1. Caroline van Gemert Field Epidemiology Training Program, Australia The Masters of Applied Epidemiology is funded by the Australian Department of Health and Ageing Social contacts of student cases of Pandemic Influenza A (H1N1) 2009 during implementation of social distancing measures in May-June 2009 Victoria, Australia

2. Background

3. Pandemic Influenza in Australia One of the first regions in southern hemisphere with cases First evidence of local transmission of pandemic influenza in Melbourne, Victoria

4. Melbourne, Australia Capital of Victoria Second-most southern capital in Australia Winter months June - August Approximately 4 million people Highly culturally and linguistically diverse

5. Role of schools in transmission of pandemic influenza School settings are important because of: High rates of contact between students Prolonged exposure in classes Contact with students in range of age groups

6. Objectives of study To describe the regular social contacts of confirmed student cases of pandemic influenza; and To describe students social contacts during the period before and after symptom onset

7. Methodology

8. Study design: Cross sectional study Case definition: Laboratory-confirmed cases who attended a Victorian primary or secondary school that had a high case-load (over 10 cases) of confirmed cases Notification period: Before 3 June 2010 Data collection: Interviewer administered interview Incentive: $30 (Australian) voucher Ethical considerations: Written consent

9. Information collected Gender Age Year level Demographics Symptom details Date of symptom onset Case details Regular school and non-school activities Group size for each group Number of primary links in each group Attendance/participation in each group in potential exposure and infectious period Social contact information

10. Analysis Preliminary analysis (presented here): Average number of groups, group size and number of primary links Participation in each activity type during potential exposure and infectious period Long-term analysis (not presented here): Modelling of social networks using social network analysis

11. Results

12. Response rates 857 confirmed cases notified to VDOH during Contain Phase 434 (50.7%) of cases excluded as they did not attend school 423 (49.3%) of cases attending one of 152 schools in Victoria 162 (38.5%) cases from seven schools had >10 confirmed cases attending the school 35 (23.4%) of eligible cases not contactable 25 (15.4%) of eligible cases refused participation / not available 99 (61.1%) of eligible cases interviewed

13. Participant description n% Schools Number of schools that students attended6100% Number of primary (junior) schools114.3% Number of secondary (middle and high) schools685.7% Gender Male4343.4% Female5656.6% Age Group 6-7 years44.0% 10-11 years55.1% 12-13 years99.1% 14-15 years4848.5% 16-17 years3333.3%

14. Regular activities reported by students Regular activities Average number of groups per participant Median size of group Average number of primary links per group n% School99100.0 4203 University class99.1 1122 Part-time work1818.2 12010 Sports4444.4 1166 Religious group/service2020.2 11755 Other activities8181.8 23020 Regular activities Average number of groups per participant Median size of group Average number of primary links per group n% School99100.0 4203 University class99.1 1122 Part-time work1818.2 12010 Sports4444.4 1166 Religious group/service2020.2 11755 Other activities8181.8 23020

15. What types of activities did students report? Sports TeamOutdoorIndividualIndoor Other activities Sports match CinemaParty Friends house Girl guides Youth Group Private tuition Part-time employment Supermarket Shop/ Department Store Fast food restaurant Cafe School- based non- classroom activities Camp Social (prom/formal) Carnival Excursion (field trip) Religious Group / Service ChurchMosqueTemple

16. Participation in potential exposure and infectious period Figure 1: Number of students that reported attending school Figure 2: Number of events reported by students Part-time work Religious groups/ activities

17. Discussion

18. Implications and recommendations from major findings 1. High level of school attendance when potentially infectious Improve communication of individual-level strategies Lower threshold for school closure? 2. Potential evidence for the role of non- classroom school- organised activities in transmission Consider cancellation of non-classroom school-organised activities 3. Potential evidence for the role of non- school based activities in transmission Students potential “bridge” of transmission Improve communication of individual-level strategies

19. Acknowledgements Participating students Victorian Department of Health Victorian Department of Education and Early Childhood Development Catholic Education Office, Melbourne Research Assistants at the Burnet Institute Margaret Hellard receives funding from the NHMRC for a Senior Research Fellowship. This work was funded by an Australian Government National Health and Medical Research Council grant (application ID 603753) for research on H1N1 Pandemic Influenza 09 to inform public policy. Authors Caroline van Gemert, Centre for Population Health, Burnet Institute, Australia and National Centre for Epidemiology and Population Health, Australian National University, Australia Isabel Bergeri, Centre for Population Health, Burnet Institute, Australia James Fielding, Victorian Department of Health, Australia and National Centre for Epidemiology and Population Health, Australian National University, Australia Nasra Higgins, Victorian Department of Health, Australia Rosemary Lester, Victorian Department of Health, Australia Hassan Vally, National Centre for Epidemiology and Population Health, Australian National University, Australia Emma McBryde, Victorian Infectious Diseases Reference Laboratory, Australia and Royal Melbourne Hospital, Australia and Department of Medicine, University of Melbourne Pip Pattison, School of Psychology, University of Melbourne Margaret Hellard, Centre for Population Health, Burnet Institute, Australia