1. Text4Health: Immunization-Registry-Linked Text Message Reminders Improve Adolescent Immunization Coverage
Melissa Stockwell, MD, MPH
Elyse Olshen Kharbanda, MD, MPH, Raquel Andres, PHD, Marc Lara, MBA, David Vawdrey, PhD, Karthik Natatajan, MS
Vaughn Rickert, PsyD
42nd National Immunization Conference Atlanta, GA April 21, 2010 
Funded by HRSA Maternal Child Health Bureau grant R40MC08961

2. Adolescent Immunization Schedule
In the past few years, three new vaccines have been added to the routine adolescent immunization schedule. These vaccines – Tdap, HPV and MCV4 – have the potential to greatly improve the health of our community. In order for these vaccines to have their greatest impact, uptake must be high. As some of you know, the yellow denotes when they vaccines are recommended – at the year visit, while the green denotes when these and other vaccines may be given to adolescents as “catch-up” vaccines
Coverage rates ofr tdap and mCva re around 40%, lower than for early childhood

3. Reminder-recalls Recommended by: AAP, SAM, AAFP, ACIP, NVAC
Meta-analysis by US Task Force on Community Preventive Services found median increase of 8% (range, −7%–31%)
More recent meta-analysis found reminder- recalls childhood vaccinations OR=1.47 (95% CI )
Traditional reminder-recalls in adolescents and underserved populations have not been very successful
Briss et al 2000; Szilagyi and Jacobson

4. Why cellular technology is ideal
Over 91% US adults use cell phones
Use may be higher in underserved populations
Stability of cell phone #s
Provide cues to action
Use with immunization registry
Wireless Quick Facts June 2009, CTIA, The Wireless Association. Available at Accessed April 5, 2010.
Blumberg et al 2006, Castano et al 2006
Immunization reminder-recalls have been well evaluated and shown to be effective in increasing immunization coverage. They are recommended by a variety of groups including theus task force on preventive services, aap and sam. So why have we decided to focus on text messaging immunization reminders? A few reasons – first we know that traditional reminder-recalls – through phone calls or letters in the mail can be challenging in low income populations due to unstable home phone number, delayed receipt of mail and expense; cellular technology may be ideal as cell phones are in widespread use – 76%... And cell numbers may actually be higher and numbers more stable than land line use; text message reminder recalls will work by providing cues to action – this is from the health belief model – one model describing immunization seeking behaviors

5. Study Objectives Primary: Secondary:
To evaluate the impact of registry-linked text messages on receipt of immunizations among adolescents in a low-income, urban community.
Secondary:
To estimate the incremental cost-effectiveness ratio for this intervention.

6. Study Setting and Design
Academic medical center in underserved community
Primarily Latino, Medicaid/SCHIP
Hospital and network of affiliated ambulatory clinics (n=6)
Randomized at practice level
2 intervention, 4 control
Pre-intervention immunization rates (child and adolescent), size of adolescent population
Part of same practice network, minority, publicly insured
Used EzVAC to automatically identify eligible adolescents
Adol population and baseline rates

7. Study Population Eligible parents Child 11-18 years old
Child visited one of 6 clinical sites in the past year
Cell phone number in hospital registration system
Child needed MCV4 and/or Tdap
Tdap: not having received Tdap, not received Td in last 2 years

8. Study Design
Weekly: random sample adolescents in need of Tdap/MCV, matched with control (age, gender)
Identified in EzVAC immunization registry
Point-of-service registry, linked to hospital billing system
All children receiving care at hospital and affiliated ambulatory clinic
Used EzVAC to automatically identify eligible adolescents
Adol population and baseline rates

9. Intervention Automated immunization text reminders
Initial message at randomization
Additional at weeks 1, 2, 6 and 7
Texts designed based on focus group input
Child’s name, clinic name, clinic phone number, walk in times
Spanish and English texts
Sent in language listed in registration system
1st message allowed switch to Spanish
Option to stop
Kharbanda EO, Stockwell MS, Fox HW, Rickert VI. Text4Health: a qualitative evaluation of parental readiness for text message immunization reminders. Am J Public Health. Dec 2009;99(12):

10. Sample text message
Chris is due for shots. Come to Audubon clinic Mon-Thu 9-11am, Fri 1-3:30pm. To stop reminders text QUIT. Para espanol text ESPANOL

11. Main Outcome Measures Primary outcome: Secondary outcome:
Receipt of needed adolescent vaccine (MCV4 or Tdap) at 4, 12 and 24 weeks after receipt first message
Secondary outcome:
Receipt of any additional needed immunization

12. Analysis
Chi square: differences in receipt of vaccine, intervention vs control
Nested ANOVA (Analysis of variance): account for effect of variance between sites
Multivariate logistic regression: impact of age, gender, race/ethnicity, insurance status and language
on the intervention effects
Generalized linear models

13. Incremental Cost Effectiveness
Costs and benefits compared to standard of care (no reminder-recalls)
Outcomes:
cost per additional patient immunized
cost per additional vaccine
Extrapolated to continue intervention for a two-year period in two populations:
A. All teens in hospital-based registry
B. Hypothetical population of 100,000 teens
Variable costs: personnel time to monitor messaging platform
Discounting not applied
A next step was to determine the incremental cost effectiveness of our text messaging intervention. In these analyses, we compared the costs and benefits of our intervention versus standard of care, which was no reminder-recalls. Our outcomes were cost per additional patient immunized and cost per additional vaccine; we then extrapolated findings from our study to continue the intervention over a two year period in 2 populations – all teens in our hospital based registry and a hypothetical population of 100,000 teens included in a population-based registry; as costs and benefits were occurring close togeether, discounting was not applied

14. Characteristics of Study Population
Intervention (ITT) Control
(N = 195) (N= 166)
Age (mean +/-SD, yrs) / /- 1.7
Gender %, (n)
Male (77) (75)
Female (118) (91)
Race/Ethnicity* %, (n)
Black, non Latino (32) (21)
Latino (101) (87)
White, non Latino (5) (6)
Other (54) (36)
Insurance %, (n)
Uninsured (23) (18)
Medicaid (145) (125)
SCHIP (8) (12)
Private (19) (11)
Primary Language %, (n)
English (81) (67)
Spanish (111) (94)
Other (3) (4)
No significant differences
Note: No significant differences between intervention and control groups

15. Messages 821 text messages were sent 7 bounces, 5 wrong numbers (6.2%)
5 families opted out (2.7%)
on the intervention effects
Generalized linear models

16. * At 12 weeks: 12.3% point difference (CI 4.4%- 20.4%)

17. At 4 weeks: 11.8% point difference (CI 5.2%- 18.5%)
Most common other vaccines administered included: Human papilloma virus, Hepatitis A, influenza, varicella, measles/mumps/rubella
At 4 weeks: 11.8% point difference (CI 5.2%- 18.5%)
At 12 weeks: 12.5% point difference (CI 3.6%- 21.4%)
At 24 weeks: 12.5% point difference (CI 2.7%- 22.3%)
Most common: HPV, Hepatitis A, influenza, varicella, MMR

18. Nested ANOVA
Nested ANOVA did not find a significant contribution due to the sites at any time points for all analyses.

19. Multivariate Analyses
Receipt of MCV and/or Tdap vaccine
4 weeks: AOR 4.12 (95% CI 1.72, 9.90)
12 weeks: AOR 2.40 (95% CI 1.34, 4.32)
24 weeks: AOR 2.48 (95% CI )
* All analyses controlled for age, gender, race/ethnicity, insurance status and language

20. Incremental Cost Effectiveness
For all teens in our hospital-based registry:
Cost per adolescent immunized: $17.71
Cost per additional vaccine: $4.32
For a hypothetical cohort of 100,000 teens
Cost per adolescent immunized: $1.71
Cost per additional vaccine: $.42
We found that the incremental cost effectiveness of our intervention, if continued over two years for all teens in our registry would be per adolescent immunized and 4.32 per additional vaccine delivered
In a hypothetical cohort of 100,000 teens we estimated that costs per adolescent immunized would be 1.71 while cost per additional vaccine delivered would be .42

21. Summary 11-18% increase (AOR 2.4-4.1) receipt MCV/Tdap
Meta-analyses 8% median change,OR 1.7
Low-income urban children and adolescents
Sustained effect, additional vaccines
Economies of scale
Briss et al 2000, Szilagyi and Jacobson et al 2005, Szilagyi et al. 2006, Irigoyen et al 2006, Hambidge et al 2004, Daley et al, 2002
Text messaging effective way to deliver immunization reminders to families, even in an underserved, adolescent population:

22. Limitations Incomplete records: 95% given at our sites
Randomized within a site not overall: carry over bias, nested ANOVA
Cell phone available: EHR, 53% our population
Not population wide: limits of capacity
Generalizability
Simplified cost analyses, assumptions
In addition, registry records may have been incomplete, and some adolescents texted may have really have not been due for vaccination; they may ave accounted for some number of patients who had visits but did not receive the needed shot
Assumptions: sustained efficacy but likely those who did not get it after a few rounds will not get it
Assume pop aging in is same number as who age out
Could be other variable costs not aware of

23. Future Directions
Dissemination to a larger immunization registry, department of health, or large group practice to improve immunization coverage
Use of reminder recalls for other age groups, other vaccines (flu)

24. Acknowledgements
Text4Health-Registry Clinical Sites
New York Presbyterian Hospital Ambulatory Care Network
Text4Health Study Team
Elyse Olshen Kharbanda, MD MPH
Harrison Fox, BA
Vaughn I. Rickert, PsyD
Raquel Andres Martinez, PhD
Oscar Pena, JD
Marcos Lara, MBA
David Vawdrey, PhD
Karthik Natarajan, MA
Balendu Dasgupta, MA
For more information visit:
This study is funded by HRSA R40MC