Safety and immunogenicity of hepatitis A vaccine in healthy adult volunteers

Compliance with multiple-dose vaccine schedules among older children, adolescents, and adults: results from a vaccine safety datalink study

OBJECTIVES

We studied compliance with multiple-dose vaccine schedules, assessed factors associated with noncompliance, and examined timeliness of series completion among older children, adolescents, and adults.

METHODS

We conducted a large, multisite, retrospective cohort study of older children, adolescents, and adults in the Vaccine Safety Datalink population from 1996 through 2004. We quantified the rates of completion of all required doses for varicella, hepatitis A, and hepatitis B vaccines according to their recommended schedules.

RESULTS

Among those who received a first dose of varicella (n = 16 075), hepatitis A (n = 594 917), and hepatitis B (n = 590 445) vaccine, relatively few completed the series (55%-65% for hepatitis B vaccine and 40%-50% for hepatitis A and varicella vaccines in most age groups). Compliance was lowest among adolescents (35.9%) and Medicaid recipients (29.7%) who received varicella vaccine and among younger adult age groups who received hepatitis A vaccine (25%-35% across those age groups). Even among series completers, there was a relatively long interval of undervaccination between the first and last doses.

CONCLUSIONS

Compliance with multiple-dose vaccine series among older children, adolescents, and adults is suboptimal. Further evaluations of strategies to improve compliance in these populations are needed.

Hepatitis A in patients with chronic liver disease - severity of illness and prevention with vaccination

Acute hepatitis A in patients with pre-existing chronic liver disease (CLD) may theoretically predispose such patients to a more severe outcome of infection. The results of reports covering epidemics and case series suggest but do not universally support this possibility. An analysis of the larger case series support the suggestion that acute hepatitis A superimposed on chronic hepatitis B infection is associated with higher peak laboratory abnormalities, more severe disease and a higher fatality rate. The safety and immunogenicity of an inactivated hepatitis A vaccination was evaluated in patients with CLD and found to be satisfactory for the protection of this group of patients.

Hepatitis A vaccine in healthy adults: a comparison of immunogenicity and reactogenicity between two- and three-dose regimens

Inactivated hepatitis A virus (HAV) vaccine was administered to 55 healthy seronegative adult volunteers to evaluate the immunogenicity and adverse reactions of two doses of HAV vaccination (25 units) in comparison with a three-dose regimen. The volunteers were randomly assigned to receive one of the two regimens: 26 were vaccinated with two doses at 0 and 24 weeks (Group 1), and 29 were vaccinated with three doses at 0, 2, and 24 weeks (Group 2). The vaccine was well tolerated and there was no serious adverse reaction. In both groups, the seroconversion rate was 100% at week 28. At week 52, all remained positive for anti-HAV regardless of a two- or three-dose regimen. No statistically significant difference in seroconversion rates and geometric mean titers could be demonstrated between the two groups. Thus, the two-dose regimen may be favorable to save cost and time for active immunization against hepatitis A.

Concomitant vaccination against hepatitis A and typhoid fever

BACKGROUND

The purpose of this study was to evaluate the reactogenicity and immunogenicity of a hepatitis A vaccine (Havrix-1440TM) when administered simultaneously with a Vi polysaccharide typhoid vaccine.

METHODS

Two open, randomized studies were conducted using 2 and 4 treatment groups respectively, at the Clinique Notre-Dame de Grâce, Belgium (Study 1) and University Hospital of Hradec Kralové, Czech Republic (Study 2).

SUBJECTS

Healthy adults aged 18-50 years were administered either both vaccines concomitantly in separate arms or a single injection of the two vaccines mixed extemporaneously (Study 1), or one injection of each vaccine alone, or the combined vaccine, or both vaccines concomitantly in separate arms (Study 2). The study measured solicited and unsolicited signs and symptoms until 28 days post-vaccination. Anti-hepatitis A and anti-Vi titers were determined in pre- and post-vaccination sera.

RESULTS

The vast majority of local and general symptoms were mild to moderate and all resolved without sequelae. No serious adverse events were reported in either study. In study 1, geometric mean antibody titers (GMTs) were similar after extemporaneous syringe mixing of both vaccines (anti-Vi = 1159 EL.U/mL; anti-HAV = 302 EL.U/mL) and after concomitant vaccination (anti-Vi = 1331 EL.U/mL; anti-HAV = 367 EL. U/mL). In study 2, GMTs following vaccination with either vaccine alone, both vaccines administered concomitantly or as a combined vaccine (anti-Vi: 1307, 1247 and 942 EL.U/mL, respectively; anti-HAV: 462, 517 and 432 EL.U/mL, respectively) were not significantly different (p = .45 for anti-HAV, p = .18 for anti-Vi). Seroconversion rates were > 94.4% in all cases.

CONCLUSIONS

The inactivated hepatitis A and Vi polysaccharide typhoid vaccines are safe and well tolerated when administered simultaneously (mixed or concomitant) and as a combined vaccine. Subjects seroconverted to both antigens to the same extent as the monovalent vaccines and there was no cross-interference in the immune profiles of the vaccines.

Safety and immunogenicity of hepatitis A vaccine in patients with chronic liver disease

Acute hepatitis A superimposed on chronic liver disease (CLD) has been associated with severe or fulminant hepatitis. An open, multicenter study was performed to compare the safety and immunogenicity of an inactivated hepatitis A vaccine in patients with CLD with that in healthy subjects. A secondary objective was to compare the safety of the hepatitis A vaccine with that of a commercial hepatitis B vaccine in subjects with chronic hepatitis C. A total of 475 subjects over the age of 18 years were enrolled into 1 of 5 groups according to history, serological data, and previous diagnosis. Patients in groups 1 (healthy adults), 2 (chronic hepatitis B), 3 (chronic hepatitis C), and 5 (other CLD not caused by viral hepatitis) were vaccinated with two doses of inactivated hepatitis A vaccine, 6 months apart. Patients in group 4 (chronic hepatitis C) received 3 doses of a recombinant hepatitis B vaccine, according to a 0-, 1-, and 6-month schedule. Local injection-site symptoms were the most common reactions reported following vaccination in all groups (35.5% of all doses), with the hepatitis B vaccine eliciting fewer injection-site symptoms than the hepatitis A vaccine (19.8% compared with 37.5%). Although a higher percentage of healthy subjects (93%) seroconverted after a single dose of the hepatitis A vaccine than did subjects with chronic hepatitis C (73.7%) or CLD of nonviral etiologies (83.1%), more than 94% of all vaccinees were seropositive for anti-HAV after the complete vaccination course. At each time point, a lower geometric mean concentration of anti-HAV was observed for each group of CLD patients compared with the healthy control subjects. In conclusion, hepatitis A vaccine was well tolerated and induced a satisfactory immune response in patients with chronic hepatitis B, chronic hepatitis C, and miscellaneous CLD.

Immunogenicity and safety of a new inactivated hepatitis A vaccine in a comparative study

A multicentre, controlled, randomised, open, comparative trial including 839 healthy adult volunteers was carried out in order to compare the immunogenicity and reactogenicity of two vaccines against hepatitis A virus (HAV) during primary immunization and after booster injection. The first vaccine was produced by Pasteur Mérieux (PM), and the second vaccine by Smith-Kline Beecham (SKB). The vaccination schedule consisted of 2 doses (months 0, 6) for PM and 3 doses (months 0, 1, and 6) for SKB. Two weeks after the first dose, the seroconversion rates among initially HAV seronegative subjects (n = 608) were 93.4% and 76.1% for the PM and SKB vaccines, respectively, the corresponding geometric mean titres (GMTs) were 59.0 mIU/ml versus 30.8 mlU/ml (modified RIA HAVAB assay, Abbott Laboratories). Two months after the beginning of immunization (one dose versus two doses) the GMTs were 138.4 and 161.6 mlU/ml, respectively. At month 7, the seroconversion rates were 100% for both vaccines, and the GMTs were 4,189 and 3,163 mlU/ml, respectively. After the first dose of vaccine, 24.6% and 19.6% of the PM and SKB vaccines reported local reactions. The rates for systemic reactions were 27.2% and 25.0%, respectively. Lower rates for local and systemic reactions were seen after booster injections and statistical differences were not observed between the two vaccines. The study also demonstrated that vaccination was as well tolerated in subjects with anti-HAV antibodies as in HAV seronegative subjects. Logistic regression analysis revealed a significant vaccine effect on seroconversion rates only at week 2 (P < 10(-4). The same conclusions were drawn from the analysis of GMT by multivariate regression.(ABSTRACT TRUNCATED AT 250 WORDS)