Hepatitis B Vaccination Among Research Participants, Seattle, Washington

We report here on a protocol to increase hepatitis B virus (HBV) vaccination in participants in 2 research studies in Seattle, Wash. Injection drug users (IDUs) in a cohort study were interviewed and screened for several bloodborne viral infections, including HBV.1 At posttest counseling, participants were informed of their test results, provided risk reduction counseling, and referred to medical services. Prevalence of core antibody to HBV (anti-HBc) was 67%, and only 14% of the participants reported prior HBV vaccination.2 Participants who were anti-HBc negative were given a voucher for a no-cost series of HBV vaccinations redeemable at a public health clinic in downtown Seattle. The clinic agreed to accept people with vouchers on a drop-in basis, reduce waiting time, and record the number of vouchers redeemed. Between February and December 1997, 120 vouchers were distributed. Of participants with vouchers, 91 (76%) did not complete any vaccinations; 6 (5%) completed 1 vaccination and 5 (4%) completed 2. Only 18 IDUs (15%) completed the series of 3 HBV vaccinations.

A similar HBV vaccination protocol was implemented for a study of men aged 15 to 22 years attending Seattle same-sex venues (the Young Men’s Survey [YMS]).3 YMS participants received counseling and testing for HIV and HBV; 32% were HBV surface-antibody positive and 5% were anti-HBc positive.4 At the posttest visit, HBV-susceptible participants were counseled and given a voucher for free vaccinations at a health department clinic. Clinic staff agreed to record when the first voucher was redeemed but could not track subsequent vaccinations. In 1998, of 285 YMS participants offered vouchers, only 9 (3%) initiated vaccination.

Only a small proportion of participants in these 2 studies initiated or completed free HBV vaccinations offered off-site. One other study has reported on efforts to improve vaccination in research subjects. In a study of IDUs in Anchorage, Alaska, a $10 incentive increased completion of the first HBV vaccination at off-site locations from 7% to 48%.5 This preincentive rate of 7% compares with 24% completion of the first vaccination in our IDU study and 3% in the YMS. On-site vaccinations have been associated with higher completion rates at needle exchanges, drug treatment centers, and HIV counseling and testing programs,6–9 but research field offices may not be able to provide this service unless medically licensed personnel are present to administer vaccinations. Previous studies have also reported frequent missed opportunities for vaccination of IDUs and men who have sex with men in health care settings.10–14

HBV screening of participants in research studies may contribute to HBV prevention if it raises awareness of the need for vaccination in research participants and identifies gaps in local public and private health services. Our findings did contribute to the decision to assign a public health nurse to provide on-site vaccination at the Seattle needle exchange, and they were used in development of a local vaccination campaign for gay men. Thus it seems that HBV screening and referral to no-cost vaccinations provided by research studies may not, alone, serve to achieve acceptable vaccination levels. Additional strategies (which may include monetary incentives) are needed.