Carolyn A Day1, Marian Shanahan2, Handan Wand3, Libby Topp4, Paul S Haber5, Craig Rodgers6, Rachel Deacon7, Nick Walsh8, John Kaldor3, Ingrid van Beek6, Lisa Maher3. 1. Discipline of Addiction Medicine, Central Clinical School (C39), Sydney Medical School, University of Sydney, NSW 2006, Australia. Electronic address: carolyn.day@sydney.edu.au. 2. National Drug and Alcohol Research Centre, University of New South Wales, NSW 2052, Australia. 3. The Kirby Institute, UNSW Australia, Sydney, NSW 2052, Australia. 4. Cancer Council NSW, Woolloomooloo, NSW 2010, Australia. 5. Discipline of Addiction Medicine, Central Clinical School (C39), Sydney Medical School, University of Sydney, NSW 2006, Australia; Drug Health Services, Royal Prince Alfred Hospital, Missenden Road, Camperdown,NSW 2050, Australia. 6. Kirketon Road Centre, South Eastern Sydney Local Health District, Kings Cross, NSW 1340 Australia. 7. Discipline of Addiction Medicine, Central Clinical School (C39), Sydney Medical School, University of Sydney, NSW 2006, Australia. 8. Department of Epidemiology and Preventive Medicine, Monash University, 89 Commercial Road, Melbourne, Victoria 3004, Australia.
Abstract
BACKGROUND:People who inject drugs (PWID) are at risk of hepatitis B virus (HBV) but have low rates of vaccination completion. The provision of modest financial incentives increases vaccination schedule completion, but their association with serological protection has yet to be determined. OBJECTIVE: To investigate factors associated with vaccine-induced immunity among a sample of PWID randomly allocated to receive AUD$30 cash following receipt of doses two and three ('incentive condition') or standard care ('control condition') using an accelerated 3-dose (0,7,21 days) HBV vaccination schedule. STUDY DESIGN: A randomised controlled trial among PWID attending two inner-city health services and a field site in Sydney, Australia, assessing vaccine-induced immunity measured by hepatitis B surface antibodies (HBsAb ≥ 10 mIU/ml) at 12 weeks. The cost of the financial incentives and the provision of the vaccine program are also reported. RESULTS: Just over three-quarters of participants - 107/139 (77%)--completed the vaccination schedule and 79/139 (57%) were HBsAb ≥ 10 mIU/ml at 12 weeks. Vaccine series completion was the only variable significantly associated with vaccine-induced immunity in univariate analysis (62% vs 41%, p<0.035) but was not significant in multivariate analysis. There was no statistically discernible association between group allocation and series completion (62% vs 53%). The mean costs were AUD$150.5, (95% confidence interval [CI]: 142.7-158.3) and AUD$76.9 (95% CI: 72.6-81.3) for the intervention and control groups respectively. CONCLUSION: Despite increasing HBV vaccination completion, provision of financial incentives was not associated with enhanced serological protection. Further research into factors which affect response rates and the optimal vaccination regimen and incentive schemes for this population are needed.
RCT Entities:
BACKGROUND:People who inject drugs (PWID) are at risk of hepatitis B virus (HBV) but have low rates of vaccination completion. The provision of modest financial incentives increases vaccination schedule completion, but their association with serological protection has yet to be determined. OBJECTIVE: To investigate factors associated with vaccine-induced immunity among a sample of PWID randomly allocated to receive AUD$30 cash following receipt of doses two and three ('incentive condition') or standard care ('control condition') using an accelerated 3-dose (0,7,21 days) HBV vaccination schedule. STUDY DESIGN: A randomised controlled trial among PWID attending two inner-city health services and a field site in Sydney, Australia, assessing vaccine-induced immunity measured by hepatitis B surface antibodies (HBsAb ≥ 10 mIU/ml) at 12 weeks. The cost of the financial incentives and the provision of the vaccine program are also reported. RESULTS: Just over three-quarters of participants - 107/139 (77%)--completed the vaccination schedule and 79/139 (57%) were HBsAb ≥ 10 mIU/ml at 12 weeks. Vaccine series completion was the only variable significantly associated with vaccine-induced immunity in univariate analysis (62% vs 41%, p<0.035) but was not significant in multivariate analysis. There was no statistically discernible association between group allocation and series completion (62% vs 53%). The mean costs were AUD$150.5, (95% confidence interval [CI]: 142.7-158.3) and AUD$76.9 (95% CI: 72.6-81.3) for the intervention and control groups respectively. CONCLUSION: Despite increasing HBV vaccination completion, provision of financial incentives was not associated with enhanced serological protection. Further research into factors which affect response rates and the optimal vaccination regimen and incentive schemes for this population are needed.
Authors: Camille C Cioffi; Derek Kosty; Christopher G Capron; Hannah F Tavalire; Robert C Barnes; Anne Marie Mauricio Journal: Public Health Rep Date: 2022-03-03 Impact factor: 3.117