“At this point there is no indication that Trump’s positive COVID status will have a long-term effect on the economy, which ultimately drives the market,” said Jill Fopiano, chief executive of O’Brien Wealth Partners in Boston. “Of course this situation is rapidly changing, and we could be in for some short-term volatility until the situation stabilizes.”

Around 12:30 p.m. the Dow Jones industrial average was little changed, after falling as much as 1.6 percent earlier. The Nasdaq, filled with more volatile tech stocks, fell 1.6 percent.

Here’s a quick look at the mind-bending issues confronting investors.

The election

Investors were already expecting the outcome of the November presidential vote to be chaotic, with delayed results and claims of fraud by the president if he appeared to be losing. That helped drive the Standard & Poor’s 500 index down nearly 4 percent last month, after five straight months of gains that more than recouped the big drop in February and March caused by the coronavirus outbreak and shutdown of big parts of the economy. Generally speaking, investors see a Trump win as better for stocks.

The VIX index, which uses options prices to track expectations for market volatility, has been indicating that the final results of the showdown between Trump and former vice president Joe Biden wouldn’t be known until mid-December, according to Fopiano at O’Brien Wealth Partners.

How soon Trump can get back on the campaign isn’t clear. The president called off all public appearances, but is able to rest and work in the White House residence, people familiar with the matter told Bloomberg. His symptoms so far have been mild.

Also unclear is the impact if Trump can’t campaign for weeks or for the rest of the campaign. Will there be calls to postpone the Nov. 3 vote? Could