May 18 (Reuters) - Nearly all 50 U.S. states were at some stage of reopening on Monday as authorities eased restrictions imposed to contain the spread of the new coronavirus and stock markets opened higher on optimism about a potential vaccine trial.
Markets were also encouraged by Federal Reserve Chairman Jerome Powell's remarks over the weekend on a gradual economic recovery, and his affirmation that more monetary stimulus was on the way if required.
The patchwork approach to restarting business activity and easing social distancing restrictions has been shaped by political divisions and demographics in the United States, where nearly 1.5 million people have been infected and nearly 90,000 have died.
Despite the widespread if gradual revival of businesses and social life, only 14 states have met the federal government's for guidelines for lifting measures aimed at fighting the pandemic, according to a Reuters analysis.
The U.S. auto industry slowly returned to life on Monday, with some vehicle assembly plants reopening. Suppliers geared up to support a sector that employs nearly 1 million people.
On a chilly and damp morning, hundreds of workers at Fiat Chrysler Automobile's (FCA) truck plant in Warren, Michigan, began lining up before 4 a.m. to start the 5 a.m. shift. Signs overhead read: "Let's restart."
"I'm a little nervous," said Larry Smith, 53, of New Baltimore, who works on wheel alignment away from the assembly line. "They made all the precautions (and) they've done everything they can to prepare us ... I'm trusting in God."
The reopening of car plants will be a closely watched test of whether workers across a range of U.S. industries can return to factories in large numbers without a resurgence of infections.
Some potential good news in the global race for a vaccine helped U.S. stocks rise nearly 3% in morning trading.
Moderna Inc said on Monday its experimental vaccine for COVID-19, the disease caused by the coronavirus, showed promise in early trials and it looks to advance the vaccine into late-stage trials in July.
In a small early-stage trial the vaccine produced virus-neutralizing antibodies similar to those found in recovered patients. Moderna shares soared 25%.
Republican governors, especially in Southern states such as Georgia and Texas, have pushed to reopen more quickly than Democratic governors whose states are home to large, densely-populated cities.
Dallas Mayor Eric Johnson said on Monday that a spike in cases reported in Texas over the weekend was likely a result of the reopening of parts of the state's economy at the beginning of May.
"These things sort of lag - the decision is made and then you don't see the result in the cases until a couple weeks later," Johnson told CNN. "So this is more than likely connected in some way to the opening of restaurants and movie theaters and retail ... a couple of weeks ago."
New York City Mayor Bill de Blasio repeated at his daily briefing that the "first half of June" will be the first opportunity to relax restrictions on non-essential businesses and social life in the city of more than 8 million people. "We will lay all this out in stages as we are ready."
Protesters chafing at restrictions have made their voices heard in various parts of the country, sometimes encouraged by President Donald Trump, a Republican eager to jumpstart the economy as he seeks re-election in November.
"REOPEN OUR COUNTRY!" Trump wrote in a Twitter post on Monday and "TRANSITION TO GREATNESS."
On Monday morning the Atilis Gym in Bellmawr, New Jersey, reopened in defiance of Democratic Governor Phil Murphy's shutdown order. The state, hardest hit by the coronavirus after its neighbor New York, has allowed non-essential retail businesses and non-essential construction to resume operations beginning on May 18.
When the gym reopened its doors for members, a crowd of supporters chanted, "USA! USA!" and waved American flags and Trump 2020 banners.
Ian Smith, the gym’s co-owner, had described the shutdown order as a "gross violation of constitutional rights."
In a Facebook post, the gym shared a series of safety measures it had taken, including limiting access to members, all of whom would have their temperature taken at the door, and it would operate at 20% of capacity.
Reporting by Maria Caspani and Rajesh Kumar Singh; writing by Grant McCool; Editing by Howard Goller