Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an acute respiratory virus. This virus causes a respiratory disease called COVID-19 and was the genesis of a global pandemic that lasted from March 11, 2020, to mid-2022.

COVID-19 typically produces minor symptoms in most people, particularly people who have received a vaccination or are in good health. In a small percentage of individuals, however, COVID-19 causes severe symptoms that include respiratory failure, sepsis, and multiple organ dysfunction syndrome, making it potentially deadly. SARS-CoV-2 infection does not always cause COVID-19 and is asymptomatic in some individuals.

SARS-CoV-2 spreads from person to person through droplets released when an infected person coughs, sneezes, or talks. It may also be spread by touching a surface with the virus on it and then touching one’s mouth, nose, or eyes, although this method of transmission is rarer. During the COVID-19 pandemic, attempts to slow or stop the spread of SARS-CoV-2 resulted in lockdowns, masking, social distancing, and several other infection prevention measures.

Clinical discussions aside, the emergence of SARS-CoV-2 introduced sweeping social and business changes in the U.S. and elsewhere:

• Many students in the U.S. attended school remotely from home for months or longer during the height of the pandemic.
• City and state governments temporarily banned large-scale, in-person events.
• Business and leisure travel ground to a near halt for a time.
• A historically significant unemployment spike in occurred in 2020.
• The “Great Resignation” saw many workers leave their jobs to retire early or seek more rewarding occupations.

The origins of SARS-CoV-2 continues to be debated. One theory holds that the virus originated from a biological laboratory in Wuhan, China. There is evidence that NIH-funded, gain-of-function research was being performed on coronaviruses in this laboratory, and some evidence suggests that a laboratory accident may have released SARS-CoV-2 into the public. The other major theory holds that SARS-CoV-2 jumped to humans from an infected animal sold at a wet market in Wuhan, China.

Since its original entry into human circulation, SARS-CoV-2 has undergone several mutations. This led to multiple variants of SARS-CoV-2 that were prevalent at different points in the COVID-19 pandemic. The main SARS-CoV-2 variants include:

• Alpha (B.1.1.7), which appeared in November 2020 and was eventually displaced by the Delta variant.
• Beta (B.1.351), which was identified in late 2020 in South Africa. Beta spread to many countries but was never common in the U.S.
• Delta (B.1.617.2), which emerged in late 2020 and became the dominant strain worldwide until displaced by the Omicron variant.
• Omicron (BA.1), which was first identified in November 2021 and, as of August 2022, is the dominant strain of SARS-CoV-2.

While technically SARS-CoV-2 refers to a virus and COVID-19 refers to the disease the virus causes, these terms have become interchangeable. This has led to terms like “asymptomatic COVID-19” and “COVID-19 testing” gaining widespread use despite being technically incorrect.

The COVID-19 pandemic had a profound impact on clinical laboratories, generating a huge demand for SARS-CoV-2 testing throughout the world.

SARS-CoV-2 testing primarily includes:

• Molecular testing, which detects the presence of the genetic material of SARS-CoV-2. Polymerase chain reaction (PCR) tests are an example of molecular diagnostics.
• Antigen testing, which looks for components of SARS-CoV-2 that elicit an immune response. Antigen tests became popular at-home testing options during the pandemic.

The increased demand for SARS-CoV-2 testing led to many new clinical laboratories coming into operations, many of which focused exclusively on such testing. As the demand for SARS-CoV-2 testing declines, these labs are having to pivot to new business models or close their doors.