We all have different ways of coping with the stress and anxiety of COVID-19. For me, reading up on the science front of the pandemic has been helpful in taking away a little bit of the largely uncontrollable feeling of uncertainty.
Coronaviruses are a family of viruses. The family itself is not new to scientists -- four of the most common human coronavirus types (229E, NL63, OC43, and HKU1) cause about a fifth of common colds. In fact, most people contract at least one type of the coronavirus at some point in their lives. But, because all known human varieties of the coronavirus resulted in illnesses that were so mild, coronaviruses were never at the forefront of scientific research.
This changed in 2003, when the pathogen causing the severe acute respiratory syndrome (SARS) outbreak was identified as a coronavirus. The outbreak infected 8,098 people worldwide, of whom 774 died. In 2019, a new type of coronavirus was identified to be causing a disease outbreak in China. This coronavirus, which has since spread worldwide, is now known as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and it is the cause of COVID-19 (coronavirus disease 2019). The effects of COVID-19 have been even more profound than SARS; as of June 5, there have been 6.42 million cases, of which 383 thousand have resulted in deaths.
So, what’s different about the coronaviruses that caused SARS and COVID-19?
The major difference is that coronaviruses that cause a cold infect the upper respiratory tract (the nose and throat), while coronaviruses that cause SARS and COVID-19 infect the lower respiratory tract (the lungs). A coronavirus particle looks like a ball (the genetic core) with spikes (membrane proteins) sticking out, and given the discrepancy in the location at which mild and severe coronaviruses thrive, the receptors of the latter latch onto receptors in the lung cells. One key lung cell receptor is ACE2, which is believed to be used by both SARS and the current coronavirus to gain entry into cells that it will infect. (Of course, there remain aspects of the research that are a mystery. For instance, the ACE2 receptor is common in the heart, but SARS does not infect heart cells.)
Another important aspect of coronaviruses is that they are armed with accessory proteins which help the virus to dodge the body’s line of defense -- its immune response. An immune response is activated when a cell detects an invader (based on the characteristics of its membrane proteins) and releases interferons, proteins which trigger cascades of antiviral activity. These processes shut down the replication of the pathogen or invader, however they also are bad for the host, as disease is largely caused by inflammation -- a crucial component of the immune response. This is why underlying medical conditions are so important; most who have died from the new coronavirus had other medical issues that rose to a head once the innate system had to fight off a virus.
It goes without saying that the current situation is unprecedented, both for the general public and for scientists. But there are measures you can take to keep yourself and others safe. As per guidelines from the Center for Disease Control and Prevention, wash your hands frequently; avoid close contact with others when you can; cover your mouth and nose with a mask when you are around others; cover your coughs and sneezes; clean and disinfect frequently touched surfaces regularly; and monitor your health.
Sources:
Makin, S. (2020, February 5). How Coronaviruses Cause Infection-from Colds to Deadly Pneumonia. Retrieved from https://www.scientificamerican.com/article/how-coronaviruses-cause-infection-from-colds-to-deadly-pneumonia1/
How to Protect Yourself & Others. (2020, April 24). Retrieved from https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html