Nov. 3. 2021 -- The rumors began last spring but were resurrected this week when a journalist tweeted erroneously that COVID-19 vaccines contain something called "luciferase." The journalist, a correspondent with the outlet Newsmax, believed that the name referenced Lucifer, another name for the devil. From there, others added more layers to the untrue story, leading scientists to take to social media and explain what luciferase really is and does.

COVID vaccines do not contain luciferase, and the chemical is not named after any of the versions of Lucifer that have dotted human stories since pre-Christian times. Rather, the name is taken from the Latin meaning of “lucifer,” which is “light bearer.” Luciferases are enzymes that act on high-energy molecules in animals like fireflies. The released energy from this breakdown gives these animals their glow, or bioluminescence.

This unexpected focus on bioluminescence offers a teachable moment about how researchers have borrowed these enzymes to use as lab tools, including in animal studies of some COVID vaccines.

One use is tracking where and when cells use genes. Genes have regions that act like switches, turning use of a gene on or off. Scientists who want to see when a cell flips a gene “on” can drop in the code for luciferase next to this genetic switch. Whenever the cell uses the target gene, it also uses the luciferase code. If researchers also add the molecule that luciferase acts on, the result is a cell that glows when it uses the gene -- and the luciferase.

Scientists also can use luciferases to tag specific cell types and follow them around in a living animal, such as a mouse. In this way, for example, they can trace a tumor cell’s journey in the body. Luciferases have been used for developing diagnostic tests for infectious diseases, including COVID, and for tracing how viruses enter cells.

In developing COVID vaccines, researchers used a luciferase in some mouse studies to track where the vaccine mRNA went in the animals. They used the enzyme only for those studies, and it is not part of either of the mRNA vaccines given to people or any of the other COVID vaccines. In other words, getting vaccinated will not cause you to glow like a firefly.

Show Sources

Twitter: @justinbaragona, Nov. 2, 2021; @angie_rasmussen, Nov 2, 2021.

Hackensack Meridian Health: “A Simple Breakdown of the Ingredients in the COVID Vaccines.”

Merriam-Webster: “Luciferase.”

Reuters: “Fact Check-Moderna’s COVID-19 vaccine does not contain luciferin or luciferase.”

Scientific American: “How and why do fireflies light up?”

Texas Medical Center: “Fireflies help kindle new tests and treatments for COVID-19.”

USF Health: “Scientific community continues to respond in force to COVID-19 pandemic.”

© 2021 WebMD, LLC. All rights reserved. View privacy policy and trust info