May 6 (Reuters) - Wall Street’s main indexes opened flat on Thursday after data showed weekly jobless claims fell more than expected, while vaccine makers came under pressure over President Joe Biden’s plan to back intellectual property waivers on COVID-19 shots. The Dow Jones Industrial Average rose 14.77 points, or 0.04%, at the open to 34,245.11. The S&P 500 opened higher by 1.55 points, or 0.04%, at 4,169.14, while the Nasdaq Composite dropped 24.60 points, or 0.18%, to 13,557.83 at the opening bell. (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Maju Samuel) Our Standards: The Thomson Reuters Trust Principles.