As Tedros Adhanom Ghebreyesus, head of the World Health Organization stated in a press conference last month, “The key message is to test, test, test.”
First of all, let’s discuss the 2 main types of COVID-19 testing that are currently being offered to the population and their differences.
The first is a nasopharyngeal swab, which detects the presence of active COVID-19 genetic material. As viruses replicate, their genetic material (i.e DNA or RNA) becomes exposed and we are able to use PCR (Polymerase Chain Reaction) technology to detect an active viral infection. Nasopharyngeal swab testing will NOT tell you if someone was previously infected and will NOT tell you if someone has antibodies in their system to COVID-19.
The second is antibody testing, which detects immune cells (i.e. Antibodies) produced against COVID-19 within the bloodstream. This can be achieved by performing a standard blood draw on a patient or finger stick. When our bodies become infected by a virus, our immune system builds specific antibodies to the virus to not only tag it for destruction, but also helps protect us from future infections as well.
Antibody finger prick testing uses a small sample of blood to look for specific biomarkers associated with Covid-19 — Immunoglobulin G (IgG) and Immunoglobulin M.
IgM – Your body makes IgM antibodies when you are first infected with a new virus or bacteria. When positive, this typically means there is an active and acute infection occurring within the body.
IgG – As your body responds to an infection it begins to convert IgM antibodies to IgG antibodies. When positive, this typically means a person has been vaccinated or has overcome an infection.
As countries across the world attempt to halt the spread of COVID-19, many of their efforts are being hampered by shortages of crucial testing kits. To combat this, the Food and Drug Administration (FDA) has granted an emergency use authorization (EUA) for coronavirus tests within the US, which allows several companies to gain regulatory approval for test kits more quickly.
Large population testing is crucial at not only localizing the prevalence within each county, but allows us to get a better idea of which patient populations (e.g., obesity, hypertension, diabetes, age) are most affected.
Nasopharyngeal testing also allows us to catch COVID-19 positive patients earlier at which point we can intervene with therapy and quarantine them if they have an active infection. Being able to test a person for antibodies to COVID-19 on the other hand, allows 2 main talking points:
COVID-19 Antibodies from previously recovered patients could help speed up the recovery of those who are in critical condition (e.g., on ventilator support, worsening oxygen levels, worsening chest x-ray) by helping to decrease the viral load quicker.
There are several studies currently underway across the U.S. on active patients in critical condition who have been transfused with COVID-19 positive plasma antibodies. People who test positive for the virus would then feel more comfortable to return to work and help re-stimulate the economy. It is thought that having positive antibodies may in fact protect those from reinfection.
We are not out of the woods just yet and still do not have a clear picture of what is to come in the near future, but if there is one thing we have learned from this is better preparedness.
We need to continue to work together and continue helping each other get a better understanding of COVID-19. We will overcome this together!