shares of cruise operators fell wednesday after the number of ships being investigated and observed by the centers for disease control and prevention as a result of covid19 cases reported has increased fueling fears that the cdc could call for another pause in sailings shares of carnival corp ccl dropped 09 in premarket trading norwegian cruise line holdings ltd nclh slid 14 and royal caribbean group rcl slumped 11 meanwhile futures es00 for the sp 500 spx slipped less than 01 ahead of the open the cdc said as of dec 28 the number of carnival ships that have reached yellow status which indicates reported cases of covid19 have met the threshold for investigation rose to 32 from 25 on tuesday for norwegian the number of yellow status ships rose to 15 from 12 while the number of royal caribbeans yellow status ships grew to 25 from 20