Enhancing Flu Vaccination Programmes Through Data Analysis

Exploring the use of data to improve flu vaccination programmes in Scotland, focusing on influenza as a case study. The article discusses methods to close the primary-secondary care loop, flu vaccine uptake success, benefits of vaccination, and insights from primary care data analysis on vaccine effectiveness and population protection.

• Flu vaccination
• Data analysis
• Public health
• Scotland
• Influenza

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1. Using Information to Close the Primary/Secondary Care Loop- Flu Vaccination Programme Arlene Reynolds & Jim McMenamin Health Protection Scotland SCIMP, Crieff, November 2013

2. Contents Influenza as a case study; How can we use routinely gathered data to close the loop and inform patient management? Aggregate level data Flu vaccine uptake & flu consultation Rates Individual level data Determinants of flu vaccine uptake & vaccine effectiveness & risk of death Now that kids are to be vaccinated how do we propose to describe the Public Health benefit?

3. Why vaccinate against Flu? In absence of a flu vaccination programme NHS Scotland would experience significant morbidity and mortality each season* 900 excess deaths 4700 excess hospitalisations 100,000 excess GP consultations *Extrapolation from - Baguelin M, Flasche S, Camacho A, Demiris N, et al. (2013) Assessing Optimal Target Populations for Influenza Vaccination Programmes: An Evidence Synthesis and Modelling Study. PLoS Med 10(10): e1001527. doi:10.1371/journal.pmed.1001527 http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001527

4. Flu Vaccine Uptake a success story Scotland is one of only three EU countries to consistently achieve a vaccine uptake of greater than 75% in those age 65 and over Uptake in under 65 s in CMO defined risk groups around 60% GP consultation rates for Influenza Like Illness (ILI) vary markedly each season but rates of illness much less in last decade c.f. pre- vaccination programme

5. What does Primary Care data tell us? Uptake by risk group? When season starts & magnitude compared with previous years? Who is affected most & Where? What Flu strains are responsible? If not Flu what is it (and do I need to treat it)? Is Flu Vaccine protecting the population?

6. Cumulative vaccine uptake by risk group over time season 2012/13 How quickly is offer of vaccine taken up? 100% Over 65 All risk groups (under 65) Chronic Respiratory Disease Chronic Heart Disease Chronic Renal Disease Chronic Liver Disease Chronic Neurological Disease Diabetes Immuno-compromised Pregnant/no risk** Pregnant/at risk** Carers 80% Vaccine uptake (%) 60% 40% 20% 0% Week 40 Week 42 Week 44 Week 46 Week 48 Week 50 Week 52 Week 2 Week 4 Week 6 Week 8 Week 10 Week 12 Week number ** The size of the pregnant population is derived from GP records on patients with pregnancy code. This results in changes in the population over the course of the season, as pregnancy status of patients changes.

7. When Season Starts & Magnitude? Since 2009 daily automated extraction of aggregate data from 99% of all practices on GP consultation rates for Influenza Like Illness (ILI) & Acute Respiratory Infections Rates vary markedly each season Timing of peaks in clinical presentations variable In the main around the time of the Festive season But earlier in 2003/4 And later in 2010/11

8. Weekly GP consultation rates for ILI by flu season Scotland (In 2012/13 = 961 practices) Weekly GP consultation rates for ILI by flu season Scotland (In 2012/13 = 961 practices) Christmas 350 2007/08 ILI rate per 100,000 pop 300 2008/09 250 2010/11 200 2011/12 150 2012/13 100 50 2009/10 0 40 42 44 46 48 50 52 2 4 6 8 10 12 14 16 18 20 8 week

9. Who is affected most? GP consultation rates for ILI in Scotland by age group; weekly rates per 100,000 population, week 40 2012 to week 32 2013 <1 1-4 5-14 15-44 45-64 65-74 >=75 80 70 ILI rate per 100,000 population 60 50 40 30 20 10 0 40 42 44 46 48 50 52 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 Week 9

10. Where? NHS board ILI consultation rates to 16th October 2013 10

11. What Flu strains are responsible? Weekly summary of GP sentinel swab positivity (number positive and percentage positive) by influenza subtype, week 40 2012 to week 20 2013 (at week 22 2013) 60 100 90 50 80 70 40 Number of positives 60 % of samples 30 50 40 20 30 20 10 10 0 0 week 11 A(H1N1)pdm09 A(H3) Type A (subtype unknown) Type B A(H1N1)pdm09 % A(H3)% Type A % Type B %

12. If its not Flu what is it? (Do I need to treat it ?) Number of laboratory confirmed seasonal respiratory pathogens submitted through Sentinel sources, week 40 2012 to week 20 2013 (at week 22 2013) 100 100 90 90 80 80 70 70 Number of positives 60 60 % positive 50 50 40 40 30 30 20 20 10 10 0 0 40 41 42 43 44 45 46 47 48 49 50 51 52 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 week Influenza virus Coronavirus Human metapneumovirus Respiratory syncytial virus Para-influenza Mycoplasma pneumoniae Rhinovirus Adenovirus % positive Influenza 12

13. The PIPeR cohort Determinants of Flu vaccine uptake & Vaccine effectiveness Daily Consultation rates for ILI ARI (including asthma) ILIARI (ILI+ARI excluding asthma) Weekly download of individual level data from each practice 170783 Patients for 2012/13 cohort Patients registered with 27 GP Practices (25 physical sites) on Sept 1, 2012 3.3% Scottish Population

14. Colours represent the different postcode areas of practice population 14

15. Vaccine Uptake 80 0-4 5-14 15-44 45-64 65-74 75+ 60 Percentage 40 20 0 Sep Oct Nov Dec Jan Feb Mar Date in 2012/13 15

16. Vaccine Uptake Female Male 20 15 Percentage 10 5 0 Sep Oct Nov Dec Jan Feb Mar Date in 2012/13 16

17. Vaccine Uptake Consultations in Previous Season 0 1 2+ 30 25 20 Percentage 15 10 5 0 Sep Oct Nov Dec Jan Feb Mar Date in 2012/13 17

18. Vaccine Uptake Urban Rural Status Urban Small Towns Rural 20 15 Percentage 10 5 0 Sep Oct Nov Dec Jan Feb Mar Date in 2012/13 18

19. Vaccine Uptake Deprivation [1,4] (4,8] (8,12] (12,16] (16,20] 20 15 Percentage 10 5 0 Sep Oct Nov Dec Jan Feb Mar Date in 2012/13 19

20. Vaccine Uptake In a Risk Group 0-4 5-14 15-44 45-64 50 40 Percentage 30 20 10 0 Sep Oct Nov Dec Jan Feb Mar Date in 2012/13 20

21. Vaccine effectiveness for entire season 21

22. Methods Method 1: Test Negative Case Control GP Sentinel Swabbing Scheme Interim & End of Season estimate Adjustment for UK site, time period, sex, flu strain Method 2: Cohort method Weekly download of individual level data from each practice Adjustment for a range of confounders Nested case control (Gold Standard) (Adhoc investigation of potential adverse reaction) Linkage to hospital data and deaths

23. Overall trivalent influenza vaccine (TIV) adjusted vaccine effectiveness (VE) against all laboratory-confirmed influenza in primary care was 51% (95% confidence interval (CI): 27% to 68%); TIV adjusted VE against influenza A alone or influenza B alone was 49% (95% CI: -2% to 75%) and 52% (95% CI: 23% to 70%) respectively. Vaccination remains the best protection against influenza. 23

24. Cohort: Calculation of vaccine effectiveness Seasonal Flu Vaccine Time dependent covariate 14 days for consultation post vaccine to count Time dependent Cox regression Comparing Unvaccinated at time of consultation Vaccinated at time of consultation. 24

25. VE Clinical endpoint VE - - - All ages Age 65+ At risk under 65 21.8% (95% CI 1.9 to 37.6) -35.4% (95% CI -173.9 to 33.1) 28.6% (95% CI 4.0 to 47.0) Period is December 01, 2012 to February 28, 2013 Adjusting for age, gender, clinical risk group, deprivation, urban/rural, seasonal vaccination in previous year, number of ILIARI consultations in the previous year. 25

26. Linking primary & secondary care data What is the increased risk of death from influenza in clinical risk groups? Data linkage - primary care, laboratory, SMR1 & NRO(S) - the SIVE project Severe Acute Respiratory Infections (SARI) due to laboratory confirmed influenza 26

27. What does risk factor analysis of SARI cases tell us? 60 300.0 Influenza cases requiring ICU GP consultations for ILI 50 250.0 number of influenza ICU cases ILI Rate per 100,000 pop 40 200.0 30 150.0 20 100.0 10 50.0 0 0.0 2 4 6 8 2 4 6 8 2 4 6 8 40 42 44 46 48 50 52 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 2010/11 2011/12 2012/13 season and week 27

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29. Vaccine effect varies for different clinical endpoints deaths by season 2000 to 2008/9 Marked variation of vaccine effectiveness in any one year need to look at the average effect over time NIHR

30. Interested in routine flu output? 30

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32. Season 2013/14 Childhood extension of seasonal influenza vaccination programme with LAIV Fluenz Phase 1 (of 3) All Scottish 2 & 3 year olds ~ 120k Pilots in primary school (age 4 to 11 years) ~ 100k TNCC - Increased swabbing resource (from 2k to 3k samples) to allow better VE by age strata Cohort Increase cohort size from 27 to 47 practices ~ 300 350k patients Expand clinical data to include rotavirus & Zoster? 32

33. Making sense of it all: Modelling, Programme Effectiveness & Benefit Realisation 33

34. Benefit Realisation- Influenza: Then, Now and Next? Health Gain? Next v Now? 200 less Indirect & direct Indirect & direct supershed ders reduced 1100 less 33000 less Then No Programme Now - Current Programme Next - Programme Extension IMPACT Measure 900 500 300 Annual Deaths Burden* High Mod Low Consultation rates Levels of infection/ risk of transmission Vaccine uptake (& Effectiveness) NA 75% (30-70) 75% (50-80)? High Mod Low Transmission 4700 2700 1600 Annual Hospitalisations Health Care Utilisation* 100000 75000 42000 Annual GP Consultation PENSIVe pilot Societal Burden Health Economic costs LSHTM LSHTM LSHTM * LSTM&H assumptions 1. Uptake limited to 30% in 2-16 years; 2. Modelling includes indirect benefit through herd-immunity protection of adult groups; 3. Census data 2010/11 England & Scotland population estimates as 53 million & 5.3 million respectively

35. The future Applicability of public health surveillance programme approach to other vaccine preventable diseases? E.g. rotavirus, shingles etc Demonstration of their public health effectiveness Single data extraction of primary care data and linkage with other NHS datasets - SPIRE 35

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37. Acknowledgements Sentinel Swabbing Scheme practices 2012/13 Bridgeton Health Centre, Aberfeldy & Kinloch Rannoch Medical Practice, Airthrey Park Medical Centre, Kilwinning Medical Practice, Glenfield Medical Practice, Ardach Health Centre, The Cairntoul Practice, Braids Medical Practice, Carnoustie Medical Group, Carstairs Surgery, Bourtreehill Medical Practice, The Craigshill Partnership, Cramond Medical Practice, Barns Medical Practice, Dr Langridge, Alva Medical Practice, Riverview Medical Centre, Greencroft Medical Centre (North), Neilston Medical Centre, The Surgery, Keith Health Centre, Kelso Medical Group, Dr Jabaroo & Partners, Liberton Medical Group, Meadowbank Health Centre (Practice 3), Newton Port Surgery, Primrose Lane Medical Practice, Ranfurly Surgery, Dornoch Medical Practice, Skerryvore Practice, Tweeddale Medical Practice, Dr Blake & Partners, Dunbar Medical Centre, Red Surgery, Riverview Practice,West End Medical Practice, Westgate Medical Practice, Yell Health Centre,Denny Cross Medical Centre PIPeR practices 2012/13 Bridgeton Health Centre, Kilwinning Medical Practice, Glenfield Medical Practice, Waverley Medical Practice, Eden Villa Practice, The Cairntoul Practice, Dr Langridge, Alva Medical Practice, The Health Centre, Riverview Medical Centre, Greencroft Medical Centre (North), Neilston Medical Centre, Dr Jabaroo & Partners, Lochinch Practice, Lochnaw Practice, Loch Ree Practice, Meadowbank Health Centre (Practice 3), Primrose Lane Medical Practice, Dr Cassidy & Partners, Bonnybank Medical Practice, Stevenston Medical Practice , Auchinleck Health Centre, Hospital Hill Surgery, Inverkeithing Medical Group, Denny Cross Medical Centre, Brown Spilg Partnership, Drs Owen, Smith & Johnstone 37