5 Things Everyone Should Know About the Coronavirus Outbreak

As disease spreads in the U.S., precautions are critical

Pipette adding fluid to one of several test tubes, possibly to test for COVID-19

While news about the coronavirus has been evolving, doctors says the best advice is to follow public health directives and take care of yourself.

Credit: Getty Images

[Originally published: January 23, 2020. Updated: March 31, 2020.] 

COVID-19, the respiratory disease caused by the new coronavirus (SARS-CoV-2), continues to spread around the world and in the United States. Many countries are asking people to stay home and self-quarantine. In early March, the World Health Organization (WHO) officially called the disease a pandemic—a disease outbreak occurring over a wide geographic area and affecting an exceptionally high proportion of the population. The U.S., which declared a national emergency in mid-March, now is reported to have the most detected cases in the world.

According to the WHO, globally there have been more than 750,000 confirmed cases of people with COVID-19 and more than 35,000 people have died from the disease—a death toll that has far surpassed that of the severe acute respiratory syndrome (SARS) epidemic that occurred in 2002 and 2003. (While some news sources report different numbers, the WHO provides official counts of confirmed cases once a day.)

In the U.S., numbers are changing daily, as different parts of the country experience different levels of COVID-19 activity. All 50 states have reported cases, with large clusters in certain areas, including New York City (the CDC is providing a daily update of the numbers in the U.S., but says data provided by state public health departments should be considered the most up to date). The CDC expects most people in the U.S. will be exposed to the virus in the coming months (such widespread transmission could mean large numbers of people needing medical care at the same time—which is why an important strategy is to try to delay the spread).  

Meanwhile, people in the U.S. are facing significant disruptions, including unprecedented cancellations, postponements, and shutdowns of everything from schools to religious services as reports of community transmission grow. States and cities across the U.S. are asking or ordering people to stay home. President Trump has activated the National Guard to assist California, New York, and Washington, which have been hit especially hard. 

SARS-CoV-2 is a virus that scientists haven’t seen before. Like other viruses—including Ebola (a deadly infectious disease that originated in Africa) and influenza—it is believed to have started in animals and spread to humans. (Specifically, SARS-CoV-2 is a betacoronavirus, which means it had its origins in bats.) Animal-to-person spread was suspected after the initial outbreak in December among people who had a link to a large seafood and live animal market in Wuhan, China. 

Scientists and public health officials are working to find answers to key questions about the severity of the disease and its transmission.

Below is a list of five things you should know about the coronavirus outbreak.

1. Information about COVID-19 is still evolving

The name coronavirus refers to spikes seen (under a microscope) on the surface of the virus (corona is the Latin word for crown). Coronaviruses cause respiratory tract illnesses that range from the common cold to such potentially deadly illnesses as SARS, also first identified in China, and Middle East Respiratory Syndrome (MERS). According to the CDC, this is the first pandemic known to be caused by the emergence of a new coronavirus—novel influenza viruses caused four pandemics in the last century (which is why the response to COVID-19 is being adapted from existing guidance developed in anticipation of an influenza pandemic). 

According to the CDC, reported illnesses have ranged from very mild (with no reported symptoms in some cases) to severe, including illness resulting in death. Older people and people of all ages with severe underlying health conditions seem to be at higher risk of developing serious illness. But doctors still don’t have a complete clinical picture of COVID-19, as evidenced by a recent CDC report noting that 20% of those who have been hospitalized for the disease in the U.S. are younger adults (between 20 and 44 years old).

“I think there are two main questions,” says Richard Martinello, MD, a Yale Medicine infectious diseases specialist and medical director of infection prevention at Yale New Haven Health. “First, we need to know how this virus is transmitted between people so we can be more precise in our efforts to stop its spread. Second, there needs to be a better understanding of the pathogenesis of the infection and resulting inflammatory response, so that knowledge can drive the development of therapeutic and preventive medications.”

There is also more to learn about how COVID-19 spreads—and how contagious it is. “Data is needed not only to better understand when those who become ill shed the virus, but also which body fluids contain the virus and how those may contaminate surfaces and even the air surrounding them,” says Dr. Martinello. 

More information is becoming available. The American Academy of Otolaryngology has called for adding anosmia (loss of smell) to a list of screening tools for COVID-19, and while evidence is still preliminary, the WHO says it is probing a possible link between the disease and the symptom. 

Meanwhile, a letter to the editor published in The New England Journal of Medicine  in mid-March showed the virus that causes COVID-19 may be stable for several hours in aerosols and for several hours to days on surfaces. Scientists from National Institutes of Health (NIH), CDC, UCLA, and Princeton University who participated in the analysis found SARS-CoV-2 was detectable in aerosols for up to three hours, copper up to four hours, cardboard up to 24 hours, and plastic and stainless steel up to two to three days. While there is much to learn, scientists involved in the analysis observed that emerging evidence suggests people who are infected might be spreading the virus without recognizing, or prior to recognizing, symptoms, according to the NIH.

But Yale Medicine Infectious Diseases specialist Jaimie Meyer, MD, MS, notes, “A lot of times people will make basic science observations in the research lab, but it takes time for us to figure out how clinically relevant it is. So, we don’t know yet know what this study means for transmissibility. Until we understand more about the granular details of how SARS-CoV-2 passes from person to person, public health dictates that people maintain social distancing, wash hands, and frequently disinfect high-touch surfaces."

2. Experts are taking steps to address COVID-19 and reduce infections

Proper testing that is made widely available will be important in understanding how the disease is transmitted and the true infection and mortality rates. In addition to COVID-19 testing being done by the CDC in the U.S., state and local public health labs in all 50 states and the District of Colombia are currently using the CDC's COVID-19 diagnostic tests, although the number of available tests is limited at this point. Until there can be comprehensive testing for COVID-19, it's difficult to know how many cases have not been identified. "Testing is still very limited in Connecticut," says Yale Medicine infectious disease specialist Manisha Juthani, MD. "This will hopefully change, but testing will have to be prioritized for those that are the sickest."

Meanwhile, doctors in the U.S. are keeping a close eye on the new virus. “With the new virus in a culture dish, they are looking at the biology and working to make drugs to treat it,” says Yale Medicine infectious diseases specialist Joseph Vinetz, MD. There is also a great deal of effort underway to assess drugs in development (and some medications currently available) to determine if they are beneficial for treating patients infected with COVID-19, adds Dr. Martinello.

“There is a clinical trial evaluating different potential therapeutics at the University of Nebraska Medical Center in Omaha, the first of which is remdesivir,” says Dr. Juthani. Remdesivir is an antiviral treatment that, according to the National Institutes of Health, was previously tested in humans with Ebola virus disease and has shown promise in animal models for treating MERS and SARS.

China currently is testing a number of therapeutics in clinical trials. In mid-March, the National Institute of Allergy and Infectious Diseases (NIAID) announced the first testing in humans of an experimental vaccine called mRNA-1273 developed by NIAID scientists and their collaborators at the biotechnology company Moderna, Inc. The first trial is testing the vaccine on 45 healthy adult volunteers, ages 18 to 55, over approximately 6 weeks. But it could take at least a year before all the necessary phases of the investigation can be completed to ensure the vaccine is safe and effective enough to make publicly available.

3. If you feel ill, here's what you can do

So far, information shows the severity of COVID-19 infection ranges from very mild (sometimes with no reported symptoms at all) to severe to the point of requiring hospitalization. Symptoms can appear anywhere between 2 to 14 days after exposure, and may include: 

  • Fever
  • Cough
  • Difficulty breathing 

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. 

Seek medical attention immediately if you experience emergency warning signs, including difficulty breathing or shortness of breath, persistent pain or pressure in the chest, new confusion or ability to arouse, or bluish lips or face. This list is not inclusive, so consult your medical provider if you notice other concerning symptoms. 

If you have traveled to an affected country, taken a cruise in the past 14 days, or been exposed to another person with COVID-19, health officials will give you instructions on limiting your activities and movement for up to 14 days to help keep the virus from spreading. “If you are recovering well from a respiratory illness that you think might be COVID-19, we encourage you to call your doctor to see if you should be treated for influenza and remain at home as you continue to recover," says Dr. Juthani. 

Patients and members of the community can call the Yale Medicine/Yale New Haven Health Call Center at  COVID-19 hotline of Yale New Haven Health at 203-688-1700 (toll-free, 833-484-1200) if they have questions. Health officials recognize that the outbreak has been stressful for everyone. 

4. There are things you can do to protect yourself

As with a cold, a flu vaccine won’t protect people from developing COVID-19. However, while doctors learn more about transmission, Dr. Vinetz says, “The best thing you can do at this point is take care of yourself the way you would to prevent yourself from getting the flu. You know you can get the flu when people sneeze and cough on you, or when you touch a doorknob. Washing hands—especially before eating and touching your face, and after going to the bathroom—and avoiding other people who have flu-like symptoms are the best strategies at this point.”

The CDC also recommends the following preventive actions:

  • 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.
  • 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.
  • It may also be important to create a household plan of action. 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 household plan that includes ways to care for loved ones if they get sick. This includes planning a way to separate a family member who gets sick from those who are healthy, if the need arises.

While everyone should take precautions, the highest risk group appears to be adults over 60 years old (the risk seems to gradually increase with age starting at age 40, according to the WHO) and those with chronic conditions (such as diabetes, heart disease, and lung disease). People in these categories especially should avoid crowded places and stock up on household items, groceries, medications, and other supplies in case they need to stay home for an extended period.  

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)

5. Precautions remain extremely important

Since threats like COVID-19 can lead to the circulation of misinformation, it’s important to trust information only from reputable health organizations and government 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,” Dr. Martinello says. Because knowledge about the new virus is evolving rapidly, you can expect recommendations to change frequently.

State and local authorities are making a variety of recommendations to slow the spread of the virus in the community. Guidelines from the White House called "15 Days to Slow the Spread" stress avoiding social gatherings of more than 10 people; using drive-thru, pick-up, or delivery options instead of eating in restaurants; avoiding discretionary travel or shopping; and staying away from nursing homes and long-term care facilities (since the elderly are at especially high risk for serious complications if they get the virus).

Many experts are also recommending that everyone practice voluntary "social distancing." 

Guidelines are evolving as doctors learn more

While no one knows for sure how the situation will progress around COVID-19, studies of influenza have shown that pandemics begin with an “investigation” phase, followed by “recognition,” “initiation,” and “acceleration” phases, according to the CDC. The peak of illnesses occurs at the end of the acceleration phase, and that is followed by deceleration, during which there is a decrease in illnesses. Different parts of the country can be in different phases of the pandemic, and the length of each phase can vary depending, in part, on the public health response.

Efforts to reduce the impact of the disease are especially important in the absence of a vaccine or treatments, and officials are approaching this in a variety of ways. This has included major restrictions on travel, along with recommendations to postpone cruise ship travel plans. Anyone who must travel should first check the CDC's latest travel advisories.

The CDC also advises people who are traveling in the U.S. to practice precautions, since they may be at higher risk of exposure if they visit an area that is experiencing community spread of COVID-19. 

Meanwhile, Yale Medicine doctors advise anyone who has concerns about COVID-19 exposure or symptoms to call their primary care doctor for instructions. Doctors at Yale Medicine and Yale New Haven Health also are encouraging all patients to sign up for MyChart, a secure online portal that allows patients to manage and receive information about their health, and enables telehealth visits (by phone or video), which is how Yale Medicine specialists are delivering most care not related to COVID-19.

Public health authorities strongly advise everyone to talk to their doctor if they think they are at risk for the flu and haven't gotten a flu shot this season. Dr. Juthani says that in addition to preventing or mitigating the severity of flu, the vaccine will simplify the evaluation of patients with flu-like symptoms if potential cases of COVID-19 surface in the community. Influenza activity typically peaks between December and February, although activity can last as late as May, so if you have flu symptoms, you should call your doctor.


Click here to visit the Yale Medicine COVID-19 resource page.