Preventing the spread of the coronavirus

Physical distancing, masks, vaccines , and other preventive measures

Getting vaccinated and boosted is the best way to reduce your risk of symptoms, especially becoming severely ill, if you get COVID-19. But right along with vaccination are steps you can take to both avoid getting infected and help prevent spreading the virus to others. They include wearing your mask when you need to, avoiding crowds, and maintaining physical distance.

Visit our Coronavirus Resource Center for more information on coronavirus and COVID-19.

What can I do to protect myself and others from COVID-19?

The following actions help prevent the spread of COVID-19, as well as other coronaviruses and influenza.

• Wear a face mask in public indoor spaces.
• Maintain at least six feet of distance between yourself and others.
• Avoid large gatherings.
• Socialize outdoors.
• Get vaccinated and boosted as soon as you are eligible.
• Avoid close contact with people who are sick.
• Minimize touching your eyes, nose, and mouth.
• Stay home when you are sick.
• Cover your cough or sneeze with a tissue, then throw the tissue in the trash.
• Clean frequently touched objects and surfaces regularly.
• Wash your hands often with soap and water.

How does coronavirus spread?

The coronavirus spreads mainly from person to person. A person infected with coronavirus — even one with no symptoms — may emit aerosols when they talk or breathe. Aerosols are infectious viral particles that can float or drift around in the air for up to three hours. Another person can breathe in these aerosols and become infected with the coronavirus.

When people are in close contact with one another, droplets that are produced when an infected person coughs or sneezes may land in the mouths or noses of people who are nearby, or possibly be inhaled into their lungs.

Transmission is less likely to happen outdoors, where air currents scatter and dilute the virus, than in a home, office, or other confined space with limited air circulation.

The risk of spread from contact with contaminated surfaces or objects is considered to be extremely low. According to the CDC, each contact with a contaminated surface has less than a 1 in 10,000 chance of causing an infection.

The virus may be shed in saliva, semen, and feces; whether it is shed in vaginal fluids isn't known. Kissing can transmit the virus. Transmission of the virus through feces, or during vaginal or anal intercourse or oral sex, appears to be extremely unlikely at this time.

Should I wear a face mask?

The coronavirus that causes COVID-19 is primarily transmitted through viral particles that float in the air or through droplets containing virus. Even people who are infected but do not have symptoms, or have not yet developed symptoms, can infect others. Masks reduce the amount of virus we breathe in and breathe out. Combined with the vaccine, masks provide a one-two punch that reduce the risk of spread — to young children who are not yet eligible for vaccines, to people with weakened immune systems, and to others who are unvaccinated. Masks also provide additional protection for the wearer, even those who are fully vaccinated.

The CDC advises all people — vaccinated and unvaccinated — to wear masks in public indoor places in areas of the country with widespread transmission of the virus. The CDC has always advised unvaccinated people to mask indoors, and also advises anyone at increased risk to wear a mask indoors, regardless of the level of community transmission.

Transmission is much less likely to occur outdoors, and masks are not needed in most outdoor settings.

What kind of mask should I wear?

Omicron is the most contagious variant we have come across yet, so high-quality, well-fitting masks are more important than ever. This is true for everyone, and even more so for anyone who is unvaccinated, at increased risk for severe illness, or caring for someone with COVID-19.

Not all masks are created equal. High quality KN95, KF94, and N95 masks have the tightest fit and the best filtration. Surgical masks are also effective at filtering out small viral particles. You can wear a cloth mask on top of a surgical mask to improve the fit. Or, you can adjust a surgical mask for a tighter fit using a method called "knotting and tucking." To knot and tuck a surgical mask, knot the ear loops of a 3-ply face mask where they join the edge of the mask, then fold and tuck the unneeded material under the edges. For video instructions on how to knot and tuck a surgical mask, click here. Avoid single-layer cloth masks, which may not be up to the task.

 When it comes to fit, make sure your mask completely covers your nose and mouth and fits snugly against the sides of your face without leaving any gaps.

The CDC has information on how to improve the fit of your mask.

The WHO offers videos and illustrations on when and how to use a mask.

What do I need to know about washing my hands effectively?

Wash your hands often with soap and water for at least 20 seconds, especially after going to the bathroom; before eating; after blowing your nose, coughing, or sneezing; and after handling anything that's come from outside your home.

• If soap and water are not readily available, use an alcohol-based hand sanitizer with at least 60% alcohol, covering all surfaces of your hands and rubbing them together until they feel dry.
• Always wash hands with soap and water if hands are visibly dirty.
• The CDC's handwashing website has detailed instructions and a video about effective handwashing procedures.

What is physical distancing and why is it important?

The COVID-19 virus primarily spreads when one person breathes in droplets or aerosols that are produced when an infected person coughs, sneezes, talks, or breathes.

Physical distancing refers to actions taken to stop or slow down the spread of a contagious disease. For an individual, it refers to maintaining enough distance (six feet or more) between yourself and another person to avoid getting infected or infecting someone else. Directives to work from home, and canceling in-person meetings and larger events help enforce physical distancing at a community level.

If I want to visit friends and family, does it matter whether we meet indoors or outdoors?

You are better off meeting friends and family outdoors. We know that coronavirus spreads when someone breathes in virus that an infected person emits through coughs or sneezes, or when they talk or breathe. Research has shown that in a confined, laboratory setting, droplets containing viral particles can remain afloat for eight to 14 minutes. Smaller infectious viral particles, called aerosols, can drift around in the air even longer.

What precautions can I take when grocery shopping?

In the grocery store, maintain at least six feet of distance between yourself and other shoppers. Wipe frequently touched surfaces like grocery carts or basket handles with disinfectant wipes. Avoid touching your face. Wearing a mask helps remind you not to touch your face and further reduces spread of the virus. Use hand sanitizer before leaving the store. Wash your hands as soon as you get home.

If you are older than 65 or at increased risk for any reason, try to limit trips to the grocery store. Ask a neighbor or friend to pick up groceries and leave them outside your house. Or have groceries delivered to your home.

Is it safe to travel once I’m vaccinated? What if I’m not vaccinated?

As a general rule, travel can increase your chance of spreading and getting COVID-19, especially if you are not vaccinated. Guidance from the CDC rstates that anyone traveling by public transportation, including plane, train, or bus, must be masked while traveling, and while in airports and train and bus stations. Requirements for vaccination and COVID-19 testing may vary by carrier, geographic location, and your vaccination status.

In addition to wearing a well-fitting mask, all travelers should maintain a physical distance of six feet from others, avoid crowds, and wash hands often. Anyone who is sick or who has tested positive for COVID-19 should not travel by public transportation if at all possible.

Stay current on travel advisories from regulatory agencies.

Can a person who has been infected with coronavirus get infected again?

The immune system responds to COVID-19 infection by stimulating white blood cells called lymphocytes to form antibodies that fight the infection. These antibodies and lymphocytes retain a temporary protective effect against reinfection. But it is only temporary. There have been many confirmed cases of reinfection with COVID-19. In other words, a person got sick with COVID-19, recovered, and then became infected again.

This has been especially true as the coronavirus has mutated into COVID-19 variants. There was a rise in reinfections with the Delta variant, and an explosive increase in the reinfection rate due to the Omicron variant. Omicron has about 50 mutations, including more than 30 mutations on the spike protein, the region of the virus that our immune systems recognize after previous infection. Because of this, Omicron is more capable than previous variants of evading our immune defenses and causing reinfection.

We have learned that vaccination plus a booster dose strengthens the natural immune response, even in those who have been previously infected, and further reduces the risk of reinfection. Although breakthrough infections after vaccination are also more common with Omicron than previous variants, vaccination continues to protect well against severe illness.

The bottom line? Get vaccinated and boosted, whether or not you’ve already had COVID-19.

Will a pneumococcal vaccine help protect me against coronavirus?

Vaccines against pneumonia, such as pneumococcal vaccine and Hemophilus influenza type B (Hib) vaccine, only help protect people from these specific bacterial infections. They do not protect against any coronavirus pneumonia, including pneumonia that may be part of COVID-19. However, even though these vaccines do not specifically protect against the coronavirus that causes COVID-19, they are highly recommended to protect against other respiratory illnesses.

Can my pet infect me with the virus that causes COVID-19?

The risk of pets such as dogs or cats spreading the COVID-19 virus to humans is low. However, pets can spread other infections that cause illness, including E. coli and Salmonella, so wash your hands thoroughly with soap and water after interacting with pets.

Can people infect pets with the COVID-19 virus?

The virus that causes COVID-19 does appear to spread from people to pets, according to the FDA, though this is uncommon. Research has found that cats and ferrets are more likely to become infected than dogs.

If you become sick with COVID-19, it’s best to restrict contact with your pets, just like you would around other people. This means you should forgo petting, snuggling, being kissed or licked, and sharing food or bedding with your pet until you are feeling better. When possible, have another member of your household care for your pets while you are sick. If you must care for your pet while you are sick, wash your hands before and after you interact with your pets and wear a face mask.

What can I do to keep my immune system strong?

Your immune system is your body's defense system. When a harmful invader — like a cold or flu virus, or the coronavirus that causes COVID-19 — gets into your body, your immune system mounts an attack. Known as an immune response, this attack is a sequence of events that involves various cells and unfolds over time.

Following general health guidelines is the best step you can take toward keeping your immune system strong and healthy. Every part of your body, including your immune system, functions better when protected from environmental assaults and bolstered by healthy-living strategies such as these:

• Don't smoke or vape.
• Eat a diet high in fruits, vegetables, and whole grains.
• Take a multivitamin if you suspect that you may not be getting all the nutrients you need through your diet.
• Exercise regularly.
• Maintain a healthy weight.
• Control your stress level.
• Control your blood pressure.
• If you drink alcohol, drink only in moderation (no more than one to two drinks a day for men, no more than one a day for women).
• Get enough sleep.
• Take steps to avoid infection, such as washing your hands frequently and trying not to touch your hands to your face, since harmful germs can enter through your eyes, nose, and mouth.

Does vitamin D protect against COVID-19?

There is no evidence that taking high-dose vitamin D protects you against getting infected with this coronavirus. In addition, if you are infected, it does not prevent a more severe illness.

However, most studies looking at people hospitalized with COVID-19 found that having an abnormally low vitamin D blood level was associated with a worse outcome, including death, compared to patients with a normal blood level. These studies are observational only, meaning they only show a link between low vitamin D levels and a higher risk of severe illness. This does not mean that the low level caused the worse outcome.

The best advice regarding COVID-19 is similar to what is recommended to maintain bone health – making sure you get enough vitamin D to meet standard requirements.

Our bodies make vitamin D when exposed to sunshine. Five to 10 minutes of sun exposure on some or most days of the week to the arms, legs, or back without sunscreen will enable you to make enough of the vitamin. Good food sources of vitamin D include fatty fish (such as tuna, mackerel, and salmon), foods fortified with vitamin D (such as dairy products, soy milk, and cereals), cheese, and egg yolks.

The recommended dietary dose of vitamin D is 600 IU each day for adults 70 and younger, and 800 IU each day for adults over 70. For adults, the risk of harmful effects increases above 4,000 IU per day.

Should I go to the doctor or dentist for nonurgent appointments?

Many medical and dental practices have instituted comprehensive safety measures to help protect you, the doctor and office staff, and other patients. If you feel anxious about visiting in person, call the practice.

Many doctor's offices are increasingly providing telehealth services. This may mean appointments by phone call, or virtual visits using a video chat service. Ask to schedule a telehealth appointment with your doctor for a new or ongoing nonurgent matter. If, after speaking to you, your doctor would like to see you in person, he or she will let you know.

What if your appointments are not urgent but also don't fall into the low-risk category? For example, if you have been advised to have periodic scans after cancer remission, if your doctor sees you regularly to monitor for a condition for which you're at increased risk, or if your treatment varies based on your most recent test results? In these and similar cases, call your doctor for advice.

Should I postpone my elective surgery?

The availability of elective surgeries and procedures throughout the United States is very fluid, and may reflect the number of cases and infection rate in a given area. If COVID-19 cases are rising in your area, it's quite possible that you already have been canceled or rescheduled by the hospital or medical center in which you are scheduled to have the procedure. If not, you should consider postponing any procedure that can wait.

That being said, keep in mind that "elective" is a relative term. For instance, you may not have needed immediate surgery for sciatica caused by a herniated disc. But the pain may be so severe that you would not be able to endure postponing the surgery for weeks or perhaps months. In that case, you and your doctor should make a shared decision about proceeding.

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Visit our Coronavirus Resource Center for more information on coronavirus and COVID-19.