More states and school districts have decided that they cannot have in-person classes for the fall semester, a sign of the country’s struggles with the pandemic and a setback for President Trump’s agenda.

Trump and officials at the White House have been pushing to reopen schools fully and send students to in-person classes because children have a lower risk of getting seriously ill due to COVID-19. States and school districts, however, worry that older staff and teachers are at higher risk of getting sick from students.