Two-Dose Hepatitis A Revaccination Schedule Optimal for Patients With HIV

A 2-dose hepatitis A virus (HAV) revaccination schedule was associated with significantly higher anti-HAV antibody titers and serologic responses among patients with HIV infection who did not respond to primary HAV vaccination. These findings were published in Clinical Infectious Diseases.

Between 2015 and2017 a large-scale outbreak of HAV infection occurred in Taiwan, triggering the implementation of an HAV vaccination program aimed at high-risk individuals. Researchers conducted this study (Clinicaltrials.gov Identifier: NCT03855176) during the vaccination program to evaluate the outcomes of a 1- and 2-dose HAV revaccination protocol among HIV-positive patients who did vs did not achieve a serologic response following primary HAV vaccination. Eligible patients (N=153) were randomly assigned 1:1 to receive either 1 (n=77) or 2 (n=76) additional HAV vaccine doses.

The primary endpoint was serologic response at week 48. Serologic response rates and anti-HAV immunoglobulin (Ig)G titers were compared between the groups at weeks 24 and 48. Factors associated with serologic response achievement were determined via multivariate logistic regression. Both the Vaqta® and the Havrix® HAV vaccines were used in this study.

Among patients included in the 1- and 2-dose vaccine groups, the mean (SD) ages were 38.2 (8.0) and 39.4 (7.0) years, 100% and 100% were men, the median HIV RNA levels were 1.3 (IQR, 1.3-1.3) and 1.3 (IQR, 1.3-1.3) log₁₀ copies/mL, and the median CD4 lymphocyte counts at baseline were 513 (IQR, 328-676) and 462 (IQR, 339-676) cells/mm³, respectively.

Patients were enrolled in the trial within a median of 2 to 2.1 years following primary HAV vaccination. Overall, 50.0% to 55.8% of patients had responded to primary HAV vaccination.

Higher serologic response rates were observed among patients in the 2-dose vaccine group vs those in the 1-dose vaccine group at weeks 4 (82.9% vs 79.2%), 24 (85.5% vs 79.2%), and 48 (80.2% vs 71.4%).

Stratified by primary response status, serologic response rates to the HAV booster during the follow-up period were similar among 1- and 2-dose vaccine recipients (range, 92.1%-97.7%). Among patients who did not respond to primary vaccination, significantly more patients in the 2- vs 1-dose vaccine group achieved a serologic response at week 48 (68.4% vs 44.1%; P =.038).

At week 48, geometric mean titers (GMT) of anti-HAV IgG antibodies were highest among 2- vs 1-dose recipients who responded to primary vaccination (GMT, 538.0 vs 256.0 mlU/mL), followed by nonresponders in the 2- vs 1-dose vaccine group (GMT, 116.6 vs 63.3 mlU/mL).

In the multivariate analysis, the only factor significantly associated with achieving a serologic response to either the 1- or 2-dose revaccination schedule was prior response to primary vaccination (adjusted odds ratio, 4.92; 95% CI, 1.58-15.3; P =.001).

This study was limited by insufficient power as the prespecified sample size was not achieved.

No severe adverse events were reported throughout the duration of the study, and no patients developed acute HAV infection.

Although serologic response rates did not significantly differ between patients in 2- vs 1-dose vaccine groups, “[A]nti HAV antibody titers were consistently higher in the two-dose group throughout the observation period,” the researchers concluded.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.