Ina Fassbender/Getty Images(NEW YORK) -- COVID-19 has been a major challenge for schools. From shutting down in March 2020 to reopening and trying to stay open, the task has been varied and in some cases monumental. This school year -- the third since the pandemic began -- has presented its own promise and challenges, from vaccines being available to millions of students, to new "test-to-stay" protocols and more transmissible variants. Still, many schools were able to stay open safely with multiple protections in place. For Elizabeth Stuart, a professor in mental health and health po...