[Originally published: Jan. 29, 2020. Updated: May 20, 2022]
Note: Information in this article was accurate at the time of original publication. Because information about COVID-19 changes rapidly, we encourage you to visit the websites of the Centers for Disease Control & Prevention (CDC), World Health Organization (WHO), and your state and local government for the latest information.
COVID-19 upended daily life in the United States as SARS-CoV-2, the virus spreading the disease, caused surges in infections across the country. After more than a year of adjusting to strict guidelines, many Americans got vaccines and started to resume a more normal life. But many more remain at risk until they get vaccinated, and experts are still tracking the emergence of virus variants that could pose new threats.
In the U.S., three vaccines are being administered (from Pfizer-BioNTech, Moderna, and Johnson & Johnson), and the Centers for Disease Control (CDC) endorses a clinical preference for the Pfizer and Moderna shots, based on the latest evidence of vaccine effectiveness, safety and rare adverse events. The CDC says everyone ages 5 and older should also get a booster shot.
Now that the highly contagious Omicron and its subvariants are the dominant variant in the U.S., worry continues as cases rise and fall throughout 2022.
Scientists and public health officials continue to work as quickly as possible to find more answers to key questions about how the disease affects the body and why some cases are more severe than others, and identify the best treatments for COVID-19.
Below is a list of five things you should know about the coronavirus.
1. What we know about COVID-19 has changed rapidly
The number of people infected by the disease continues to change every day. While the impact of the disease varies by location, there are more than 519.5 million confirmed cases of people with COVID-19 around the globe and more than 6.2 million people have died from the disease, according to the WHO. (While some news sources report different numbers, the WHO provides official counts of confirmed cases once a day.)
The CDC provides a rough picture of the outbreak in the U.S. here, currently putting the total confirmed and probable cases at more than 81.5 million and estimating more than 994,000 deaths. The CDC also reports that 82.6% of adults and children ages 5 and older in the U.S. have had at least one vaccination shot and 70.4% of people in the same age group are fully vaccinated (meaning they have received two doses of the Pfizer or Moderna vaccine, or one dose of Johnson & Johnson’s single shot inoculation).
According to the CDC, reported COVID-19 illnesses have ranged from mild (with no reported symptoms in some cases) to severe to the point of requiring hospitalization, intensive care, and/or a ventilator. COVID-19 illnesses can also lead to death. While people of all ages can be infected, the risk for complications increases with age. People living in a nursing home or long-term care facility, and people of all ages with underlying health conditions (such as diabetes, heart disease, lung disease, and obesity) also are at high risk for serious illness.
COVID-19 also has led to serious illness and even death in younger and middle-aged adults who are otherwise healthy. While most children have mild or no symptoms, some have gotten severely ill. As with adults, even if children have no symptoms, they can spread the virus to others.
While most people recover in a matter of weeks, some adults and children experience post-COVID conditions known as "long COVID," which can appear weeks after infection and can include a range of new, returning, or ongoing health problems. These range from fatigue and muscle pain to—in extreme cases—autoimmune conditions and multisystem inflammatory syndrome, a condition where different body parts become swollen. Even people who had mild symptoms or no symptoms at all when they were infected can have post-COVID conditions.
It helps that experts have a better idea now about how the virus is transmitted from one person to another. According to the CDC, COVID-19 is spread in three ways:
- By breathing in air when close to an infected person who is exhaling small droplets and particles that contain the virus;
- Having these droplets and particles land on the eyes, nose, or mouth:
- Or touching the eyes, nose, and mouth with hands that have the virus on them.
In general, the CDC says, the more closely you interact with others and the longer that interaction, the higher the risk of COVID-19 spread, and indoor spaces are more risky than outdoor spaces.
In addition, droplets can land on surfaces, and people may get the virus by touching those surfaces, although, according to the CDC, this is not thought to be the main way COVID-19 spreads.
Viruses are known to change constantly. Scientists are working to learn more about these variants and their spread, and how they could affect the severity of illness in people who get the virus. They have been studying Omicron closely since it surfaced. There is also more to learn about how long the vaccines can protect people.
2. Strict measures are critical for slowing the spread of the disease
Near the beginning of the pandemic, public health experts directed their efforts toward "flattening the curve." If you mapped the number of COVID-19 cases over time, the expectation was that it would peak at some point—on a graph this peak would mirror a surge in patients (which could overwhelm hospitals and health care providers). Flattening the curve would mean there would be fewer patients during that period, and hospitals would be better able to manage the demands of patients who are sick with COVID-19 and other illnesses.
But toward the end of 2020, a steady increase in cases in the U.S. was becoming what some described as a third wave (or, maybe, a third peak), if not a continuation of a single wave that started in the spring and never stopped. As cold weather drove more people indoors, many government officials around the country halted some of the plans they had to reopen, implementing new restrictions that included curfews, limiting the number of people who could gather indoors, and establishing mask mandates.
The idea is that if enough people are protected either because they have had the disease or they’ve been vaccinated, herd immunity will start to protect even those people who have not been infected. While the timeline for herd (or population) immunity is still uncertain, researchers believe we will likely not reach it any time soon. As was seen with the highly contagious Delta variant, which became the predominant virus during the summer of 2021, experts are now concerned that outbreaks of the Omicron variant—the current predominant virus—could affect overall progress.
3. Infection prevention is key
Vaccination remains a key strategy for avoiding infection. All adults are eligible to be vaccinated, as well teenagers and children as young as 5 for the Pfizer-BioNTech vaccine. While three vaccines are available, the CDC expresses a preference for the Pfizer-BioNTech or Moderna vaccines. It also says everyone who is eligible should get a booster shot five months after completing a primary Pfizer-BioNTech or Moderna series, or two months after the J&J single-shot—people ages 12 and older who are immunocompromised and adults over 50 should also get a second booster shot. Children ages 5 and older must get the Pfizer-BioNTech booster; anyone over 18 can choose any one of the three vaccines, regardless of which vaccine they had for their primary vaccination.
A weakened immune system can make you more likely to develop severe illness from COVID-19. For this reason, some adults and children with immunocompromising conditions may be advised to get a third dose of Pfizer-BioNTech or Moderna to complete their primary series (this is not to be confused with the booster dose, which is additional), and a second booster shot. More information on how to stay fully protected is available on the CDC website.
Information on where to get the vaccine is available on Vaccines.gov.
There are other things you can and should continue to do to protect yourself. The CDC recommends the following preventive actions for anyone who has not been vaccinated:
- Wash hands with soap and water for at least 20 seconds. Dry them thoroughly with an air dryer or clean towel. If soap isn’t available, use a hand sanitizer with at least 60% alcohol.
- Stay home if you’re sick.
- Avoid touching nose, eyes, and mouth. Use a tissue to cover a cough or sneeze, then dispose of it in the trash.
- Wear a mask that fits snuggly over your nose, mouth and chin.The CDC says different types of masks and respirators can provide different levels of protection than others, depending on the mask and how it is used. It says loosely woven cloth masks provide the least protection, while well-fitting disposable surgical masks and KN95s offer more protection, and well-fitting National Institute for Occupational Safety and Health (NIOSH)-approved respirators (including N95s) offer the highest level of protection. Overall, the agency recommends that you wear the most protective mask you can that fits well and that you will wear consistently. The CDC provides a guide to masks and guidance for choosing a mask on its website.
Keep about 6 feet between yourself and others. The CDC advises avoiding nonessential indoor spaces and crowded outdoor settings. A mask is not a substitute for social distancing.
- Use a household wipe or spray to disinfect doorknobs, light switches, desks, keyboards, sinks, toilets, cell phones, and other objects and surfaces that are frequently touched.
- Create a household plan of action in case someone in your house gets sick with COVID-19. You should talk with people who need to be included in your plan, plan ways to care for those who might be at greater risk for serious complications, get to know your neighbors, and make sure you and your family have a plan for caring for a sick person. This includes planning a way to separate a family member who gets sick from those who are healthy, if the need arises.
- Plan visits with friends and family outdoors if possible. If you must visit them indoors, make sure the space can accommodate social distancing, and open doors and windows to make sure the space is well-ventilated. The CDC also recommends avoiding travel.
If you are fully vaccinated:
- You should wear a mask regardless of local transmission if you have a weakened immune system or, because of your age or an underlying medical condition, you are at increased risk for severe diseases, or if someone in your household is in that situation or is unvaccinated, according to the CDC.
If you are pregnant:
- In August 2021, the CDC urged pregnant people to get vaccinated. Pregnant people are at an increased risk for severe illness from COVID-19 when compared to those who aren’t pregnant, as well as for increased risk for preterm birth (delivering the baby earlier than 37 weeks), and possibly other poor pregnancy outcomes, according to the CDC.
However, local rules may vary, and fully vaccinated people must follow local business and workplace guidance, and take precautions as directed in health care settings.
4. Experts are working rapidly to find solutions
In the U.S., widely available testing is important in understanding the true infection and mortality rates of COVID-19. While health providers across the country are using a variety of tests—and still learning about the most accurate approach—two kinds of tests are important to know about: viral tests help diagnose a current infection and antibody tests can tell if you’ve had a previous one. Health care providers and state and local health departments make determinations about who should be tested.
Meanwhile, scientists continue to study the virus closely. In addition to the vaccines that are now available in the U.S. and other countries, multiple vaccines are being studied. What’s more, companies that have produced vaccines are looking at whether they might need to tweak them to better protect against new mutations of the virus, as scientists continue to study how those mutations are affecting the rate of contagion and their potential for causing severe disease.
Doctors are also refining their approaches to treating COVID-19. The antiviral drug remdesivir, is the first and only drug to receive full FDA approval after some evidence showed it could reduce the number of days spent in the hospital. Other COVID-19 treatments, including Paxlovid, an antiviral pill, are also available.
5. If you feel ill, here's what you should do
Everyone should watch out for symptoms of COVID-19, whether or not they are fully vaccinated. Anyone who thinks they have been exposed should get tested and stay home and away from others. Symptoms can appear anywhere between 2 to 14 days after exposure. According to the CDC, symptoms may include:
- 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. The CDC will continue to update its symptoms list as it learns more about COVID-19.
You should call your medical provider for advice if you experience these symptoms, especially if you have been in close contact with a person known to have COVID-19 or live in an area with ongoing spread of the disease. The CDC has a Coronavirus Self-Checker that may help you determine whether you should seek help.
Most people will have a mild illness and can recover at home without medical care. Seek medical attention immediately if you or a loved one is at home and experiencing emergency warning signs, including difficulty breathing, persistent pain or pressure in the chest, new confusion, inability to stay awake, or bluish lips or face. This list is not inclusive, so consult your medical provider if you notice other concerning symptoms.
Be aware of the information and resources that are available to you
Because knowledge about the new virus is evolving rapidly, you can expect information and recommendations to change frequently. Threats like COVID-19 can lead to the circulation of misinformation, so it’s important to trust information only from reputable health organizations and sources such as the CDC and the WHO. “The public health infrastructure in the U.S. is a critical resource for leading the federal, state, and local response,” says Richard Martinello, MD, a Yale Medicine infectious diseases expert.
The pandemic has been stressful for everyone, and this can have serious impacts on mental health. If you, or someone you care about, are feeling overwhelmed with emotions like sadness, depression, or anxiety, or feel like you want to harm yourself or others, call 911, or the Substance Abuse and Mental Health Administration’s Disaster Distress Helpline: 1-800-985-5990 or text TalkWithUs to 66746. (TTY 1-800-846-8517). You can call the National Domestic Violence Hotline at 1-800-799-7233 (TTY: 1-800-787-3224.)
Note: Information provided in Yale Medicine articles is for general informational purposes only. No content in the articles should ever be used as a substitute for medical advice from your doctor or other qualified clinician. Always seek the individual advice of your health care provider with any questions you have regarding a medical condition.