The stock market’s rally back to all-time highs might not have been possible without optimism over a Covid-19 vaccine. And that means progress and setbacks toward that goal could continue to drive the market in the weeks and months ahead.

Analysts at UBS rolled back the market tape to take a look at how stocks have reacted to positive and negative vaccine-related news since the coronavirus pandemic hit. They concluded that optimism around vaccine developments added around 6.5 percentage points to the S&P 500’s return since May.