Economists have become less bullish about U.S. economic recovery from the COVID-19 induced recession amid concerns about a potential second wave of the virus, according to a survey released Monday.

A panel of 52 economists has lowered the forecast for U.S. economic growth rate for the fourth quarter of 2020 as well as 2021, the National Association for Business Economics (NABE) said in its October Outlook Survey.

The median forecast calls for a 25 percent real GDP (inflation-adjusted GDP) growth in the third quarter and that would reverse much of the 31 percent decline from the second quarter, the survey said.

However, the median forecast for real U.S. GDP growth for the fourth quarter of 2020 was lowered to an annual rate of 4.9 percent from 6.8 percent in the prior survey in June.

The median real U.S. GDP growth estimate for 2021 is 3.6 percent, compared with an expected increase of 4.8 percent in the June survey.

Panelists still have a negative outlook regarding the balance of risk to economic growth, with 66 percent indicating that the balance of risk through 2020 is weighted to the downside, the NABE said.

About 55 percent of the panel consider a second wave of COVID-19 as the greatest downside risk to economic growth. Other downside risks include fiscal policy inaction, a political/geopolitical event, and an increasing number of bankruptcies, according to the NABE.

Eric Rosengren, president of the Federal Reserve Bank of Boston, recently warned that a second wave of COVID-19 infections in the fall and winter and the lack of further fiscal aid could make the U.S. economic recovery more gradual than hoped.

About half of panelists put the odds of a "double-dip" recession in the United States at 20 percent or less, while 12 percent of panelists place those odds at 50 percent or greater, according to the NABE survey.

Economists remain divided over when the U.S. economy will return to pre-pandemic GDP levels, with roughly 38 percent saying the second half of 2021, 32 percent saying the first half of 2022 and 22 percent believing it will occur in the second half of 2022, the survey showed.

The survey also showed that panelists expect the U.S. economy to grow at an annual rate of 25 percent in the third quarter after contracting 31.4 percent in the second quarter. But for the whole year 2020, the U.S. economy is expected to contract by 4.3 percent.