By Mischa Frankl-Duval

U.S. stock futures edged higher Wednesday as investors weighed the risks to the economy from rising coronavirus-infection levels against the prospect of vaccines that could halt the pandemic.

Futures tied to the S&P 500 index ticked up 0.3%. Contracts linked to the Dow Jones Industrial Average and the Nasdaq-100 indexes also posted muted gains.

Optimism that vaccines will curtail infection levels and propel the economic rebound next year has bolstered investors' risk appetite this week. Relatively low death rates even as Covid-19 cases rise, suggesting that doctors have better treatment options available than they did in the spring, is also helping buoy sentiment. Those factors, combined with sweeping measures by central banks to backstop markets, is pushing stocks higher.

"Markets are increasingly confident now that we're in the midst of another phase of monetary easing," said Derek Halpenny, head of research for global markets in the European region at MUFG Bank. That "is enough to kind-of offset the growing concerns of the near-term deterioration in Covid infections, in particular in the U.S., given that we'll have Covid vaccines at some point in 2021."

Ahead of the New York opening bell, shares in Lowe's dropped over 6%. The home-improvement retailer said it expects fourth-quarter adjusted operating income as a percentage of sales to be about flat compared with the prior-year period due to Covid-19-related operating expenses.

Rival Target's shares rose 2.4% after the retailer said sales rose steadily in its most recent quarter as demand for household goods and home office supplies continued to grow during the pandemic.

Pfizer shares rose 2.4% after the drugmaker said final results from its joint clinical trial with BioNTechSE showed its coronavirus inoculation was 95% effective. Pfizer plans to seek authorization for the vaccine within days, the companies said Wednesday.

In broader markets, a litany of concerns including new restrictions on social and business activity, and the halting pace of economic recovery, are weighing on sentiment. Hopes for a large fiscal stimulus package are also ebbing, investors said.

Federal Reserve Chairman Jerome Powell on Tuesday also cautioned that the economy faces significant challenges and uncertainty because of the increased spread of the coronavirus. He also said it was too soon to say how a potential vaccine would change the outlook, with the possibility of widespread vaccination still many months away.

The number of newly reported Covid-19 cases rose on Tuesday, and hospitalizations hit another record in the U.S. With cases on the rise, more states are implementing new restrictions on people's activity. Ohio imposed on Tuesday a statewide curfew, requiring residents to stay at home from 10 p.m. to 5 a.m.

In bond markets, the yield on 10-year Treasurys ticked down to 0.862%, from 0.872% on Tuesday. That was its lowest level in almost two weeks.

"When you look at the U.S., the prospect for either near-term fiscal policy or sizable medium-term fiscal policy is much reduced," said James McCormick, a strategist at NatWest Markets. "What you're seeing over the last couple of days is genuine disappointment starting to seep into bond markets."

Oil prices edged higher. Brent crude, the international benchmark, gained almost 2% to $44.51 a barrel.

The quarterly earnings season is still under way, giving investors a view into the health of major American businesses. After markets close, Nvidia and L Brands will disclose their earnings.

Data on new-home construction will be available at 8:30 a.m., offering fresh insights into the strength of the American housing market. That has been one of the few bright spots in the U.S. economy this year.

Overseas, the pan-continental Stoxx Europe 600 ticked up 0.4%.

Most major Asian equity benchmarks ended the day higher. Japan's Nikkei 225 index dropped 1.1% by the close of trading after local authorities said there had been a jump in coronavirus cases.

Write to Mischa Frankl-Duval at Mischa.Frankl-Duval@wsj.com

(END) Dow Jones Newswires

11-18-20 0738ET