What is a Coronavirus?

When we hear the term coronavirus, our minds immediately jump to the most recent and destructive COVID-19 pandemic that shook the world in the past 2-3 years. It’s a scary topic to broach, but awareness of an evolving threat is more crucial.

It’s important to note that coronavirus is not necessarily synonymous with COVID-19 – the latter being a type of the former. the two terms are used synonymously. This article will attempt to inform you about what coronavirus is, the types of viruses that are prevalent, the threats from each type, and other attendant issues.

What are Coronaviruses?

Coronaviruses are a category of viruses distinguished by their peculiar surface dotted with spikes like little crowns – hence the term “corona”. They are responsible for viral infections ranging in severity from the mild common cold to the more severe pandemics we have seen over the past couple of decades.

Common Coronaviruses

The most common types include 229E (alpha coronavirus), the HKU1 (beta coronavirus), NL63 (alpha coronavirus), and the OC43 (beta coronavirus).

The OC43 (beta coronavirus) alongside the 229E (alpha coronavirus) is responsible for the common cold. They are both single-stranded RNA viruses that are enveloped and positive- sense, which means they have an outer cover that protects genetic material during travel to and from the host organism, and it contains viral mRNA that translates the RNA sequence directly into proteins.

The 229E (alpha coronavirus will cause symptoms like sneezing, coughing, a sense of unwellness, and headaches, while the OC43 (beta coronavirus) will also cause certain respiratory symptoms along with possible presentations of pharyngitis, rhinitis, and/or abdominal complaints.

The HKU1 (beta coronavirus) provokes more severe complications of respiratory illnesses such as bronchiolitis and pneumonia, with many cases requiring hospitalizations if symptoms exacerbate. This makes it very similar to the SARS variant.

The NL63 (alpha coronavirus) is a more moderate viral infection that presents with the symptoms of the common cold. Co-infections and co-morbidities may complicate the infection by worsening breathing problems. It is more likely to infect people with compromised or weakened immune systems, or children and infants.

All coronaviruses are transferred between animals and people, which means they are zoonotic. For example, in the case of the OC43 (beta coronavirus), the virus is transmitted from cattle to humans, whereas the 229E (alpha coronavirus) infects bats and humans and causes transmission between them.

Coronaviruses That Have Caused Pandemics/Epidemics

The following variants of coronaviruses are the best known globally as they have been responsible for infections across populations both within countries and regions and across the world. Let's see how they are similar and how they differ.


The SARS-COV virus or the Severe Acute Respiratory Syndrome Coronavirus is a coronavirus variant that originated in Guangdong Province in China in 2002, gradually spreading worldwide by 2003.

International attention was aroused when several acute and critical cases of pneumonia were reported from Hong Kong, Canada, Taiwan, and Singapore – pointing to the possible facilitation of virus transmission through ease of travel.

The source of the SARS-COV virus was believed to be horseshoe bats, while civet cats were the intermediary hosts. Civet cats along with some other mammals were thought to harbor these viruses and amplify their transmissibility, potency, and replicability. The SARS -COV is a beta coronavirus, responsible for SAR/COV-2 or COVID-19 and MERS as well.

As a response to the outbreak in 2003, the World Health Organization (WHO) convened the GOARN - Global Outbreak Alert and Response Network to coordinate logistical support, epidemiological information, and clinical intervention, and streamline the same in all affected countries.

When the People’s Republic of China banned wildlife trade and the related animal markets, there were no more naturally occurring human cases reported from Guangdong i.e., no more cases of the virus jumping from the animals to humans.

MERS Coronavirus

The Middle East Respiratory Syndrome Coronavirus is a highly pathogenic and highly transmissible type of coronavirus that was first identified in 2012, in Saudi Arabia. It then went on to be reported in several other countries like Germany, Bahrain, Algeria, Philippines, the Netherlands, Yemen, Iran, Jordan, and South Korea to name a few, although 80% of cases were confined to Saudi Arabia, with external cases linked to travel.

Morality rates were significantly high – at 35% of all infections- although it is possible that because some people have no symptoms or very mild symptoms there might have been undercounting. Symptoms include shortness of breath, fever, possible development of pneumonia, and gastrointestinal issues like diarrhea.

The origin of the MERS virus is thought to be from dromedary camels in the Middle East, either through indirect exposure or direct exposure from occupational activities. Some human-to-human transmission was reported in healthcare settings.


SARS-COV-19 is a novel coronavirus similar in most ways to its predecessor SARS-COV in terms of symptoms, receptor binding strategies and potential, and methods of transmission. However, there may be differences in terms of transmissibility, which COVID sub-types seem to possess in greater strength.

However, SARS-COV was much more severe in comparison, although COVID-19 mortality has been high as well, especially amongst the elderly., those with comorbidities like liver, kidney, or heart disease.

There have been many sub-types of COVID-19 including delta and omicron. However, there are approved mRNA vaccines from pharmaceutical companies like Moderna and Pfizer that are administered in two doses, as well as booster shots.

Although there is no cure, the United States F.D.A. has authorized the use of antivirals like molnupiravir for mild cases in adults, a ritonavir- nirmatrelvir combination called Paxlovid that blocks enzyme activity necessary for COVID replication, and remdesivir for serious complications and people needing hospitalization and/or oxygen supplements.


Viruses are notorious for adapting in their ability to infect and create morbidity.

It’s up to us to take the necessary precautions such as wearing a mask to prevent the transmission of airborne infected droplets, washing/ sanitizing your hands after touching surfaces, shaking hands, or after coming into contact with an infected person, maintaining social distancing, and avoiding crowded places as much as possible.

Updated on: 21-Mar-2023


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