Persistence of Hepatitis A Antibody in Healthy Adults ~32 Years Post Vaccination.

Open Label Study to Assess the ~32-Year Persistence of Hepatitis A Antibody Among Participants in the Pivotal, Double-Blind, Placebo-Controlled Efficacy Study of VAQTA (Study 023-001)

Status

UNKNOWN

Phases

Phase 4

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT06184230

Enrollment

300

Registered

2023-12-28

Start date

2024-01-31

Completion date

2025-06-30

Last updated

2023-12-28

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Hepatitis A

Brief summary

The goal of this clinical trial is to evaluate the persistence of Hepatitis A antibody \ 32 years post vaccination in healthy adults. The questions this study will answer are: 1) how long antibody persists and 2) The immune response to an additional dose of vaccine among those with no detectable antibody. Participants will be asked to provide a blood specimen. Those with no detectable antibody will be offered an additional dose of vaccine. The kinetics of antibody response in this population will be summarized.

Interventions

BIOLOGICALHepatitis A Vaccine

Hepatitis A Vaccine

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

BASIC_SCIENCE

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Consent obtained * Participated in original hepatitis A study in 1991 * No detectable hepatitis A antibody \ 32 years after study start

Exclusion criteria

* Receipt of any dose of hepatitis A vaccine other than the hepatitis A vaccine used in the initial studies * History of hepatitis A * Receipt of blood transfusion or blood products, including immunoglobulins, within the past 6 months. * Receipt of any vaccine within the 14 days before receipt of the additional dose of hepatitis A vaccine or scheduled to receive any vaccine within 30 days after receipt of a booster dose of vaccine.

Design outcomes

Primary

Measure	Time frame	Description
Persistence of Antibody	32 Years	Hepatitis A antibody

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026