Hepatitis A Vaccine Response in Human Immunodeficiency Virus-infected Patients: The Interchangeability of Single Dose versus Double: A Prospective Look.

Sir,

Hepatitis A virus (HAV) infection is problematic in HIV-infected patients. Comparison of single-antigen hepatitis A (HAVRIX) or double-antigen combined hepatitis A and hepatitis B (TWINRIX) vaccines showed better results in HIV-positive patients who received TWINRIX than those who received HAVRIX, depending on CD4 count. There is literature that indicates that the seroconversion rate is dependent on dose,[12] which is our focus. We report the rate of seroconversion in HIV patients of various levels of immunocompromised state in those given different doses of vaccine. This was a prospective, randomized, nonblinded, single-center study at an urban ambulatory care HIV clinic directed at giving primary and HIV-specific care. Patients were included in the study if they had either a single or double dose of hepatitis vaccine. Antibodies for HAV were measured pre- and post-vaccination using the Vitros ECi immunodiagnostic system through the Laboratory Corporation of America (LabCorp). A positive test includes an antibody cutoff of <0.80 for anti-HAV total antibodies and a no detection of anti-HAV IgM at a cutoff of <0.80. Fisher's exact test was used for categorical variables in relation to antibody response after vaccination. Logistic regression was used for continuous variables in relation to antibody response. Of 1217 screened patients who received the hepatitis A vaccine, 40 were included, among them, 23 were male (57.5%) and 26 (65%) were African-American. Thirty-six (90%) patients had CD4 counts higher than 200 cells/mm3. Twenty-five (62.5%) patients had an HIV-1 viral load lower than 200 copies/mL. The median age was 47 years. Half of the patients received a single dose, while the other half received a double dose of the hepatitis A vaccine. Patients were included if they completed a series of hepatitis A vaccine after having a negative hepatitis A antibody. Table 1 outlines the results of the univariable analysis, in relation to the dependent variable (positive antibody response). Only age showed statistical significance, with younger age associated to antibody response after vaccination. In our experience, one or two doses appeared to provide comparable rates of immunogenicity. Virologic suppression and the CD4 count at the time of vaccination did not contribute to seroconversion rates. We previously observed that patients who receive a single dose even with high CD4 counts do not show higher rates of seroconversion, as with more recent studies.[34] In contrast to the previous studies, we did not observe that women show higher rates of seroconversion when given standard doses of the hepatitis A vaccine and, in our cohort, half of the participants responded to vaccination.[56] The main limitation of our study is the small sample size. While there may be no difference in the immune response of the HIV-positive patients who received either the single or the double dose, differences may become evident in studies with large sample size, enabling a comparison of patient groups with different CD4 counts, different contributing comorbidities, and levels of immunocompromise. Due to the small sample size, larger prospective, multi-center studies are needed to generate more reliable and convincing results.

Table 1

Demographics

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Conflicts of interest

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