Coronavirus

Transmission

COVID-19 is transmitted via aerosols and infects cells of the respiratory tract. The virus is thought to spread mainly from person-to-person who are in close contact with one another (within 6 feet). Less commonly, people may become infected by touching a contaminated surface and then touching their face. The time from infection until occurrence of symptoms (incubation period) is usually 2-14 days. Recent studies suggest that COVID-19 may be spread by infected individuals who are asymptomatic.

Signs and symptoms

Common presenting symptoms include fever, shaking chills, cough, shortness of breath, fatigue, muscle aches, and loss of smell. The elderly and patients with hypertension and heart disease are particularly susceptible to severe disease with hypoxia, pneumonia, ARDS, multiorgan failure, septic shock, and thrombotic events. The fatality rate, based on existing data, is estimated to be 1-2%.  Symptoms usually appear 2-14 days after exposure to the virus. Children generally have mild illness with symptoms similar to adults.

SARS-CoV-2 Coronavirus

SARS-CoV-2, the causative agent of COVID-19, is a Coronavirus, a group of RNA viruses that cause diseases in many animals including humans. Several human Coronaviruses are among the causes of the common cold. The SARS and MERS coronaviruses cause more serious respiratory disease.

Coronaviruses are members the family Coronaviridae. They are enveloped viruses with positive-sense single-stranded RNA genomes that range in size from 26 to 32 kilobases, making them among the largest of the RNA viruses. The nucleocapsid has helical symmetry and is wrapped in an icosahedral protein shell. The name Coronavirus is derived from the characteristic club-shaped spikes that project from their surface which, when the virus is viewed by electron microscopy, looks like the solar corona.

Genetic analysis has revealed that SARS-CoV-2 genetically clusters with the genus Betacoronavirus together with two bat-derived strains. It is thought to have a zoonotic origin and is 96% identical to the genomes of other bat coronaviruses.

Prevention

Keeping distance between yourself and other people outside of your home (staying at least 6 feet away), avoiding groups, crowded places and mass gatherings. You could spread COVID-19 to others even if you do not feel sick.

Wash your hands frequently (with soap and water for at least 20 seconds, especially after blowing your nose, coughing, or sneezing and after you’ve been in a public place. Avoid touching your eyes, nose and mouth with unwashed hands.

If soap and water are not available, use a hand sanitizer that contains at least 60% alcohol. Cover all surfaces of your hands and rub them together until they feel dry.

Cover your mouth and nose with a cloth face cover* when around others to protect yourself from getting the virus or to protect others in case you are infected. It is not necessary to wear a face mask in a private setting, however it is important to always cover your mouth and nose with a tissue when you cough, or sneeze inside of your elbow. Throw tissues in the trash and immediately wash hands with soap and water for at least 20 seconds, or use hand sanitizer.

Clean AND disinfect frequently touched surfaces daily. This includes tables, doorknobs, light switches, countertops, handles, desks, phones, keyboards, toilets, faucets, and sinks. If surfaces are dirty, clean them. Use detergent or soap and water prior to disinfection. Then, use a household disinfectant. 

*Cloth face coverings should not be placed on young children under age 2, anyone who has trouble breathing, or is unconscious, incapacitated or otherwise unable to remove the mask without assistance.

Individuals who are at higher risk should take extra precautions. Those at high risk for severe illness include:

• People aged 65 years and older.
• Residents of nursing homes or long-term care facilities.

People of all ages with underlying medical conditions, particularly if not well controlled, including:

• People with chronic lung disease or moderate to severe asthma.
• People who have serious heart conditions
• People who are immunocompromised
  • Many conditions can cause a person to be immunocompromised, including cancer treatment, smoking, bone marrow or organ transplantation, immune deficiencies, poorly controlled HIV or AIDS, and prolonged use of corticosteroids and other immune weakening medications
• People with severe obesity (body mass index [BMI] of 40 or higher.
• People with diabetes
• People with chronic kidney disease undergoing dialysis

People who live or work with high-risk patients.

• Healthcare workers
• Employees of nursing homes and other chronic care facilities

Diagnosis

Clinicians are not able to accurately diagnose coronavirus based on signs and symptoms alone. Detection of viral RNA by reverse transcription polymerase chain reaction (RT-PCR) using primers highly specific for SARS-CoV-2 is the most common method used to confirm the diagnosis. Isothermal amplification methods are also available. Testing is typically done on respiratory samples obtained by a nasopharyngeal swab, nasal swab, saliva, sputum sample, or bronchoaveolar lavage (BAL) sample. Over 80 different viral RNA detection tests have received emergency use authorization by the FDA and many others are used world-wide. Viral antigen testing is another method for detecting the virus in respiratory samples. Rapid viral antigen tests, such as lateral flow tests, are less sensitive than RNA detection methods, but they can be performed at the site of patient care such as the physicians’ office or emergency department. These tests offer the possibility of identifying an infected patient early in the course of the disease and during the patient’s visit to the health care facility. Serology tests to determine the presence of antibody, which indicates prior exposure to the virus, are available, but their performance varies widely.

Treatment

Most people have mild symptoms and can recover at home without medical care. Get rest, stay hydrated and take over-the-counter medications to feel better, such as acetaminophen. Monitor your symptoms and stay in touch with your doctor. You should stay at home except to get medical care unless you have trouble breathing.

Currently there are no effective direct-acting antiviral drugs. Remdesivir has shown the ability to reduce hospital stay in patients with severe disease in one study. However, no reduction in mortality was observed. Many other studies of remdesivir in COVID-19 are ongoing.  

Recommended Reading

https://www.cdc.gov/coronavirus/2019-nCoV/index.html

https://www.fda.gov/emergency-preparedness-and-response/counterterrorism-and-emerging-threats/coronavirus-disease-2019-covid-19#new