Hepatitis B is a liver disease that can range from a brief, mild illness to a serious, enduring ailment, but it can be prevented through a vaccine. Individuals who inject drugs are at high risk for the disease, but researchers have found that offering small financial incentives significantly increases the likelihood that they will complete a course of hepatitis B virus vaccination.
The research was led by investigators at the National Addiction Centre at King's College London in the UK, along with colleagues at Imperial College London and University College London. They publish their results in The Lancet.
In the UK, hepatitis B virus (HBV) affects around 22% of injecting drug users, but the study authors note that this percentage is much higher in other countries. While medication can slow the spread of the disease, there is currently no cure.
According to the Centers for Disease Control and Prevention (CDC), there were an estimated 43,000 new cases of HBV in the US, but the official number of reported cases was much lower, as many individuals do not know they are infected.
Though an estimated 800,000 to 1.4 million people in the US have a chronic HBV infection, the CDC say rates of acute Hepatitis B have declined by 82% since 1990, when routine vaccination in children was put in place.
The disease is usually spread when blood, semen or other bodily fluids from an infected person enters the body of someone who is not infected, but it can also be spread by sharing needles or syringes, or it can be passed from an infected mother to her baby at birth.
Researchers from this latest study note that around 15-25% of people with untreated chronic HBV die of liver disease. Though the vaccine for this disease is highly effective, the rate of uptake is quite low.
In the US, public health strategies employing financial incentives have gained popularity recently, but such programs are not as common in the UK, where the study took place.
'Size of increase in vaccination was striking'
To investigate how a reward-based scheme would work, the team enrolled 210 individuals receiving treatment for heroin addiction from 12 different National Health Service (NHS) drug treatment facilities in the UK.
These patients received one of three voucher schedules:
- Group 1: treatment as usual, which consisted of HBV vaccination without incentive
- Group 2: a £10 ($16.74) voucher at three different vaccinations, or
- Group 3: a £5 ($8.37) voucher at the first vaccination, a £10 voucher at the second and a £15 ($25.12) voucher at the third.
After comparing how well the three approaches worked, the researchers found that only 9% of participants in the first group completed all of their scheduled vaccinations.
However, 45% of participants in the second group completed their vaccinations, and 49% of participants in the third group - which involved escalating rewards - completed theirs.
This means the individuals who were given vouchers in increasing increments were at least 12 times as likely to complete the full vaccination course within 28 days, compared with those who did not receive a financial reward.
Prof. John Strange, lead investigator from the National Addiction Centre at King's College London, says:
"That monetary incentives increase compliance is unremarkable, but the size of the increase we observed was striking. Injecting drug users are at high risk of infection and transmission of hepatitis B. This is a potentially life-saving vaccine, and increasing its uptake among this group has important benefits to public health, as well as to the individual."
The team also found that around 80% of the study participants who received financial rewards attended appointments on time, which means resources were used more efficiently.
Speaking with Medical News Today, Prof. Tim Weaver, another study author, noted that their findings have "an important public health benefit by virtue of the reduced risk of hepatitis B transmission."
Prof. Strang adds that more work is needed to "refine the reward scheme to increase further the uptake and completion of vaccination."