Dr Tendesayi Kufa

1. Willingness to participate in trials and to be vaccinated with new tuberculosis vaccines in HIV -infected adults Dr Tendesayi Kufa

2. Background • New TB vaccines are needed to meet global targets for TB control • HIV-infected individuals are an important target population for new vaccines • At least three vaccine candidates in phase I/II trials involving people with HIV • Phase III trials will require large numbers of participants • Little data on willingness to participate in TB vaccine trials and to be vaccinated with newly licenced vaccine

4. Objectives • Describe willingness to participate in TB vaccine trials among HIV-infected in care • Describe willingness to be vaccinated with newly licenced TB vaccine • Determine factors associated with the willingness

5. Methods- design and setting • Design • Cross-sectional design • Context • Vaccine preparedness study to estimate TB incidence in HIV+ with high CD4 counts • Setting • 2 primary care clinics in Ekurhuleni North sub-district Gauteng

6. Methods – eligibility criteria • Inclusion criteria • Known HIV positive • CD4 counts >300 cells/µl in preceding 12 months • Living or working in catchment area of clinic • 18 years or older • Willing and able to give consent • Exclusion • Acutely ill • Pregnant (enrolled but not followed up)

7. Methods- study procedures • Patients invited to take part at point of registration for HIV care • Questionnaires with questions on demographics, TB and HIV history, TB knowledge and perception of risk administered • One questionnaire contained two Likert type scales with 5 and 6 items respectively to measure willingness

8. Methods – measurement scales • Items in scales selected based on factors identified as barriers/facilitators to willingness • for each item, responses were scored: 5=“strongly agree”, 4=“agree”, 3= “disagree” 2= “strongly disagree” 1= “I don’t know” • Item scores were summed to give overall score on each scale • Internal consistency reliability determined during analysis by determining values of Cronbach α • α > 0.70 considered acceptable

10. Willingness to participate scale, α=0.92 I would be willing to : • take part in studies to test if a new injection to prevent TB works or not • let my family members take part in studies to test if a new injection to prevent TB works or not • let my children take part in studies to test if a new injection to prevent TB works or not • let my children take part in studies to test a new injection to prevent TB if I was convinced it would work • let my children take part in studies to test a new injection to prevent TB even if it was painful • let my children take part in studies to test a new injection to prevent TB even if it made me a little sick (like vomiting, rashes, fever)

11. Willingness to be vaccinated scale, α=0.69 Once a new injection to prevent TB has been shown to work in studies, I would be willing to get it: • If it became available at my clinic • For my family or household members if it became available at my clinic • For my children if it became available at my clinic • Even if it made me a little sick (like vomiting, rashes, fever) • Even if I had to pay for it

12. Outcomes and statistical analysis • Outcomes • Willingness to participate in a trial of new TB vaccine (defined as scored ≥24 out of possible score of 30) • Willingness to be vaccinated with new TB vaccine (defined as scores ≥ 20 out of possible score of 25) • Data analysis • Descriptive statistics used to describe the population • Univariable and multivariable binomial regression was used to estimate prevalence ratios (PR)associated with outcomes

13. Findings Study summary 2191 screened 1352 (61.7%) Ineligible (96% because of low CD4 counts ) 839 (38.3%) enrolled 12 (1.4%) Duplicate enrolments / missing data 827 (98.6%) analysed 771 (93.2%) responded to all 6 items on WTP scale 765 (92.5%) responded to all 5 items on WTV scale

14. Study population

15. Willingness to participate in trials • Overall WTP was 84.5% • 63% responded “strongly agree” to all items in the scale • Associated with: • Correctly identifying TB symptoms [aPR 1.10 (1.03- 1.17), p=0.003]* • Considering oneself at risk of TB [aPR 1.07 (1.01- 1.13), p=0.024]* *model adjusted for age, previous TB, IPT use, CPT use, knowledge of symptoms, knowledge of TB/HIV association and perception of risk

16. Willingness to be vaccinated • Overall willingness to be vaccinated was 92.6% • 59% responded “strongly agree” to all items in the scale • Associated with: • Being employed [aPR 1.04 (95% CI 1.01- 1.08), p=0.014]* • Considering oneself at risk of TB [aPR 1.05 (95% CI 1.01- 1.09), p=0.02]* *model adjusted for employment, knowledge of symptoms, knowledge of TB/HIV association and perception of risk

17. Limitations • Hypothetical willingness does not translate to actual participation • Scales not previously validated • Likert scales • Social desirability • Uniform scale intervals

18. Conclusions • WTP and willingness to be vaccinated were high in this population • Associated with knowledge of TB, perception of risk and employment • Education to improve knowledge of TB and risk factors may increase WTP/ willingness to be vaccinated

19. Acknowledgements • Staff and patients • Aurum • Violet Chihota, Salome Charalambous, Gavin Churchyard • Study team- Sarah Yates, Joseph Makhura , Marcia Masevhe, Jessie Witkoei, Salome Mahlangu, Lebogang Masia. • KNCV • Suzanne Verver, Ellen Mitchell • Funders • EDCTP