According to Pfizer and BioNTech's COVID-19 vaccine label in the FDA's Fact Sheet for Healthcare Providers, each Pfizer vaccine dose for children ages 5 through 11 contains 10 micrograms (mcg) of modRNA, while fully-approved Comirnaty authorized for use in individuals 12 years of age and older contains 30 mcg of modRNA.

Pfizer, on its website, confirms its COVID-19 vaccine contains modRNA: "ModRNA stands for nucleoside-modified messenger RNA and in the synthesis of the RNA used in this vaccine platform, some nucleosides, which are important biological molecules that constitute DNA and RNA, are replaced by modified nucleosides to help enhance immune evasion and protein production." The company says modRNA instructs the cells to produce desired proteins.

Yet the Centers for Disease Control and Prevention (CDC) states on its website (pdf) that mRNA COVID-19 vaccines are "made of mRNA," or "messenger RNA."