Abstract
Background: Children living with HIV are at increased risk of disease from Haemophilus influenzae type b (Hib). Data are limited on the immunogenicity of a two-dose, catch-up schedule for Hib conjugate vaccine (HibCV) among HIV-infected children accessing antiretroviral therapy (ART) late. Objectives: The objectives of the study were to: (1) evaluate baseline immunity to Hib and the immunogenicity and safety of two doses of HibCV among HIV-infected Indian children; and (2) document the threshold antibody level required to prevent Hib colonization among HIV-infected children following immunization. Methods: We conducted a prospective cohort study among HIV-infected children 2-15 years of age and HIV-uninfected children 2-5 years of age. HIV-infected children received two doses of HibCV and uninfected children received one. Serum anti-Hib PRP IgG antibodies were measured at baseline and two months after immunization in the HIV-infected children. Nasopharyngeal (NP) swabs were collected at baseline and follow-up. Results: 125 HIV-infected and 44 uninfected children participated. 40% of HIV-infected children were receiving ART and 26% had a viral load >100,000 copies/mL. The geometric mean concentration of serum anti-Hib PRP antibody increased from 0.25 μg/mL at baseline to 2.65 μg/mL after two doses of HibCV, representing a 10.6-fold increase (p < 0.0001). 76% percent of HIV-infected children mounted an immune response. Moderate or severe immune suppression, trimethoprim/sulfamethoxazole prophylaxis, and lower baseline antibody levels were associated with lower post-vaccine serum anti-Hib PRP IgG antibodies. A serum anti-Hib PRP IgG antibody level ≥3.3 μg/mL was protective against Hib NP colonization. There were no differences in adverse events between HIV-infected and uninfected children. Conclusion: Including a catch-up immunization schedule for older HIV infected children in countries introducing Hib vaccines is important. Older HIV-infected children with delayed access to ART and without suppressed viral loads mounted an adequate immune response following two doses of HibCV.
Original language | English (US) |
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Pages (from-to) | 2267-2274 |
Number of pages | 8 |
Journal | Vaccine |
Volume | 34 |
Issue number | 19 |
DOIs | |
State | Published - Apr 27 2016 |
Keywords
- Anti-Hib PRP IgG
- Conjugate vaccines
- HIV
- Haemophilus influenzae type b
- Immune response
- Nasopharyngeal carriage
ASJC Scopus subject areas
- Molecular Medicine
- Immunology and Microbiology(all)
- veterinary(all)
- Public Health, Environmental and Occupational Health
- Infectious Diseases