COVID-19 is an abbreviation for the novel (or new) coronavirus. ‘CO’ stands for ‘corona,’ ‘VI’ for ‘virus,’ ‘D’ for disease, and ’19’ for ‘2019.’ It is a new disease that has not previously been seen in humans and was first identified in Wuhan China in late 2019, as a cluster of pneumonia of unknown cause.
Coronaviruses are a large family of viruses that are known to cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).
- The virus that causes COVID-19 most commonly spreads between people who are in close contact with one another (within about 6 feet, or 2 arm lengths).
- It spreads through respiratory droplets or small particles, such as those in aerosols, produced when an infected person coughs, sneezes, sings, talks, or breathes.
- These particles can be inhaled into the nose, mouth, airways, and lungs and cause infection.
- Droplets can also land on surfaces and objects and be transferred by touch. A person may get COVID-19 by touching the surface or object that has the virus on it and then touching their own mouth, nose, or eyes. Spread from touching surfaces is not thought to be the main way the virus spreads.
- It is possible that COVID-19 may spread through the droplets and airborne particles that are formed when a person who has COVID-19 coughs, sneezes, sings, talks, or breathes. There is growing evidence that droplets and airborne particles can remain suspended in the air and be breathed in by others, and travel distances beyond 6 feet (for example, during choir practice, in restaurants, or in fitness classes). In general, indoor environments without good ventilation increase this risk.
- COVID-19 seems to be spreading easily and sustainably in the community (“community spread”) in many affected geographic areas. Community spread means people have been infected with the virus in an area, including some who are not sure how or where they became infected.
Learn more about the science about how this virus infects the body and how our body’s immune system reacts by watching this interview with WHO’s technical lead for COVID-19, Dr Maria Van Kerkhove.
Clean your hands often
- Wash your hands often with soap and water for at least 20 seconds especially after you have been in a public place, or after blowing your nose, coughing, or sneezing.
- If soap and water are not readily available, use a hand sanitizer that contains at least 60% alcohol. Cover all surfaces of your hands and rub them together until they feel dry.
- Avoid touching your eyes, nose, and mouth with unwashed hands.
- This simple practice can help reduce respiratory illnesses in the general population by 16-21%.
Wear a mask
- Wear a mask in public settings, like on public and mass transportation, at events and gatherings, and anywhere they will be around other people.
- Masks may help prevent people who have COVID-19 from spreading the virus to others.
- Masks are most likely to reduce the spread of COVID-19 when they are widely used by people in public settings.
- Masks should NOT be worn by children under the age of 2 or anyone who has trouble breathing, is unconscious, incapacitated, or otherwise unable to remove the mask without assistance.
- Masks with exhalation valves or vents should NOT be worn to help prevent the person wearing the mask from spreading COVID-19 to others.
Avoid close contact
- Avoid shaking hands. Greet people with a wave or a nod instead.
- Maintain at least 6 feet distance between yourself and anyone who is coughing or sneezing.
- Put distance between yourself and other people if COVID-19 is spreading in your community. This is especially important for people who are at higher risk of getting very sick.
Stay home if you’re sick
- Stay at home if you begin to feel unwell, even with mild symptoms such as headache and slight runny nose, until you recover. Avoiding contact with others and visits to medical facilities will allow these facilities to operate more effectively and help protect you and others from possible COVID-19 and other viruses.
- If you develop fever, cough and difficulty breathing, seek medical advice promptly as this may be due to a respiratory infection or other serious condition. Call in advance and tell your provider of any recent travel or contact with travelers.
Cover coughs and sneezes
- Cover your mouth and nose with a tissue when you cough or sneeze or use the inside of your elbow.
- Throw used tissues in the trash.
- Immediately wash your hands with soap and water for at least 20 seconds. If soap and water are not readily available, clean your hands with a hand sanitizer that contains at least 60% alcohol.
Clean and disinfect
- Clean and disinfect frequently touched surfaces daily. This includes tables, doorknobs, light switches, countertops, handles, desks, phones, keyboards, toilets, faucets, and sinks.
- If surfaces are dirty, clean them. Use detergent or soap and water prior to disinfection.
- COVID-19 vaccines are effective at preventing COVID-19 disease, especially severe illness and death.
- COVID-19 vaccines reduce the risk of people spreading COVID-19.
- Even if you’re vaccinated, you should still watch out for symptoms of COVID-19, especially if you’ve been around someone who is sick. If you have symptoms of COVID-19, you should get tested and stay home and away from others.
Data regarding the real-world effectiveness of community masking are limited to observational and epidemiological studies.
- An investigation of a high-exposure event, in which 2 symptomatically ill hair stylists interacted for an average of 15 minutes with each of 139 clients during an 8-day period, found that none of the 67 clients who subsequently consented to an interview and testing developed infection. The stylists and all clients universally wore masks in the salon as required by local ordinance and company policy at the time.
- In a study of 124 Beijing households with > 1 laboratory-confirmed case of SARS-CoV-2 infection, mask use by the index patient and family contacts before the index patient developed symptoms reduced secondary transmission within the households by 79%.
- A retrospective case-control study from Thailand documented that, among more than 1,000 persons interviewed as part of contact tracing investigations, those who reported having always worn a mask during high-risk exposures experienced a greater than 70% reduced risk of acquiring infection compared with persons who did not wear masks under these circumstances.
- A study of an outbreak aboard the USS Theodore Roosevelt, an environment notable for congregate living quarters and close working environments, found that use of face coverings on-board was associated with a 70% reduced risk.
- Investigations involving infected passengers aboard flights longer than 10 hours strongly suggest that masking prevented in-flight transmissions, as demonstrated by the absence of infection developing in other passengers and crew in the 14 days following exposure.
- Several other studies have confirmed the benefit of universal masking in community level analyses: in a hospital system, a German city, Arizona, a panel of 15 other U.S. states and Washington, D.C., as well as both Canada and the U.S. nationally.
Each analysis demonstrated that, following directives for universal masking, new infections fell significantly.
Adults of any age with certain underlying medical conditions are at increased risk for severe illness from the virus that causes COVID-19. Severe illness from COVID-19 is defined as hospitalization, admission to the ICU, intubation or mechanical ventilation, or death.
Adults of any age with the following conditions are at increased risk of severe illness from the virus that causes COVID-19:
- Chronic kidney disease
- COPD (chronic obstructive pulmonary disease)
- Heart conditions, such as heart failure, coronary artery disease, or cardiomyopathies
- Immunocompromised state (weakened immune system) from solid organ transplant
- Obesity (body mass index [BMI] of 30 kg/m2 or higher but < 40 kg/m2)
- Severe Obesity (BMI ≥ 40 kg/m2)
- Sickle cell disease
- Type 2 diabetes mellitus
COVID-19 is a new disease. Currently there are limited data and information about the impact of many underlying medical conditions and whether they increase the risk for severe illness from COVID-19. Based on what we know at this time, adults of any age with the following conditions might be at an increased risk for severe illness from the virus that causes COVID-19:
- Asthma (moderate-to-severe)
- Cerebrovascular disease (affects blood vessels and blood supply to the brain)
- Cystic fibrosis
- Hypertension or high blood pressure
- Immunocompromised state (weakened immune system) from blood or bone marrow transplant, immune deficiencies, HIV, use of corticosteroids, or use of other immune weakening medicines
- Neurologic conditions, such as dementia
- Liver disease
- Overweight (BMI > 25 kg/m2, but < 30 kg/m2)
- Pulmonary fibrosis (having damaged or scarred lung tissues)
- Thalassemia (a type of blood disorder)
- Type 1 diabetes mellitus
People with COVID-19 have had a wide range of symptoms reported – ranging from mild symptoms to severe illness. Symptoms may appear 2-14 days after exposure to the virus. People with these symptoms may have COVID-19:
- Fever or chills
- Shortness of breath or difficulty breathing
- Muscle or body aches
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
This list does not include all possible symptoms.
Influenza (flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by infection with a coronavirus first identified in 2019, and flu is caused by infection with influenza viruses.
COVID-19 seems to spread more easily than flu. However, as more people become fully vaccinated against COVID-19, the spread of the virus that causes COVID-19 should slow down. More information is available about COVID-19 vaccines and how well they work.
Compared to flu, COVID-19 can cause more serious illnesses in some people. COVID-19 can also take longer before people show symptoms and people can be contagious for longer. More information about differences between flu and COVID-19 is available in the different sections below.
Because some of the symptoms of flu, COVID-19, and other respiratory illnesses are similar, the difference between them cannot be made based on symptoms alone. Testing is needed to tell what the illness is and to confirm a diagnosis. People can be infected with both flu and the virus that causes COVID-19 at the same time and have symptoms of both influenza and COVID-19.
While more is learned every day about COVID-19 and the virus that causes it, there are still things, such as post-COVID conditions, that are unknown. This page compares COVID-19 and flu, given the best available information to date.
Stay home except to get medical care
- Stay home. Most people with COVID-19 have mild illness and can recover at home without medical care. Do not leave your home, except to get medical care. Do not visit public areas.
- Take care of yourself. Get rest and stay hydrated. Take over-the-counter medicines, such as acetaminophen, to help you feel better.
- Stay in touch with your doctor. Call before you get medical care. Be sure to get care if you have trouble breathing, or have any other emergency warning signs, or if you think it is an emergency.
- Avoid public transportation, ride-sharing, or taxis.
Separate yourself from other people
- As much as possible, stay in a specific room and away from other people and pets in your home. If possible, you should use a separate bathroom. If you need to be around other people or animals in or outside of the home, wear a mask.
- Tell your close contacts that they may have been exposed to COVID-19. An infected person can spread COVID-19 starting 48 hours (or 2 days) before the person has any symptoms or tests positive. By letting your close contacts know they may have been exposed to COVID-19, you are helping to protect everyone.
- Additional guidance is available for those living in close quarters and shared housing.
- See COVID-19 and Animals if you have questions about pets.
- If you are diagnosed with COVID-19, someone from the health department may call you. Answer the call to slow the spread.
Monitor your symptoms
- Symptoms of COVID-19 include fever, cough, or other symptoms listed above.
- Follow care instructions from your healthcare provider and local health department. Your local health authorities may give instructions on checking your symptoms and reporting information.
Cover your coughs and sneezes
- Cover your mouth and nose with a tissue when you cough or sneeze.
- Throw away used tissues in a lined trash can.
- Immediately wash your hands with soap and water for at least 20 seconds. If soap and water are not available, clean your hands with an alcohol-based hand sanitizer that contains at least 60% alcohol.
Clean your hands often
- Wash your hands often with soap and water for at least 20 seconds. This is especially important after blowing your nose, coughing, or sneezing; going to the bathroom; and before eating or preparing food.
- Use hand sanitizer if soap and water are not 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.
- Soap and water are the best option, especially if hands are visibly dirty.
- Avoid touching your eyes, nose, and mouth with unwashed hands.
Avoid sharing personal household items
- Do not share dishes, drinking glasses, cups, eating utensils, towels, or bedding with other people in your home.
- Wash these items thoroughly after using them with soap and water or put in the dishwasher.
Clean all “high-touch” surfaces everyday
- Clean and disinfect high-touch surfaces in your “sick room” and bathroom; wear disposable gloves. Let someone else clean and disinfect surfaces in common areas, but you should clean your bedroom and bathroom, if possible.
- High-touch surfaces include phones, remote controls, counters, tabletops, doorknobs, bathroom fixtures, toilets, keyboards, tablets, and bedside tables.
- If a caregiver or other person needs to clean and disinfect a sick person’s bedroom or bathroom, they should do so on an as-needed basis. The caregiver/other person should wear a mask and disposable gloves prior to cleaning. They should wait as long as possible after the person who is sick has used the bathroom before coming in to clean and use the bathroom.
- Clean and disinfect areas that may have blood, stool, or body fluids on them.
- Use household cleaners and disinfectants. Clean the area or item with soap and water or another detergent if it is dirty. Then, use a household disinfectant.
- Be sure to follow the instructions on the label to ensure safe and effective use of the product. Many products recommend keeping the surface wet for several minutes to ensure germs are killed. Many also recommend precautions such as wearing gloves and making sure you have good ventilation during use of the product.
- Most EPA-registered household disinfectants should be effective.
If someone is showing any of these signs, seek emergency medical care immediately:
- Trouble breathing
- Persistent pain or pressure in the chest
- New confusion
- Inability to wake or stay awake
- Bluish lips or face
This list is not all possible symptoms. Please call your medical provider for any other symptoms that are severe or concerning to you.
Call 911 or call ahead to your local emergency facility: Notify the operator that you are seeking care for someone who has or may have COVID-19.
Call ahead before visiting your doctor
- Call ahead. Many medical visits for routine care are being postponed or done by phone or telemedicine.
- If you have a medical appointment that cannot be postponed, call your doctor’s office, and tell them you have or may have COVID-19. This will help the office protect themselves and other patients.
If you are sick, wear a mask over your nose and mouth
- You should wear a mask over your nose and mouth if you must be around other people or animals, including pets (even at home).
- You don’t need to wear the mask if you are alone. If you can’t put on a mask (because of trouble breathing, for example), cover your coughs and sneezes in some other way. Try to stay at least 6 feet away from other people. This will help protect the people around you.
- Masks should not be placed on young children under age 2 years, anyone who has trouble breathing, or anyone who is not able to remove the mask without help.
Note: During the COVID-19 pandemic, medical grade masks are reserved for healthcare workers and some first responders.
No, if a nurse tests positive they are to quarantine at home. If symptomatic they stay home as well. It they are tested, they stay home until the test results come back.