I know this is a trying time for everyone. With many schools, offices, stores, entertainment and sporting venues etc. closed, it has been very difficult for a lot of us to cope. Realtime Lab (RTL) is trying to help in any way that we can. We are continuing our mission to help people suffering from chronic and unexplained conditions. We are maintaining our exceptional turn-around time and we have, in the last few months, brought on more testing to help with the Covid pandemic. In this post, I’m going to talk about the history of the Covid virus and how we are helping in determining who is contagious and who has antibodies against the virus.
COVID-19, also known as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first linked to Wuhan, China in December of 2019 (1). This is the third coronavirus pneumonia in the past 20 years. The first being the SARS virus, which appeared in Guangdong, China in 2002 and resulted in 774 deaths. In 2012, the Middle East respiratory syndrome coronavirus, which was first detected in Saudi Arabia, caused 858 fatalities(2). All of these viruses are single-stranded positive-sense RNA viruses, which primarily infect mammals. Many domestic and wild animals, including cattle, bats, cats, and dogs, may serve as hosts for coronaviruses, and it is generally understood that these animal coronaviruses do not spread among humans. However, when they do, they can lead to deadly diseases because the viruses are not recognized by the human immune system(3). For COVID-19 the common symptoms are fever (77-98%), cough (59-82%), fatigue (38-70%), sputum production (28-56%), and headache (7-34%) (4, 5).
One of the many components of stopping a pandemic is tracking who is contagious. Early on it became evident that this was going to be difficult with COVID-19 because not only were patients that were presymptomatic contagious, but there was a large contingent of asymptomatic patients who were also contagious. Different reports show that somewhere from 45-75% of patients could be asymptomatic but could still pass on the virus(6). This makes it very difficult to track the progression of the virus, contain the virus, and protect individuals that might be at risk if they contracted the virus and developed symptoms. We at RTL decided to assist in this endeavor by performing PCR testing utilizing the Thermo-Fisher EUA. Thermo-Fisher was one of the first companies to receive an EUA through the US FDA. This procedure (depicted in Figure 1) utilizes samples collected by nasal swabs to collect both human cells and possibly viral particles. Once the specimen is extracted, we use primers, which are specifically designed to recognize sequences on the viral RNA genome, to detect the presence of the virus. This is done using a fluorescent probe which is then monitored in real time as the PCR reaction progresses.
In the future we hope to assist companies and other groups to determine which individuals can safely enter a workplace environment. However, this can only be accomplished through constant testing to ensure that no one later contracts the virus.
The second avenue of testing that we have commenced is serological or antibody testing. This will indicate which patients have been exposed to the virus. Typically, when a person is exposed to a virus, bacteria, fungus, etc. they develop antibodies towards the particular antigen. The progression of COVID-19 is depicted in FIGURE 2. In this figure you see the typical asymptomatic window of day 0 to day 5. During this time you can only detect the presence of the virus using the PCR test. The next window is the IgM window which occurs from day 7 to say 28. We decided not to test this type of antibody because of the overlap with the PCR test, which occurs earlier and is more sensitive. The next antibody that the body starts to produce is IgG, which occurs at about day 14 and progresses to some unknown date. For some viruses, this length of time could be six months and for others the immunity could last years. Studies show that a very large percentage, 80-95%, of those that showed symptoms of COVID-19 start to produce IgG antibodies (7). However, what kind of protections having antibodies bestows is currently unknown.
The process of our test is depicted in FIGURE 3. The patient needs to provide blood through a blood draw. Hopefully in the future this can also be managed through a finger stick and dried blood spot. The blood is spun in order to separate out the serum, which is then loaded into wells. Detector antibodies in the wells will interact with COVID-19 antibodies that the patient may be presenting. If this occurs, a color change will result in the wells.
Illustrated from Arizona Republic
For both our COVID-19 virus test and our antibody test we are getting results out in under 48 hours. We understand that this is a difficult time for everyone and we want to make things easier in any way we can. In order to provide more information, we are offering a free webinar with Dr. Ann Shippy about how she is treating her patients with COVID-19. As always, we want our clients to make informed choices. We wish all of you good health.
- N. Zhu et al., A Novel Coronavirus from Patients with Pneumonia in China, 2019. N Engl J Med 382, 727-733 (2020).
- E. de Wit, N. van Doremalen, D. Falzarano, V. J. Munster, SARS and MERS: recent insights into emerging coronaviruses. Nat Rev Microbiol 14, 523-534 (2016).
- Y. Chen, Q. Liu, D. Guo, Emerging coronaviruses: Genome structure, replication, and pathogenesis. J Med Virol 92, 418-423 (2020).
- X. W. Xu et al., Clinical findings in a group of patients infected with the 2019 novel coronavirus (SARS-Cov-2) outside of Wuhan, China: retrospective case series. BMJ 368, m606 (2020).
- W. J. Guan et al., Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med 382, 1708-1720 (2020).
- R. Yang, X. Gui, Y. Xiong, Comparison of Clinical Characteristics of Patients with Asymptomatic vs Symptomatic Coronavirus Disease 2019 in Wuhan, China. JAMA Netw Open 3, e2010182 (2020).
- A. Wajnberg et al., Humoral immune response and prolonged PCR positivity in a cohort of 1343 SARS-CoV 2 patients in the New York City region. medRxiv, 2020.2004.2030.20085613 (2020).
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