What is COVID-19?
Coronavirus disease 2019—better known as COVID-19—is an illness caused by a type of virus called a coronavirus. There are many types of coronavirus, including some that cause the common cold. The coronavirus that causes COVID-19 was first identified in 2019.
The COVID-19 pandemic
Because the virus that causes COVID-19 is new (it is sometimes referred to as novel coronavirus) and very few people have immunity to it, it was able to spread rapidly from person to person, community to community, country to country, and ultimately around the world. The worldwide spread of a disease is known as a pandemic.
From the news reports, it’s easy to believe that COVID-19 is an unprecedented challenge. In fact, there have been several pandemics throughout history, including the bubonic plague (“Black Death”) in the 1300s, the Spanish flu pandemic in 1918, and, more recently, the Ebola outbreak in 2014. Comparing COVID-19 to other pandemics is difficult, as each differs in how contagious the disease is, what strategies can be adopted to contain it, and how quickly measures to treat it can be developed. In regard to this latter point, research toward the development of a COVID-19 vaccine has been undertaken with unprecedented speedand in 2020 the first mRNA-based vaccine was authorized for COVID-19 prevention under Emergency Use Authorization by the FDA. Since then, two other COVID-19 vaccines were authorized or approved for use in the United States to prevent COVID-19.
How COVID-19 spreads
The virus that causes COVID-19 spreads from person to person through respiratory droplets that are shed when an infected person coughs, sneezes, or talks. It is also possible to catch the virus by touching a contaminated surface or object and then touching your mouth, nose, or eyes, though this is believed to be a less common method of getting the disease.
Who is at risk?
One of the unusual features of COVID-19 is that some people who become infected develop mild symptoms—or no symptoms at all—whereas others become severely ill, sometimes requiring hospitalization and in some cases developing life-threatening illness. Based on what is currently known, the people at highest risk of getting severely ill from COVID-19 are older adults and people who have serious underlying medical conditions—especially if the underlying disease is not well controlled. Of particular concern are people with any of the following:
- Chronic lung disease
- Moderate to severe asthma
- Serious heart conditions
- Chronic kidney disease
- Liver disease
- Any conditions that can cause a person to be immunocompromised, including cancer treatment, smoking, bone marrow or organ transplantation, immune deficiencies, prolonged use of corticosteroids or other medications that can weaken the immune system
- Severe obesity (body mass index [BMI] of 40 or higher)
For individuals who develop signs of COVID-19, symptoms appear anywhere from 2 days to 2 weeks after exposure to the virus. A wide range of symptoms has been reported, such as
- Shortness of breath/difficulty breathing
- Muscle/body aches
- Loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
COVID-19 prevention and risk management
The main way to prevent COVID-19 is to get vaccinated. Two mRNA vaccines (Pfizer and Moderna) have been approved by the US FDA for use as a two-dose series for prevention of COVID-19 in individuals 16 (Pfizer) and 18 (Moderna) years of age and older. The Johnson & Johnson (Janssen) replication-incompetent adenovirus type 26 (Ad26) vaccine (JNJ-78436735) is authorized under Emergency Use Authorization to prevent COVID-19 in individuals 18 years of age and older. The Centers for Disease Control and Prevention (CDC) guidance on vaccine and booster schedules, as well as additional boosters for immunocompromised patients (which includes most cancer patients), can be found here. For additional information regarding which vaccines have been approved or are authorized under Emergency Use Authorization and their recommended booster schedule, please visit our FAQ section here.
Additional risk management strategies
Because coronavirus spreads through respiratory droplets, being in close contact with a person who has COVID-19 increases the risk of becoming infected. The risk increases when the close contact includes actions in which respiratory droplets are most readily spread, such as talking, singing, and exercising. Adding to the challenge is that it is often impossible to know who is infected, because it can take up to 2 weeks for an infected person to feel unwell or to show symptoms.
Among the strategies that can help reduce the risk of becoming infected, hand washing (for at least 20 seconds!) may be the most important. The physical action of washing removes contaminants from the hands. Additionally, soap is actually able to break apart several disease-causing germs (including coronavirus), reducing their ability to cause infection. When soap is not available, using hand sanitizer can produce similar benefits (though it is important to use hand sanitizers that contain at least 60% alcohol). Getting in the habit of regular hand-washing—especially after coughing, sneezing, visiting a public place, or touching items that have been recently handled by others—is highly recommended.
Another simple—but, for many, surprisingly difficult!—measure that can help reduce the risk of infection is avoiding touching your face (particularly your eyes, nose, and mouth) with unwashed hands.
Daily cleaning and disinfecting of high-touch surfaces (for example, doorknobs, drawer pulls, light switches, counters, phones, keyboards, toilets, faucets, and sinks) can help minimize the risk of coronavirus spread. The Environmental Protection Agency maintains a list of recommended household disinfectants, which can be found here.
Finally, it is important to remain alert for symptoms like fever, cough, or shortness of breath. This is especially true if you have been outside your home frequently (for example, because of running errands or going to a workplace). If you develop one or more of the symptoms of COVID-19, take your temperature. If symptoms persist or worsen contact your doctor.
Some prevention recommendations are designed to protect others from the possibility of being infected by you (remember: you can have and spread COVID-19 without knowing it). These include covering your mouth and nose with a mask when around others and (of course) covering coughs and sneezes—ideally with a tissue (but the inside of your elbow will do in a pinch). Be sure to throw the tissue in the trash immediately after use (this advice does NOT apply when you use the inside of your elbow).
Two types of test have been developed for COVID-19, a viral test and an antibody test. Viral tests use a sample taken with a swab from deep inside your nose and indicate whether you are currently infected with coronavirus. Results from viral tests are available anywhere from 1 hour to 2 days after the test is performed. Antibody tests cannot tell whether you have an active infection, and instead look for antibodies in a blood sample to tell whether you have previously had COVID-19.
For most people, COVID-19 produces mild illness with symptoms that can be managed from home without the need to visit a medical office. For these individuals, testing is regarded by several authorities as being unnecessary to their care.
Go to COVIDtests.gov to order free testing kits. Every home is eligible to order two sets of four at-home tests.
- Avoid exposure
- Wash hands often
- Cover mouth and nose with face covering
- Cover coughs and sneezes
- Clean and disinfect