronavirus,” Philip Tierno, Ph.D., clinical professor in the departments of microbiology and pathology at NYU Langone Medical Center, tells SELF.
Remember that the vast majority of new coronavirus cases are spread through respiratory droplets. With that said, unless you and anyone you live with aren’t leaving the house at all, now’s as good a time as ever to make sure you’re staying on top of your cleaning.
Whenever you leave home, you could theoretically pick up the virus and bring it back to where you live. So can any people you live with. This doesn’t mean you need to worry about going above and beyond in keeping everything as clean and disinfected as possible at all times, especially if that would just stress you out. Routine cleaning measures will suffice, Tierno says—things like disinfecting high-touch places in your home that can be particularly germy, like doorknobs and light switches. You can bump up how often you do these things based on how often you have to be in public places right now. If, for example, you can’t work from home, once you get back to your place and wash your hands, you can disinfect anything you touched on your way in, like a light switch.
When it comes to what to use as a disinfectant, the American Chemistry Council's Center for Biocide Chemistries (CBC) put together a list of products that the U.S. Environmental Protection Agency has approved for combating emerging pathogens (like the new coronavirus). When in doubt, the CDC also recommends using regular soap and water for things like light switches, doorknobs, and countertops. And in Tierno’s opinion, a diluted bleach solution (four teaspoons of bleach per quart of water) is “the best and cheapest disinfectant you could use for your house.”
Lastly, there’s not yet official guidance on whether you should do things like use disinfectant wipes on any packages you bring into your house or immediately throw anything you wear outside into the laundry. You can take these steps if they make you feel better, though.
This isn’t an exhaustive list, and it may need to be updated as we learn more about how this virus is transmitted, but these are the biggest things experts suggest to prevent infection and transmission. Also important: Make sure you’re staying generally healthy and your vaccinations are up to date (including your annual flu shot). This is helpful because it keeps you from catching an illness that might require seeing a doctor or going to the hospital, Lipsitch says. That helps free up medical care for more people with COVID-19.
“This is really a social problem, and it needs social interventions,” Lipsitch says. “So, by doing all those things, we not only protect ourselves, but we slow down the spread of the virus.”
Now let’s go over what we know about how the new coronavirus is transmitted in certain people (and pets).
Does the new coronavirus spread in children?
Experts aren’t sure. According to the CDC, there haven’t been many confirmed cases of the new coronaviruses in children, and even fewer with severe complications. New information is coming out every day (often several times a day), but a report from the WHO noted that only 2.4% of COVID-19 cases in China happened in people 18 and under, and 0.2% of those cases were critical.
Before we get too excited, it’s important to note that these low numbers might be due to a coronavirus testing bias, Aaron Milstone, M.D., epidemiologist and professor of pediatrics at Johns Hopkins Medicine, tells SELF. “In order to confirm someone has the virus, they have to get tested,” Dr. Milstone says. “Kids are not that sick, so they may not be getting tested. It doesn't mean kids don't have the virus. It just means if they have mild symptoms and they're not presenting to health care…they're not being identified.”
Even with that in mind, it’s encouraging that there aren’t a lot of severe new coronavirus cases in children, Dr. Milstone says. Some experts believe this will ultimately help us understand much more about the disease. There is, however, the pesky fact that even children with mild cases (or no symptoms at all) can potentially spread the virus to other people via the same mechanisms we covered above. So, if you have or care for any little ones, it’s still important to make sure they’re adhering to the same recommendations above to reduce their risk of infection and transmission.
Can pregnant people transmit the new coronavirus to fetuses?
Given the physiological and immune-related changes people experience during pregnancy, pregnant people can be more susceptible to respiratory infections overall, including COVID-19, the CDC says. Unfortunately, there isn’t enough information available to say how much of an increased risk there might be. If you’re pregnant, you should still take extra caution to avoid getting sick with any infectious respiratory disease.
There is a bit of good news, though: “I will say the data right now seems to suggest that there is no transmission from mothers to the fetus,” Bertha Hidalgo, Ph.D., assistant professor in the department of epidemiology and associate scientist at the University of Alabama at Birmingham School of Public Health, tells SELF, adding that most of the available research is observational, so it’s not enough to make a definitive conclusion. The virus also hasn’t been found in samples of amniotic fluid or breast milk. But if you’re pregnant and at all worried about the new coronavirus, don’t hesitate to check in with your health care provider to talk through your concerns.
Can the new coronavirus spread from people to pets (and vice versa)?
Though some coronaviruses (including the new coronavirus) do like to hang out in animals, you can rest assured that there haven’t been any recorded cases of pets passing the illness to their owners in the United States, the CDC says. This doesn’t mean, however, that your sweet pets aren’t full of their own germs that you should try to avoid when you can, pandemic or not. This is why it’s smart to continue to practice good hand hygiene (and good hygiene in general) when you’re around animals.
Whether or not your pets carry illness is only half of the equation, right? The other thing you might be wondering is if you can transmit the new coronavirus to your pets. The CDC recommends that people with the illness limit contact with their cuddly animal friends (the same way you would with cuddly human friends). To the best of your ability, leave pet caretaking to other people in your household if you can. And if you do have to take care of your pet when you have the new coronavirus, make sure you wash your hands before and after, and consider wearing a face mask.
The situation with coronavirus is evolving rapidly. The advice and information in this story is accurate as of press time, but it's possible that some data points and recommendations have changed since publication. We encourage readers to stay up to date on news and recommendations for their community by checking with their local public health department.
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