Multilaboratory Comparison of Pneumococcal Multiplex Immunoassays Used in lmmunosurveillance of Streptococcus pneumoniae across Europe

Surveillance studies are required to estimate the impact of pneumococcal vaccination in both children and the elderly across Europe. The World Health Organization (WHO) recommends use of enzyme immunoassays (EIAs) as standard methods for immune surveillance of pneumococcal antibodies. However, as levels of antibodies to multiple serotypes are monitored in thousands of samples, a need for a less laborious and more flexible method has evolved. Fluorescent-bead-based multiplex immunoassays (MIAs) are suitable for this purpose. An increasing number of public health and diagnostic laboratories use MIAs, although the method is not standardized and no international quality assessment scheme exists. The EU Pneumo Multiplex Assay Consortium was initiated in 2013 to advance harmonization of MIAs and to create an international quality assessment scheme. In a multilaboratory comparison organized by the consortium, agreement among nine laboratories that used their own optimized MIA was assessed on a panel of 15 reference sera for 13 pneumococcal serotypes with the new WHO standard 007sp. Agreement was assessed in terms of assay accuracy, reproducibility, repeatability, precision, and bias. The results indicate that the evaluated MIAs are robust and reproducible for measurement of vaccine-induced antibody responses. However, some serotype-specific variability in the results was observed in comparisons of polysaccharides from different sources and of different conjugation methods, especially for serotype 4. On the basis of the results, the consortium has contributed to the harmonization of MIA protocols to improve reliability of immune surveillance of Streptococcus pneumoniae

Pertussis-Specific Memory B-Cell and Humoral IgG Responses in Adolescents after a Fifth Consecutive Dose of Acellular Pertussis Vaccine

In order to impede the increase in pertussis incidence in the adolescent group, a school-leaving booster dose administered at the age of 14 to 16 years will be introduced in Sweden in 2016. Preceding this introduction, an open-label, randomized, multicenter, clinical trial without a control group and with blinded analysis was performed, investigating both safety and immunogenicity. Reported here are the memory B-cell and serological responses detected in a smaller cohort (n = 34) of the 230 subjects recruited to the study. All subjects had received primary vaccination consisting of three doses of diphtheria-tetanus-5-component pertussis (DTaP5) vaccine, at 3, 5, and 12 months of age, and a tetanus-low-dose diphtheria-5-component pertussis (Tdap5) vaccine booster at 5.5 years. In this study, the subjects were randomly assigned and received either a Tdap1 or Tdap5 booster. Of the 230 participants, 34 subjects had samples available for evaluation of IgG-producing memory B-cell responses. Both vaccine groups had significant increases in pertussis toxin-specific serum IgG levels, but only the 1-component group showed significant increases in pertussis toxin-specific memory B cells. The 5-component group had significant increases in filamentous hemagglutinin- and pertactin-specific memory B-cell and serum IgG levels; these were not seen in the 1-component group, as expected. In conclusion, this study shows that a 5th consecutive dose of an acellular pertussis vaccine induces B-cell responses in vaccinated adolescents.Funding Agencies|Statens Serum Institute; Sanofi Pasteur MSD (Sweden)</p

B-cell responses after intranasal vaccination with the novel attenuated Bordetella pertussis vaccine strain BPZE1 in a randomized phase I clinical trial

AbstractDespite high vaccination coverage, pertussis is still a global concern in infant morbidity and mortality, and improved pertussis vaccines are needed. A live attenuated Bordetella pertussis strain, named BPZE1, was designed as an intranasal vaccine candidate and has recently been tested in man in a phase I clinical trial. Here, we report the evaluation of the B-cell responses after vaccination with BPZE1. Forty-eight healthy males with no previous pertussis-vaccination were randomized into one of three dose-escalating groups or into a placebo group. Plasma blast- and memory B-cell responses were evaluated by ELISpot against three different pertussis antigens: pertussis toxin, filamentous haemagglutinin and pertactin. Seven out of the 36 subjects who had received the vaccine were colonized by BPZE1, and significant increases in the memory B-cell response were detected against all three tested antigens in the culture-positive subjects between days 0 and 28 post-vaccination. The culture-positive subjects also mounted a significant increase in the filamentous haemagglutinin-specific plasma blast response between days 7 and 14 post-vaccination. No response could be detected in the culture-negatives or in the placebo group post-vaccination. These data show that BPZE1 is immunogenic in humans and is therefore a promising candidate for a novel pertussis vaccine. This trial is registered at ClinicalTrials.gov (NCT01188512)

Further investigations of the IgE response to tetanus and diphtheria following covaccination with acellular rather than cellular Bordetella pertussis

Background: It has previously been shown in an uncontrolled study that the IgE response to vaccine antigens is downregulated by co-vaccination with cellular Bordetella pertussis vaccine. Methods: In the present study, we compared in a controlled trial the humoral immune response to diphtheria toxoid (D) and tetanus toxoid (T) in relation to co-vaccinated cellular or acellular B pertussis vaccine. IgE, IgG4, and IgG to D and T were analyzed at 2, 7, and 12 months of age in sera of children vaccinated with D and T (DT, N = 68), cellular (DTPw, N = 68), 2- or 5-component acellular B pertussis vaccine (DTPa2, N = 64; DTPa5, N = 65). Results: One month after vaccination, D-IgE was detected in 10% sera of DTPw-vaccinated children, whereas vaccination in the absence of whole-cell pertussis resulted in 50%-60% IgE positivity. Six months after vaccination, the IgE antibody levels were found to be more persistent than the IgG antibodies. These diphtheria findings were mirrored by those for tetanus. Only minor differences between vaccine groups were found with regard to D-IgG and T-IgG. No immediate-type allergic reactions were observed. Conclusion: Cellular (but not acellular) B pertussis vaccine downregulates IgE to co-vaccinated antigens in infants. We assume that the absence of immediate-type allergic reactions is due to the high levels of IgG antibodies competing with IgE antibodies

Antibody Response Patterns to Bordetella pertussis Antigens in Vaccinated (Primed) and Unvaccinated (Unprimed) Young Children with Pertussis▿

In a previous study, it was found that the antibody response to a nonvaccine pertussis antigen in children who were vaccine failures was reduced compared with the response in nonvaccinated children who had pertussis. In two acellular pertussis vaccine efficacy trials in Sweden, we studied the convalescent-phase enzyme-linked immunosorbent assay (ELISA) geometric mean values (GMVs) in response to pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), and fimbriae (FIM 2/3) in vaccine failures and controls with pertussis. In Germany, the antibody responses to Bordetella pertussis antigens PT, FHA, PRN, and FIM-2 were analyzed by ELISA according to time of serum collection after onset of illness in children with pertussis who were vaccine failures or who were previously unvaccinated. Antibody values were also compared by severity of clinical illness. In Sweden, infants who had received a PT toxoid vaccine and who were vaccine failures had a blunted response to the nonvaccine antigen FHA compared with the response in children who had received a PT/FHA vaccine. Similarly, infants who had pertussis and who had received a PT/FHA vaccine had a blunted response to the nonvaccine antigens PRN and FIM 2/3 compared with the response in children who were vaccine failures and who had received a PT, FHA, PRN, and FIM 2/3 vaccine. In Germany, in sera collected from 0 to 15 days after pertussis illness onset, the GMVs for all 4 antigens (PT, FHA, PRN, and FIM-2) were significantly lower in an unvaccinated group than in children who were diphtheria-tetanus-acellular pertussis (DTaP) vaccine failures. In the unvaccinated group, the GMV of the PT antibody rose rapidly over time so that it was similar to that of the DTaP vaccine recipients at the 16- to 30-day period. In contrast, the antibody responses to FHA, PRN, and FIM-2 at all time periods were lower in the diphtheria-tetanus vaccine (DT) recipients than in the DTaP vaccine failures. In both Sweden and Germany, children with less severe illness had lower antibody responses than children with typical pertussis. Our findings indicate that upon exposure and infection, previous vaccinees have more-robust antibody responses to the antigens contained in the vaccine they had received than to Bordetella antigens that were not in the vaccine they had received. In addition, over time the antibody responses to FHA, PRN, and FIM-2 were greater in children with vaccine failure (primed subjects) than in unvaccinated children (unprimed subjects) whereas the responses to PT were similar in the primed and unprimed children, as determined from sera collected after 15 days of illness. Our findings lend support to the idea that DTaP vaccines should contain multiple antigens

Antibody Responses to Bordetella pertussis Fim2 or Fim3 following Immunization with a Whole-Cell, Two-Component, or Five-Component Acellular Pertussis Vaccine and following Pertussis Disease in Children in Sweden in 1997 and 2007

Bordetella pertussis fimbriae (Fim2 and Fim3) are components of a five-component acellular pertussis vaccine (diphtheria–tetanus–acellular pertussis vaccine [DTaP5]), and antibody responses to fimbriae have been associated with protection. We analyzed the IgG responses to individual Fim2 and Fim3 in sera remaining from a Swedish placebo-controlled efficacy trial that compared a whole-cell vaccine (diphtheria-tetanus-whole-cell pertussis vaccine [DTwP]), a two-component acellular pertussis vaccine (DTaP2), and DTaP5. One month following three doses of the Fim-containing vaccines (DTwP or DTaP5), anti-Fim2 geometric mean IgG concentrations were higher than those for anti-Fim3, with a greater anti-Fim2/anti-Fim3 IgG ratio elicited by DTaP5. We also determined the responses in vaccinated children following an episode of pertussis. Those who received DTaP5 showed a large rise in anti-Fim2 IgG, reflecting the predominant Fim2 serotype at the time. In contrast, those who received DTwP showed an equal rise in anti-Fim2 and anti-Fim3 IgG concentrations, indicating that DTwP may provide a more efficient priming effect for a Fim3 response following contact with B. pertussis. Anti-Fim2 and anti-Fim3 IgG concentrations were also determined in samples from two seroprevalence studies conducted in Sweden in 1997, when no pertussis vaccine was used and Fim2 isolates predominated, and in 2007, when either DTaP2 or DTaP3 without fimbriae was used and Fim3 isolates predominated. Very similar distributions of anti-Fim2 and anti-Fim3 IgG concentrations were obtained in 1997 and 2007, except that anti-Fim3 concentrations in 1997 were lower. This observation, together with the numbers of individuals with both anti-Fim2 and anti-Fim3 IgG concentrations, strongly suggests that B. pertussis expresses both Fim2 and Fim3 during infection

Pandemic influenza A(H1N1)pdm09 seroprevalence in Sweden before and after the pandemic and the vaccination campaign in 2009.

The immunity to pandemic influenza A(H1N1)pdm09 in Sweden before and after the outbreaks in 2009 and 2010 was investigated in a seroepidemiological study. Serum samples were collected at four time points: during 2007 (n = 1968), in October 2009 (n = 2218), in May 2010 (n = 2638) and in May 2011 (n = 2513) and were tested for hemagglutination inhibition (HI) antibodies. In 2007, 4.9% of the population had pre-existing HI titres ≥40, with the highest prevalence (20.0%) in 15-24 year-olds, followed by ≥80 year-olds (9.3%). The overall prevalence of HI titres ≥40 had not changed significantly in October 2009. In May 2010 the prevalence had increased to 48.6% with the highest percentages in 5-14 year-olds (76.2%) andlowest in 75-79 year-olds (18.3%). One year later the prevalence of HI titres ≥40 had increased further to 52.2%. Children 5-14 years had the highest incidence of infection and vaccine uptake as well as the highest post-pandemic protective antibody levels. In contrast, the elderly had high vaccine uptake and low attack rate but low levels of protective antibodies, underlining that factors other than HI antibodies are involved in protection against influenza A(H1N1)pdm09. However, for all age-groups the seroprevalence was stable or increasing between 2010 and 2011, indicating that both vaccine- and infection-induced antibodies were long-lived

Pertactin-deficient isolates: evidence of increased circulation in Europe, 1998 to 2015.

IntroductionPertussis outbreaks have occurred in several industrialised countries using acellular pertussis vaccines (ACVs) since the 1990s. High prevalence of pertactin (PRN)-deficien