A study published in January 2022 by the journal Cell "detected vaccine mRNA collected in the GCs [germinal centers] of LNs [lymph nodes] on days 7, 16, and 37 postvaccination, with lower but still appreciable specific signal at day 60." The study did not look beyond 60 days, so the mRNA may remain longer. These findings are consistent with other studies showing that the side effects of Covid-19 vaccines tend to worsen with each dose. This is more likely to occur if mRNA stays in the body because the most fundamental principle of toxicology is that all substances become toxic at high doses. The CDC's webpage "Understanding mRNA COVID-19 Vaccines" claims without evidence and contrary to these facts that "the mRNA and the spike protein don't last long in the body" and that "our cells break down mRNA and get rid of it within a few days after vaccination."