Incidence per 100,000 population of reported pertussis cases in the Netherlands in 1993–2007, for 0-2-year-olds and for all ages.

<p>Incidence per 100,000 population of reported pertussis cases in the Netherlands in 1993–2007, for 0-2-year-olds and for all ages.</p

Prevalence (%) of coughing symptoms in the past year according to age in individuals with IgG-Ptx concentration≥62.5 EU/ml in 1995-96 and in 2006-07.

<p>Prevalence (%) of coughing symptoms in the past year according to age in individuals with IgG-Ptx concentration≥62.5 EU/ml in 1995-96 and in 2006-07.</p

image_1.PDF

Introduction<p>To reduce the pertussis disease burden, nowadays several countries recommend acellular pertussis (aP) booster vaccinations for adults. We aimed to evaluate the immunogenicity of a first adult aP booster vaccination at childbearing age.</p>Methods<p>In 2014, healthy adults aged 25–29 years (n = 105), vaccinated during infancy with four doses of whole-cell pertussis (wP) vaccine, received a Tdap (tetanus, diphtheria, and aP) booster vaccination. Blood samples were collected longitudinally pre-booster, 2 and 4 weeks, and 1 year and 2 years post-booster. Tdap vaccine antigen-specific antibody levels and memory B- and T-cell responses were determined at all time points. Antibody persistence was calculated using a bi-exponential decay model.</p>Results<p>Upon booster vaccination, the IgG levels specific to all Tdap vaccine antigens were significantly increased. After an initial rapid decline in the first year, PT-IgG antibody decay was limited (15%) in the second year post-booster. The duration of a median level of PT-IgG ≥20 IU/mL was estimated to be approximately 9 years. Vaccine antigen-specific memory B- and T-cell numbers increased and remained at high levels although a significant decline was observed after 4 weeks post-booster. However, Th1, Th2, and Th17 cytokine production remained above pre-booster levels for 2 years.</p>Conclusion<p>The Tdap booster vaccination in wP-primed Dutch adults induced robust long-term humoral and cellular immune responses to pertussis antigens. Furthermore, PT-IgG levels are predicted to remain above the presumed protective cut-off for at least 9 years which might deserves further attention in evaluating the current recommendation to revaccinate women during every new pregnancy.</p

Age-specific seroprevalence of IgG-Ptx concentrations in children 0–9 years of age in 1995-96 (upper figure) and in 2006-07 (lower figure).

<p>Note: on the x-axis the age-group, number tested and in brackets the percentage targeted by the acellular vaccine are indicated. In 2006-07 children below 4 years of age could have been primed with either whole-cell or acellular vaccine in infancy (nationwide coverage circa 96%), and children 4–9 years of age could have been primed with whole-cell vaccine and may have received a preschool booster with acellular vaccine (nationwide coverage circa 90%).</p

Risk factors for an IgG-Ptx concentration >62.5 EU/ml in individuals >9 years in 2006-07 (n = 5830).^*

<p>*for 179 persons (3%) data on one or more variables was missing.</p><p>**in children below 14 years the mothers highest educational level was asked; low  =  no education or primary education, middle =  junior technical school, lower general or intermediate vocational secondary education, high =  higher vocational or higher general secondary education, pre-university or university education.</p

Age-specific seroprevalence of IgG-Ptx concentrations in individuals >9 years in 1995-96 (upper figure) and in 2006-07 (lower figure).

<p>Age-specific seroprevalence of IgG-Ptx concentrations in individuals >9 years in 1995-96 (upper figure) and in 2006-07 (lower figure).</p

Risk ratios and 95% confidence intervals for the comparison of seroprevalence and reported incidence of pertussis in individuals >9 years in 2006-07 vs. 1995-96.

<p>Risk ratios and 95% confidence intervals for the comparison of seroprevalence and reported incidence of pertussis in individuals >9 years in 2006-07 vs. 1995-96.</p

Number of samples within each age-cohort, GMTs and seroprevalence of SBA (titers ≥8) in the pre- and post-MenC introduction eras.

a<p>Number between brackets is the number of samples included in the seroprevalence calculation (% samples≥8) and in not the GMT calculation, because only a SBA titer ≥16 could be given for these samples.</p><p>*<i>P</i>-values calculated for differences between prevalence of SBA titers ≥8 pre- and post-MenC immunization with chi-square distribution, LR chi-square probability.</p><p>**Calculated with Fishers exact t-test.</p><p>GMT, geometric mean titer; NP, not possible; NA, not applicable; mo, age in months; y, age in years.</p

MenC-specific IgG and serum bactericidal antibody levels.

<p>MenC PS-specific IgG (A) and seroprevalence of SBA titers ≥8 (B) within each age-cohort, pre- and post-introduction of the MenC conjugate vaccine. Error bars indicate 95% confidence intervals. Between the vertical lines cohorts are indicated that were all immunized in the catch-up campaign of 2002. Age at bloodsampling is indicated in years or as stated otherwise (mo  =  age in months).</p

Number of samples within each age-cohort, GMCs and seroprevalence of MenC PS-specific IgG (≥2 µg/ml) in the pre- and post-MenC introduction eras.

<p>*<i>P</i>-values calculated for differences between IgG GMC pre- and post-introduction of the MenC vaccine with the Wilcoxon two-sided Z-test.</p><p>GMC, geometric mean concentration; NA, not applicable; mo, age in months; y, age in years.</p