The coronavirus pandemic and global oil glut have driven down energy prices, reducing the U.S. inflation rate, as well as idling oil rigs in Midland, Texas.

U.S. consumer prices in April posted their largest monthly decline since the last recession after energy prices collapsed and efforts to contain the new coronavirus disrupted demand for a wide array of goods and services.

The Labor Department said the consumer-price index fell by 0.8% last month, the second month in a row prices have eased since the pandemic reached the U.S. and the biggest drop since 2008. Business closures and stay-home orders aimed at containing the virus have created cheap oil, and falling prices for airfares, clothing, cars and other goods and services.

Excluding the volatile food and energy categories, so-called core prices decreased 0.4%, the largest monthly drop in records dating to 1957.

“I’m hard pressed to see inflationary pressures now or any time soon,” Federal Reserve Bank of Chicago President Charles Evans told reporters last week. “We couldn’t even get inflation sustainably up to 2% during the last expansion, which was the longest on record since World War II.” Related Video The Latest Consumer-Spending Report, Explained You may also like Up Next The Latest Consumer-Spending Report, Explained The Latest Consumer-Spending Report, Explained Consumer spending fell 7.5% in March, prompting further concerns about the impact of the coronavirus pandemic on the economy. Here’s why consumer spending is so important and how it can signal if the country is heading toward a recession. Photo: Getty Images

The Fed’s preferred inflation gauge is the personal consumption expenditures price index, which has tended to run a little cooler than the CPI, which measures what Americans pay for everything from appliances to airfares. But the two generally move in the same direction.

Lately, energy prices are the biggest drag on both. As recently as January, a barrel of U.S. oil cost more than $60. On April 20, U.S. crude futures for delivery the following month fell below $0 a barrel for the first time in oil market history. The coronavirus killed demand for fuel. A price war between Saudi Arabia and Russia alongside broad overproduction added to the oil glut.

Fed officials will look past oil markets and focus more on core prices. At least for now, coronavirus-related developments are pushing those lower as well. Prices for airfares, hotels and apparel fell at a historically rapid pace in March. More is likely amid government-mandated shutdowns and consumer caution.

“Beyond the next few months, we believe that weak demand at home and abroad, an unprecedented sharp increase in unemployment leading to more labor market slack, and the significant appreciation of the dollar during March should all push inflation lower,” said Barclays economist Blerina Uruçi.

A near-term, worst-case scenario would be an extended period of deflation—when there are so many idle economic resources that businesses and workers are forced to lower prices and wages to generate demand for their goods and services.

That seems unlikely with the Fed and U.S. Treasury pumping trillions of dollars into the economy and a consensus building around a sharp but relatively short downturn.

A New York Fed survey out Monday found consumer inflation expectations for the next year and three years increased slightly—both now stand at 2.6%. “Respondents, however, increasingly disagree about the future path of inflation,” the survey said.

The market outlook appears less anchored. Yield movements in the Treasury inflation-protected securities, or TIPS, market show that compensation for inflation expected in five years fell sharply in March before rebounding slightly, albeit at historically low levels.

Fed officials believe that consumer and market expectations for inflation affect behavior, becoming almost a self-fulfilling prophecy. SHARE YOUR THOUGHTS

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Another, longer-term concern is that large amounts of government borrowing and rising costs of doing business could push inflation uncomfortably high. Low rates and printing money spurred consumer-price inflation after World War II and during the 1970s.

But with the loss of 20.5 million jobs and unemployment hitting a post-World War II high in April, the focus is more immediately on building a fiscal and monetary bridge until the coronavirus is contained.

“In the near term it’s more likely, we think here at the Dallas Fed, we’ll have disinflation,” Dallas Fed President Robert Kaplan said earlier this month. "That’ll be in the shorter run, the next year or two. I do worry about, as we get back over the next few years to full capacity, with some of this stimulus and the size of the Fed’s balance sheet, do we start creating inflationary pressures? But that’s not going to be for two or three years.”

Write to Jeffrey Sparshott at jeffrey.sparshott@wsj.com