15 days to flatten the curve has now become “until there are zero cases”.

Teachers lobbied to go to the head of the vaccination line. Once they got that (vaccinations for teachers in Virginia started this week), they now wish to keep school closed until “zero new cases” of Covid-19.

Science and Health Safety data support and require that no one should return to in person instruction until there is a widely available scientifically proven vaccine or highly effective treatment. The metric for Safe Reopening should be 14 days of zero community spread.

Source: Fairfax teacher’s union letter to the school district

Same thing  in California – the teacher’s union lobbied to go the front of the line, and 3 weeks later after their demands were met, the unions said they do not wish to re-open classrooms.