Coronavirus 101 (ePub)

Coronavirus 101 is a book about the 2019-20 pandemic. What is the 2019-20 coronavirus? It is the ongoing pandemic, leading health experts into a frenzy and the general public into disarray. The 2019-20 coronavirus outbreak was first identified in Wuhan, Hubei, China, in December 2019 and was officially recognized as a pandemic by the World Health Organization (WHO) on March 11, 2020. The 2019-20 coronavirus is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since 2019, more than 335,000 cases of COVID-19 have been reported in almost two hundred countries and villages, resulting in thousands of fatalities in early 2020.

The symptoms of COVID-19 are variable depending on the type of variant contracted, ranging from mild symptoms to a potentially fatal illness. Common symptoms include coughing, fever, loss of smell (anosmia) and taste (ageusia), with less common ones including headaches, nasal congestion and runny nose, muscle pain, sore throat, diarrhea, eye irritation, and toes swelling or turning purple, and in moderate to severe cases, breathing difficulties. People with the COVID-19 infection may have different symptoms, and their symptoms may change over time. Three common clusters of symptoms have been identified: one respiratory symptom cluster with cough, sputum, shortness of breath, and fever; a musculoskeletal symptom cluster with muscle and joint pain, headache, and fatigue; and a cluster of digestive symptoms with abdominal pain, vomiting, and diarrhea. In people without prior ear, nose, or throat disorders, loss of taste combined with loss of smell is associated with COVID-19 and is reported in as many as 88% of symptomatic cases. Of people who show symptoms, 81% develop only mild to moderate symptoms (up to mild pneumonia), while 14% develop severe symptoms (dyspnea, hypoxia, or more than 50% lung involvement on imaging) that require hospitalization, and 5% of patients develop critical symptoms (respiratory failure, septic shock, or multiorgan dysfunction) requiring ICU admission. At least a third of the people who are infected with the virus do not develop noticeable symptoms at any point in time. These asymptomatic carriers tend not to get tested and can still spread the disease. Other infected people will develop symptoms later (called "pre-symptomatic") or have very mild symptoms and can also spread the virus.

As is common with infections, there is a delay between the moment a person first becomes infected and the appearance of the first symptoms. The median delay for COVID-19 is four to five days, possibly being infectious on 1-4 of those days. Most symptomatic people experience symptoms within two to seven days after exposure, and almost all will experience at least one symptom within 12 days. Most people recover from the acute phase of the disease. However, some people-over half of a cohort of home-isolated young adults identified in June 2021 continued to experience a range of effects, such as fatigue, for months even after recovery. This is the result of a condition called long COVID, which can be described as a range of persistent symptoms that continue for weeks and/or months at a time. Long-term damage to organs has also been observed after the onset of COVID-19. Multi-year studies are underway to further investigate the potential long-term effects of the disease. The Omicron variant became dominant in the U.S. in December 2021. Symptoms with the Omicron variant are less severe than they are with other variants.