The referenced post was written Peter Saunders, CEO of Christian Medical Fellowship, a UK-based organization with 4,500 UK doctors and 1,000 medical students as members.
The earliest undisputed manuscript of a New Testament book is the John Rylands papyrus (p52) (pictured above), dated from 117 to 138. This fragment of John’s gospel survives from within a generation of composition. Since the book was composed in Asia Minor and this fragment was found in Egypt, some circulation time is demanded, surely placing composition of John within the first century. Whole books (Bodmer Papyri) are available from 200.
Most of the New Testament, including all the gospels, is available in the Chester Beatty Papyri manuscript from 150 years after the New Testament was finished (ca. 250).
No other book from the ancient world has as small a time gap between composition and earliest manuscript copies as the New Testament.