What the CDC says about how the Covid vaccine works
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Started by cutworm - Jan. 3, 2021, 11:43 p.m.

New Approach to Vaccines

mRNA vaccines are a new type of vaccine to protect against infectious diseases. To trigger an immune response, many vaccines put a weakened or inactivated germ into our bodies. Not mRNA vaccines. Instead, they teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies. That immune response, which produces antibodies, is what protects us from getting infected if the real virus enters our bodies.

Facts about COVID-19 mRNA Vaccines

They cannot give someone COVID-19.

  • mRNA vaccines do not use the live virus that causes COVID-19.

They do not affect or interact with our DNA in any way.

  • mRNA never enters the nucleus of the cell, which is where our DNA (genetic material) is kept.
  • The cell breaks down and gets rid of the mRNA soon after it is finished using the instructions.
  • A Closer Look at How COVID-19 mRNA Vaccines Work


    COVID-19 mRNA vaccines give instructions for our cells to make a harmless piece of what is called the “spike protein.” The spike protein is found on the surface of the virus that causes COVID-19.
    COVID-19 mRNA vaccines are given in the upper arm muscle. Once the instructions (mRNA) are inside the immune cells, the cells use them to make the protein piece. After the protein piece is made, the cell breaks down the instructions and gets rid of them.
    Next, the cell displays the protein piece on its surface. Our immune systems recognize that the protein doesn’t belong there and begin building an immune response and making antibodies, like what happens in natural infection against COVID-19.
    At the end of the process, our bodies have learned how to protect against future infection. The benefit of mRNA vaccines, like all vaccines, is those vaccinated gain this protection without ever having to risk theserious consequences of getting sick with COVID-19.
  • Understanding mRNA COVID-19 Vaccines | CDC
  • And this  from CDC
  • Understanding How COVID-19 Vaccines Work | CDC

Types of Vaccines

Currently, there are three main types of COVID-19 vaccines that are or soon will be undergoing large-scale (Phase 3) clinical trials in the United States. Below is a description of how each type of vaccine prompts our bodies to recognize and protect us from the virus that causes COVID-19. None of these vaccines can give you COVID-19.

  • mRNA vaccines contain material from the virus that causes COVID-19 that gives our cells instructions for how to make a harmless protein that is unique to the virus. After our cells make copies of the protein, they destroy the genetic material from the vaccine. Our bodies recognize that the protein should not be there and build T-lymphocytes and B-lymphocytes that will remember how to fight the virus that causes COVID-19 if we are infected in the future.
  • Protein subunit vaccines include harmless pieces (proteins) of the virus that cause COVID-19 instead of the entire germ. Once vaccinated, our immune system recognizes that the proteins don’t belong in the body and begins making T-lymphocytes and antibodies. If we are ever infected in the future, memory cells will recognize and fight the virus.
  • Vector vaccines contain a weakened version of a live virus—a different virus than the one that causes COVID-19—that has genetic material from the virus that causes COVID-19 inserted in it (this is called a viral vector). Once the viral vector is inside our cells, the genetic material gives cells instructions to make a protein that is unique to the virus that causes COVID-19. Using these instructions, our cells make copies of the protein. This prompts our bodies to build T-lymphocytes and B-lymphocytes that will remember how to fight that virus if we are infected in the future.
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By cutworm - Jan. 3, 2021, 11:45 p.m.
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A more in depth article here:

COVID-19 and mRNA Vaccines—First Large Test for a New Approach | Infectious Diseases | JAMA | JAMA Network

The Genetic Advantage

Current antiviral vaccine designs can be described as falling into 2 camps: protein based or gene based. Protein-based vaccines deliver the immune system–stimulating antigen to the body. This category includes whole-inactivated (killed) vaccines, as in the polio and flu shots, and subunit vaccines and virus-like particles, like in the hepatitis B and human papillomavirus vaccines.

Gene-based vaccines take a different tack. They carry the genetic instructions for the host’s cells to make the antigen, which more closely mimics a natural infection. In the case of coronaviruses, the antigen of interest is the surface spike protein the virus uses to bind and fuse with human cells. “You’re not giving them the protein—you’re giving them the genetic material that then instructs them how to make that spike protein, to which they make an antibody response that hopefully is protective,” University of Pennsylvania vaccinology professor Paul Offit, MD, explained in a JAMA livestream in June.

The approach isn’t entirely unfamiliar. In live-attenuated vaccines, like the measles, mumps, and rubella shot, weakened viruses incorporate their genetic instructions into host cells, causing the body to churn out viral copies that elicit antibody and T-cell responses. In newer gene-based designs—viral vector, DNA, and mRNA vaccines—scientists synthesize and insert genetic instructions from the pathogen of interest to induce immune responses.

The viral vector technique transports genetic information in a less harmful virus—often a common cold–causing adenovirus—that’s sometimes engineered so it can’t replicate in the host. DNA and mRNA vaccine designs deliver naked nucleic acids or, more recently, encapsulate them in a carrier nanoparticle. Within each of these versatile platforms, the same production and purification methods and manufacturing facilities can be used to make vaccines for different diseases.

These highly adaptable techniques were waiting in the wings when COVID-19 hit. “The people who jumped on this right away are the people who had vaccine platforms that were conducive for this that were simply sitting there,” said Louis Picker, MD, associate director of the Oregon Health & Science University’s Vaccine and Gene Therapy Institute. “All they had to do is basically figure out what part of [the virus] they were going to put in the vaccine and then run with it.”

Thanks to research beginning in 2002 on the severe acute respiratory syndrome coronavirus and then the Middle East respiratory syndrome coronavirus, which emerged a decade later, scientists knew to focus their initial attention on the novel coronavirus’ spike protein. They also already knew which genetic modifications would stabilize the spike in its “prefusion” configuration—important for a robust and safe antibody response—and those that would make the mRNA less inflammatory and therefore safer. They had also learned how to purify mRNA to rid it of contaminants and how to protect it from degrading too quickly in the body by encasing it in lipid carrier molecules. These delivery vehicles, already in use with therapeutic small interfering RNAs, also help mRNA cross the cell membrane and may even have an immune-stimulating adjuvant effect.

Many of these innovations weren’t possible until recently, according to Barney Graham, MD, PhD, deputy director of the NIAID Vaccine Research Center. “Over the last 10 years, vaccinology has just changed radically,” he said. “I’ve been doing this kind of work for a long time and the kinds of things that can be done now, the technologies available, the way we can understand things in a very detailed level is really stunning to me.”

By metmike - Jan. 4, 2021, 1:19 a.m.
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cutworm,

Thanks very much for this wonderful educational information!