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

doi:10.1371/journal.pone.0161714

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. 2016 Sep 22;11(9):e0161714. doi: 10.1371/journal.pone.0161714. eCollection 2016.

Authors

Anne Esther Njom Nlend^{1

2}, Philippe Salomon Nguwoh^{3

4

5}, Christian Taheu Ngounouh⁵, Hyppolite Kuekou Tchidjou⁶, Constant Anatole Pieme^{2

3}, Jean Mbede Otélé³, Véronique Penlap^{3

7}, Vittorio Colizzi^{8

9

10}, Roger Somo Moyou^{2

8

11}, Joseph Fokam^{2

8

9}

Affiliations

¹ Pediatric Service, National Insurance Fund Welfare Hospital, Yaoundé, Cameroon.
² Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon.
³ Higher Institute of Health Professions, Yaoundé, Cameroon.
⁴ Ministry of Public Health, Yaoundé, Cameroon.
⁵ Institute of Science and Technology Applied to Health, Yaoundé, Cameroon.
⁶ Bambino Gesu Paediatric Hospital, Rome, Italy.
⁷ Department of Biochemistry and Microbiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon.
⁸ Chantal BIYA International Reference Centre for Research on HIV/AIDS prevention and management, Yaoundé, Cameroon.
⁹ University of Rome Tor Vergata, Rome, Italy.
¹⁰ UNESCO Interdisciplinary Board of Biotechnology, Rome, Italy.
¹¹ Institute of Research in Medicine and Medicinal plants, Yaoundé, Cameroon.

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.

Grants and funding

The study was sponsored by the research team. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.