NEW YORK, Jan 14 (Reuters) - A group of big-city mayors has asked the incoming Biden administration to bypass state governments and send vaccine shipments directly to them, as U.S. coronavirus infections on Thursday topped the 23 million mark.

In a letter to President-elect Joe Biden, some three dozen mayors of cities including New York, Los Angeles, Chicago and Houston said they were best positioned to help the new administration meet its goal of inoculating 100 million Americans in its first 100 days.

"While it is essential to work with state and local public health agencies, healthcare providers, pharmacies, and clinics, there is a need to be nimble and fill gaps that are unique to each local area," they said in their letter dated Wednesday.

"Mayors have the ability and expertise to build the local partnerships necessary and fill these gaps, especially when it comes to reaching disadvantaged communities," the letter said.

Biden plans to unveil a stimulus proposal on Thursday that will include resources for the coronavirus vaccine rollout.

The country's mass vaccination effort has fallen far short of the early goals of federal health officials, who had hoped to have 20 million first shots of the two-dose regimen administered by the end of 2020.

Only 11.1 million vaccinations have been administered out of more than 30 million doses that were distributed to states by Thursday, according to data from the U.S. Centers for Disease Control and Prevention.

The mayors, with 40 million people in their cities, said very few of them were currently receiving vaccines directly from the federal government. They cited New York's history of having vaccinated 5 million people for polio in two weeks as evidence of their efficiency.

"That level of outreach is what your administration needs to meet its goal," they said.

The U.S. Food and Drug Administration has authorized a vaccine from Pfizer Inc and partner BioNTech and a second vaccine from Moderna Inc for emergency use. Both require two doses, while a Johnson & Johnson vaccine, targeted to roll out in March, requires only one shot.

Biden is set to assume office on Jan. 20 with the United States, the third-most populous country, topping the world in both total coronavirus infections and deaths.

CONCERNS HOSPITALIZATION NUMBERS COULD RISE

The virus had infected 23,027,112 people, or nearly 7% of the U.S. population, by Thursday afternoon, rising by roughly 1 million people every six days over the past five weeks, according to a Reuters tally. The death toll stood at 385,324.

Even adjusting for population, the United States leads most of the world and all major industrialized nations in infections, and its adjusted death toll is exceeded only by the UK and Italy in the industrialized world, according to a Reuters analysis.

While the number of COVID-19 patients sick enough to require hospitalization has been fairly stable over the past week, with 130,214 reported on Wednesday night, several state officials worried that the number could increase.

Not only was there an uptick in new cases between Jan. 5 and 9, including a one-day record of 294,482 last Friday, following the year-end holidays, but there have since been a few potential super-spreader events, including the Jan. 6 storming of the U.S. Capitol by supporters of outgoing President Donald Trump.

So far, four U.S. lawmakers have announced they have tested positive for COVID-19 after they were forced to flee attackers and hole up for hours with other lawmakers and their staffs, some of whom were maskless.

Many members of Congress have been vaccinated, including 66-year-old Adriano Espaillat, a New York City Democrat. He was the fourth lawmaker to test positive even though he said he had received a second dose last week. He noted that vaccinations take time to become effective.

Some evidence suggests the vaccines may start protecting recipients within 10 to 14 days after the first dose, but their effects have not been studied as a single-dose shot.

In Ohio, Governor Mike DeWine told a news briefing that hospitalizations were up over a 21-day period, although he had yet to see a surge from the Christmas holiday period.

In New Jersey, state health officials have cited a model that projects a rise in hospitalizations, which generally lag the onset of new cases, in the next week. (Reporting by Peter Szekely; Additional reporting by Michael Erman, Maria Caspani and Barbara Goldberg in New York, Rick Cowan and Susan Heavey in Washington, and Anurag Maan in Bangalore; Editing by Peter Cooney)