BERLIN, June 21 (Reuters) - German financial watchdog BaFin is investigating possible insider trading of vaccine maker"s CureVac (5CV.DE) shares, which fell after the biotech firm announced its COVID-19 vaccine proved only 47% effective, Rheinische Post newspaper reported on Monday. BaFin will investigate whether employees at CureVac or Bayer could have used their insider knowledge of the vaccine study results and sold shares in good time, the newspaper added. Shares in CureVac dropped more than 50% on Thursday following the company"s announcement, erasing more than 6 billion euros ($7.2 billion) from the company"s market value. read more A BaFin spokesperson declined to comment on individual cases but said the authority examines unusual price movements to determine whether there is any suspicion of market abuse or manipulation. CureVac said it was not aware of the audit and had not been contacted by the watchdog regarding any proceedings.