The mRNA vaccine, and what we know and don’t know yet
Development and distribution of the vaccine to protect against COVID-19 has moved very quickly, leaving many people with questions about what’s happening.
What is a vaccine?
The website at www.vaccines.gov/basics explains that, “A vaccine is made from very small amounts of weak or dead germs that can cause diseases — for example, viruses, bacteria or toxins.”
The National Institutes of Health (NIH) website breaks it down further, explaining that there are three basic types of vaccines. The most common type are whole pathogen vaccines that “consist of entire pathogens that have been killed or weakened so that they cannot cause disease.… Many of the vaccines in clinical use today fall into this category.”
Less common are subunit vaccines, which “include only the components, or antigens, that best stimulate the immune system.” These vaccines need to be boosted with adjuvants to trigger an immune response.
The NIH website describes nucleic acid vaccines as an “investigational approach” that “involves introducing genetic material encoding the antigen or antigens against which an immune response is sought.”
The mRNA vaccine
The new COVID-19 vaccines are a type of nucleic acid vaccine, using what is known as mRNA or “messenger RNA.” The mRNA vaccines had been considered unstable and difficult to deliver to cells, but have become more reliable.
The Centers for Disease Control and Prevention (CDC) website goes into more detail, explaining that 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.”
The COVID-19 mRNA vaccine will “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.”
Although there are not yet any licensed mRNA vaccines in use, “researchers have been studying and working with them for decades,” according to the CDC. “Interest has grown in these vaccines because they can be developed in a laboratory using readily available materials. This means the process can be standardized and scaled up, making vaccine development faster than traditional methods of making vaccines.”
The CDC offers this reassurance: “mRNA vaccines do not use the live virus that causes COVID-19” and they “cannot give someone COVID-19.”
Also, “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.”
What is an EUA
The new COVID-19 mRNA vaccine was developed by Pfizer, a U.S. company with ties to the Northwest Corner, and a Germany company called BioNTech.
It has not been approved by the Food and Drug Administration but it is being used because of an EUA or Emergency Use Authorization from the FDA. Another vaccine, by a company called Moderna, could be released very soon; the FDA’s Vaccines and Related Biological Products Advisory Committee was expected to meet Dec. 17 to discuss and possibly approve it.
Pfizer-BioNTech have done clinical trials on “approximately 20,000 individuals 16years of age and older,” who “have received at least one dose of the vaccine,” according to Pfizer’s website.
In the trials, Pfizer said, the “vaccine has been shown to prevent COVID-19 following two doses given three weeks apart. The duration of protection against COVID-19 is currently unknown.”
Among the many things not known yet about the new COVID-19 vaccines is how they will work in the real world, as opposed to a closed lab setting. It remains to be seen what will happen when someone is vaccinated and then goes out among people who have not yet been vaccinated and perhaps are infected but don’t know it.
Even for those who are observing a fairly strict quarantine, it’s possible that within one household or family unit there will be some people who have been immunized and others who have not.
For these and other reasons, the CDC recommends continuing to follow social distancing protocols: Wear a face mask, avoid crowds and indoor gatherings and stand 6 feet apart or more. Wash your hands often and thoroughly.
Even people who have already been infected and have recovered should continue to practice safety protocols. The jury is still out, according to the CDC, on post-infection immunity and how long it lasts.
“Since this virus is new, we don’t know how long natural immunity might last,” according to the CDC website. “Some early evidence — based on some people — seems to suggest that natural immunity may not last very long.”
It is also not yet known whether mass vaccination will protect the community at large through what is known as “herd immunity.”
The CDC warns that, “Experts do not know what percentage of people would need to get vaccinated to achieve herd immunity to COVID-19.
“Herd immunity is a term used to describe when enough people have protection — either from previous infection or vaccination — that it is unlikely a virus or bacteria can spread and cause disease.
“As a result, everyone within the community is protected even if some people don’t have any protection themselves.
“The percentage of people who need to have protection in order to achieve herd immunity varies by disease.”
It is also not known yet how long the immunity provided by the new vaccines will last.
Where to learn more
Most of the information in this article was collected from various Centers for Disease Control (CDC) information pages; the Department of Health and Human Services (HHS); the National Institutes of Health; and the U.S. Food and Drug Administration.
Those websites are frequently updated and are the best places to get definitively correct and detailed information.
There is also specific information on the new vaccines at the websites of Pfizer and Moderna.
Specific information on Connecticut’s plans can be found at the state of Connecticut’s COVID-19 portal at https://portal.ct.gov/Coronavirus; and in this week’s article on Page A1 by Debra A. Aleksinas.