(CNN Español) – The United States is about to have two coronavirus vaccines. The one already approved, that of Pfizer and BioNTech, and the one that is still in the authorization process, that of Moderna.
Although both vaccines are based on RNA messenger technology, they differ greatly. In this episode, Dr. Huerta explains them.
You can listen to this episode on Apple Podcasts, Spotify, or your favorite podcast platform, or read the transcript below.
Hello, I’m Dr. Elmer Huerta and this is your daily dose of information about the new coronavirus. Information that we hope will be useful to take care of your health and that of your family.
The Modern Vaccine: When Is It Approved?
At a virtual meeting in Washington on December 17, 21 experts, members of the US Food and Drug Administration’s group of immunization advisers, voted 20 in favor of abstaining. use, as a matter of urgency, the vaccine in the Moderna laboratory.
The only vote against was cast by Dr. Michael Kurilla, director of the Clinical Innovation Division at the National Center for the Advancement of Translational Sciences, which is part of the US National Institutes of Health. Dr. Kurilla said he would have preferred the authorization to be addressed only to people at high risk because, in his opinion, a general statement for people over the age of 18 is too broad.
The following, as with the Pfizer vaccine authorization, is that the FDA accepts the recommendation of its experts. The United States Centers for Disease Control and Prevention (CDC) immunization advisory committee then meets within 48 hours of that decision to finally decide who will receive the vaccine.
On the other hand, it is very likely that the commission will reaffirm that the first to be vaccinated will be health workers and elderly residents of long-term care institutions.
Pfizer and Moderna vaccine: similarities
The Modern Vaccine uses the same RNA messenger technology as the Pfizer vaccine, but there are important similarities and differences that we will discuss below.
The main similarity is that both use the new technology of RNA or messenger RNA, which does not use the complete virus, but a genetic sequence of the viral genome in its final product.
What scientists have done is to decipher the genetic structure of the apex, an antenna-like structure made up of proteins that allow the virus to enter the cell.
The virus’s genome contains instructions for making its own spike proteins, and researchers have decoded this instruction manual to make it.
This instruction manual is actually a molecule called messenger RNA 1273, which, after being purified, is the vaccine.
When injected into humans, this 1273 messenger RNA is taken up by human cells, which begin to produce spike proteins. He tricks the defense system into believing that the body is being attacked by the whole virus. The body responds with the production of neutralizing antibodies, which protect against future infections.
Pfizer and Moderna vaccine: differences
However, the differences include the fact that the Pfizer vaccine is authorized for use in adolescents aged 16 to 17 years. While the Moderna vaccine has been approved for people over the age of 18.
Another difference is that the Moderna vaccine contains 100 micrograms of mRNA, while the Pfizer vaccine contains 30 micrograms. The reason for the large difference between these doses is not known, although some scientists believe it could be because the genetic sequences of the mRNAs of both vaccines have small differences in code.
Another difference is that the Pfizer vaccine is given every 21 days, while Moderna is given every 28 days.
Another important difference is the freezing point at which they must be stored.
Pfizer needs to be at minus 70 degrees Celsius. Modern requires storage at a temperature of minus 20 degrees Celsius.
Temperature: a big difference between the two vaccines
This difference is very important, because the Moderna vaccine can be stored in regular freezers. This would make it more useful in small towns that do not have the specialized freezers that the Pfizer vaccine requires.
Another important difference is the coating that delicate mRNA molecules use to preserve and transport them in cells. That envelope is made up of microscopic fat particles called nanoparticles. Pfizer’s are manufactured in Acuitas’ Canadian lab, while Moderna manufactures its own nanoparticles.
This difference in fat nanoparticles makes a difference in freezing the needs of vaccines and may also affect the way they work.
Brian Ferguson, an immunology researcher at Cambridge University, told the newspaper The Financial Times, Having some inflammatory activity, it is possible that these nanoparticles have an action that helps the immune system produce antibodies and T cells targeting the Sars-CoV-2 virus.
In conclusion, despite the use of the same RNA messenger technology and over 94% efficacy, the two vaccines show important differences, the clinical significance of which will be known when both begin to be used in the real world, outside of clinical trials. control.
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