Walgreens Boots Alliance Inc WBA.O fell 4.5% as the drugstore chain maintained its full-year earnings forecast due to declining COVID vaccinations. By Shreyashi Sanyal and Amruta Khandekar June 30 (Reuters) - U.S. stocks slipped on Thursday, setting the Dow up for its worst first six months since 1962, on concerns that a dogged pursuit by central banks to tame inflation would hamper global economic growth. Fears over slowing growth and surging prices have rippled through markets, with recession worries taking center stage as monetary policymakers across the world look to aggressively raise borrowing costs.