A recent study has comprehensively explored how mRNA vaccines travel and degrade within the human bloodstream. This research aimed to enhance the safety and efficiency of these vaccines, particularly by minimizing commonly experienced side effects such as headaches, fever, and fatigue.
A new investigation conducted by scientists from RMIT University and the Doherty Institute has unveiled the first in-depth study on the circulation and breakdown of mRNA vaccines in human blood.
The primary goal of this study was to boost the safety and efficacy of vaccines, focusing on reducing prevalent side effects like headaches, fever, and fatigue.
Since the introduction of the initial COVID-19 mRNA vaccines, researchers have utilized this technology to create vaccines and treatments for various other illnesses, including cancer.
These mRNA vaccines employ genetic instructions rather than a weakened virus to stimulate the body into producing a protein that initiates an immune response. Their swift development, adaptability to new variants, and excellent safety profile have made them critical tools in the global effort against the COVID-19 pandemic.
Published in ACS Nano, the study analyzed blood samples from 19 participants over 28 days following a Moderna SPIKEVAX mRNA booster shot. The research team uncovered key information about the distribution and breakdown of the vaccine components in the bloodstream, which is vital for the creation of safer and more effective vaccines.
Dr. Yi (David) Ju, a DECRA Fellow with the Australian Research Council at RMIT University, co-led the study alongside Professor Stephen Kent from The University of Melbourne and a Laboratory Head at the Doherty Institute.
Minimizing the Side Effects of mRNA Vaccines
These vaccines are engineered to remain in the lymph nodes to generate antibodies against infections, but the researchers noted that a small portion of the vaccine also enters the bloodstream.
Ju shared, “The degree to which the vaccine enters the bloodstream differs among individuals, which might account for some side effects like fever, headache, and fatigue that are reported post-vaccination.”
“This variation in the vaccine’s presence in the blood could trigger inflammatory reactions, potentially leading to these side effects in certain individuals.”
“Understanding the link between the quantity of the vaccine circulating in the bloodstream and these side effects will be crucial for subsequent research.”
“Importantly, the amounts of the vaccine that enter the bloodstream are very small, so people can be assured that mRNA vaccines are both safe and effective.”
Duration of mRNA Vaccine Presence in the Bloodstream
The study found that the mRNA and its fatty nanoparticle shell peaked in the bloodstream within two days after vaccination, with some mRNA remaining detectable for as long as a month.
The research team initially speculated that it was the antibodies formed in response to a common vaccine component called polyethylene glycol (PEG) that determined the retention time of vaccines in blood circulation. However, they discovered that anti-PEG antibodies were not the only factors influencing this process.
Ju noted that the breakdown of mRNA within the body was likely affected by a complex interplay of individual factors.
“The mRNA vaccine in the bloodstream is akin to a message in a bottle. It’s safeguarded by its fatty nanoparticle shell as it circulates, but what happens to it depends mainly on how the body reacts to the shell, not merely the message it carries,” Ju explained.
“Nevertheless, we still observed that higher levels of mRNA and fatty nanoparticles in the blood corresponded with a more significant increase in anti-PEG antibodies, indicating that some individuals might develop heightened antibodies to PEG.”
Creating Safer and More Effective mRNA Vaccines
Kent indicated that if individuals developed elevated levels of anti-PEG antibodies in response to mRNA vaccines, it could diminish the effectiveness of possible future mRNA treatments for other diseases, including cancer, as their bodies would eliminate these therapeutics more swiftly.
“By gaining insight into how these components are distributed in the body, we can better guide the design of future vaccines to minimize associated risks. Our study provides crucial understanding for the enhancement of mRNA vaccines, ensuring their safer and more efficient use,” Kent stated.
This information could lead researchers to refine the fatty nanoparticle formulations, enhancing mRNA stability, which might prolong the immune response and reduce the chance of rapid elimination from the body. Further studies could also seek methods to prevent vaccines from entering the bloodstream.
“By identifying the personal factors influencing mRNA circulation, future vaccines could be personalized, improving their efficacy on an individual basis,” Ju suggested.
‘Blood distribution of SARS-CoV-2 lipid nanoparticle mRNA vaccine in humans’ is featured in ACS Nano.
This research received funding from the Australian Research Council, the National Health and Medical Research Council, and the Victorian Critical Vaccinees Collection.
