Immunogenicity, reactogenicity and adherence to a combined hepatitis A and B vaccine in illicit drug users

Let It "B"? The role of Hepatitis B universal vaccination among italian problematic drug users

Hepatitis B virus (HBV) hepatitis is extremely common among problematic drug users (DUs). As of 2012, 47 of the 53 European countries had implemented a universal hepatitis B vaccination programme, a scenario that could radically change its spread. Even so, drug users are still one of the main groups at risk of being infected by HBV, exposing the fact that universal vaccination still has not managed to reach an optimal level of contagion protection. In order to evaluate the role of universal HBV vaccination in protecting against risk behaviour related to the use of illicit drugs, a group of 748 DUs, 511 male and 237 female, was tested for HBV markers, at their first access to public addiction clinics in the metropolitan area of Bologna, Italy. 487 were born after 1981, so they were eligible to have received HBV vaccination in adolescence or at birth; in these subjects antibodies against HBV core antigen had the significant prevalence of 6.2%. Universal HBV vaccination has shown evidence of protecting against infection in the general population. These results, amongst the first to evaluate actual protection in DUs vaccinated at birth or during adolescence, show that compulsory universal vaccination does not solve the problem of HBV transmission in the most at risk groups and that additional strategies must be studied and implemented to address this issue.

Recommendations for the prevention, diagnosis, and treatment of chronic hepatitis B and C in special population groups (migrants, intravenous drug users and prison inmates)

The global spread of hepatitis B virus (HBV) and hepatitis C virus (HCV), their high chronicity rates and their progression to cirrhosis and hepatocellular carcinoma, are major public health problems. Research and intervention programmes for special population groups are needed in order to assess their infection risk and set up suitable prevention and control strategies. Aim of this paper is to give health care professionals information on HBV and HCV infections amongst migrants, drug users and prison inmates. The manuscript is an official Position Paper on behalf of the following Scientific Societies: Italian Association for the Study of the Liver (A.I.S.F.), Italian Society of Infectious and Tropical Diseases (S.I.M.I.T.), Italian Federation Department's Operators and Addiction Services (FederSerD), Italian Prison Medicine and Healthcare Society (S.I.M.S.Pe.). The considered population groups, having a high prevalence HBV and HCV infections, require specific interventions. In this context, the expression "special population" refers to specific vulnerable groups at risk of social exclusion, such as migrants, prison inmates, and intravenous drug users. When dealing with special population groups, social, environmental and clinical factors should be considered when selecting candidates for therapy as indicated by national and international guidelines.

Hepatitis A Virus among Drug Users and the Role of Vaccination: A Review

In countries with advanced economies better health and hygiene conditions, along with the introduction, in some cases, of global vaccination, have relegated most viral hepatitis to marginal social groups and, in particular, drug users (DUs). The availability of safe and effective vaccines for hepatitis A virus (HAV) and B (HBV) may play a major role in combating this phenomenon. Despite the availability of a safe and effective vaccine for over a decade and the recommendations of international health organizations, vaccinations against HAV among DUs are not as widely known and available as are HBV vaccinations. The purpose of this review article is to present the most significant data in the literature on the prevalence of HAV among DUs and the role of targeted vaccination. To our knowledge, the present article is the first to solely deal with vaccination against HAV in DUs. Immunization after the administration of anti-HAV vaccine has been demonstrated in DUs even if they have responded significantly less than either the general population or carriers of chronic liver disease. All the vaccines were well tolerated and adherence to the vaccine schedule was good. Further studies are needed to optimize the timing and doses of vaccine to be administered to DUs, especially to assess adherence and antibody persistence. Vaccination campaigns are feasible among DUs and have proven to be highly cost-effective.

Antibody response to hepatitis B vaccine in substance use disorder patients

The objectives of this study were to assess the prevalence of prognostic factors previously known to be associated with poor antibody response to hepatitis B vaccination in a sample of veterans presenting for substance use disorders treatment at a Veterans Health Administration (VA) Medical Center, assess vaccination response, and identify markers for poor response in this population. Results indicated that most participants had multiple prognostic factors previously known to be associated with poor antibody response including male gender, age over 40, smoking, and obesity. The rate of seroconversion in this sample was 51.9%. This is substantially lower than seen in healthy adults. Alcohol dependence was the only significant independent negative predictor of seroconversion in this sample. Substance use disorders treatment providers who are considering adding hepatitis B vaccination services to their clinics should be aware that the antibody response to the hepatitis B vaccination is inconsistent and that patients with particular demographic characteristics may be at heightened risk of poor antibody response.

Combined hepatitis A and B vaccine: providing a bright future for preventing hepatitis

The first combined hepatitis A and B vaccine has been available in the United States since 2001. The vaccine provides protection against viral hepatitis with rapid seroprotection and lasting immunogenicity. This review outlines the product's components, clinical efficacy and opportunities for use in special circumstances. The vaccine has a good safety profile and has good tolerability. The combined hepatitis A and B vaccine is a well studied vaccine that provides rapid seroconversion with a good safety profile.

Bloodborne viral hepatitis infections among drug users: the role of vaccination

Drug use is a prevalent world-wide phenomenon and hepatitis virus infections are traditionally a major health problem among drug users (DUs). HBV and HCV, and to a lesser extent HAV, are easily transmitted through exposure to infected blood and body fluids. Viral hepatitis is not inevitable for DUs. Licensed vaccines are available for hepatitis A and hepatitis B. The purpose of this overview is to show some epidemiological data about HBV and the other blood-borne viral hepatitis among DUs and to summarize and discuss use of hepatitis vaccinations in this population. Successful vaccination campaigns among DUs are feasible and well described. We try to focus on the most significant results achieved in successful vaccination programs as reported in scientific literature. Vaccination campaigns among DUs represent a highly effective form of health education and they are cost-saving.

Outbreaks of hepatitis A in England and Wales associated with two co-circulating hepatitis A virus strains

During 2002, an upsurge in frequency of hepatitis A outbreaks among injecting drug users was observed in England and Wales. As lack of risk factor information and the high mobility of the cases made linkage of outbreaks difficult, the relationship of nucleotide sequences in the VP1/2PA junction of the hepatitis A virus (HAV) genome amplified from serum of case-patients was investigated. A total of 204 HAV RNA positive sera obtained from a network of 23 laboratories were studied. Comparison of the sequences identified two principal strains: ES1 (n=95) belonging to type IB, and ES2 (n=72) to type IIIA. Of the remaining samples, 15 were type IA, 11 were type IB and 11 were type IIIA. ES1 predominated in Doncaster and other towns in Trent and northern England, and ES2 in the Midlands and southern England; the difference in geographical distribution between these two strains was significant (P<0.0001). In comparison to the sporadic cases, cases infected by either ES1 or ES2 tended to be younger, injecting drug users, people in contact with injecting drug users, or those with a history of incarceration in prisons or homelessness (P<0.0001). Cases infected by ES1 tended to be younger than those by ES2 (P<0.0001). The association of the outbreaks to two geographically restricted strains implicates two principal transmission pathways associated with injecting behavior. Identifying these routes may be conducive to preventing further outbreaks.

Schedules for hepatitis B vaccination of risk groups: balancing immunogenicity and compliance

INTRODUCTION

Vaccination is an important tool in hepatitis B prevention. However, several vaccine doses are required to induce long-term protection. Several at-risk groups have difficulties in adhering to the standard vaccination schedule.

OBJECTIVES

This paper aims to review the use of accelerated hepatitis B vaccination schedules, in terms of immunogenicity and compliance.

RESULTS

Accelerated schedules (0.1.2.12 months) or super-accelerated schedules (0.7.21.360 days) have been shown to result in higher proportions of healthy vaccinees reaching anti-HBs antibody levels >or=10 IU/l more rapidly. A fourth completing dose is required to lift antibody levels to an equal height, as does a standard (0.1.6 months) schedule. Accelerated schedules do also increase the uptake of hepatitis B vaccine, that is the proportion of vaccinees who receive three doses. However, completing the schedule with a fourth dose is usually more difficult than completing a standard 0.1.6-month schedule. Several additional tools can help to increase the compliance (eg, reminder systems, outreach services and incentive schemes).

CONCLUSION

For rapid seroconversion and almost immediate protection in the short term, a (super)accelerated schedule could be used in at-risk groups. As long-term protection data with these (super) accelerated schedules have not been documented yet, a fourth dose at month 12 is still required. A shortened schedule (0.1.4 months) might be an alternative worth considering compared with the standard 0.1.6, as it convenes to internationally accepted minimum dose intervals and offers earlier protection. There is a clear need to study the long-term protection and effectiveness of the primary part of (super)accelerated schedules.

Vaccine immunogenicity in injecting drug users: a systematic review

Injection drug use is a prevalent global phenomenon; one not bound by a country's level of development or geographical location. Injection drug users (IDUs) are at high risk for a variety of parenterally acquired and transmitted infections. Licensed vaccines are available for some of these infectious diseases, such as tetanus, influenza, and hepatitis A and B viruses; however, there have been conflicting reports as to their immunogenicity in IDUs. We summarise the lessons learned from studies evaluating the immunogenicity of vaccination strategies in IDUs. A common theme across these diseases is that although there is a tendency towards decreased antibody responses after immunisation, there is no conclusive evidence linking these observations to a decrease in clinical protection from infection. There is a clear need for definitive studies of vaccination strategies in IDUs; however, a synthesis of the available published evidence suggests that immunisation does result in effective clinical protection from disease in this population. The inclusion of IDUs as a high-risk study population in future trials evaluating HIV and hepatitis C virus vaccines will help to assess the immunogenicity of candidate vaccines against parenteral exposure, and also to evaluate the efficacy of candidates as promising antigens become available.

Twinrix®vaccination schedules among injecting drug users

Twinrix is the only licensed vaccine that provides dual protection against infection with hepatitis A virus (HAV) and hepatitis B virus (HBV). The standard vaccination schedule for Twinrix is 0, 1 and 6 months. However, many high-risk populations, such as injecting drug users (IDUs), do not complete the vaccination series and, thus, do not acquire sufficient immunity against HAV and HBV. Twinrix can be administered using an accelerated vaccination schedule of 0, 7 and 21 days, with a booster recommended at 12 months. This manuscript reviews the available literature on vaccinating IDUs against HAV and HBV. The authors conclude that there is insufficient evidence regarding whether the accelerated Twinrix HAV/HBV vaccination schedule would yield a greater number of IDUs protected against both HAV and HBV.