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What Exactly is COVID-19 and How Do the Vaccines Work?

Yes COVID-19 is a deadly virus...but how does it spread from person to person to hijack our cells? In this post, we're discussing the latest COVID-19 news paired with easy-to-understand explanations of the virus' mutative properties and vaccine purpose.


Here we are in June of 2022, approximately two and a half years after the first reported case of COVID-19. From purchasing hundreds of surgical masks to conversing behind plastic barriers, the COVID-19 virus has certainly challenged the meaning of "normal" living. But have you ever stopped to wonder what exactly a virus is, why it makes your body sick, and how a vaccine helps your immune system? In this article, we will answer all of these questions and give some updates on the emerging variant...so keep reading!



History of the Virus


COVID-19 is the illness caused by the novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) which is a single member of a larger family of coronaviruses. These viruses have spikes covering their spherical surface which help the virus attach to cells for infection. In fact, it is this "crown" of spikes that the coronaviruses are named after.


It is thought that all seven human coronaviruses might have been transmitted to humans from other animals. Coronaviruses are found in humans and in other animal species, including bats, cats, and livestock. When scientists sequenced and analyzed the SARS-CoV-2 genome—the unique genetic code of this virus—they found that this virus is most closely related to a virus that was circulating in intermediate horseshoe bats. However, the exact source of the virus isn't confirmed.



How Viruses Attack


Viruses are very small microbes that contain genetic material (DNA or RNA), though they are not cells and cannot live independently. This is why viruses use host cells inside another species to grow and reproduce themselves. Viruses are found in many types of organisms, from animals and plants to bacteria and fungi. Some viruses are limited to the habitat of one animal, whereas others can survive in multiple hosts, and even withstand drying out on an exposed surface.


A virus begins its attack by recognizing and attaching to a specific receptor site on the host cell membrane. This relationship can be thought of as a precise lock (receptor) and key (virus), which is why not all animal cells are suitable for every virus. The term tropism is another way to refer to the ability of a virus to affect different types of cells.


https://courses.lumenlearning.com/suny-wmopen-biology2/chapter/virus-infections-and-hosts/


Once the virus is in contact with its host cell, it or its genetic material can pass the membrane in a couple of ways:

  1. Bacteriophages, or the spider-like viruses that infect bacteria, will typically fuse with the cellular membrane and expel the nucleic acids, leaving the capsid or shell on the outside of the cell. This specific process is pictured above in the second step.

  2. A virus with an envelope or an outer-membrane layer (think of this as a bubble with the virus inside) may directly fuse with and enter the cell membrane.

  3. Very sneaky viruses can trick the host cell into taking them in by a bulk transport process called endocytosis.


Once inside, the viral genome is replicated and more viral proteins are made so that more virus particles can be assembled. In simple terms, the virus becomes an evil scientist that takes over the host cell and uses its resources to make a "virus army," essentially reprogramming it to become a virus factory.


The last step of the virus lifecycle is the release of completed viral particles from the host cell, where they are now able to infect adjacent cells. Some viruses leave through a process called lysis where the host cell bursts and dies. Others exit through exocytosis, meaning they travel through the host cell's own export pathways.


The last step in the virus lifecycle is the release of newly made viruses from the host cell. Different types of viruses exit the cell by different routes: some make the host cell burst (a process called lysis or budding), while others exit through the cell's own export pathways (exocytosis), and others yet bud from the plasma membrane, taking a patch of it with them as they go.



What About the Vaccine?


So now that we know how COVID-19 is able to hijack our cells, let's take a look at how vaccinations help our bodies prepare for battle. In general, vaccines are injections that trigger an immune response within an organism, causing the production of antibodies that can recognize and fight a specific infection.



This preparation essentially trains our immune system to identify and attack the infection when it’s next encountered.


https://courses.lumenlearning.com/suny-wmopen-biology2/

chapter/virus-infections-and-hosts/



When you get a COVID-19 vaccine, you are being injected with a tiny package of genetic material, or mRNA, that carries special instructions to create part of the virus—specifically, the protein that's responsible for the spikes on the virus's surface that are used to stick to host cells. This mRNA tells your body's cells to start producing partial versions of the spike protein. Because these proteins are partial, they generally aren't harmful, though they may cause a fever or aches in some.


The existence of these foreign partial proteins alerts your body's immune system to design antibodies and begin training immune cells to identify and kill any cells with spikes like these. So, your defense system is now trained and prepared in case you encounter and are infected by the real SARS-CoV-2 virus.



Current COVID-19 Updates


Many disease and research centers are staying up to date on the number of COVID-19 cases across the nation.

On June 23rd, 2022, the CDC released this map of the US to demonstrate the COVID-19 community levels.


The orange regions are high level, yellow are medium level, and green are low level. For more statistics, visit cdc.gov.





New cases of COVID-19 continue to pop up daily. Specifically, the CDC recently reported that there have been 769,614 new cases in the last seven days within the U.S. Because the level of vaccine distribution has plateaued and will not likely experience a dramatic increase short term (especially due to many settings having a weak healthcare infrastructure) many experts are doubtful that herd immunity can be obtained. The term herd immunity is when an infection hits dead ends because a community's immunity is so high. Without this immunity, the infection rate is able to increase rapidly.


Besides getting vaccinated, there are many things that you can do on a day-to-day basis to help slow the spread of COVID-19. Wearing a well-fitting mask, avoiding crowds and poorly ventilated spaces, washing your hands often, covering coughs and sneezes, and monitoring your health daily are all easy ways to slow the SARS-CoV-2 virus's progression.



Remember that viruses are like bank robbers who are simply trying to go from bank to bank to survive. By putting up roadblocks, spreading out the banks, and training the staff, these bank robbers will have a WAY harder time succeeding.




Look out for more information on COVID-19 here at humanbodydigest.com. Visit our Instagram page @humanbodydigest for more pocket-sized information on a wide range of science topics and interact with us by submitting a question that will inspire a new post!



Sources


1. CDC. (2021, May 7). Scientific brief: SARS-COV-2 transmission. Centers for Disease Control and Prevention. Retrieved January 5, 2022, from https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/sars-cov-2-transmission.html

2. Goulding, J. (n.d.). Virus replication. British Society for Immunology. Retrieved January 5, 2022, from https://www.immunology.org/public-information/bitesized-immunology/pathogens-and-disease/virus-replication

3. Johns Hopkins Medicine. (2022, July 29). What is coronavirus? Johns Hopkins Medicine. Retrieved January 8, 2022, from https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus

4.Libretexts, L. T. (2022, June 9). 21.2A: Steps of virus infections. Biology LibreTexts. Retrieved January 5, 2022, from https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(Boundless)/21%3A_Viruses/21.02%3A_Virus_Infections_and_Hosts/21.2A%3A_Steps_of_Virus_Infections

5. Louten, J. (2016, May 6). Virus transmission and epidemiology. Essential Human Virology. Retrieved January 5, 2022, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7148619/

6. Ratini, M. (2022, January 21). How coronavirus is transmitted: Here are all the ways it can spread. WebMD. Retrieved January 5, 2022, from https://www.webmd.com/lung/coronavirus-transmission-overview#1

7. Ryu, W.-S. (2017, May 6). Virus life cycle. Molecular Virology of Human Pathogenic Viruses. Retrieved January 5, 2022, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7158286/

8. WHO. (2021, February 10). WHO-convened global study of origins of SARS-COV-2: China part. World Health Organization. Retrieved January 5, 2022, from https://www.who.int/publications/i/item/who-convened-global-study-of-origins-of-sars-cov-2-china-part

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