Four important questions about the RNA Covid-19 vaccine
Unlike the vaccines we have used for other diseases, Pfizer BioNTech and Moderna Covid-19 vaccines are both developed using ribonucleic acid (RNA) technology. So, how do they work, are they safe, and what else do we know about them?
1. How does the vaccine work?
RNA is closely related to DNA and exists in all living cells. It is called messenger RNA. The chain is a genetic code sequence that tells the cell what protein to build to function.
Professor Luke O'Neill, head of the Department of Biochemistry at Trinity College Dublin, explained what an mRNA vaccine is.
In order to produce RNA vaccines, scientists have developed some synthetic versions of viral messenger RNA.
When injected into the human body, our cells read it as instructions to start building proteins, in this case, including Covid-19’s unique "spike" protein.
Then, our body produces antibodies to fight the viral proteins produced by our cells, thereby generating an immune response. If we encounter a real virus in the future, this can prepare our immune system to fight the real virus.
This is different from the way some other vaccines work, in which a small part of the virus itself or the whole virus (weakened or dead) is injected into the body to trigger an immune response.
Graphic showing how the RNA vaccine works
A synthetic version of part of the virus' genetic code was injected. It tells our cells to start building viral proteins, triggering an immune response.
2. How is RNA vaccine development different from other vaccine development?
RNA vaccines are expected to be faster, cheaper, more adaptable and easier to mass produce than other vaccines because:
They can be generated quickly. RNA vaccines are based on a biochemical synthesis process, which involves fewer components and fewer steps than more complex traditional methods (such as the use of inactivated live viruses). This means they can enter clinical trials faster and be manufactured faster after the trials are completed-within weeks and months.
Their development cost should be lower. Compared to the much larger micrograms of protein required for many other vaccines, only a small amount of RNA needs to be delivered to human cells. This means that the purchase price of each dose of vaccine should be cheaper, although it depends on the price set by the pharmaceutical company and the delivery cost.
They can be more adaptable and easier to manufacture on a large scale. The same RNA vaccine platform can be used to produce vaccines against different diseases (including known diseases and emerging diseases). In theory, manufacturing plants can use this platform to produce a variety of vaccines, while other vaccines, such as MMR (measles, mumps and rubella) and Ervebo (one of the Ebola vaccines), require their own dedicated manufacturing plants.
3. Are there other RNA vaccines?
Pfizer-BioNTech and Moderna vaccines are the first RNA vaccines approved for the treatment of any disease.
However, researchers have been using this technology for some time, and people have been vaccinated with RNA vaccines in clinical trials for other diseases, such as cancer.
One of the main challenges in the past was figuring out how to deliver RNA vaccines into cells to survive—our bodies naturally want to destroy foreign RNA molecules.
This new use of RNA is possible because of the large amount of research funding and focus during the pandemic, which led to breakthroughs in new technologies. This cutting-edge method can completely change the development of vaccines for future disease outbreaks.
Researchers at Imperial College London are also using RNA technology to develop vaccines, including Covid-19.
4. Is the vaccine safe?
Any vaccine must undergo rigorous testing before it is approved for use to ensure that it is safe and effective.
Approximately 43,500 people participated in the Pfizer-BioNTech clinical trial, and 30,000 people participated in the Moderna clinical trial. Safety was evaluated throughout the process, and no major side effects were reported during phase I, II, and III trials.
Once the trial is completed and the complete data is analyzed, regulatory agencies around the world will review it and decide whether the vaccine can be approved for use in their country. They view all preclinical, clinical and manufacturing process data, including safety and effectiveness data.
Once approved, vaccines will be monitored when they are given to priority high-risk populations to understand how they perform in different populations and look for very rare side effects or long-term safety issues. So far, among the millions of people who have been vaccinated, a few have had very rare allergic reactions.
Nothing in medicine is 100% safe, and when millions of people are vaccinated, very rare side effects may occur. This is the same for all vaccines.
In the past decade, we have seen the health and economic impact of influenza, SARS, Zika virus, Ebola virus and now Covid-19. There will definitely be more outbreaks, but we don’t know when and where they will appear, which makes preparations difficult. If we can hone new methods of developing vaccines, we will be better prepared for any future outbreaks and be able to save more lives with vaccines faster.
This is why the emergency funding gap for the global response to Covid-19 must be addressed. Only through appropriate financial support can innovations such as RNA vaccines become possible.