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* Moderna up as late-stage study for COVID-19 vaccine begins

* Hasbro tumbles after profit miss

* Senate Republicans likely to unveil $1 trillion aid proposal

* Indexes up: Dow 0.28%, S&P 0.62%, Nasdaq 1.46% (New throughout, updates prices, market activity and comments to late afternoon, changes byline, adds NEW YORK dateline)

By Sinad Carew

July 27 (Reuters) - Wall Street's main indexes were higher on Monday as investors monitored progress in government stimulus efforts along with rising U.S. COVID-19 cases and restrictions around the world.

Apple Inc, Amazon.com Inc, Facebook Inc and Alphabet Inc were among the top boosters of the S&P 500 ahead of their quarterly reports due out this week. The technology-heavy Nasdaq outperformed the S&P and the Dow.

U.S. Senate Republicans were expected on Monday to unveil a $1 trillion coronavirus aid proposal, which would need to be negotiated with Democrats before enhanced unemployment benefits expire on Friday.

Investors anxiously awaited a stimulus agreement, yet some worried the aid package would provide insufficient support for the economy in unemployment benefits particularly. These concerns were reflected in gains in assets viewed as safe havens such as the big growth companies and gold, according to Kristina Hooper, Chief Global Market Strategist at Invesco in New York.

"Today's story is about concerns that the economic recovery will be slow and halting. That's from a combination of an inability to bend the virus curve and what is shaping up to be a small stimulus package that may not address all the needs being created by this terrible crisis," said Hooper.

"We know the fragility of U.S. households and we also know that much of the economic recovery we've seen so far can be attributed to stimulus," she added.

Trillions of dollars in fiscal and monetary stimulus have been pivotal in bringing the S&P 500 to within 5% of its February record high.

On Monday, as the world confronted the prospect of rising COVID-19 infections, nations in Asia and Europe imposed new restrictions.

In the United States, where infection rates have climbed since June, two baseball games were canceled due to the virus while President Donald Trump's national security adviser Robert O'Brien was the most senior official to test positive.

Other concerns included a diplomatic row between the United States and China, and an unexpected rise in U.S. jobless claims last week.

At 2:24 p.m. ET, the Dow Jones Industrial Average rose 73.1 points, or 0.28%, to 26,542.99, the S&P 500 gained 20.06 points, or 0.62%, to 3,235.69 and the Nasdaq Composite added 151.62 points, or 1.46%, to 10,514.80.

The technology sector, up more than 1%, was the biggest percentage gainer among the S&P's 11 major sectors while materials was next, boosted by shares of gold miners. Financials, utilities and energy were the only sectors in the red.

Investors maintained their focus on earnings, with 189 S&P 500 companies scheduled to report results this week. About 80% of the 130 S&P 500 firms that have reported so far have beaten a low bar of earnings estimates, according to IBES Refinitiv data.

Few expected any major announcement at a two-day Federal Reserve meeting, but analysts said policymakers were likely to lay the groundwork for more action later this year.

Moderna Inc jumped 9% as it started a U.S. government-backed late-stage trial to assess its COVID-19 vaccine candidate in about 30,000 adults.

Hasbro Inc dropped 7% after the toymaker missed quarterly estimates due to production shutdowns during coronavirus lockdowns.

Advancing issues outnumbered declining ones on the NYSE by a 1.48-to-1 ratio; on Nasdaq, a 1.23-to-1 ratio favored advancers.

The S&P 500 posted 16 new 52-week highs and no new lows; the Nasdaq Composite recorded 56 new highs and 26 new lows. (Additional reporting by Medha Singh and Devik Jain in Bengaluru; Editing by Shounak Dasgupta and David Gregorio)

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US STOCKS-Wall Street rises as investors monitor progress of stimulus and virus - Yahoo Finance