HIV-Infected or -Exposed Children Exhibit Lower Immunogenicity to Hepatitis B Vaccine in Yaoundé, Cameroon: An Appeal for Revised Policies in Tropical Settings?

Anne Esther Njom Nlend, Philippe Salomon Nguwoh, Christian Taheu Ngounouh, Hyppolite Kuekou Tchidjou, Constant Anatole Pieme, Jean Mbede Otélé, Véronique Penlap, Vittorio Colizzi, Roger Somo Moyou, Joseph Fokam

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Abstract

BACKGROUND: Since 2005, anti-hepatitis B virus (anti-HBV) vaccine is part of the Expanded Program on Immunization (EPI) for infants born in Cameroon, with 99% anti-HBV coverage. In a context of generalized HIV epidemiology, we assessed paediatric anti-HBV vaccine response according to HIV status, feeding option and age in a tropical context.

METHODOLOGY: Prospective, observational and cross-sectional study conducted among 82 children (27 [IQR: 9-47] months, min-max: 6-59), after complete anti-HBV vaccination (Zilbrix Hepta: 10μg AgHBs) at the Essos Health Centre in Yaounde, Cameroon, classified as group-A: HIV unexposed (28), group-B: HIV-exposed/uninfected (29), group-C: HIV-infected (25). Quantitative anti-HBs ELISA was interpreted as "no", "low-" or "protective-response" with <1, 1-10, or ≥10 IU/L respectively; with p-value<0.05 considered significant.

RESULTS: Children were all HBV-unexposed (AcHBc-negative) and uninfected (HBsAg-negative). Response to anti-HBV vaccine was 80.49% (66/82), with only 45.12% (37/82) developed a protective-response (≥10IU/L). According to HIV status, 60.71% (17/28) developed a protective-response in group-A, vs. 51.72% (15/29) and 20% (5/25) in group-B and group-C respectively, Odds Ratio (OR): 2.627 [CI95% 0.933-7.500], p = 0.041. According to feeding option during first six months of life, 47.67% (21/45) developed a protective-response on exclusive breastfeeding vs. 43.24% (16/37) on mixed or formula feeding, OR: 1.148 [CI95% 0.437-3.026], p = 0.757. According to age, protective-response decreased significantly as children grow older: 58.33% (28/48) <24 months vs. 26.47% (9/34) ≥24 months, OR: 3.889 [CI95% 1.362-11.356], p = 0.004; and specifically 67.65% (23/34) ≤6 months vs. 0%, (0/5) 33-41 months, p = 0.008.

CONCLUSIONS: Anti-HBV vaccine provides low rate of protection (<50%) among children in general, and particularly if HIV-exposed, infected and/or older children. Implementing policies for early vaccination, specific immunization algorithm for HIV-exposed/infected children, and monitoring vaccine response would ensure effective protection in tropical settings, pending extensive/confirmatory investigations.

Original languageEnglish
Pages (from-to)e0161714
JournalPLoS One
Volume11
Issue number9
DOIs
Publication statusPublished - Sep 23 2016
Externally publishedYes

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Njom Nlend, A. E., Nguwoh, P. S., Ngounouh, C. T., Tchidjou, H. K., Pieme, C. A., Otélé, J. M., Penlap, V., Colizzi, V., Moyou, R. S., & Fokam, J. (2016). HIV-Infected or -Exposed Children Exhibit Lower Immunogenicity to Hepatitis B Vaccine in Yaoundé, Cameroon: An Appeal for Revised Policies in Tropical Settings? PLoS One, 11(9), e0161714. https://doi.org/10.1371/journal.pone.0161714