The Novel Coronavirus: What Are Novel Viruses, and How Do They Impact Public Health?

SARS-CoV-2, the virus that causes COVID-19, is a “novel coronavirus.” This means it’s different from all viruses like it.

There are hundreds of different coronaviruses. Most infect animals like pigs, camels, bats, and cats. But they can jump from animals to humans. When they do, they cause upper respiratory infections — like the common cold. 

It’s very rare that animal coronaviruses jump to people and then spread among people. But over the last two decades, three coronaviruses have jumped from animals to humans and led to serious, widespread illness and death.

What does ‘novel’ mean in medicine and virology?

The word “novel” comes from the Latin word “novus,” which means “new.” In medicine, “novel” refers to a virus or bacteria that wasn’t known to affect humans. This means that the bug is either brand new or was only found in animals or other life forms. 

What is a novel coronavirus?

Coronaviruses are a family of viruses named for the crown-like spikes on their surface. The word “corona” means “crown.” The first human coronaviruses were identified in the mid-1960s. Today, there are seven coronaviruses, including SARS-CoV-2, that are known to affect humans. 

Four of the seven human coronaviruses cause mild to moderate illness. They make up 10% to 30% of upper respiratory tract infections in adults. The other three, including SARS-CoV-2, can cause more serious illnesses, like pneumonia and other lower respiratory tract infections. 

When animal coronaviruses evolve and are able to infect humans, these viruses are considered to be novel. Over time, these viruses change so they can attach to different host cells, allowing them to enter the cells of new species. Since these viruses had not been seen in humans, scientists and researchers must learn how the virus infects human cells and causes disease. This is necessary to develop potential treatments and vaccines.

What about novel influenza (flu) viruses?

When you’ve heard of novel viruses in the past, it may have been in the context of novel influenza (flu) viruses — but not coronaviruses. Seasonal influenza type A and type B viruses (influenza A and B viruses) appear during each year’s cold and flu season. But  there are also novel influenza A viruses. These flu strains infect animals but have also infected humans during influenza outbreaks. 

Examples of novel flu virusesinclude avian influenza A viruses (bird flu) that humans get from exposure to infected poultry as well as swine/variant influenza A viruses (swine flu) that humans get from exposure to infected pigs. Researchers closely monitor novel flu viruses to make sure they don’t set off a pandemic.

When have there been examples of other novel coronaviruses?

SARS-CoV-2 is the first novel coronavirus to cause a pandemic in the last century. Two other recent examples of novel coronaviruses have been SARS-CoV and MERS-CoV.  

SARS-CoV, the virus that causes severe acute respiratory syndrome (SARS), was first reported in November 2002 and quickly spread to 26 countries before being contained after about 4 months. Since 2004, there have been no reported cases of SARS.  

Almost a decade later, MERS-CoV, the virus that causes Middle East respiratory syndrome (MERS), emerged in September 2012, spreading to 27 countries. MERS still exists today, but only a few thousand cases are reported worldwide. The virus doesn’t easily pass from person to person, so it hasn’t caused a pandemic. 

Is SARS-CoV-2 (COVID) the same as SARS-CoV (SARS)?

Although there are some similarities between SARS-CoV (SARS) and SARS-CoV-2 (COVID), they are caused by different viruses. SARS and COVID illness are also very different.

People who get COVID can spread the virus earlier on compared to people who get SARS. And people with COVID who have minimal symptoms or are completely asymptomatic can still pass the COVID virus to others. On the other hand, SARS was only reported to be transmitted from people who already had symptoms. That means COVID can spread more easily and is harder to contain than SARS.

What do novel viruses mean for public health?

Novel viruses present a lot of questions for public health that need quick answers in order to contain the spread of the virus. These question include:

• How easily does the virus pass from person to person?  

• How soon do people develop symptoms after being exposed to the virus?

• How long are people contagious with the virus?

• Can the immune system easily fight off the virus?

• How quickly can people develop antibodies to the virus, and how long will the antibodies last?

With COVID, researchers were able to build on research from the SARS and MERS outbreaks. Within 2 weeks of discovering COVID, researchers from the National Institute of Allergy and Infectious Diseases (NIAID) figured out how the virus gets into human cells. And within 2 months, there were phase-1 trials for the COVID vaccine and remdesivir, an antiviral treatment against COVID. 

Pandemics pass through three phases:

• Pre-pandemic investigation and recognition: This is when officials have detected the virus, but case numbers are still low. Researchers quickly try to learn about the virus, so they can prevent spread and develop treatments and vaccines.

• Initial wave and acceleration: This is when cases rise and hit a peak. As cases rise, facility closures, social distancing, medications, and vaccines (if available) can slow the spread of the disease.  

• Deceleration: This occurs after the peak. Public health officialscreate measures to contain the virus, and the number of cases starts to fall.

How quickly a pandemic goes through these phases depends on how the virus behaves and the public health response. 

Why trust our experts?

Written by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

Our editorial standards

Meet our experts