Wall Street stocks dropped Friday as investors digested data on the latest coronavirus vaccine and monitored the ongoing gyrations of GameStop and other volatile equities. Johnson & Johnson said its Covid-19 vaccine has an overall efficacy of 66 percent, with 85 percent effectiveness in preventing severe Covid-19 across all geographical regions, but only 57 percent success rate in preventing a variant in South Africa. The J&J vaccine has been eagerly anticipated because it requires only one shot, in contrast to other options now on the market. Shares of GameStop and AMC Entertainment soared again Friday after online platform Robinhood lifted restrictions on trades. The companies have shot higher this week following a campaign by investors organized on a Reddit group in opposition to investors who have bet on declines. About 45 minutes into trading, the Dow Jones Industrial Average was down 0.6 percent at 30,414.05. The broad-based S&P 500 dipped 0.5 percent to 3,769.10, while the tech-rich Nasdaq Composite Index also shed 0.5 percent to 13,277.03. Companies reporting results included Eli Lilly, Chevron and Caterpillar. Lilly and Caterpillar rose early Friday, while Chevron dropped. jmb/cs