1. H1N1 I NFLUENZA S URVEILLANCE AND R ESPONSE : B OSTON P UBLIC S CHOOLS 5/18/09 TO 6/19/09 Catherine Cairns, MPH Julia E. Gunn, RN, MPH Boston Public Health Commission

2. S CHOOL C LOSURES High, sustained rates of absenteeism caused by influenza-like illness led to temporary school closures in certain instances. School closures were recommended on a case by case basis, and lasted an average of 7 days.

3. H1N1 C ASES AMONG 5-17 Y EAR O LDS IN B OSTON, BY D ATE OF S YMPTOM O NSET

4. E XCESS A BSENTEEISM S CORES AT B OSTON P UBLIC S CHOOLS, C LOSED VS. N ON - CLOSED SCORES Points were assigned each day for excess absenteeism over a February baseline: <0% = 0 points 0-4% = 1 point 5-9% = 2 points 10-14% = 3 points 15-19% = 4 points >20% = 5 points

5. D AILY V ARIANCE IN A TTENDANCE (F EB B ASELINE ), C LOSED VS. N ON - CLOSED

6. B URDEN OF H1N1 I NFLUENZA A CTIVITY : S CHOOL A SSESSMENT F INDINGS Compared to schools that remained open, closed schools: experienced greater burden of H1N1 influenza activity, as measured by staff out sick and students sent home sick; were more likely to experience difficulty keeping ill students out of school (44% vs. 27%), and; were more likely to describe stressors affecting their ability to respond to H1N1 in their school (100% vs. 57%).

7. B URDEN OF H1N1 I NFLUENZA A CTIVITY : S CHOOL A SSESSMENT F INDINGS Peak % staff out median (range) Peak % students seen by nurse median (range) Peak % students sent home median (range) N (Closed)*868 Closed Schools23 (8-56)8 (3-27)4 (1-12) N (Non-closed)*251630 Non-closed Schools13 (0-27)8 (0-18)2 (0-8) *Not all information is available for each school assessed