Low Immune Response to Hepatitis B Vaccine among Children in Dakar, Senegal

HBV vaccine was introduced into the Expanded Programme on Immunization (EPI) in Senegal and Cameroon in 2005. We conducted a cross-sectional study in both countries to assess the HBV immune protection among children. All consecutive children under 4 years old, hospitalized for any reason between May 2009 and May 2010, with an immunisation card and a complete HBV vaccination, were tested for anti-HBs and anti-HBc. A total of 242 anti-HBc-negative children (128 in Cameroon and 114 in Senegal) were considered in the analysis. The prevalence of children with anti-HBs ≥10 IU/L was higher in Cameroon with 92% (95% CI: 87%–97%) compared to Senegal with 58% (95% CI: 49%–67%), (p<0.001). The response to vaccination in Senegal was lower in 2006–2007 (43%) than in 2008–2009 (65%), (p = 0.028). Our results, although not based on a representative sample of Senegalese or Cameroonian child populations, reveal a significant problem in vaccine response in Senegal. This response problem extends well beyond hepatitis B: the same children who have not developed an immune response to the HBV vaccine are also at risk for diphtheria, tetanus, pertussis (DTwP) and Haemophilus influenzae type b (Hib). Field biological monitoring should be carried out regularly in resource-poor countries to check quality of the vaccine administered

Checklist of items retained from the STROBE statement.

<p>Checklist of items retained from the STROBE statement.</p

Characteristics of the studies presenting incidence rate of switching to second-line ART.

**<p>as stated in the article.</p><p>NA: not available.</p

Characteristics of the studies presenting incidence rate of switching to second-line ART.

<p>NA: not available.</p

Flow diagram of study selection process.

<p>Flow diagram of study selection process.</p

Characteristics of the studies presenting incidence rate of switching to second-line ART.

<p>Characteristics of the studies presenting incidence rate of switching to second-line ART.</p

Evolution of the CD85j - NKG2D dNK subset during the first trimester of pregnancy.

<p>Decidual mononuclear cells were analyzed by flow cytometry immediately after isolation. The dNK cells were defined by the CD3⁻/CD56⁺ population within the decidual cells. (A) CD85j and NKG2D co-expression was analyzed on samples taken at 57 days (early, red), 63 days (middle, blue) and 78 days of gestation samples (late, green). Representative donor analyses are shown individually and overlaid (right dot plot). (B) Linear regression for each subset, percentage within the dNK cells (Y) and day of gestation (X). The analyses were performed on decidual cells from 28 different donors, individually represented by a dot.</p

Spearman correlation coefficient (p-value) of surface expression between NK receptors (n = 28).

<p>*Bold data are statistically significant (p-value ≤0.004).</p

NK receptor repertoire evolution of dNK cells during the first trimester of pregnancy.

<p>Expression of NK receptors on decidual mononuclear cells was analyzed between 8 and 12 weeks of gestation. Graphs represent the percentage of marker expression (Y) and the day of gestation (X). The line represents the linear regression. A p-value<0.05 was significant. The analyses were performed on decidual cells from 28 different donors, individually represented by a dot.</p