Moderna shares fall 17.57% as leaked cancer vaccine data hits stock

Moderna shares fell 17.57% to 202.63 dollars on 22 October 2026, according to our end-of-day data. The move is measured against the previous close (the price when trading ended the day before).

Reports say the drop came after data on a cancer vaccine leaked. The reports do not say who released the data or what it showed.

One report says the leak threatens a record rally (a sustained rise in the share price) from August. The reports do not say how the data became public.

The reports do not say what happens next.