caroline van gemert field epidemiology training program, australia the masters of applied...
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Caroline van GemertField 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
Background
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
Melbourne, Australia
• Capital of Victoria• Second-most southern
capital in Australia• Winter months June -
August• Approximately 4 million
people• Highly culturally and
linguistically diverse
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
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
Methodology
Methodology
• 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
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
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
Results
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
Participant description
n %
Schools
Number of schools that students attended 6 100%
Number of primary (junior) schools 1 14.3%
Number of secondary (middle and high) schools 6 85.7%
Gender
Male 43 43.4%
Female 56 56.6%
Age Group
6-7 years 4 4.0%
10-11 years 5 5.1%
12-13 years 9 9.1%
14-15 years 48 48.5%
16-17 years 33 33.3%
Regular activities reported by students
Regular activitiesAverage
number of groups per participant
Median size of group
Average number of
primary links per groupn %
School 99 100.0 4 20 3
University class 9 9.1 1 12 2
Part-time work 18 18.2 1 20 10
Sports 44 44.4 1 16 6
Religious group/service 20 20.2 1 175 5
Other activities 81 81.8 2 30 20
Regular activitiesAverage
number of groups per participant
Median size of group
Average number of
primary links per groupn %
School 99 100.0 4 20 3
University class 9 9.1 1 12 2
Part-time work 18 18.2 1 20 10
Sports 44 44.4 1 16 6
Religious group/service 20 20.2 1 175 5
Other activities 81 81.8 2 30 20
What types of activities did students report?
Sports
Team
Outdoor
Individual
Indoor
Other activities
Sports match
Cinema
Party
Friends houseGirl 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
Church
MosqueTemple
Participation in potential exposure and infectious period
School0
102030405060708090
100
Num
ber o
f stu
ents
University class
Part-time employment
Sport Religious ac-tivity/service
Other activi-ties
0102030405060708090
100
Participated in potential exposure periodParticipated in potential infectious period
Num
ber o
f eve
nts
Figure 1: Number of students that reported attending school
Figure 2: Number of events reported by students
Part-time workReligious groups/activities
Discussion
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
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
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