S&P 500 Closes Down 2.3% as Variant Spooks Investors

What implications does the high trading volume have for traders and market analysts?

What sectors were identified as the worst performers on the day, and what percentage decline did they experience?

How did the performance of vaccine makers like Moderna and Pfizer reflect the market's response to the pandemic?

What factors contributed to the high trading volume observed on the day discussed in the text?

In what way did the trading volume on this particular day compare to typical Black Friday trading volumes?