Medically reviewed on July 14, 2020. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
COVID-19 (coronavirus disease 2019) is an infectious disease caused by the novel coronavirus SARS-CoV-2—or severe acute respiratory syndrome coronavirus 2. This new (or novel) coronavirus disease was detected in China in late 2019 and has since spread globally.
But what exactly is this virus?
With the research, news, and numbers changing daily, it’s important to take a closer look at the details of coronavirus to better aid your understanding of the new reality brought on by the pandemic.
Here, we’ll cover aspects of the virus—like its origin, types of transmission, mortality rate, symptoms, coronavirus testing, and prevention.
Many experts believe that the novel coronavirus may have originated in bats. Since the virus transferred to humans in Wuhan, China toward the end of 2019, the virus has spread from person to person around the world.
Coronaviruses are a family of viruses that can infect both humans and animals. The viruses are common in animals like camels and cows, but transmission from animal to humans—which is what occurred with the novel coronavirus—is rare.
Once the novel coronavirus mutated, allowing it to jump from animals to humans, it then spread from person-to-person through respiratory droplets produced by people with the infection (via coughing, sneezing, or talking). The transmission of the infection is similar to how germs spread in the flu or common cold. The infection leads to coronavirus disease 2019, or COVID-19. Many cases of COVID-19 are mild, though some can lead to severe illness and death.
As the virus continues to spread, staying up-to-date with the current state of the global pandemic can prove challenging. Learning more about the virus in terms of region, types of transmission, age, and mortality rate can help you better understand the pandemic’s growth and impact.
To shed more light on how exactly the virus spreads, the World Health Organization (WHO) has described different transmission classifications for transmission. Here is how the WHO summarizes the five classifications of virus transmission.
Community transmission: Evidenced by (1) the inability to relate confirmed cases through chains of transmission for a large number of cases, or (2) by increasing rates of positive test results as determined through sentinel samples (routine systematic testing of respiratory samples from established laboratories).
Local transmission: Indicates locations where the source of infection is within the reporting location.
Imported cases: Indicates locations where all cases have been acquired outside the location of reporting.
Under investigation: Indicates locations where the type of transmission has not been determined for any cases.
Interrupted transmission: Indicates locations where interruption of transmission has been demonstrated.
As the pandemic progresses, more people around the world are dying from COVID-19. The amount of deaths differs depending on the country. When considering how dangerous the novel coronavirus is, two metrics are useful: mortality rate and case-fatality rate.
In this context, mortality rate refers to the number of deaths due to COVID-19 compared to a given size of an overall population—typically 100,000. According to data compiled by Johns Hopkins University, the mortality rate of COVID-19 is about 46.5 in the United States.
The case-fatality rate is the proportion of people with COVID-19 who die due to the condition—and depends on the age and health of the population under consideration, the availability of tests, and the healthcare systems of each country.
For COVID-19, deaths are highest in the elderly and those who have pre-existing health conditions, like diabetes, heart disease, and asthma. The CDC estimates these case-fatality rates for people in the following age ranges:
To track COVID-19 deaths in the United States and across the world over time, see this tracking chart from the New York Times—which is regularly updated to provide up-to-date, reliable measurements of the pandemic’s impact.
Currently the subject of active research, the symptoms of the novel coronavirus are thought to occur from 2 to 14 days after transmission. However, it’s important to note that some people can be asymptomatic and can transmit the infection even when they aren’t experiencing coronavirus symptoms.
Here are the common symptoms (including flu-like symptoms) that have been linked to COVID-19.
Some people also experience:
The symptoms of coronavirus can range from mild to severe depending on the person. It’s estimated that most people—about 80%—recover without needing special treatment. About 15% of people become severely ill and require hospitalization, while 5% become critically ill. For the most up-to-date list of symptoms, please view the CDC website here.
Understanding the available options for COVID-19 testing can help keep you and your loved ones safer during these trying times.
Currently, some people get tested for the novel coronavirus if they are experiencing COVID-19 symptoms or they have had exposure to someone who is infected. If you have a fever and respiratory distress, a healthcare provider may test for the virus in the following way: taking a swab, sending it to the lab for analysis, then waiting for results.
Additionally, there are drive-thru coronavirus testing sites available throughout the country. At these sites, individuals drive to the site, talk to medical personnel, and get on-site testing with a sample taken from the respiratory tract via swab.
The FDA has also authorized some at-home coronavirus tests.
Because there is currently no vaccine for the coronavirus disease, the Centers for Disease Control and Prevention (CDC) recommends following these steps to reduce the risk of infection.
Additionally, coronavirus social distancing helps decrease the spread of this infectious disease among people. This refers to avoiding crowds and mass gatherings, standing six feet away from others, and staying home unless it’s necessary to go out (to get groceries or prescriptions, for example). If you recently returned from a place that’s experiencing a surge in coronavirus infections, it may be best to self-quarantine to make sure you aren’t unknowingly spreading the infection to others.
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