learn about COVID-19, its impact, and what you can do about it.
One of the major challenges that face defeating COVID-19 is that being a novel coronavirus (meaning it is a strain that has not been identified in humans before) there is yet to be any vaccine against COVID-19. Time is of the essence with hundreds of research teams across the globe searching for a virus. With the necessity of a vaccine to return to ‘normal,’ what would normally be a 10-year process must be significantly shortened. Currently (as of August 17, 2020), 138 vaccines are in the pre-clinical stage (have not been tested in humans), 25 are in phase one trials (smallest human trials testing safety), 15 are in phase two trials (slightly larger trials focusing on the efficacy of the vaccine), 7 are in phase three trials (largest trials studying safety, efficacy, and dosing) with none approved yet.
One vaccine currently in phase III of testing was made by Moderna, Inc., a company based in Cambridge, Massachusetts. Their vaccine is known as mRNA-1273. Moderna moved quickly; just two days after the Chinese authorities shared the Sars-CoV-2 (the virus that causes COVID-19) genetic sequence, Moderna and the NIH finalized mRNA-1273’s genetic sequencing and started preparations for manufacturing the vaccine (Moderna).
First, scientists isolated the sequence in the Sars-CoV-2 sequence that coded for the spike protein (a protein on the surface of Sars-CoV-2 which binds to human cell receptors). By binding to a receptor, the virus’ membrane fuses with the membrane of the human cell and the virus is able to enter it. Due to the crucial role that the spike protein plays in causing coronavirus, it has been identified as a possible vaccine candidate.
Scientists then encoded the genetic code containing the instructions to produce the spike protein in an mRNA (messenger RNA) molecule. This mRNA could be used as a vaccine. The mRNA molecule can be injected like a flu vaccine. Once injected, the mRNA is taken to immune cells in the lymph nodes. Cells receive the instructions to code for the spike protein, simulating exposure to the coronavirus. Immune cells exposed the virus would learn how to gain immunity and protect the body against COVID-19 (active acquired immunity). Therefore, should the body contract COVID-19, the immune cells would know how to fight it off due to the immune response generated from the vaccine.
Phase one of testing began on March 16 after FDA approval on March 4 (Moderna). On March 23 Moderna announced that their vaccine could be used in emergencies starting the fall of 2020, even though the official vaccine would not be released for another probable 12-18 months. On May 12, Moderna received an FDA Fast Track designation which increases communication with the FDA and speeds up the testing process so that a vaccine can be produced more quickly. Moderna announced positive interim data from Phase 1 trials on May 18, and shortly after on May 29 phase two began. Phase III of trials began on Jul 27 in partnership with the NIH and BARDA. These trials are occurring in 89 sites across the United States, 24 of which are part of the CoVPN (INIH Coronavirus Prevention Network) (Moderna). Half of the participants will receive two 100 microgram injections of the vaccine, while the other half will receive two injections of a saline placebo. The two injections will be given 28 days apart. This trial is a double-blind trial, the gold standard for research meaning that both researchers and patients do not know which participants are receiving the vaccine, thus eliminating potential bias.
While this virus is still in clinical trials, the results thus far are promising and the US government has purchased 100 million doses of the vaccine. Hopefully this virus will continue to show its efficacy and safety in phase III, so it will be available to the public soon.
Written by Jennifer Do-Dai
“Fast Track.” U.S. Food and Drug Administration, FDA, www.fda.gov/patients/fast-track-breakthrough-therapy-accelerated-approval-priority-review/fast-track.
Kommenda, Niko, and Frank Hulley-Jones. “COVID Vaccine Tracker: When Will We Have a Coronavirus Vaccine?” The Guardian, Guardian News and Media, 17 Aug. 2020, www.theguardian.com/world/ng-interactive/2020/aug/17/covid-vaccine-tracker-when-will-we-have-a-coronavirus-vaccine.
“Moderna's Work on a COVID-19 Vaccine Candidate.” Moderna, Inc., 2020, www.modernatx.com/modernas-work-potential-vaccine-against-covid-19.
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