Immunogenicity of Inactivated Swine H1N1 Vaccine In HIV Infected Children - The Miami Cohort Study

Patients will be recruited from HIV-1 outpatient clinic at the time the novel H1N1 vaccine becomes available. Demographic data will be collected after enrollment including HIV-1 viral load (VL) and CD4 count from last visit, antiretroviral therapy, gender and age. Patients will be asked to document adverse reactions observed during this study such as tenderness, pain, redness, and swelling at the injection site as well as systemic adverse reactions such as headache, malaise, and muscle aches. A subject will be withdrawn from the study if a serious adverse reaction occurs such as allergic reaction to a vaccine component or development with a progressive neurological disorder without definitive diagnosis. Statistical analysis will be performed after the viral load and CD4 counts are resulted from the day 30. The microneutralization assays and the titers will be analyzed post day 7 and 37. If the cohort does not seem to generate adequate responses, the study will be discontinued and no further samples collected.

Vaccination:

Since immunocompromised persons may have a diminished immune response to Influenza A (H1N1) 2009 Monovalent Vaccine, a higher antigen load will be used for this study as recommended by the National Center for Immunization and Respiratory Diseases and Centers for Disease Control and Prevention. All of the patients will be given a 0.5 ml intramuscular doses of A/California/7/2009 H1N1 strain inactivated vaccine in the deltoid muscle; all patients will receive a second dose after 4 weeks. Each vaccine dose will contain 15 µg each of H1N1 monovalent antigen. Patients under the age of 9 will receive the second vaccine as standard of care, while patients 9 and older will receive a second dose as part of this study.

Study Design:

This is a pilot study designed to recruit 72 patients with CD4 counts of ≥200. Patients will be enrolled on a first come first serve basis and will attempt to reach equal numbers in gender. A dose (15 µg) of the vaccine will be administered at day 0 and 30. Blood samples will be collected as in Table 1 (see Below). At each visit, the total maximum amount collected will be 17.5 ml divided in three individual samples: The first sample will be 5 ml for serum separation used in the detection of Hemagglutination inhibition (HI) titers and micro-neutralization (MN) assays. The second sample will be 10 ml processed for viral load, CD4 counts and ELISPOT functional B cell assays. The third sample will be 2.5 ml collected in a Paxgene RNA tube for future microarray testing. Based on the HI titer and MN responses obtained, the patients will be classified into three distinct subgroups: (a) high responders with ≥ 4 fold titer increases compared to baseline, (b) moderate responders with ≥ 2 and < 4 fold increases and (c) low responders with < 2 fold increases. From these subgroups, up to 25 complete patient's samples from the high and low responders will be selected for microarray studies. The microarray will compare readings from all visits. These preliminary data will serve the basis for future humoral and innate immunity gene activation.

Hemagglutination inhibition (HI) and microneutralization (MN) assays will be performed on blood samples collected as described in Table 1. Two individual samples will be collected in each visit, one will be used for serum separation used in the detection of HI titers and the second sample for viral load, CD4 counts, ELISPOT and Microarray testing. Based on the HI and MN titer responses obtained, the patients will be classified into three distinct subgroups: (a) high responders with ≥ 4 fold titer increases compared to baseline, (b) moderate responders with ≥ 2 and < 4 fold increases and (c) low responders with < 2 fold increases. From these subgroups, up to 25 complete samples from the high, moderate and low responders will be selected for viral load and microarray studies.