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Session 91
Poster Abstracts Vaccine Trials in Human Subjects Friday, 1:30 - 3:30 pm Hall A |
Background: Hepatitis A infection remains a health risk
for HIV-infected persons. While the inactivated hepatitis A virus (HAV) vaccine
affords protection to immunocompetent persons > 95%
of the time, rates of developing protective antibody in HIV+ persons
range from 9 to 94%. The effect of HIV viremia on HAV
vaccine response has not previously been reported.
Methods: In this retrospective cohort study of a 906-patient
HIV clinic, HIV-infected patients who had received HAV vaccine were identified.
Medical records were reviewed for demographics, number of vaccine doses, CD4+
T-cell nadir and count at time of vaccination, HIV viral load at time of
vaccination, and antiretroviral therapy at time of vaccination. For continuous
and dichotomous variables, t-test and
χ2 were used, respectively. Univariate
and multivariate analysis by logistic regression were used to determine factors
which predicted a successful immune response (reactive HAV antibody) after HAV
vaccination.
Results: Of the 906 patients, 189 (21%) had evidence of
prior HAV infection and 347 (38%) had received at least 1 dose of HAV vaccine;
235 had IgG antibody data before and after
vaccination. Of these, 112 (48%) developed a reactive antibody response after
vaccination. Only HIV viral load < 1000 copies/mL
was predictive of successful antibody response. The median HIV viral load in
the responders was < 400 copies/mL and the median viral
load in non-responders was 1846 copies/mL. The table
below shows the differences between the vaccinees who
developed a reactive HAV antibody (responders) and those who did not:
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Responders |
Non-responders |
p Value |
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n = 112 |
n = 123 |
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African American |
78 (70%) |
80 (65%) |
0.23 |
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Female |
38 (34%) |
36 (24%) |
0.39 |
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Median age (range) |
39 (19 to 62) |
37 (18 to 71) |
0.97 |
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CD4 nadir (range) |
234 (0 to 1150) |
212 (0 to 994) |
0.07 |
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Received 2 injections |
75 (32%) |
76 (32%) |
0.58 |
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CD4 at Vax#1 (range) |
438 (5 to 1701) |
397 (0 to 1224) |
0.08 |
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Viral load < 1000 copies/mL at Vax#1 |
73 (65%) |
56 (46%) |
<0.001 |
Conclusions:
Suppression of HIV replication at time
of HAV vaccination is associated with an increased likelihood of developing a
protective antibody response in HIV-infected persons. Neither nadir CD4+
T-cell count nor the value at time of vaccination predicted antibody response.
These results suggest the significance of control of viral replication at time
of HAV vaccination. The low rate of HAV vaccination response (48%) suggests the
importance of developing new approaches to vaccination in HIV-infected persons.
Keywords: Hepatitis A Vaccine; HIV; Antibody response
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