Using Information to Close the Primary/Secondary Care Loop-

Flu Vaccination Programme

Arlene Reynolds & Jim McMenaminHealth Protection Scotland

SCIMP, Crieff, November 2013

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?

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.1001527http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001527

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

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?

Cumulative vaccine uptake by risk group over time

season 2012/13

** 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.

0%

20%

40%

60%

80%

100%

Week40

Week42

Week44

Week46

Week48

Week50

Week52

Week2

Week4

Week6

Week8

Week10

Week12

Week number

Vac

cin

e u

pta

ke (

%)

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

How quickly is offer of vaccine taken up?

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

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Weekly GP consultation rates for ILI by flu season Scotland

(In 2012/13 = 961 practices)

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GP consultation rates for ILI in Scotland by age group;

weekly rates per 100,000 population, week 40 2012 to week 32 2013

Who is affected most?

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Where? NHS board ILI consultation rates to

16th October 2013

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What Flu strains are responsible?

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If its not Flu what is it?(Do I need to treat it…?)

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

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Colours represent the different postcode areas of practice population

Vaccine Uptake

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Date in 2012/13

Pe

rce

nta

ge

Sep Oct Nov Dec Jan Feb Mar

02

04

06

08

0

0-45-1415-4445-6465-7475+

Vaccine Uptake

16

Date in 2012/13

Pe

rce

nta

ge

Sep Oct Nov Dec Jan Feb Mar

05

10

15

20

FemaleMale

Vaccine Uptake

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Date in 2012/13

Pe

rce

nta

ge

Sep Oct Nov Dec Jan Feb Mar

05

10

15

20

25

30

012+

Consultations in Previous Season

Vaccine Uptake

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Date in 2012/13

Pe

rce

nta

ge

Sep Oct Nov Dec Jan Feb Mar

05

10

15

20

UrbanSmall TownsRural

Urban Rural Status

Vaccine Uptake

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Date in 2012/13

Pe

rce

nta

ge

Sep Oct Nov Dec Jan Feb Mar

05

10

15

20

[1,4](4,8](8,12](12,16](16,20]

Deprivation

Vaccine Uptake

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Date in 2012/13

Pe

rce

nta

ge

Sep Oct Nov Dec Jan Feb Mar

01

02

03

04

05

0

0-45-1415-4445-64

In a Risk Group

Vaccine effectiveness

for entire season

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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

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“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. “

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.

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VE – Clinical endpoint

Adjusting for age, gender, clinical risk group, deprivation, urban/rural, seasonal vaccination in previous year, number of ILIARI consultations in the previous year.

Period is December 01, 2012 to February 28, 2013

VE - All ages 21.8% (95% CI 1.9 to 37.6)- Age 65+ -35.4% (95% CI -173.9 to 33.1)- At risk 28.6% (95% CI 4.0 to 47.0)

under 65

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

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What does risk factor analysis of SARI cases tell us?

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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

Interested in routine flu output?

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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?

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

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Benefit Realisation- Influenza: Then, Now and Next?

IMPACT Measure

Then – No

Programme

Now - Current

Programme

Next - Programme Extension

Health Gain? Next v Now?

Burden*Annual Deaths

900 500 300 200 less

Levels of infection/ risk of transmission

Consultation rates High Mod LowIndirect &

direct

NA 75% (30-70) 75% (50-80)?Indirect &

directVaccine uptake (& Effectiveness)

High Mod Low“supershed

ders” reduced

Transmission

Health Care Utilisation*

Annual Hospitalisations

4700 2700 1600 1100 less

Annual GP Consultation

100000 75000 42000 33000 less

Societal Burden

Health Economic costs

LSHTM LSHTM LSHTMPENSIVe

pilot

* 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

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

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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