Dataset Information

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

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: 10?g 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.

SUBMITTER: Njom Nlend AE

PROVIDER: S-EPMC5033457 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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

Njom Nlend Anne Esther AE Nguwoh Philippe Salomon PS Ngounouh Christian Taheu CT Tchidjou Hyppolite Kuekou HK Pieme Constant Anatole CA Otélé Jean Mbede JM Penlap Véronique V Colizzi Vittorio V Moyou Roger Somo RS Fokam Joseph J

PloS one 20160922 9

<h4>Background</h4>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.<h4>Methodology</h4>Prospective, observational and cross-sectional study conducted among 82 children (27 [IQR: 9-47] months, min-max: 6-59), after com ...[more]

PMID: 27656883

Similar Datasets

Project description:BACKGROUND:The rapid and unplanned urbanization of African cities is considered to increase the risk of urban malaria transmission. The present study objective was to assess factors influencing the spatio-temporal distribution of Anopheles gambiae s.l. larvae in the city of Yaoundé, Cameroon. METHODS:All water bodies were checked once every 2 months for the presence of mosquito larvae from March 2017 to May 2018 in 32 districts of Yaoundé. Physico-chemical characteristics including the size, depth, turbidity, pH, temperature, conductivity, sulfates, organophosphates, hydrogen peroxide (H2O2), conductivity, iron and calcium were recorded and analyzed according to anopheline larvae presence or absence. High resolution satellite images from landsat sentinel Enhanced Thematic Mapper were used for spatial mapping of both field and environmental variables. Bivariate and multivariate logistic regression models were used to identify variables closely associated with anopheline larvae distribution. RESULTS:A total of 18?696 aquatic habitats were checked and only 2942 sites (15.7%) contained anopheline larvae. A high number of sites with anopheline larvae (? 69%) presented late instar larvae (L3, L4 and pupae). Anopheline mosquito larvae were sampled from a variety of breeding sites including puddles (51.6%), tire prints (12.9%), wells (11.7%) and drains (11.3%). Bivariate logistic regression analyses associated anopheline larvae presence with the absence of predators, absence of algae, absence of vegetation and depth of less than 1?m. Conductivity, turbidity, organophosphates, H2O2 and temperature were significantly high in breeding sites with anopheline larvae than in breeding sites without these larvae (P?<? 0.1). Anopheline species collected included An. coluzzii (91.1%) and An. gambiae s.s. (8.9%). GIS mapping indicated a heterogeneous distribution of anopheline breeding habitats in the city of Yaoundé. Land cover analysis indicated high variability of the city of Yaoundé's landscape. CONCLUSIONS:The data confirms adaptation of An. gambiae s.l. to the urban domain in the city of Yaoundé and calls for urgent actions to improve malaria vector control.

Project description:Immunization is the most cost-effective health intervention in the world yet, vaccination uptake is still low with less than 50% of children aged 12–23 months fully vaccinated in Cameroon by 2018. The objective of this study was to estimate the burden of vaccine hesitancy associated with routine vaccines in Yaounde-Cameroon. A two-stage cross-sectional cluster survey was conducted in Yaoundé in November 2021, targeting parents/guardians of children 0–59 months. Clusters were selected with probability proportionate to size (PPS) and household’s selection done using a restricted sampling method. Data collection was done using an interviewer-administered questionnaire, “Core Closed Questions” and “Likert Scale Questions” proposed by the WHO Vaccine Hesitancy Technical Working Group in 2014. Vaccine hesitancy was analyzed as proportions of parent’s/guardian’s self-reported vaccine refusal or delay in vaccination with 95% confidence interval. This was stratified by household wealth level and tested using Chi-Square test to appreciate the effect of household wealth on vaccine hesitancy. A total of 529 participants were enrolled out of 708 visited, giving a non-response rate of 25%. In total, vaccine hesitancy was reported in 137(25.90[22.35–29.80] %), and oral polio vaccine(OPV) was the most affected vaccine with hesitancy of 10%. Vaccine hesitancy prevalence did not vary significantly across different households’ wealth levels (p-value = 0.3786). However, in wealthy households’ refusal of vaccines (14%) was less than in poorer households (20%). Lack of trust was reported as the leading cause of vaccine refusal (43%). Vaccine hesitancy prevalence in Yaounde is high and oral polio vaccine(OPV) was the most affected vaccine. The level of weath does not affect vaccine hesitancy and lack of trust was the leading cause of vaccine hesitancy related to routine immunization in Yaounde-Cameroon. We, recommend that the burden of vaccine hesitancy should be assessed at national scale and root causes investigated.