Today, I want to talk about potential effects of ionized lipid nanoparticles used in vaccines to transport cargo, such as viral genomic materials. Let’s start by looking at an excellent review published recently discussing the ranges of side effects that individuals experience from two mRNA vaccine candidates produced by Pfizer and Moderna .
Sore arms, pains, swelling, fevers (sometimes severe), flu-like symptoms, and fatigue are among the chief complaints. However, it is believed that most people will escape “severe” side effects, defined as those that prevent daily activity, and fewer than 2% of recipients of the Pfizer and Moderna vaccines developed severe fevers of 39°C to 40°C.
Interestingly, the reactogenicity,or the physical inflammatory responses to vaccination is believed to be caused by the nanoparticles in vaccines. Animals models exhibited the same type of inflammation, pain, swelling, fever, and flu-like responses when injected with nanoparticles which do not encapsulate virus mRNA genetic materials. In a study on lipid nanoparticle vaccines for the dengue virus, mice that received lipid nanoparticles alone showed statistically significant increases in IgG responses, despite the lack of viral encapsulation .
Both Pfizer and Moderna vaccines encapsulate CoV2 RNA genetic codes in lipid nanoparticles no larger than 0.1 micron in diameter. These oily liquid droplets serve to enclose and protect the fragile genetic instructions of the virus during manufacturing process, transportation and storage, before final injection into people . Pfizer obtains its nanoparticles from Acuitas, a Canadian company, while Moderna uses a proprietary lipid technology. It is believed that not all nanoparticles are equal as the quality of the nanoparticle affects viral mRNA stability and viability. Moderna’s vaccine can survive storage for six months at -20C, the temperature of a standard domestic or medical freezer, while the Pfizer/BioNTech vaccine needs to be stored and transported at -70C.
What can be the potential issues with using nanoparticles to protect viral mRNA in vaccines? Nanoparticles can cause severe oxidative stress, leading to cytotoxicity, apoptosis and DNA damage depending upon the type of lipid nanoparticle used [4, 5, 6].