The coronavirus outbreak could close down many U.S. classrooms for the rest of the school year, blowing a hole in kids’ math and reading skills, tanking test scores for years to come and making it a scramble for some to even finish high school.

Kansas schools that have shuttered through the end of the school year likely are just the first in line, with governors in California, New Jersey and Ohio signaling the same is possible for their states. Many schools initially announced closures for a short period, but with warnings from the White House growing more dire, shutdowns are extending — even though the CDC says it’s not certain that will halt the spread of the virus. The CDC has said in its updated guidance for schools that closures of eight weeks or more may affect community spread, but hand-washing and home isolation have had more impact.

Testing is being postponed or scrapped entirely as schools rush instead to gear up for remote learning and figure out how to distribute school meals. As of Thursday morning, an estimated 43.9 million school students were enrolled in at least 95,000 public or private schools that are closed now, are scheduled to close or were closed and reopened, according to Education Week.