There are hundreds of coronaviruses, most of which circulate among animals including pigs, camels, bats and cats.
Coronaviruses are named for the crown-like spikes on their surface. There are four main sub-groupings of coronaviruses, known as alpha, beta, gamma, and delta.
Human coronaviruses were first identified in the mid-1960s. The seven coronaviruses that can infect people are:
229E (alpha coronavirus) NL63 (alpha coronavirus) OC43 (beta coronavirus) HKU1 (beta coronavirus)
- MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS)
- SARS-CoV (the beta coronavirus that causes severe acute respiratory syndrome, or SARS)
- SARS-CoV-2 (the novel coronavirus that causes coronavirus disease 2019, or COVID-19)
Animal to human transmission
Sometimes those viruses jump to humans—called a spillover event—and can cause disease.
About seven coronaviruses are known to cause human disease, four of which are mild: viruses 229E, OC43, NL63 and HKU1.
Three of the coronaviruses can have more serious outcomes in people, and those diseases are SARS (severe acute respiratory syndrome) which emerged in late 2002 and disappeared by 2004; MERS (Middle East respiratory syndrome), which emerged in 2012 and remains in circulation in camels; and COVID-19, which emerged in December 2019 from China and a global effort is under way to contain its spread.
Cause of COVID-19
COVID-19 is caused by the coronavirus known as SARS-CoV-2.
- runny nose
- sore throat
- general feeling of being unwell
Human coronaviruses can sometimes cause lower-respiratory tract illnesses, such as pneumonia or bronchitis. This is more common in people with cardiopulmonary disease, people with weakened immune systems, infants, and older adults.
Common human coronaviruses usually spread from an infected person to others through:
- the air by coughing and sneezing
- close personal contact, like touching or shaking hands
- touching an object or surface with the virus on it, then touching your mouth, nose, or eyes before washing your hands
In the United States, people usually get infected with common human coronaviruses in the fall and winter, but you can get infected at any time of the year. Young children are most likely to get infected, but people can have multiple infections in their lifetime.
- Protect yourself from getting sick wash your hands often with soap and water for at least 20 seconds
- avoid touching your eyes, nose, or mouth with unwashed hands
- avoid close contact with people who are sick
- Protect others when you are sick stay home while you are sick
- avoid close contact with others
- cover your mouth and nose when coughing or sneezing
- clean and disinfect objects and surfaces
Sometimes, respiratory secretions are tested to figure out which specific germ is causing your symptoms.
If you are found to be infected with a common coronavirus (229E, NL63, OC43, and HKU1), that does not mean you are infected with the 2019 novel coronavirus.
There are different tests to determine if you are infected with 2019 novel coronavirus. Your healthcare provider can determine if you should be tested.
There is no vaccine to protect you against human coronaviruses and there are no specific treatments for illnesses caused by human coronaviruses. Most people with common human coronavirus illness will recover on their own. However, to relieve your symptoms you can:
- take pain and fever medications (Caution: do not give aspirin to children)
- use a room humidifier or take a hot shower to help ease a sore throat and cough
- drink plenty of liquids
- stay home and rest
- If you are concerned about your symptoms, contact your healthcare provider.