Some scholars argue the Tacitus passage is a Christian interpolation.

A handful have, but the passage is accepted as authentic by nearly all classicists and historians, including those hostile to Christianity. The reasons are strong. It survives in the manuscript tradition without variation, it is written in Tacitus’s distinctive compressed style, and it is insulting to Christians, calling their faith a pernicious superstition and describing them as hated for their abominations. A Christian forger would not have written that about his own side.