How Does Coronavirus Spread?

Medically Reviewed by Dan Brennan, MD on January 03, 2023
6 min read

With cases of COVID-19 continuing to spread across the globe, health officials are focused on slowing the spread. By understanding how coronavirus spreads, you can take the right steps so you don't get sick and infect others.

Experts believe the virus that causes COVID-19 spreads mainly from person to person. There are several ways this can happen:

  • Droplets or aerosols. This is the most common transmission. When an infected person coughs, sneezes, or talks, droplets or tiny particles called aerosols carry the virus into the air from their nose or mouth. Anyone who is within 6 feet of that person can breathe it into their lungs.
  • Airborne transmission. Research shows that the virus can live in the air for up to 3 hours. It can get into your lungs if someone who has it breathes out and you breathe that air in. Experts are divided on how often the virus spreads through the airborne route and how much it contributes to the pandemic.
  • Surface transmission. A less common method is when you touch surfaces that someone who has the virus has coughed or sneezed on. You may touch a countertop or doorknob that's contaminated and then touch your nose, mouth, or eyes. The virus can live on surfaces like plastic and stainless steel for 2 to 3 days. To stop it, clean and disinfect all counters, knobs, and other surfaces you and your family touch several times a day.
  • Fecal-oral. Studies also suggest that virus particles can be found in infected people's poop. But experts aren't sure whether the infection can spread through contact with an infected person's stool. If that person uses the bathroom and doesn't wash their hands, they could infect things and people that they touch.

The virus most often spreads through people who have symptoms. But it is possible to pass it on without showing any signs. Some people who don't know they've been infected can give it to others. This is called asymptomatic spread. You can also pass it on before you notice any signs of infection, called presymptomatic spread.

Sometimes, a person can trace how they got the virus because they know that they've been in contact with someone who's sick. In other cases, the cause is unknown. Community spread is when someone gets the virus without any known contact with a sick person.

Some pets have tested positive for the coronavirus. Not all of these animals had signs of illness, but some had mild symptoms. The animals may have caught the virus from close contact with humans who were infected.

Public health officials say they are still studying COVID-19 but it appears that humans can transmit it to pets but not as likely that pets can transmit it to humans.

Many experts say the omicron COVID variant appears to be more infectious than the previous dominant strain, delta. The CDC predicted that omicron would probably spread more easily than the original SARS-CoV-2 virus.

Researchers say that on average, every person who has COVID-19 will pass it on to 2 or 2.5 others. One study says that number is even higher, with one sick person infecting between 4.7 and 6.6 others.

By comparison, someone who has the flu will probably give it to an average of 1.1 to 2.3 others. But one person with measles might spread it to 12 to 18 others.

Although children tend to get infected with the coronavirus less often and have milder symptoms than adults, they can still catch and spread it. Some have become seriously ill and even died.

It's highly unlikely that you'll catch COVID-19 from packages, groceries, or food. The important thing is to limit your contact with other people. If case levels are high in your community and if you do your own shopping, try to keep at least 6 feet away from others in the store. That might not be possible all the time, so wear a face mask, too. If you use a delivery service, have them leave groceries, food, or packages outside your front door if you can.

Wash your hands for at least 20 seconds before and after bringing things into your home. If you want, you can wipe down plastic, metal, or glass packaging with soap and water. Then clean and disinfect countertops and anything else you or your bags have touched.

There are COVID-19 vaccines available, and you are encouraged to be vaccinated. You should still try to limit your contact with other people. CDC guidelines suggest:

  • Work from home if you can.
  • Avoid travel if you’re planning on going somewhere with very high levels of COVID. This is especially important if you or someone you live with is older or has a health condition that raises the chances of serious COVID-19 illness.
  • Visit with family and friends by phone and computer instead of in person.
  • If you go out, try to stand at least 6 feet (about two arm lengths) away from people.
  • If you aren’t fully vaccinated, always wear a mask in indoor public places. That goes for people 2 years old and older. 
  • If you’re fully vaccinated, wear a mask indoors in public places if you’re in an area with substantial or high amounts of COVID going around.
  • Wash your hands often.
  • If you’re sick, stay in a separate bedroom away from others in your home.
  • Do your shopping, especially for groceries or drugstore items, online if possible.
  • If your pet runs a fever, coughs, or has other possible symptoms of COVID-19, call your veterinarian. If the pet tests positive for the virus, your vet may recommend that you isolate them at home. Try not to worry -- most pets get mild cases of COVID and fully recover.
  • Clean up pet waste properly. Wash your hands afterward and after you touch them, their food, or their toys.
  • If you have COVID-19 symptoms, limit contact with your pet. That means no petting, snuggling, kissing, licking, sharing food, or sleeping in the same bed. If you can’t have someone else take care of your animals, wear a face mask when you’re around them, and wash your hands before and after you interact with them.

It may seem extreme to limit large gatherings, ask people to work from home, and occasionally close schools, restaurants, and theaters. But health experts say these are the best ways to slow the spread of the virus. As some places ease these rules, keep in mind that the virus hasn’t gone away. Be careful about your contact with others.

To stop the spread of coronavirus, people who are sick need to self-quarantine, or stay away from those who are well. Because you may not show symptoms right away, you should also self-isolate if you know that you've come into contact with someone who has COVID-19.

  • Stay at home.
  • Don't have visitors.
  • Wash your hands often with soap and warm water.
  • Don't share personal items like dishes, utensils, and towels.
  • Clean frequently touched surfaces like counters, doorknobs, phones, and remote controls.

If you've tested positive for COVID-19, isolate yourself. Stay at home in a room that's separate from everyone else, if possible. Avoid contact with other people and pets. Wear a face mask when you have to be near other people.

If your symptoms get worse, call your doctor or hospital before you go in. Follow their instructions to get medical help.

Isolate yourself until there's no chance that you could spread the virus. Your doctor can tell you when it's safe to stop.