Immune Activation and Viral Replication after Vaccination with an Influenza A H1N1 2009 Vaccine in HIV-Infected Children Receiving Antiretroviral Therapy

Immunization with a pandemic influenza A H1N1 2009 was recommended for HIV-infected patients. However, there is limited information concerning the impact of immunization with this vaccine on immune activation and HIV viral replication. In this study, 45 HIV-infected children and adolescents receiving antiretroviral therapy were immunized with a 2-dose series of nonadjuvated monovalent influenza A H1N1 2009 vaccine upon enrollment and approximately 1 month later. Immunogenicity was determined by haemagglutination inhibition assay. The level of immune activation was determined by identification of CD38 and HLA-DR on CD8+ T cells. Patients were divided into 2 groups which include patients who had an undetectable HIV viral load (HIV detectable group) and patients who show virological failure (HIV nondetectable group). The results showed seroconversion rate of 55.2% in HIV nondetectable group, whereas 31.3% was found in HIV detectable group. Both groups of patients showed no major increase in immune activation after immunization. Interestingly, a decrease in the frequency of CD8+ T cells that coexpressed CD38 and HLA-DR was observed after immunization in both groups of patients. We suggested that immunization with influenza A H1N1 2009 vaccine can induce immune response to the pandemic virus without major impact on HIV viral replication and immune activation.     

Immunogenicity and safety of monovalent influenza A (H1N1) 2009 in HIV-infected Thai children

To evaluate the immunogenicity and safety of the monovalent pandemic influenza A (H1N1) 2009 (pH1N1) vaccine in HIV-infected Thai children, 2 doses, 28 days apart, of non-adjuvant monovalent pH1N1 vaccine (Panenza^® by Sanofi Pasteur, 15 μg/dose) provided by the National Health Promotion Program of the Thai Ministry of Public Health were given to HIV-infected children. Immunogenicity was measured by hemagglutination inhibition test (HAI) using two antigens, pH1N1 (A/Thailand/104/09) and seasonal influenza A H1N1 (A/Brisbane/59/07-like), at baseline, and 28 days after each dose. Serologic response was defined as four-fold rising of HAI titer or HAI titer ≥1:40 for those with baseline titer ≤1:10. Adverse events were recorded for 7 days after each vaccination. Of the 119 HIV-infected children enrolled, 60 (50.4%) were female with a median (IQR) age of 10.4 (7.2-13.7) years. All but 2 (98.3%) children were receiving antiretroviral therapy. At baseline, the median CD4 cell count was 782 (570-1149) cells/mm³, 91 (80.5%) children had HIV RNA level <40 copies/ml. The baseline HAI titer ≥1:40 for pH1N1 and seasonal H1N1 were 45.4%, and 39.5%, respectively. At 28 days after doses 1 and 2, the serologic response rates for pH1N1 were 54.2% and 67.8% with the geometric mean titer of 109.9 and 141.8; and serologic response rate when tested with seasonal H1N1 were 2.5% and 3.5%, respectively. The presence of baseline HAI titer for pH1N1 or seasonal H1N1 was found to be associated with serologic response. The vaccine was well tolerated. The results suggested that monovalent pH1N1 vaccine was immunogenic and safe in well controlled HIV-infected children with low level of cross reacting antibody to seasonal H1N1.     

Lipodystrophy and reversal of facial lipoatrophy in perinatally HIV-infected children and adolescents after discontinuation of stavudine

Lipodystrophy (LD) was evaluated in 205 children receiving antiretroviral therapy by a single investigator: 51 (24.9%) had LD; 46 peripheral lipoatrophy, three central lipohypertrophy and two combined type. All cases of peripheral and combined LD also had facial lipoatrophy. Serial photographs were provided by the families to confirm the severity of facial lipoatrophy. Forty-six (95.8%) children with peripheral or combined LD, and 75 (48.7%) without LD were exposed to stavudine (d4T) for a median duration of 45.9 versus 26.4 months (P = 0.005). In multivariate analysis, exposure to d4T for more than three months was the only factor associated with peripheral or combined LD (P < 0.001). Noticeable improvement of facial lipoatrophy was found in 11/48 (22.9%) children after a mean duration of 45.6 months following d4T discontinuation, mostly occurring during early adolescence.     

A comparative study of the serological response to Japanese encephalitis vaccine in HIV-infected and uninfected Thai children

We report a prospective study of mouse brain derived inactivated Japanese encephalitis (JE) vaccine, given in 3-dose EPI program to human immune deficiency virus (HIV)-exposed Thai infants. 18 HIV-infected receiving antiretroviral therapy with median baseline CD4 of 33.1%, and 92 HIV-uninfected children were studied. All but one HIV-infected child seroconverted after the second dose. The geometric mean titers (GMTs) 3 months after the second and third doses in HIV-infected vs HIV-uninfected children were 247 vs 938 (p = 0.022), and 2273 vs 24069 (p = 0.009), respectively. Urticaria or angioedema found in 4% and 6% in HIV-infected and -uninfected children, respectively (p = 1.0). The vaccine was safe and immunogenic but antibody response in HIV-infected children was not as high as in uninfected children.