CASES study:  COVID-19 Arapahoe SErosurveillance Study

COVID-19 which stands for coronavirus disease 2019, was first identified in Wuhan, China. In late December 2019, doctors identified a cluster of patients with a viral pneumonia syndrome in Wuhan which became the first cases of known COVID-19. COVID-19 is a respiratory disease that can cause a range of symptoms with some individuals having mild while others have more severe illness.

Shortly after the first cases of COVID-19 were seen in Wuhan, the virus causing the disease was identified. SARS-CoV-2, the virus that causes COVID-19, is a novel coronavirus, meaning that it is a virus never seen before in humans. It is thought to spread mostly from person-to-person through respiratory droplets when someone infected with the virus sneezes, coughs, or talks. When people are in close contact with each other (within about 6 feet) it is more likely to spread and infect someone new. The virus can also spread indirectly by touching an object that is contaminated with the virus and then touching your face.

After the virus was discovered in China, SARS-CoV-2 quickly spread to the rest of the world, leading to the current COVID-19 pandemic, and reached the United States with the first documented case in Snohomish County, Washington on January 20, 2020 The United States now has community spread of SARS-CoV-2 which is why we want to understand who in the community has had the viral infection and where it has spread within our community.

Early reports from China raised concerns that health care workers were at higher risk for COVID-19, the disease caused by SARS-CoV-2. In the US, it is assumed that First Responders including firefighters, police and emergency medical service employees, similar to healthcare practitioners, are at high risk for exposure to SARS-CoV-2. However, little is known about COVID-19 in this population. To ensure the health and safety of First Responders, both at work and in the community, we need to understand the prevalence (the percent of people who were infected with the virus) of SARS-CoV-2 within this population and how that prevalence changes over time. 

Since SARS-CoV-2, the virus that causes COVID-19 disease, is a novel virus that infects humans we need to learn more about how the immune system responds to viral infection. We will test first responders at multiple timepoints to understand how the virus spreads and how antibodies change over time among a higher risk community.

In addition to looking at how the virus spreads, the CASES project will also test two new methods of looking at antibodies in the blood. Antibodies are something your body produces to help fight an infection and can be used to test for whether you have ever been infected with the virus. During phase 1 of the study, we will collect venous blood and blood from a finger stick. This blood will be tested for antibodies using three methods:

1. A validated ELISA (Enzyme-Linked ImmunoSorbent Assay) antibody test (the “best” test) using venous blood.
2. An experimental Multiplex antibody assay using venous blood.
3. Both tests using blood from the finger stick instead of venous blood. 

ELISA: The validated ELISA test for antibodies from Exsera BioLabs (see CU Anschutz Research Roll Out Antibody Test) will be used to determine whether an individual has truly been exposed to the virus by testing for antibodies in venous blood. This test will tell us if someone is a “true” positive or “true” negative. This is a very good test but can be expensive to complete, uses more blood than other tests, and requires face-to-face contact during the blood draw. 

Multiplex: As an alternative to the ELISA we are going to use venous blood taken from participants to test a Multiplex assay for antibodies to SARS-CoV-2. A multiplex assay is a less expensive way of testing for SARS-CoV-2 antibodies and uses less blood than the ELISA test meaning we can test more people using less resources. If this test is validated it can be used by future studies. 

Finger Stick: Performing venous blood draws for testing of SARS-CoV-2 in the community requires trained phlebotomists to use personal protective equipment, which is limited. We want to test whether the ELISA and Multiplex assays described above are just as accurate if we use finger stick blood rather than venous blood. A participant will use a lancet (finger prick) to obtain a small drop of their own blood that is then gently dabbed on filter paper and dried. This eliminates the need for personal protective equipment or trained personnel to draw blood and, if found to be effective, will be a safe alternative for SARS-CoV-2 antibody testing.

Sensitivity and specificity are measures of how well a test provides an accurate result. The sensitivity of a test tells us how good that test is at identifying people who are “true-positives”, or the percent who test positive, among those who truly have the disease. The specificity tells us how good the test is at identifying people who are “true-negatives”, or the percent who test negative, among those who truly do not have the disease. The ELISA Assay (the “best” test)we will be using in the CASES study has a sensitivity of 90%-100% and a specificity near 100%. The high sensitivity and specificity of this test reveal that it is very good for figuring out who is truly negative and truly positive. However, no test is 100% accurate and there is the possibility that the results can be incorrect. Therefore, it is important to talk to your healthcare provider about your test results.

If you test positive for antibodies to SARS-CoV-2 it can mean several things. You most likely were exposed to the virus, had the COVID-19 infection  and now have antibodies to the virus in your blood. You could also have a current infection, however most people who have had COVID-19 will recover by the time antibodies show up in the blood. Since no tests are 100% accurate, you could also have a false positive. The CDC does not recommend modifying workplace or living situations based only on serologic test results. In addition, a positive result does not mean you are immune to the virus. If you have a positive antibody test result and are having COVID-19 symptoms (cough, fever, shortness of breath etc.) you should speak with your medical provider.

There are several things you can do to keep yourself and others safe. Educate yourself on how the virus is spread. Wash your hands often with soap and water for at least 20 seconds and use hand sanitizer. Avoid touching your nose, eyes, and mouth. Avoid close contact with anyone who is sick, whether inside or outside of your home. Wear a mask to cover your nose and mouth when you are around others which will help to prevent spreading COVID-19 to others even if you do no feel ill. Clean and disinfect surfaces that you touch daily using soap and water and a household disinfectant. Finally, monitor your health and be alert for COVID-19 like symptoms like fever, cough, shortness of breath, and other symptoms as stated by the CDC

Because the virus SARS-CoV-2 and the disease COVID-19 are new in the human population, scientists around the world are rapidly reporting new information.  This can make it seem difficult to keep up on the latest information. To learn more about COVID-19 and SARS-CoV-2 please ensure you are getting information from trusted sources, including official public health and safety authorities.

The US Centers for Disease Control and Prevention: Coronavirus Disease 2019 – Frequently Asked Questions

FEMA Coronavirus Rumor Control: FEMA Coronavirus Rumor Control

The US Centers for Disease Control and Prevention: CDC: COVID-19 Serology Surveillance Strategy