What is the novel coronavirus and how does testing work?

This undated electron microscope image made available by the U.S. National Institutes of Health in February 2020 shows the Novel Coronavirus SARS-CoV-2, yellow, emerging from the surface of cells, blue/pink, cultured in the lab. Also known as 2019-nCoV, the virus causes COVID-19. The sample was isolated from a patient in the U.S. (NIAID-RML via AP)

Information provided below is compiled from various sources, including the Centers for Disease Control and Prevention, the Hamilton County Health Department and others.

What is the novel coronavirus?

Coronaviruses are a family of viruses, some of which cause respiratory illness in humans. The virus exhibits a crown-like halo, when viewed under an electron microscope, which is how it got its name.

Coronaviruses have been found circulating among animals, such as camels, cats and bats and a few have jumped to people - a spread that is defined by epidemiologists as "zoonotic."

Prior to December 2019, there were four coronaviruses that were known to be circulating among people, two of which were discovered in the 1960's and two more discovered in the past 2 decades. These coronaviruses caused about 25% of colds.

Two other coronaviruses have emerged over the past two decades that have caused severe illness and death. One caused Severe Acute Respiratory Syndrome (SARS), a disease that emerged in 2002, that infected about 8,000 and killed about 800. The mortality rate for this virus was about 11%.

Another coronavirus causes Middle East Respiratory Syndrome (MERS). The virus emerged in Saudia Arabia in 2012 and has sickened about 2,500 and killed about 860. The mortality rate for MERS has been estimated at about 29%.

The viruses that cause SARS and MERS aren't easily transmissible between people, and public health officials have been able to control their spread. There has been no community spread of SARS since 2003, according to the World Health Organization. SARS is thought to have originated in bats, then jumped to civet cats, and then to humans. MERS is believed to have passed from camels to humans.

In December, another coronavirus emerged that shared some of the same genes as SARS, and therefore has been named SARS-CoV-2019, by the WHO. The understanding of this virus, which causes the disease COVID-19, is evolving almost daily, as scientists have raced to understand how contagious it is, its incubation period, it's morbidity and mortality rate, and how it passes between people.

The most recent WHO report suggested that the average mortality rate for COVID-19 is 3.4%, but this number continues to evolve.

On Jan. 30, the World Health Organization declared 2019-nCoV, a coronavirus, a public health emergency of international concern and on March 10, declared it a pandemic. The last time it declared a pandemic was the swine flu in 2009.

What is the testing protocol?

Health care providers (clinicians at hospitals, emergency departments, medical offices, urgent cares) should contact their local/state health department immediately to notify them of patients with fever and lower respiratory illness who they suspect may have COVID-19. Clinicians should use their judgment to determine if a patient has signs and symptoms compatible with COVID-19 and whether the patient should be tested. Most patients with confirmed COVID-19 have developed fever and/or symptoms of acute respiratory illness (e.g., cough, difficulty breathing). Priorities for testing may include:

  1. Hospitalized patients who have signs and symptoms compatible with COVID-19 in order to inform decisions related to infection control.

  2. Other symptomatic individuals such as, older adults and individuals with chronic medical conditions and/or an immunocompromised state that may put them at higher risk for poor outcomes (e.g., diabetes, heart disease, receiving immunosuppressive medications, chronic lung disease, chronic kidney disease).

  3. Any persons, including healthcare personnel, who within 14 days of symptom onset had close contact with a suspect or laboratory-confirmed COVID-19 patient, or who have a history of travel from affected geographic areas within 14 days of their symptom onset.

There are epidemiologic factors that may also help guide decisions about COVID-19 testing. Documented COVID-19 infections in a jurisdiction and known community transmission may contribute to an epidemiologic risk assessment to inform testing decisions. Clinicians are strongly encouraged to test for other causes of respiratory illness (e.g., influenza).

Mildly ill patients should be encouraged to stay home and contact their health care provider by phone for guidance about clinical management. Patients who have severe symptoms, such as difficulty breathing, should seek care immediately. Older patients and individuals who have underlying medical conditions or are immunocompromised should contact their physician early in the course of even mild illness. All patients should call a provider before arriving in case they have special protocols in place, according to the Hamilton County Health Department.

"One common misconception is that people think the proper way to go about testing is to head to a doctor's office, an ER, or even a lab. The best thing to do is to call to report symptoms – and that's what we've been telling our members. If symptoms warrant testing, a health care provider will advise where to go for testing, and a health care provider must perform the testing to be sent to an appropriate lab. While the number of tests available are increasing, it is important to follow those steps to make sure those most at risk are tested and to minimize frustration around the pathway to being screened," Dr. Andrea Willis, chief medical officer of BlueCross BlueShield Tennessee.

Clinicians should continue to work with their local and state health departments to coordinate testing through public health laboratories. In addition, COVID-19 diagnostic testing, authorized by the Food and Drug Administration under an Emergency Use Authorization (EUA), is becoming available in clinical (commercial) laboratories. This additional testing capacity will allow clinicians to consider COVID-19 testing for a wider group of symptomatic patients.

Testing for the new virus has lagged across the country, meaning there are likely more people infected by COVID-19 than reported.

For more coronavirus frequently asked questions, read more here.