Order Reprints Text size Medical workers carry cold storage boxes containing injection material during a Phase 3 trial of the Johnson & Johnson Covid-19 vaccine. Angel Garcia/Bloomberg The stock market hasn’t been this spooked since Halloween. The Dow Jones Industrial Average slipped 283.71 points, or 0.9%, this past week, to 30,814.26, while the Nasdaq Composite dropped 1.5%, to 12,998.50. The S&P 500 fell 1.5%, to 3768.25, its largest decline since the week ended Oct. 30, though back then it dropped 5.6%. Still, it was the S&P 500’s first weekly drop of more than 1% since then, a sign that investors, unflappable until now, really were taken aback by what they saw.