The Centers for Disease Control and Prevention, the Department of Health and Human Services and the White House Covid-19 Task Force have discussed whether to press mayors and governors in the Midwest and South, where the highly transmissible Delta variant is spreading quickly, to once again require mask mandates, according to three senior Biden health officials. But the administration ultimately concluded that many people who are not vaccinated are also those who have resisted wearing masks. Instead, the federal government will try to convince hesitant Americans to get vaccinated by working with state officials and trusted community members to communicate the benefits of the shots, the three senior officials said. The president’s team is not confident that the new campaign will change hearts and minds, the two officials said, but it is falling back on old messaging in part because top administration officials are unsure what other tactics will work.