What is the 2019 coronavirus?
In early 2020, a new virus began generating headlines all over the world because of the unprecedented speed of its transmission.
Its origins have been traced to a food market in Wuhan, China, in December 2019. From there, it’s reached countries as distant as the United States and the Philippines.
The virus (officially named SARS-CoV-2) has been responsible for over 100 million infections globally, causing around 2.5 million deaths. The United States is the country most affected.
The disease caused by contracting SARS-CoV-2 is called COVID-19, which stands for coronavirus disease 2019.
Doctors and scientists are learning new things about this virus every day. So far, we know that COVID-19 may not cause any symptoms for some people.
You may carry the virus for 2 days or up to 2 weeksTrusted Source before you develop symptoms.
Some common symptoms that have been specifically linked to COVID-19 include:
- shortness of breath
- a cough that gets more severe over time
Less common symptoms include:
- repeated shaking with chills
- sore throat
- muscle aches and pains
- loss of taste or smell
- a stuffy or runny nose
- gastrointestinal symptoms such as diarrhea, nausea, and vomiting
- discoloration of fingers or toes
- pink eye
However, individuals with COVID-19 may have some, all, or none of the above symptoms.
For instance, fever is often referred to as the most common symptom of COVID-19. However, a July 2020 study of 213 people with mild disease found that only 11.6 percent of them had experienced fever.
Most people with COVID-19 will only have a mild case.
According to the National Institute of Health’s COVID-19 treatment guidelines, people are characterized as having a mild case if they:
- have any of the typical symptoms of COVID-19 (such as cough, fatigue, or loss of taste or smell)
- don’t have shortness of breath or abnormal chest imaging
Mild cases can still have long-lasting effects. People who experience symptoms months after first contracting the virus — and after the virus is no longer detectable in their body — are referred to as long haulers.
According to a February 2021 research letter in JAMA Network Open, approximately one-thirdTrusted Source of people with COVID-19 had persistent symptoms as long as 9 months after infection.
A December 2020 literature review estimated that 17 percent of people with COVID-19 are actually asymptomatic. This means they have no symptoms at all.
Twenty percent of people who have COVID-19 and require any sort of senior care services are asymptomatic. The authors evaluated data from 13 studies to come up with their estimates.
A January 2021 literature review looked at 61 studies and reports about COVID-19. The researchers concluded that:
- At least one-third of all cases are asymptomatic.
- Almost 75 percent of people who are asymptomatic when they receive a positive polymerase chain reaction (PCR) test result will remain asymptomatic. PCR tests include nasal swab tests.
Call emergency medical services if you have or someone you care for has any of the following symptoms:
- trouble breathing
- blue lips or a blue face
- persistent pain or pressure in the chest
- excessive drowsiness
The Centers for Disease Control and Prevention (CDC)Trusted Source is still investigating the full range of symptoms.
COVID-19 versus the flu
The 2019 coronavirus causes more deaths than the seasonal flu.
According to the CDC, an estimated 0.04 to 0.16 percentTrusted Source of people who developed the flu during the 2019–2020 flu season in the United States died by April 4, 2020.
In comparison, about 1.80 percent of those with a confirmed case of COVID-19 in the United States have died as of March 2, 2021.
The flu and COVID-19 share many of the same symptoms. Common flu symptoms include:
- runny or stuffy nose
- sore throat
- body aches
Coronaviruses are zoonotic. This means they first develop in animals before being transmitted to humans.
For the virus to be transmitted from animals to humans, a person has to come into close contact with an animal that has the infection.
Once the virus develops in people, coronaviruses can be transmitted from person to person through respiratory droplets. This is a technical name for the wet stuff that moves through the air when you exhale, cough, sneeze, or talk.
The viral material hangs out in these droplets and can be breathed into the respiratory tract (your windpipe and lungs), where the virus can then lead to an infection.
It’s possible that you could acquire SARS-CoV-2 if you touch your mouth, nose, or eyes after touching a surface or object that has the virus on it. However, this is not thoughtTrusted Source to be the main way that the virus is passed on.
SARS-CoV-2 can also be passed on via airborne transmission of small infectious particles that may linger in the air for minutes to hours.
However, contraction of an infection through close contact with people with SARS-CoV-2 — and their respiratory droplets — is currently thought to be much more common.
The 2019 coronavirus hasn’t been definitively linked to a specific animal.
Researchers believe that the virus may have been passed from bats to another animal — either snakes or pangolins — and then transmitted to humans.
This transmission likely occurred in the open food market in Wuhan.
You’re at high risk for contracting SARS-CoV-2 if you come into contact with someone who’s carrying it, especially if you’ve been exposed to their saliva or been near them when they’ve coughed, sneezed, or talked.
Without taking proper preventive measures, you’re also at high risk if you:
- live with someone who has contracted the virus
- are providing home care for someone who has contracted the virus
- have an intimate partner who has contracted the virus
Older adults and people with certain health conditions have a higher riskTrusted Source for severe complications if they contract the virus. These health conditions include:
- serious heart conditions, such as heart failure, coronary artery disease (CAD), and cardiomyopathies
- chronic kidney disease
- chronic obstructive pulmonary disease (COPD)
- obesity, which occurs in people with a body mass index (BMI) of 30 or higher
- sickle cell anemia
- a weakened immune system from a solid organ transplant
- type 2 diabetes
COVID-19 and pregnancy
Pregnancy also puts you at a higher risk for complications from COVID-19.
The CDCTrusted Source reports that pregnant women are more likely to experience severe COVID-19 illness than nonpregnant women.
For instance, pregnant women entered the intensive care unit (ICU) at nearly three times the rate of nonpregnant women. Mortality rates for pregnant women are also higher.
According to a study from September 2020Trusted Source, women with COVID-19 are also more likely to have a preterm birth than women without COVID-19.
Transmitting the virus from mother to child during pregnancy isn’t likely, but the newborn is able to contract the virus after birth.
How are coronaviruses diagnosed?
COVID-19 can be diagnosed similarly to other conditions caused by viral infections: using a blood, saliva, or tissue sample.
However, most tests use a cotton swab to retrieve a sample from the inside of your nostrils.
Locations that conduct tests include:
- the CDC
- some state health departments
- commercial companies
- certain pharmacies
- clinics and hospitals
- emergency rooms
- community testing centers