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Response to Primary Immunization to Tetanus, Diphtheria, H. influenzae Type B and Measles in HIV-Infected Children on HAART
A. Pracanica*, P. Russo, C. A. Zaccarelli-Filho, R. Succi, A. Santos, L. Weckx, and M. I. de Moraes-Pinto
Fed. Univ. of São Paulo, Brazil
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Background: Studies in the pre-HAART era have shown that HIV-infected children had a poor response to immunization. Children on HAART may have a different response to vaccination.
Methods: 15 HIV-infected children (HIV) were compared to 32 seroreverters (SR) and to 27 healthy children born to HIV-negative mothers (CNT) in a prospective study at the Federal University of São Paulo, Brazil. The mean age of use of HAART was at 3.7 months of age. Antibody response to primary immunization was assessed by ELISA at 24 months of age. Statistical analysis was performed on log-transformed data.
Results: HIV children had mean tetanus and Hib antibody levels similar to CNT and SR: tetanus antibodies: (IU/mL): CNT: 0.81; SR: 0.70; HIV category 1: 0.88; HIV category 2/3: 0.31; HIV category N/A: 0.64 and HIV category B/C: 0.25; (ANOVA, p>0.05); Hib antibodies (mug/mL): CNT: 5.3; SR: 11.9; HIV category 1: 6.1; HIV category 2/3: 2.6; HIV category N/A: 5.8 and HIV category B/C: 1.5, (ANOVA, p>0.05). All HIV, SR, and CNT children had protective antibody levels to tetanus and Hib (Fisher exact test, p>0.05). However, response to measles and diphtheria immunization was poor and dependent on good immunologic/clinical categories. Mean measles antibody levels (IU/mL) were lower in HIV category 2/3 (0.03) and HIV category B/C (0.08) when compared to SR (1.05) or CNT (0.61) (Tukey, p=0.01). The percentage of children with protective antibody levels was also different among CNT (89%); SR (100%); HIV category N/A (90%) and HIV category B/C (25%); HIV category 1 (83%); HIV category 2/3 (62%) (Fisher exact test, p<0.05). Mean diphtheria antibody levels (IU/mL) were lower in HIV category B/C (0.08) when compared to SR (1.02) and HIV category N/A (0.96) (Tukey, p<0.05). The same happened when we compared HIV category 2/3 (0.07) to SR (1.02) and HIV category 1 (0.55) (Tukey, p<0.05). All CNT, HIV category 1 and HIV category N/A children had protective antibody levels, while only 95% SR, 80% HIV category B/C and 89% HIV category 2/3 were protected (Fisher exact test, p<0.001).
Conclusions: Response to primary immunization in HIV-infected children on HAART depends both on the antigen and clinical/immunologic status. HIV-infected children in categories 1 and N/A respond to vaccination as well as healthy noninfected children.
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