Answering Questions About the mRNA Vaccine
Part 1 of 2
The rollout of the Moderna coronavirus vaccines has reached rural areas around Montana, including the Ruby Valley. Healthcare workers and nursing home residents have been the first to receive the vaccine and most of the population should have an opportunity to obtain the first of two doses of the vaccine by the end of April. The only vaccines which have received FDA emergency use authorization to date are produced by Moderna and Pfizer/Bio-N-Tech. Both vaccines use a new technology called messenger RNA (mRNA). What is an mRNA vaccine? Why is it different? Is it safe? How long will protection last? Here are the answers to those questions and a few more, in our two part series.
What is an mRNA vaccine and how is it different from a traditional vaccine?
In answering this question, it’s probably best to start by explaining what a vaccine is. Vaccines train the immune system to identify a virus and generate an immune response to fight it. Traditional vaccine development has been around since 1796 in Europe and as early as 1000CE in China. Traditional vaccines can be very time consuming to create as the virus is grown in a biological material such as hen’s eggs. The virus is then weakened or inactivated and used for the vaccine. Rather than using a weakened or inactivated virus to create vaccines, mRNA vaccines provide cells with the information needed to create proteins that generate an immune response. Once the immune response is generated, the body is prepared to attack a live virus.
mRNA molecules are not alien to the body. They are manufactured naturally in the nucleus of the cell in order to create various proteins. mRNA tells cells in the body how to create specific amino acids which combine to create proteins.
Why haven’t mRNA vaccines been developed for other viruses?
Early research using mRNA to build vaccines was slow to develop because (1) ordinary mRNA doesn’t produce many proteins, (2) the molecules degrade quickly and (3) RNA can set off a serious immune response that isn’t related to the intended immune response. However, the concept of using mRNA to fight disease made sense because the body uses it naturally to make tiny proteins to keep the body alive and healthy. The problem with synthetic mRNA is that the body senses an intruder and fights it before the mRNA has a chance to create the needed proteins.
Researchers have been investigating the use of mRNA for vaccines for over 20 years and the challenges encountered in the early research have been resolved. Tests have been ongoing to use mRNA for other diseases such as the flu and Zika virus. However, this research was not deemed to be urgent. With the pandemic, a large volume of funding and research resources became focused on expeditiously developing the Covid-19 vaccine using mRNA technology.
Clinical trials are also underway to test the application of mRNA to fight certain cancers.
Is mRNA safe?
The mRNA coronavirus vaccines are safe. mRNA vaccines do not alter your DNA and do not enter the nucleus of the cell where DNA is located. mRNA degrades quickly in the body, typically within two days.
Because these vaccines were developed so quickly, some people have been concerned that safety protocols were bypassed. In the past ten years, over 20 clinical trials have been conducted using mRNA vaccines to fight the flu, Zika and cancer. Typically, the FDA takes months or years to review the results of clinical trials due to bureaucratic backlog. For the coronavirus, the standard three stages of clinical trials received expedited FDA review due to the urgency of the pandemic. The FDA monitored the clinical trials on a rolling basis rather waiting until after each trial was completed.
Another factor that accelerated the process of rolling out the vaccines was the production of large quantities vaccine during the third stage of testing. Typically, producing large quantities of vaccine prior to FDA approval is a substantial financial risk for the drug makers. Pfizer chose to shoulder this risk but Moderna received money from the U.S. government for production, alleviating some of the financial risk.
The FDA gave emergency use authorization for the Pfizer/Bio-N-Tech and Moderna vaccines only after they were proven to be safe and effective.
More questions and answers to come!
Please check our blog next week for answers to more questions about the mRNA vaccines. We address the duration of the vaccine’s protection, why you need two shots and more!