Important Tips to Deal with SARS-CoV-2 at Home, Work, and in the Community
What We Know About the 2019 Novel (New) Coronavirus that Causes COVID-19
There is still much to learn about the novel coronavirus known as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2, formerly provisionally known as 2019-nCoV) which causes coronavirus disease 2019 (COVID-19). The first reported case of COVID-19 occurred in China only 4 short months ago on November 17, 2019. According to the South Morning China Post, it first presented in a 55 year old man from China’s Hubei province. On December 27, 2019, Dr. Zhang Jixian of the Hubei Provincial Hospital of Integrated Chinese and Western Medicine alerted Chinese health authorities that the disease was caused by a novel coronavirus. With roughly 180 confirmed infections by that point, the capital city of Hubei province, Wuhan, soon emerged as the epicenter of the coronavirus epidemic.
The family of viruses which comprise coronaviruses (CoV) are responsible for a variety of illnesses ranging from the common cold, to more serious diseases like Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV-1). Coronaviruses are so named because their virions (virus particles) resemble the aura around the sun, known as a solar corona.
Left image: CG representation of coronavirus; Right image: SARS-CoV-2 (blue) under electron microscope
Coronaviruses typically affect birds and mammals, although the symptoms of the disease differ markedly between species. When transmitted to humans, coronaviruses cause either upper or lower respiratory tract infections, with lower respiratory infections being far more serious (e.g., pneumonia).
Scientists currently believe the novel coronavirus originated in a bat, due to a 96% genetic similarity between a Rhinolophus affinis horseshoe bat coronavirus called RaTG13 and human coronavirus. However, the receptor-binding domain (RBD) – a specific area of the genome of the coronavirus that’s crucial to locking onto and entering a cell – for RaTG13 and SARS-CoV-2 diverged back in 1969, making it unlikely the transmission between bats and humans was directly related to this virus.
The current theory is that bat coronavirus was transmitted to an intermediate host animal – possibly a pangolin – where it developed the ability for the spike proteins to bind to human ACE2 receptors, before crossing back into bats and being contracted by a human being. Similarly, according to the World Health Organization (WHO), SARS-CoV and MERS-CoV were transmitted to humans by civet cats and dromedary camels, respectively.
What We Learned from Earlier Coronaviruses
Scientists know from prior coronavirus outbreaks that human-to-human transmission typically occurs via respiratory droplets. When a person infected with coronavirus coughs or sneezes, they emit microscopic drops containing the virus from their nose and/or mouth. Those droplets may contact the facial orifices (i.e., nose, eyes, mouth), skin, or clothing of people nearby, or land on surfaces such as desks or countertops.
Transmission of these diseases via respiratory droplets generally occurs when they are inhaled through the mouth or nose, or when someone touches the droplets and rubs one of the openings on their face. According to the Centers for Disease Control (CDC), these droplets tend to travel up to 6 feet (1.8 meters) before gravity pulls them to the ground.
Early studies show that SARS-CoV-2 can live on surfaces for up to 3 days, depending on the type of surface and environmental conditions. Viruses typically live longer outside the body in lower temperature, low humidity, and low sunlight conditions. The coronavirus also tends to live longer on flat and hard surfaces like countertops, than it does on rough and soft surfaces like clothing. For example, a recent study demonstrated the virus could live up to 3 hours in aerosol form, up to 24 hours on cardboard, and up to 72 hours on plastic and stainless steel. However, at present it appears that community (i.e., person-to-person) rather than surface transmission (i.e., fomites) is the primary means by which coronavirus is spreading.
How Serious is the Coronavirus?
Very serious. No vaccine currently exists for SARS-CoV-2, and the development of a vaccine for coronavirus is not expected for 12-18 months according to most experts. Further, SARS-CoV-2 is a novel coronavirus, so there has been no known prior human exposure. Thus, humans lack the antibodies our bodies have built up over time and through exposure to fight viruses that are older and more common, such as influenza (flu) .
Early indications from China are that this particular coronavirus is much more virulent than the flu, with mortality rates that are 10-20x higher than influenza. Mortality is particularly elevated among high risk groups, such the elderly, and people with underlying medical conditions (e.g., heart disease, diabetes, lung disease, blood disorders, kidney disease, pregnancy, liver disease, and immune deficiencies). The data on coronavirus mortality is new, and it’s possible other factors could dramatically alter these early figures.
For example, the data below allowed for high rates of hospitalization in serious cases of coronavirus, which represent roughly 20% of infections based off current data. Thus, it’s likely mortality rates would be higher if the healthcare system in other countries were further taxed by more rapid spread of the virus.
Conversely, approximately 80% of coronavirus cases appear to be asymptomatic or less severe. The high number of less severe cases of coronavirus may at first appear to be a good sign. However, less severe cases could lead to higher transmission rates of the virus, thereby increasing its spread. Further, people with less severe cases may not be inclined to undergo testing, which leads to underreporting of infections by individuals who may believe they are suffering from a more common virus.
There are a variety of maps to track the spread of the coronavirus pandemic, which can be helpful to understanding the spread of coronavirus in your community and those of your loved ones. As of the writing of this article, there are only 68 confirmed cases of coronavirus in Texas, though that figure is expected to increase dramatically as more testing becomes available.
What You Can Do To Prevent The Spread of Coronavirus
There are many steps you can take to limit your exposure to coronavirus, the potential for contracting the virus, and the possibility of transmitting it if you become infected. The best way to prevent infection is to limit exposure to the virus by taking precautionary steps, such as:
- Hand Washing: Wash your hands with soap and water regularly for 20 seconds or longer.
- Hand Sanitizer: Use of alcohol-based hand sanitizer containing at least 60% alcohol is acceptable, unless your hands are dirty.
- Cover Coughs & Sneezes: Instead of using your hand to cover your nose and mouth when coughing or sneezing, use the inside of your shoulder or elbow. This will lessen the transmission of respiratory droplets when your hands contact surfaces.
- Don’t Touch Your Face: Avoid touching your face – particularly your nose, eyes, and mouth – as it reduces the coronavirus’s ability to enter your body.
- Disinfect Surfaces: Regular cleaning and disinfecting of commonly touched surfaces (e.g., doorknobs, countertops, light switches, toilets, faucets, mobile phones, handles, desks, keys, elevator buttons, keyboards) will reduce or eliminate respiratory droplets containing the virus.
- See here for a list of disinfecting products the CDC believes to be effective against SARS-CoV-2.
- Social Distancing: Limiting social interaction (e.g., restaurants, bars, gyms, concerts, events, school) can slow the pace of viral transmission, and allow our healthcare system to better manage treatment of infected people with serious cases requiring ventilation.
- Social distancing is designed primarily to slow spread of the virus, and flatten the exponential growth curve in early virus transmission.
- See data below regarding the efficacy of social distancing, which compares the highly disparate responses of Philadelphia and St. Louis to the 1918 flu pandemic.