The Centers for Disease Control and Prevention (CDC) has released an interim pre-pandemic planning guidance document, titled "Community Strategy for Pandemic Influenza Mitigation in the United States," below, that includes a planning guide for elementary and secondary schools. This guide, at Appendix 6 of document, contains a long list of issues a school district should consider in the event of a pandemic that requires the closing of schools. Specifically, the document encourages school districts to consider whether sick leave policies are adequate, to devise an alternative staffing plan, to plan for alternative learning opportunities for students, and to make plans to deal with numerous other issues. For more information on legal issues related to school closings, see the second link.
[CDC Interim Pre-pandemic Planning Guidance]
[NSBA document on legal issues related to school closures]