The public awareness push includes 275 participating organizations that will speak to communities where skepticism of the coronavirus vaccine remains high.WASHINGTON — The Biden administration on Thursday morning announced an ambitious advertising campaign intended to encourage as many Americans as possible to be vaccinated against the coronavirus.The campaign, with ads in English and Spanish that will air throughout April on network TV and cable channels nationwide, as well as online, comes as the administration is rapidly expanding access to coronavirus vaccines.President Biden announced last week a new goal of administering 200 million doses by his 100th day in office, doubling his initial goal of “100 million shots in the arms” of Americans that he set when he was inaugurated. And last month, in an address to the nation, he announced a goal of making all adults in the United States eligible for a vaccine by May 1. Governors and public health officials in more than 40 states have said that they will meet or beat that deadline.But deep skepticism about the vaccine remains a problem, particularly among Black people, Latinos, Republicans and white evangelicals. Administration officials expect to soon face the possibility of supply exceeding demand if many Americans remain reluctant to be vaccinated. And widespread opposition to vaccination could set back a return to a more normal way of life as the virus continues to spread.Two hundred and seventy-five organizations will participate in the administration’s new public awareness push — including NASCAR, the Catholic Health Association of the United States and the North American Meat Institute — that is aimed at communities where vaccine hesitancy remains high. Among the organizations are many Catholic and evangelical groups that are expected to help address religious concerns about the Johnson & Johnson vaccine, which uses abortion-derived fetal cell lines.The group is collectively called the Covid-19 Community Corps, administration officials said, and participating organizations are able to reach millions of Americans who trust those individual groups.A new poll by the Kaiser Family Foundation this week found that the number of Black adults willing to be vaccinated had increased substantially since February. But 13 percent of respondents over all said that they would “definitely not” get a vaccine. Among Republicans and white evangelical Christians, almost 30 percent of each group said that they would “definitely not” get a shot.Administration officials said their research showed that vaccine messaging from medical professionals and community leaders, rather than from celebrities or the president, was often more persuasive.“We are not always the best messengers,” Jen Psaki, the White House press secretary, said last month when speaking about vaccine hesitancy among conservatives.The full list of participating organizations includes health professionals, scientists, community organizations, faith leaders, businesses, rural stakeholders, civil rights organizations, sports leagues and athletes. The Department of Health and Human Services is also joining the vaccine education effort with the release of frames with the slogan “Let’s Get Vaccinated” that Facebook users can attach to their profile photographs.Part of the challenge of persuading skeptical Americans are the personal and varied reasons for vaccine hesitancy.“I’ve got some pockets where they cite religious reasons with the Johnson & Johnson vaccine,” said Shirley Bloomfield, the chief executive of N.T.C.A. — The Rural Broadband Association, who has been sharing with the White House what she hears from her group’s members. “There are a lot of pockets where people have already had Covid and a sense of, ‘Well, we’ve all already gotten it, so we’re not really pressed.’”The advertisements are hopeful in tone and are intended as a call to action, saying that everyone can play a part in ending the pandemic by getting vaccinated.To press that point even more, the Department of Health and Human Services has separately bought a multimillion-dollar ad in Black and Spanish-language media, as well as in outlets that reach Asian-Americans and tribal communities, reinforcing the message about the safety and efficacy of coronavirus vaccines.The administration announced last week that it was allocating close to $10 billion to increase vaccine access and confidence in minority communities that have been hardest hit by the pandemic.Biden officials have been working with many of the groups involved in the Covid-19 Community Corps since the presidential transition, but the formal rollout of a promotional campaign had to wait, they said, until the vaccine supply was at a level where people could quickly act on the information provided to them.