COVID-19 Information

What is a novel coronavirus?

Coronaviruses are a family of viruses that can affect animals and humans. Coronaviruses are named for the crown-like spikes on their surface (“corona” is Latin for “crown”).

Some coronaviruses commonly circulate in the United States and usually cause upper respiratory symptoms such as cough or runny nose, although some can cause more serious illness. 

There are seven coronaviruses that can infect people, four of which are common, which means that our bodies have built up immunity to them and they are less likely to make us seriously ill. The other three are MERS-CoV (Middle East Respiratory Syndrome coronavirus), SARS-CoV (Severe Acute Respiratory Syndrome coronavirus), and SARS-CoV-2 (the novel coronavirus that causes coronavirus disease 2019, or COVID-19). These three viruses evolve from viruses that initially only infected animals.

A “novel” coronavirus is a new strain that has not been previously identified in humans. A novel coronavirus like COVID-19 is more contagious than the viruses that cause influenza and common cold because it is new to humans. Humans have no way to prepare for it, and their immune systems are not ready to fight it. This results in the virus causing more cellular damage and producing more inflammatory cells, thus making it more dangerous to many humans.

Sources: CDC, Mayo Clinic

How does COVID-19 spread in the body?

Viruses have spike proteins on their surface to allow them to attach and enter our cells. The spike protein on SARS-CoV-2 is used to attach to the ACE2 receptor. This receptor can be found on many cells of our body (alveoli of the lungs, heart, brain, blood vessels). If a cell has the ACE2 receptor the virus can use it’s spike protein to attach and enter the cell. Think of the ACE2 receptor as the lock and the spike protein as the key. If you have the right key, you can enter the structure.

Once inside a few initial host cells, the virus hijacks the cell’s machinery and sets those host cells to work churning out copies of itself. Within hours, thousands of new virus particles begin bursting forth, ready to infect more cells. As the virus multiplies, an infected person may shed copious amounts of it, especially during the first week or so. Symptoms may be absent at this point. 

Although SARS-CoV-2 is less deadly than the original SARS virus, which emerged in 2002, it replicates more rapidly. Also unlike SARS, which primarily infects the lungs, SARS-CoV-2 replicates throughout the airway, including in the nose and throat, making it highly contagious – like the common cold.

Sources: Science Mag, University of California San Francisco

How does COVID-19 spread between people?

Respiratory droplets and aerosols

Since it is a respiratory virus, you can spread coronavirus through your nose and mouth. Sneezing, coughing, yelling, and even talking (yes, just talking!) could expel respiratory droplets, which can contain the virus if you’re infected.

More importantly, tinier droplets called aerosols can also come out of your mouth. Viruses can hitch a ride on these tiny, invisible droplets, being suspended in the air for hours, floating throughout a room like smoke. In fact, coronavirus can live for up to 3 hours in the air in aerosols, meaning you could breathe in the virus from the air in a room where an infected person breathed/coughed/sneezed up to 3 hours before. This is similar to other contagious respiratory diseases, like flu (which can live in the air for 2-3 hours) and measles (which can live in the air for up to 2 hours).

Contaminated surfaces

Contact with an infected person can transfer the virus from them to you. An infected person may touch their nose or mouth, picking up some virus on their hands – the same hands they use to shake yours. Then you touch your nose or face – boom, you’ve infected yourself.

Virus-containing respiratory droplets from someone’s nose or mouth can land on nearby surfaces, such as doorknobs, handrails, and tables, creating contaminated objects (called fomites). The virus can live on surfaces for hours or days, up to 5 days on certain objects. If you touch an infected surface then touch your face, nose, or eyes, you could indirectly infect yourself. 

Transmission through respiratory droplets or aerosols is much more common than through contaminated surfaces.

Source: Biospace