Coronaviruses are common viruses that most people get some time in their life. Human coronaviruses usually cause mild to moderate upper-respiratory tract illnesses.
Coronaviruses are named for the crown-like spikes on their surface. There are three main sub-groupings of coronaviruses, known as alpha, beta and gamma, and a fourth provisionally-assigned new group called delta coronaviruses.
Human coronaviruses were first identified in the mid 1960s. The five coronaviruses that can infect people are: alpha coronaviruses 229E and NL63 and beta coronaviruses OC43, HKU1, and SARS-CoV, the coronavirus that causes severe acute respiratory syndrome.
Coronaviruses may also infect animals. Most of these coronaviruses usually infect only one animal species or, at most, a small number of closely related species. However, SARS-CoV can infect people and animals, including monkeys, Himalayan palm civets, raccoon dogs, cats, dogs, and rodents.
Human coronaviruses usually cause mild to moderate upper-respiratory tract illnesses of short duration. Symptoms may include runny nose, cough, sore throat, and fever. These viruses can sometimes cause lower-respiratory tract illnesses, such as pneumonia. This is more common in people with cardiopulmonary disease or compromised immune systems, or the elderly.
SARS-CoV can cause severe illness. To learn more, see Symptoms of SARS
Laboratory tests can be done to confirm whether your illness may be caused by human coronaviruses. However, these tests are not used very often because people usually have mild illness. Also, testing may be limited to a few specialized laboratories.
Specific laboratory tests may include:
- virus isolation in cell culture,
- polymerase chain reaction (PCR) assays that are more practical and available commercially, and
- serological testing for antibodies to human coronaviruses.
Nose and throat swabs are the best specimens for detecting common human coronaviruses. Serological testing requires collection of blood specimens.
The ways that human coronaviruses spread have not been studied very much, except for SARS. However, it is likely that human coronaviruses spread from an infected person to others through
- the air by coughing and sneezing, and
- close personal contact, such as touching or shaking hands.
These viruses may also spread by touching contaminated objects or surfaces then touching your mouth, nose, or eyes.
In one case, the SARS virus was though to spread through infected stool that got into the air; people breathed this in and got infected.
There are currently no vaccines available to protect people against human coronavirus infection. Individuals may be able to reduce their risk of infection by—
- washing hands often with soap and water,
- not touching eyes, nose, or mouth, and
- avoiding close contact with people who are sick.