We are living in a historic moment — in the past few months, we have been thrown into an era of social distancing, economic recession, and work-from-home. This is due to a novel virus called Severe Acute Respiratory Syndrome Coronavirus 2 — better known as SARS-CoV-2 or Coronavirus. The term Coronavirus also refers to a class of viruses — the coronaviruses — which cause respiratory infections and can lead to serious illnesses like pneumonia. SARS-CoV-2 is a newly mutated strain that, when contracted, results in Coronavirus Disease (COVID-19).
Today, we’re in the COVID-19 Pandemic of 2020. Remember this moment because the great economic and social upheaval will, without a doubt, be in every history book for decades. Though it isn’t the first epidemic of (many of) our lives, it is certainly one of the most serious. The previous decades have been host to the H1N1 pandemic (2009) and the HIV/AIDS pandemic (1980s and 1990s), to name a few. However, many of us who lived through these pandemics can attest to the fact that things are different this time. This disease is defining our day-to-day lives on micro- and macro-scales alike.
Definitions and Nomenclature
Pandemics, epidemics, and outbreaks are terms used to describe the spread of a contagious disease. An outbreak is generic for any sudden onset of something — for example, there can be an outbreak of violence. In our case, it’s a sudden rise in the number of reported cases of a disease. Similarly, an epidemic is a sudden rise in reported cases of a disease, but the differentiating factor is that an epidemic specifically refers to an unexpected, widespread occurrence. You can have an outbreak of a disease in a small geographic area, but it’s an epidemic when that outbreak reaches an unexpected number of cases in a larger area. There is no definitive size for the area — only that the size is unexpected. A pandemic is an epidemic of greater proportions. A disease pandemic is when the disease has spread across multiple countries and affects a much larger number of people. Again, there are no definitive areas or cases that make it a pandemic, but Dr. Andres Romero, a disease specialist at Providence Saint John’s Health Center, states, “We assume with a pandemic that everyone can be potentially exposed” .
Previously on World Health: Epidemics of Our Time
HIV/AIDS Pandemic (1981 — present)
Human Immunodeficiency Virus (HIV) is an infectious virus that targets white blood cells, which can lead to Acquired Immunodeficiency Syndrome (AIDS). Transmission occurs through sharing bodily fluids, with many cases reported after having unprotected sex or sharing drug needles. In recent years, over 37 million people were reported living with HIV.
H1N1 Flu Pandemic (2009–2010)
H1N1, also called Swine Flu, spreads from person to person through droplets and contact — often referred to as airborne. This means people may become infected from the air if the person is within proximity (generally agreed upon as 6 feet or closer), and from body fluids or infected surfaces. The flu could be transmitted across species, using pigs as an intermediate host, and constantly evolves as it pulls pieces from other strains of the virus, making it difficult to target against. The outbreak began in California in 2009, and quickly spread across the United States and abroad in the following months. A vaccine was developed and the pandemic was contained 16 months after a public health emergency was declared by the World Health Organization (WHO).
Ebola Virus Epidemic (2014–2015)
Ebola is an infectious virus that can only be contracted through direct contact with infected bodily fluids. Symptoms of Ebola make infection more likely because those already infected suffer from vomiting, diarrhea, and external bleeding. The ebola epidemic of 2014 involved the unprecedented spread of Ebola in urban regions of West Africa.
Zika Virus Epidemic (2015–2016)
Zika virus is another infectious virus that is contracted through direct contact with infected bodily fluids. In 2015, Zika cases spread to the western hemisphere and led to many reported cases in the Latin America region. Mosquitos were common carriers of the disease given the tropical climate and method of transmission.
Current Pandemic: COVID-19
What makes COVID-19 different and how worried should you be? When we compare and contrast COVID-19 to the epidemics of the past, there are good and bad points to mention.
First of all, the method of transmission may be by direct contact, from person to person and droplets, or by indirect contact, through infected surfaces and airborne . Once the virus has been picked up, it must be deposited into the body via mucus membrane (eyes, nose, mouth) or through an open wound. This is more advantageous to us than, say, H1N1 which spreads through the air and can be ingested simply by passing by. Therefore, your likelihood of contracting the disease is much more controllable by following the guidelines suggested by health professionals:
- Wash your hands thoroughly with soap. SARS-CoV-2, like many viruses, is encased in a lipid envelope (layer of fat) that will break apart when exposed to soap. Also, it creates a slick medium that causes contaminants to slip right off your skin.
- Don’t touch your face — at least until you observe rule 1. That way, even if you have picked up the virus, it won’t be near your mucus membrane.
- Observe social distancing. Every time you leave your home — where you know there’s no contamination — you risk entering a contaminated area. You could pick up the virus and bring it home with you. You’re no longer safe!
We should tack on another rule for the sake of being thorough — cover open wounds. If an infected person were to sneeze or cough towards your arm and your arm had an open wound, you could be infected through droplets of saliva.
This is where our comparatively good points end. COVID-19 is not to be taken lightly. One of the most important things to know about COVID-19 is its risk of contagion.
Risk of contagion is described as how easily a virus can spread from person to person. COVID-19 is considered highly contagious by the CDC, largely due to how sustainable it is in the environment and how easily it spreads.
Coronavirus exhibits “community spread” meaning some people in an infected area are not sure when or how they became infected — they’ve had no contact with another infected person nor visited “high risk” locations. This fact points to the idea that Coronavirus might be able to survive in the environment for long periods of time.
After infecting a host, viruses replicate and spread within the body. The body takes measures to kill the virus. Therefore, a virus’s perpetuity depends on transferring to a new host. The only ways to do so are direct travel, an intermediary host, or surviving in the environment. Direct travel is ideal for the virus, but we’re smart enough to prevent this, if we follow the rules above! If there is no intermediary, the virus must survive in the environment until a new host can become infected. An article published in the American Society for Microbiology Journals reports respiratory viruses exhibit various inactivation rates per hour outside a host. Coronaviruses, such as the one that causes COVID-19, are “middle of the road”  — inactivation is faster than the flu, but slower than rhinovirus (which causes the common cold). Additionally, this inactivation rate varies with the surface on which the virus is resting. COVID-19 exhibited activity for up to 3 hours on metallic surfaces (door handles), up to 24 hours on porous surfaces (cardboard), and up to 3 days on select surfaces (plastic and stainless steel)!
Another theory of why COVID-19 exhibits “community spread” is because the disease may spread when infected people are asymptomatic — either not yet exhibiting symptoms or don’t exhibit symptoms when infected. The CDC states on their website that this is not believed to be the main method for which COVID-19 spreads, but is suspected because of the rapidity of new cases. The rapid spread can be followed on this interactive map posted by the Open COVID-19 Data Curation Group here.
What it’s like to get infected
- The first 2 to 14 days after initial exposure, a person may not develop symptoms. The average asymptomatic period is about 5 days.
- Once inside the body, the virus begins infecting epithelial cells in the lining of the lung. A protein on the receptors of the virus can attach to a host cell’s receptors and penetrate the cell. Inside the host cell, the virus begins to replicate until it kills the cell. This first takes place in the upper respiratory tract, which includes the nose, mouth, larynx and bronchi.
- The patient begins to experience mild versions of the following symptoms: dry cough, shortness of breath, fever and headache, and muscle pain and tiredness, comparable to the flu. Some patients have reported gastrointestinal symptoms such as nausea and diarrhea, however it’s relatively uncommon.
- Symptoms become more severe once the infection starts making its way to the lower respiratory tract.
- 80% of patients have a mild to moderate disease from infection. A case of “mild” COVID-19 includes a fever and cough more severe than the seasonal flu but does not require hospitalization. That is because the body’s immune response is able to contain the virus in the upper respiratory tract.
- The 13.8% of severe cases and 6.1% critical cases are due to the virus trekking down the windpipe and entering the lower respiratory tract, where it seems to prefer growing. As the virus continues to replicate and journeys further down the windpipe and into the lung, it can cause more respiratory problems like bronchitis and pneumonia.
- When pneumonia occurs, the thin layer of alveolar cells is damaged by the virus. The body reacts by sending immune cells to the lung to fight it off. This is one of the life-threatening battles that occurs between the host response and the virus, leading to either recovery or death.
- Once oxygen is restricted, other major organs will also be affected by less oxygen in the blood stream including the liver, kidney and brain.
- A small number of severe cases can develop into acute respiratory distress syndrome (ARDS), which requires a patient to be placed on a ventilator to supply oxygen. However, if too much of the lung is damaged and not enough oxygen is supplied to the rest of the body, respiratory failure could lead to organ failure and death.
Perhaps the most avid point this blog will make, the one you should take to heart, is that there is currently no treatment for COVID-19 and no vaccination available to prevent COVID-19. Following the rules listed above is your best defense — leave your home only when necessary and wash your hands thoroughly upon returning. The likelihood of coming into contact with SARS-CoV-2 depends on where you live and what risks you take. Reduce the risk as much as you can! COVID-19 is unpleasant to say the least, and potentially life-threatening for children, seniors, and many at-risk groups. From all of us here at Macromoltek, we hope you and your loved ones stay safe out there.
Links and Citations:
 Caceres, Vanessa. “What’s the Difference Between an Epidemic and Pandemic?” U.S.News. U.S. News Health, 13 March 2020. Web. 26 March 2020. Retrieved from https://health.usnews.com/conditions/articles/whats-the-difference-between-an-epidemic-and-pandemic
 Santarpia, Joshua, et al. “Transmission Potential of SARS-CoV-2 in Viral shedding Observed at the University of Nebraska Medical Center.” MedRXiv. 26 March 2020. Web. 26 March 2020. Retrieved from https://www.medrxiv.org/content/10.1101/2020.03.23.20039446v2
 Boone, Stephanie A, and Charles P. Gerba. “Significance of Fomites in the Spread of Respiratory and Enteric Viral Disease.” American Society for Microbiology Journals 73.6 (2007): 1687–1696. Web. 26 March 2020. Retrieved from https://aem.asm.org/content/aem/73/6/1687.full.pdf
 U.S Department of Health and Human Services. “New coronavirus stable for hours on surfaces”. U.S Department of Health and Human Services. National Institutes of Health, 17 March 2020. Web. 26 March 2020. Retrieved from https://www.nih.gov/news-events/news-releases/new-coronavirus-stable-hours-surfaces
CORRECTION (March 27, 2020 12:53 p.m.): Previous version of this blog post gave less specific information regarding the transmission of H1N1 and COVID-19. Thanks to Dr. Austin G Meyer of Ohio State University for pointing this out.
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