Translating influenza surveillance and research into public health practice in New Zealand

1. Translating influenza surveillance and research into public health practice in New Zealand Dr. Sue Huang Director, WHO National Influenza Centre Institute of Environmental Science and Research Wellington, New Zealand The 5th NIC meeting, Vientiane, Lao, 7-10 June 2011

2. Outline • Impact of surveillance & research on vaccination policy • Impact of surveillance & research on antiviral intervention • Impact of surveillance & research on non-pharmaceutical interventions • border control (case isolation & quarantine) • Social distancing measures (school holidays etc)

3. National Influenza Surveillance in New Zealand • Inter-pandemic period • Sentinel GP based surveillance • Laboratory based surveillance • ICD code based morbidity and mortality surveillance • Pandemic period • National notification • Public health surveillance for arriving travellers • ICU utilisation • Pandemic serosurvey • Transmission dynamic study

4. Outline • Impact of surveillance & research on vaccination policy • Impact of surveillance & research on antiviral intervention • Impact of surveillance & research on non-pharmaceutical interventions • border control (case isolation & quarantine) • Social distancing measures (school holidays etc)

5. Predominant Influenza Strains, 1990-2010

6. Comparison of the average mortality rates between 1997-2003 and 1990-1996 by age group

7. Largest increase in younger age groups (1-4, 5-19 years) No increase in oldest age group, but highest pre-existing immunity Baseline vs Serosurvey immunity

8. Very young children (0-4 years) had much higher hospitalization rate than children aged 5-19 years. Eligibility policy for pandemic vaccine: extend to include all children aged < 5 years. Hospitalisation rates by age group

9. Outline • Impact of surveillance & research on vaccination policy • Impact of surveillance & research on antiviral intervention • Impact of surveillance & research on non-pharmaceutical interventions • border control (case isolation & quarantine) • Social distancing measures (school holidays etc)

10. Oseltamivir resistance monitoring

11. Outline • Impact of surveillance & research on vaccination policy • Impact of surveillance & research on antiviral intervention • Impact of surveillance & research on non-pharmaceutical interventions • border control (case isolation & quarantine) • Social distancing measures (school holidays etc)

12. Public Health surveillance – Border control • Measures: screen arriving passengers, isolate a suspected case isolation, quarantine of contacts, test for each suspected case, offer oseltamivir treatment and prophylaxis • 6 weeks delay for the virus to establish sustained transmission

13. Social distance measure--- school holiday? • Proportions of pandemic influenza H1N1 09 cases in New Zealand June-August 2009 : • Value = 1 indicates that proportion of pH1N1 cases in an age group is the same as their proportion of the population • Value > 1 indicates over-presentation of an age group

14. Acknowledgement • Serosurvey study group: • Don Bandaranayake, Ange Bissielo, Tim Wood, Graham Mackereth, Virginia Hope -- ESR • Michael G. Baker – WN School of Medicine • Richard Beasley – Medical Research Institute • Stewart Reid – Ropata Medical Centre, Lower Hutt • Sally Roberts – Auckland DHB, Auckland • Shevaun Paine- transmission dynamic study • Sentinel GPs and nurses and serosurvey GPs. • Local influenza coordinators within 24 Public Health Units • Participating hospital virology laboratories in Auckland, Christchurch, Waikato and Wellington • Staff from National Influenza Centre, as well as Population & Environmental Health Group at ESR • Public Health Directorate from the Ministry of Health for hospitalisation and mortality data • WHOCC in Melbourne • Funding support from the Ministry of Health

15. Thank you