How Long Does the Coronavirus Live on Surfaces? How Do I Know If I'm Immune? Your Covid-19 Questions, Answered

Everything you need to know about the coronavirus.
person lathering hands with soap and water
Photograph: Jena Ardell/Getty Images

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1. How long does coronavirus hang around on surfaces?

Two studies released in the New England Journal of Medicine and The Lancet took a look at the coronavirus’s shelf life. After introducing it to various surfaces in a lab environment, researchers found that the virus remains infective for 24 hours on cardboard packages and less than three hours on printer or tissue paper. Smoother surfaces tended to harbor viral particles for much longer; three to four days on plastic and up to seven days on stainless steel and, alarmingly, surgical masks.

The CDC says you’re less likely to become infected by surface transmission than by coming into contact with respiratory droplets, but disinfecting high-use surfaces, like doorknobs and kitchen counters, daily is still critical. Wipe these surfaces down with paper towels and a cleaning spray, and then sanitize them with disinfecting sprays or wipes. If you can’t find disinfectant, try the homemade bleach solution from WIRED’s comprehensive guide to cleaning all your stuff.

2. Should I stop ordering packages?

There’s very little risk of catching coronavirus from a package delivery, according to the CDC—even if it’s shipped from a Covid-19 hot spot. Most deliveries take at least this long to travel from the warehouse to your front door and are exposed to frequent shifts in temperature and humidity that reduce the virus’s likelihood of survival.

If you’d like to be extra cautious, you can spritz a solution of at least 62 percent alcohol onto your package and let it rest for a few minutes before wiping it off. Don’t forget to wash your hands after opening, and refrain from touching your face.

You might also consider cutting back on nonessential purchases, since many warehouse employees are facing increased risks by working long hours in close quarters, some without essential benefits.

3. Is it safe to eat out or order delivery?

The government is now urging everyone in the United States to avoid eating out in restaurants and bars and to suspend unnecessary shopping trips. Many eateries are still open for delivery and to-go service during the shut-down, but is it safe to eat food prepared by someone else? Fortunately, there’s currently no evidence of coronavirus transmission through food. Few viruses can survive basic food safety measures, and fewer still can endure the acidic rollercoaster that is the human digestive system.

WHO is advising everyone to wash fruits, vegetables, and their hands before cooking. Use a separate cutting board when preparing raw meat, and cook it to the proper temperature before eating. If you’re especially anxious, follow guidelines for those with weakened immune systems and order foods that have been well-cooked (sorry, sushi).

It’s probably safe to order out, but should you? Orders through Instacart, Doordash, and other delivery services have skyrocketed in the last few weeks as more of the population stays home, but gig workers are elevating their risk levels when they go out in public. Worker organizations are putting pressure on delivery companies to offer better benefits to their drivers, and a few companies are now considering such measures.

4. I’m recovering from the coronavirus. When is it safe to interact with others?

If you’ve tested positive for Covid-19 or are experiencing mild symptoms, it's important to self-quarantine as soon as possible to avoid spreading it further. After symptoms begin to abate, the CDC has a few guidelines to ensure you come out of hiding safely, without infecting others. Wait at least seven days after first experiencing symptoms, and 3 days after your fever subsides (without the help of fever-reducing medicine) before leaving isolation.

If you have access to testing in your area, you can also confirm you’ve recovered by retaking the test and receiving a negative result.

5. Are there tests available to determine immunity? How long does immunity last?

Everyone wants to go back to work, school, and life as we remember it, so everyone is eager for some kind of way to measure immunity in the general populace. When you contract an illness like the coronavirus, your body fights the infection by producing several different types of antibodies. Some of these antibodies can linger in your body long after you recover, providing an extra boost to your immune system if it should ever come into contact with the same strain again.

Serological tests, which measure the presence of antibodies in the blood, are being promoted as a potential green light back into society. But little is known about the body’s immune response to coronavirus and how long such protection could last. A study that measured the body’s response to SARS, another coronavirus, found that antibodies were present in the blood of recovered patients for an average of two years after onset. While this could provide a yardstick of what to expect, more research and time, enough for ill patients to recover and be studied, is needed to develop a good picture.

In March, the FDA granted a stay on its lengthy approval process for such tests, as long as developers meet certain criteria before marketing their products. Patients recovering from coronavirus generally build up an antibody response 1 to 2 weeks after contracting the disease, so the opportune time to test is after recovery. It’s still early days for serological testing in the US, and many clinics and hospitals are still trying to evaluate and source the best materials, but your healthcare provider can tell you what’s available in your area.

6. If I think I might have coronavirus, can I get tested?

Red tape and faulty kits contributed to a major testing shortage in the United States, just as the rate of infection started picking up in late February. On Feb. 29, the FDA lifted some regulatory restrictions on certified clinical labs, which is why you’re now seeing drive-through testing operations in a few locations. More tests are likely on the way, but for now medical facilities are prioritizing tests for those facing the greatest health risks: namely health care workers, those over the age of 65 or with underlying health conditions, and those already hospitalized for a potential coronavirus case.

Still, if you have symptoms of the virus, even if you’re relatively young and healthy, call your doctor. They can determine whether you meet the requirements for testing, or if it’s better to quarantine yourself at home. The CDC and many state and local public health websites have self-check questionnaires you can take to assess your symptoms and, in some locations, make an appointment at a drive-through testing facility or lab.

7. How does the coronavirus spread?

Covid-19 is a respiratory virus, and, much like influenza and others in this category, it spreads when humans cough or sneeze out tiny droplets of mucus and saliva. If it lands on a hard surface like a doorknob or countertop, the virus can survive anywhere from a few hours to a few days. New research suggests that coronavirus particles may also be able to survive for a few hours in aerosol form, contained in smaller droplets suspended in the air. When you come into contact with a droplet, either by being in close proximity to a forceful sneezer or by touching a surface that said sneezer has touched with their sneezey hands, you can become infected. Though coronavirus can’t be absorbed through your skin, it can enter your system when you touch your mouth, nose or eyes, or through a cut.

8. Is coronavirus airborne?

Whether or not the coronavirus is “airborne” is a contentious topic. The virus has been found to be present in larger respiratory droplets, like those typically let loose when someone coughs or sneezes, but these larger particles can only travel about 3 feet. Smaller particles, those less than 5 microns wide, are light enough that they can float in the air for several hours, and they’re also more likely to be expelled when you’re talking or breathing. If a viable amount of the virus were found in these smaller particles, known as aerosols, it could mean that there are infective particles present in the air around a sick person long after they expel them.

WHO currently maintains that there is not enough evidence to suggest that such small particles can carry a potentially infective amount of the virus in the air, but a few recent studies that analyzed samples of air around infected hospital patients found trace amounts of the virus in this size particle. Some scientists believe WHO’s stance is too conservative, and that the 5 micron cutoff may be arbitrary. The CDC is less conclusive, saying the science is still “uncertain,” but also urging healthcare facilities to take extra precautions when performing procedures.

9. Is it a good idea to get a pneumococcal vaccine? A flu shot?

It is generally a great idea to get a flu shot every year and the pneumococcal vaccine if you’re over 65 or immunocompromised, but neither will help treat or prevent the coronavirus. Pneumococcal vaccines help your body fight bacterial pneumonia, but are powerless against the viral pneumonia that sets in in severe coronavirus cases.

A flu shot, which targets the influenza virus, is similarly ineffective against coronavirus, but could help healthcare facilities from getting overcrowded when flu season starts again in the fall.

10. Is there an increased risk for people with underlying health conditions?

Patient data collected in China, Italy and the US suggests that people with certain pre-existing conditions who contract Covid-19 are more likely to be hospitalized or have a severe case. According to a CDC analysis of patient outcomes in the US, 78 percent of coronavirus patients who were admitted to the ICU had one or more underlying conditions. The highest risk conditions are hypertension, diabetes, chronic lung disease and cardiorespiratory disease.

Early research published in the New England Journal of Medicine that looked at more than 1,000 Wuhan residents who contracted the coronavirus found that patients with diabetes, hypertension or heart disease, experienced a higher rate of infection than the general public, and nearly 15 percent of patients with serious coexisting disorders faced severe complications or death.

If you have an underlying health condition, take extra precautions, like staying home and having a friend or family member do the grocery shopping. Check in with your doctor if you start to notice symptoms or have questions specific to your condition.

11. Is anyone working on a cure?

The first human trial of a potential coronavirus vaccine started on March 16, just two months after scientists in China shared the genetic sequence of the virus with the world. And last Friday, WHO announced the launch of a global study of drug therapies called the Solidarity trial, which will allow participating hospitals and patients to test promising new drugs and treatments to fight coronavirus. All in all, more than 20 companies are working on developing vaccines and more still are testing other drugs and treatments, like Chloroquine and plasma therapy. Scientists at Stanford are even working to develop a Crispr-based technology to battle coronavirus or for use in future pandemics. Still, a fully developed vaccine is not expected to be available to the general public for another year or so.

12. Can I give coronavirus to my pets, or vice versa?

Despite reports of a Pomeranian in Hong Kong testing “weakly positive” for Covid-19 in early March, there isn’t any evidence that coronavirus is spreading from humans to pets, or vice versa. Domesticated animals like dogs and cats share a lot of the same cell receptors as we do, but viruses face additional hurdles when crossing a species barrier that make entering cells and then replicating unlikely.

The American Veterinary Medical Association and the CDC say that animals aren’t a vector for transmission of the disease between people, so it’s okay to interact with someone else’s pet (and walk your neighbor’s dog if they’re sick or high risk).

To be safe, practice good hygiene by washing your hands after animal snuggles, and if you do get sick, sequester yourself from all family members, even your furry ones.

13. What does it mean to "flatten the curve"?

When coronavirus hit Wuhan, China, it traveled fast. By February hospitals were filled to capacity, and the waiting list to get an ambulance stretched into the hundreds. Medical practitioners hadn’t yet gotten a handle on what they were dealing with, so social distancing measures weren’t taken until it was too late. As a result, the epidemic curve, a graphic representation of the rapid spike in infections, was steep.

Flattening the Curve
Data-Visualization: Sam Whitney; CDC

To keep hospitals and doctors’ offices from becoming overwhelmed with sick patients, the ultimate goal for public health authorities is to flatten this curve. Social distancing measures can make a serious impact when they’re implemented early, so that, over time, all patients get the resources they need.

14. What is social distancing?

Aside from being good news for introverts, social distancing is a public health tactic that helps communities slow down the transmission and spread of contagious illnesses like the coronavirus. Research has shown that in urban areas and regions where a disease is spreading, taking measures like working from home, shutting down schools, and canceling large events can significantly reduce the rate of new infections.

It’s a good idea to check in with your local government and public health authority to find out what guidance is in place in your community. The CDC recommends everyone wash their hands frequently, keep a physical distance of 6 feet or more between yourself and anyone coughing or sneezing, and continue not touching your face (because we know you’ve been doing a great job so far).

15. How do I keep it together while stuck at home?

We get it, it’s rough to be stuck at home, no matter if you live alone, with your significant other, a larger family, a few friends, or some (near) complete strangers. Astronauts, after all, go through extensive psychological testing before they get the green light to be locked in with one another 250 miles up on the ISS. Quarantine can strain even the steadiest of relationships, so maintaining self-awareness, establishing structure, and allowing yourself a little “you” time (even if it’s cheap entertainment) is critical.

If you’ve got kids at home, it’s even more important to maintain a daily routine. Try to stick to a typical schedule: breakfast at breakfast time, schoolwork or structured playtime during the day, and some activity in the afternoon. If you need to lean on television or a tablet more heavily in the next few weeks, don’t sweat it too much. Most learning will need to happen via screen, and letting your kids connect with their friends while isolated can help keep them sane. Check out WIRED’s guide to gear in the time of coronavirus for some of the best subscription services, toys, and games to keep the family entertained.

16. Any tips for those working at home?

Covid-19 has ushered in the largest involuntary remote working experiment to date, with many desk workers now being asked to stay at home and clock in remotely. Will it prove once and for all that a common workspace is irrelevant, or will it reinforce the need for in-person collaboration? It’s too soon to tell, but there are a few ways those just now testing the work-from-home waters can make the transition easier.

Create a space dedicated to work, outside of the bedroom and away from the couch, if you can. Put on some clothes you wouldn’t be totally embarrassed to enter the office in, and keep the TV off until you’re done for the day. It’s hard to believe, but when you don’t have the mental partition of a commute to and from the office to help you decompress at the end of a day, it can be difficult to disengage. Try powering down Slack or email at the end of the day and take a quick walk around the block. Even under a shelter-in-place order, most locations are letting folks get out for some fresh air and exercise. Just don’t forget to keep a little distance (about 6 feet) between you and anyone else who’s out and about.

Read all of our coronavirus coverage here.

17. Does hand-washing work?

Yes! Washing your hands with soap and water for at least 20 seconds is one of the most effective ways to prevent catching or spreading coronavirus (or any virus, for that matter). A virus is contained within a fatty lipid barrier, which it uses to bind to your cells and spread throughout your body. When you break this greasy envelope, you kill the virus. What’s tough on grease? Hand soap and sanitizer (you can even make your own).

Though a virus on your hands can’t break the skin barrier to infect you (except through a cut or abrasion), it can enter your system if you touch your face and it wends its way into one of the many openings there. So wash your hands, and seriously, don’t touch your face.

18. What are “mild” symptoms?

Early analysis indicates that about 80 percent of coronavirus cases are nonsevere, but what does that mean? According to WHO, mild symptoms include the sniffles, coughing, sore throat, and a low-grade fever—pretty much a cold. If you’re showing mild respiratory symptoms, even if you think it might be coronavirus, the CDC recommends you isolate at home and contact your health care provider. Telemedical services are now provided through most health insurance plans, and staying put for your appointment reduces the risk of transmission to others.

If you start experiencing more severe symptoms like sustained difficulty breathing, gastrointestinal distress, confusion, or are coughing up blood or large amounts of mucus, inform your doctor to evaluate whether or not you need additional treatment.

19. When should I go to the hospital?

If you or a loved one are experiencing a medical emergency, it’s a good time to call 911. If you believe that you or someone in your household might have the coronavirus, though, be sure to make that clear to the operator. Medical professionals and hospital staff can catch the virus too, and the last thing they want is to become a vector and pass the virus on to someone else already in care.

If you’re having mild symptoms, however, hospitals want you to stay home. More serious symptoms like strained breathing, chest pain, or life-threatening complications from an underlying illness might warrant a visit to the hospital, but it’s still a good idea to call first. Hospitals have enhanced protocol to handle potential coronavirus patients, like wearing masks and donning protective gear.

We will update these questions frequently. This was last updated on April 18, 2020


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