Following mRNA vaccine injection into muscle cells, translated spike protein levels peak after 24 hours, vaccine mRNA has a half-life of 48 to 72 hours, and the lipid nanoparticle vehicle degrades within hours.
"make the spike protein, which itself has been shown to peak after 24 hours, and then after 48 hours, the spike protein—half-life of the protein that's made is degraded. This is not very long-lasting. The mRNA itself also has a half-life somewhere between, you know, 48 to 72 hours, and the lipid nanoparticle has this a very short—like within hours, it really only lasts long enough to protect the mRNA from being degraded." (said at 0:29:12)
Preclinical biodistribution and pharmacokinetic models of mRNA-lipid nanoparticle (LNP) vaccines demonstrate that mRNA translation and antigen production are transient, with peak expression occurring early (typically within 24 to 48 hours) and rapid clearance of the lipid vehicle and translated protein over several days. However, human pharmacokinetic and observational studies show wider kinetic variability, with trace levels of vaccine-derived mRNA and spike antigen detectable in systemic circulation and lymph nodes for up to several days or weeks in some individuals, rather than strictly clearing within a few hours to 72 hours.
- context: Vaccine mRNA Can Be Detected in Blood at 15 Days Post-Vaccination. (Biomedicines 2022)
"We found that vaccine-associated synthetic mRNA persists in systemic circulation for at least 2 weeks." (abstract, results, passage verified)
pubmedfull study (doi) - context: Biodistribution of mRNA vaccines in rats: Enrichment in injection site and lymph tissues a… (Molecular therapy. Nucleic acids 2026)
"Levels of vaccine components declined rapidly in circulation and tissues, with model-based projections indicating concentrations at low or below quantifiable levels by ∼2 weeks. Unbound (free) spike protein was transient after mRNA-1273 vaccination (modeled decline < 5 days) and did not accumulate with repeated dosing." (abstract, results, passage verified)
pubmedfull study (doi)