Coronaviruses: Strains, Symptoms, and Prevention

Author: Disabled World (DW)
Updated/Revised Date: 30 Jul 2026

Table of Contents:
Synopsis - Definition - About This Section - FAQs - Publications - Subtopics

Synopsis

An overview of human coronaviruses, including the seven known strains such as SARS, MERS, and COVID-19, plus how they spread and ways to prevent infection.

At a Glance

• 1 - Coronaviruses are named for the crown-like spikes on their surface and fall into four groups: Alpha, Beta, Gamma, and Delta.
• 2 - The 2002 to 2003 SARS outbreak caused 8,098 probable cases and 774 deaths, with no known infections reported since 2004.
• 3 - HCoV-229E and HCoV-OC43 are among the viruses responsible for the common cold, yet can cause pneumonia in infants, older adults, and immunocompromised people.
• 4 - The first human coronaviruses were identified in the 1960s, following an infectious bronchitis virus found in chickens and two cold viruses named 229E and OC43.

Topic Definition

Coronaviruses

Coronaviruses are a large family of viruses named for the crown-like spikes that stud their outer surface, and they are grouped into four main types known as Alpha, Beta, Gamma, and Delta. In people they most often cause mild to moderate upper respiratory illnesses like the common cold, but some strains have proven far more dangerous, including the viruses behind severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and coronavirus disease 2019 (COVID-19). Seven strains are currently known to infect humans, and several of them, such as SARS, MERS, and COVID-19, originally circulated in animals before evolving to spread from person to person. They carry a protein called a replicase in their genome that lets the RNA virus copy itself using the host cell's own machinery, and they spread mainly through coughing, sneezing, close personal contact, and touching contaminated surfaces.

Overview

Coronaviruses are a large family of viruses that usually cause mild to moderate upper-respiratory tract illnesses in humans. However, three coronaviruses have caused more severe and fatal diseases in people: SARS coronavirus (SARS-CoV), which emerged in November 2002 and caused severe acute respiratory syndrome (SARS); MERS coronavirus (MERS-CoV), which appeared in 2012 and caused Middle East respiratory syndrome (MERS); and SARS-CoV-2, which emerged in 2019 and causes coronavirus disease 2019 (COVID-19).

How Many Coronaviruses Are There?

There are seven strains of human coronaviruses currently known:

• 1) Human coronavirus 229E (HCoV-229E (alpha coronavirus)) - HCoV-229E is associated with a range of respiratory symptoms, ranging from the common cold to high-morbidity outcomes such as pneumonia and bronchiolitis. Along with Human coronavirus OC43, it is among the viruses responsible for the common cold.
• 2) Human coronavirus HKU1 (beta coronavirus) - Human coronavirus HKU1 was first identified in January 2005 in a 71-year-old man who was hospitalized with acute respiratory distress and radiographically confirmed bilateral pneumonia. The man had recently returned to Hong Kong from Shenzhen, China.
• 3) Middle East Respiratory Syndrome Coronavirus (MERS-CoV) Formerly known as novel coronavirus 2012, and HCoV-EMC, it was first reported in 2012 in Saudi Arabia and has since caused illness in people in more than 25 other countries, including the U.S. Most people reported to have MERS-CoV infection developed severe acute respiratory illness, including fever, cough, and shortness of breath. Only two patients in the U.S. have ever tested positive for MERS-CoV infection - both in May 2014.
• 4) Human coronavirus NL63 (HCoV-NL63, New Haven coronavirus (alpha coronavirus)) - Human coronavirus NL63, or HCoV-NL63, is a species of Alpha coronavirus that was identified in late 2004 in the Netherlands. Infection with the virus has been confirmed worldwide and is associated with many common symptoms and diseases. Associated diseases include mild to moderate upper respiratory tract infections, severe lower respiratory tract infection, croup, and bronchiolitis.
• 5) Human coronavirus OC43 (HCoV-OC43 (beta coronavirus)) - Along with HCoV-229E, a species in the Alpha coronavirus genus, HCoV-OC43 are among the known viruses that cause the common cold in humans. Both viruses can cause severe lower respiratory tract infections, including pneumonia in infants, the elderly, and immunocompromised individuals such as those undergoing chemotherapy and those with HIV-AIDS.
• 6) Newly discovered coronavirus (COVID-19), formerly known as Wuhan pneumonia or Wuhan coronavirus or nCov-19 - The virus has been named "SARS-CoV-2" and the disease it causes has been named "Coronavirus disease 2019" (abbreviated "COVID-19"). On January 9, 2020, the World Health Organization (WHO) reported that Chinese authorities identified a novel (new) coronavirus. The virus is currently associated with an outbreak of pneumonia in Wuhan City, Hubei Province, China. Additional cases have been identified in a growing number of other international locations, including the United States.
• 7) SARS-CoV - Beta coronavirus that causes severe acute respiratory syndrome, or SARS. First recognized in China in November 2002. It caused a worldwide outbreak in 2002-2003 with 8,098 probable cases, including 774 deaths. Since 2004, there have not been any known cases of SARS-CoV infection reported anywhere in the world.

Human coronaviruses can sometimes cause lower-respiratory tract illnesses, such as pneumonia or bronchitis. This is more common in cardiopulmonary disease, people with weakened immune systems, infants, and older adults. Sometimes coronaviruses that infect animals can evolve and make people sick and become a new human coronavirus. Three recent examples of this are COVID-19, SARS-CoV, and MERS-CoV.

The Coronaviruses HCoV-229E, -NL63, -OC43, and -HKU1 continually circulate in the human population and cause respiratory infections in adults and children worldwide.

MERS-CoV and SARS-CoV have been known to cause severe symptoms frequently. MERS symptoms usually include fever, cough, and shortness of breath, which often progress to pneumonia. 3 or 4 out of every ten patients reported with MERS have died.

MERS is caused by a coronavirus called "Middle East Respiratory Syndrome Coronavirus" (MERS-CoV). MERS-CoV is not the same coronavirus that caused severe acute respiratory syndrome (SARS) in 2003. However, like the SARS virus, MERS-CoV is similar to coronaviruses found in bats. MERS-CoV has been shown to spread between people who are in close contact.

Most people infected with MERS-CoV develop a severe acute respiratory illness with symptoms of fever, cough, and shortness of breath. Some people were reported as having a mild respiratory illness. There are no specific treatments for illnesses caused by MERS-CoV. Around 50% of those who contracted the illness died. Medical care is supportive and helps relieve symptoms.

Human coronaviruses are most commonly spread via:

• Fecal Contamination: Rarely.
• Air - Coughing and sneezing.
• Close Personal Contact: Such as touching or shaking hands.
• Touching something affected with the virus: Then touch your mouth, nose, or eyes before washing your hands.

There are currently no known treatments or vaccines for illnesses caused by human coronaviruses. Most people with common human coronavirus illnesses recover on their own. Things to help relieve your symptoms include:

• Take pain and fever medications (Caution: do not give Aspirin to children).
• If you are mildly sick, you should drink plenty of liquids, stay home and rest.
• Use a room humidifier or a hot shower to help ease a sore throat and cough.

To help protect against human coronavirus infection by reducing your risk of infection, try:

• Avoiding close contact with sick people.
• Avoid touching your eyes, nose, or mouth with unwashed hands.
• Washing your hands often with soap and water for at least 20 seconds.

If you have cold-like symptoms, help protect others by:

• Staying home while you are sick.
• Avoiding close contact with others.
• Cleaning and disinfect objects and surfaces
• Cover your mouth and nose with a tissue when you cough or sneeze, throw the tissue in the trash and wash your hands.

2019 - 2020 Wuhan Coronavirus Outbreak

The 2019 - 2020 Wuhan, China, pneumonia outbreak was traced to a new coronavirus, which is now labeled as COVID-19 by WHO. It was initially identified in mid-December 2019 in Wuhan in central China as an emerging cluster of people with pneumonia with no clear cause. It was linked primarily to stallholders who worked at the Huanan Seafood Wholesale Market, selling live animals. (Wikipedia).

On 22 January 2020, the Journal of Medical Virology published a report with genomic analysis that reflects that snakes in the Wuhan area are "the most probable wildlife animal reservoir" for the virus, but more research is required.

On 23 January 2020, Wuhan was placed under quarantine, and all public transport in and out of Wuhan was suspended. Nearby cities of Huanggang, Ezhou, Chibi, Jingzhou, and Zhejiang were also placed under quarantine from 24th January 2020.

Frequently Asked Questions

What is the difference between a cold caused by a coronavirus and COVID-19?

Common cold coronaviruses usually cause mild upper respiratory symptoms, while COVID-19 is caused by SARS-CoV-2 and can range from no symptoms to severe respiratory illness and complications.

How long do coronaviruses survive on surfaces?

Survival time varies by virus, surface, and conditions, ranging from hours to several days, which is why regular cleaning and hand washing help reduce the risk of transmission.

Can pets and animals carry coronaviruses?

Many animals carry their own coronaviruses, and some strains have jumped from animals to humans, though most animal coronaviruses do not infect people.

Are there vaccines for any human coronaviruses?

Vaccines have been developed for COVID-19, but there are no widely available vaccines for the common cold coronaviruses or for MERS and SARS.

How can I tell if my respiratory illness is a coronavirus?

Because symptoms overlap with other respiratory infections, only laboratory testing can confirm a specific coronavirus, so consult a healthcare provider if you are concerned.

Who is most at risk of severe illness from coronaviruses?

Infants, older adults, and people with weakened immune systems or heart and lung conditions face a higher risk of severe lower respiratory complications.

How long does it take to recover from a coronavirus infection?

Mild common cold coronavirus infections often clear within a week or two, while more severe illnesses from strains like MERS or COVID-19 can require much longer recovery.

Curated and edited by Ian C. Langtree, Founder & Editor-in-Chief, Disabled World. This section is maintained by the Disabled World editorial team.

Last updated: 30 Jul 2026