A Phase II,randomized, immunogenicity and safety study of a quadrivalent meningococcal conjugate vaccine,MenACYW-TT,in healthy adolescents in the United States

BackgroundMenACYW-TT is an investigational quadrivalent meningococcal conjugate vaccine intended for use in individuals ≥6 weeks of age. We evaluated the safety and immunogenicity of MenACYW-TT when compared to a licensed quadrivalent conjugate meningococcal vaccine (Menveo®; MCV4-CRM; GlaxoSmithKline, Italy), and when co-administered with tetanus, diphtheria, acellular pertussis (Tdap) and human papilloma virus (HPV4) vaccines in healthy meningococcal vaccine-naïve adolescents (10–17 years old) in the United States of America.MethodsIn this pivotal Phase II, open-label, multicenter study, 1715 participants were randomized to receive MenACYW-TT, MCV4-CRM, MenACYW-TT co-administered with Tdap and HPV4, or Tdap and HPV4 vaccines alone (NCT02199691).The primary objective was to evaluate whether antibody responses to MenACYW-TT antigens were non-inferior to antibody responses after MCV4-CRM administration. Meningococcal antibody titers were determined using human complement serum bactericidal assay (hSBA) with titers measured at baseline, and 30 days post vaccination (D30). A vaccine seroresponse was defined as baseline titers <1:8 with post-vaccination titers ≥1:8 or baseline titers ≥1:8 with a ≥4-fold increase at post-vaccination. Safety data were collected up to six months post-vaccination.ResultsNon-inferiority was demonstrated for MenACYW-TT vs MCV4-CRM (primary endpoint), and for MenACYW-TT co-administered with Tdap and HPV4 vs MenACYW-TT alone (secondary endpoint). The vaccine seroresponse rate was higher with MenACYW-TT than with MCV4-CRM, for each serogroup: A: 75.6% vs 66.4%; C: 97.2% vs 72.6%; W: 86.2% vs 66.6%; Y: 97.0% vs 80.8%. The safety profiles of MenACYW-TT, MCV4-CRM, and Tdap and HPV4 vaccines, administered with or without MenACYW-TT, were comparable. There were no vaccine-related serious adverse events.ConclusionsThe MenACYW-TT vaccine was well tolerated and generated an immune response that was non-inferior to the licensed MCV4-CRM vaccine. Immunogenicity and safety profiles were comparable when MenACYW-TT was administered with or without Tdap and HPV4 vaccines in meningococcal vaccine-naïve adolescents.     

Immunogenicity of reduced antigen content tetanus-diphtheria-acellular pertussis vaccine in adolescents as a sixth consecutive dose of acellular pertussis-containing vaccine

Three hundred and nineteen adolescents aged 10-12 years who had been previously vaccinated with five doses of acellular pertussis-containing vaccines received single doses of Tdap (reduced-antigen-content tetanus, diphtheria, acellular pertussis) and hepatitis A vaccines in a double-blind crossover trial. Long-term antibody persistence following vaccination with Tdap at pre-school age was similar to that following vaccination with DTaP (diphtheria-tetanus-acellular pertussis). After the sixth dose booster, Tdap induced a vigorous immune response, consistent with protection against diphtheria, tetanus and pertussis diseases.     

Two consecutive randomized controlled pertussis booster trials in children initially vaccinated in infancy with an acellular vaccine: The first with a five-component Tdap vaccine to 5-year olds and the second with five- or monocomponent Tdap vaccines at age 14–15 years

Prior study children from a DTaP efficacy trial were recruited at ages 5 and 15 years to randomized booster trials addressing immunogenicity and reactogenicity; 475 preschool children received mixed or separate injections of a reduced antigen vaccine (Tdap5, Sanofi Pasteur MSD) and an inactivated polio vaccine, and 230 adolescents received the same or another booster vaccine (Tdap1, SSI, Denmark).Pre-vaccination antibody concentrations against pertussis antigens were significantly higher at 15 than 5 years of age, probably due to natural boosting between the studies. Tdap5 induced comparable anti-PT concentrations at both ages, but antibody responses were significantly higher to filamentous haemagglutinin, pertactin and fimbriae 2/3 in adolescents. As expected, a higher amount of PT (Tdap1, 20 μg) induced a stronger anti-PT response than a lower amount (Tdap5, 2.5 μg).The frequency of adverse events was low and there were no serious adverse reactions. All local reactions had an early onset and a short duration. A large swelling or redness of more than half of the upper arm circumference was reported in 8/475 5-year-olds and in 6/230 15-year-olds. Children vaccinated with Tdap5 reported more moderate pain in adolescence than at preschool age, whereas itching was only reported in preschool children.Sweden introduced DTaP vaccines in 1996 after a 17-year hiatus with no general pertussis vaccination and pertussis was still endemic at the time of the studies. The frequency of adverse events was nevertheless low in both preschool children and adolescents and antibody responses were adequate. These studies document immunogenicity and reactogenicity in a trial cohort consecutively vaccinated with acellular pertussis vaccines from infancy to adolescence.The adolescent study was registered at ClinicalTrials.gov on 26 March 2009 (NCT00870350).     

Whole-cell or acellular pertussis vaccination in infancy determines IgG subclass profiles to DTaP booster vaccination

IntroductionDuration of protection against pertussis is shorter in adolescents who have been immunized with acellular pertussis (aP) in infancy compared with adolescents who received whole-cell pertussis (wP) vaccines in infancy, which is related to immune responses elicited by these priming vaccines. To better understand differences in vaccine induced immunity, we determined pertussis, diphtheria, and tetanus (DTaP) vaccine antigen-specific IgG subclass responses in wP- and aP-primed children before and after two successive DTaP booster vaccinations.MethodsBlood samples were collected in a cross-sectional study from wP- or aP-primed children before and 1 month after the pre-school DTaP booster vaccination at age 4 years. Blood samples were collected from two different wP- and aP-primed groups of children before, 1 month and 1 year after an additional pre-adolescent Tdap booster at age 9 years. IgG subclass levels against the antigens included in the DTaP vaccine have been determined with fluorescent-bead-based multiplex immunoassays.ResultsAt 4 years of age, the IgG4 proportion and concentration for pertussis, diphtheria and tetanus vaccine antigens were significantly higher in aP-primed children compared with wP-primed children. IgG4 concentrations further increased upon the two successive booster vaccinations at 4 and 9 years of age in both wP- and aP-primed children, but remained significantly higher in aP-primed children.ConclusionsThe pertussis vaccinations administered in the primary series at infancy determine the vaccine antigen-specific IgG subclass profiles, not only against the pertussis vaccine antigens, but also against the co-administered diphtheria and tetanus vaccine antigens. These profiles did not change after DTaP booster vaccinations later in childhood. The different immune response with high proportions of specific IgG4 in some aP-primed children may contribute to a reduced protection against pertussis.ISRCTN65428640; ISRCTN64117538; NTR4089.     

Systematic review of reporting rates of adverse events following immunization: An international comparison of post-marketing surveillance programs with reference to China

Background

China is the most populous country in the world, with an annual birth cohort of approximately 16 million, requiring an average of 500 million vaccine doses administered annually. In China, over 30 domestic and less than 10 overseas vaccine manufacturers supply over 60 licensed vaccine products, representing a growing vaccine market mainly due to recent additions to the national immunization schedule, but data on post-marketing surveillance for adverse events following immunization (AEFI) are sparse.

Objectives

To compare reporting rates for various categories of AEFI from China with other routine post-marketing surveillance programs internationally.

Methods

Systematic review of published studies reporting rates of AEFI by vaccine, category of reaction and age from post-marketing surveillance systems in English and Chinese languages.

Results

Overall AEFI reporting rates (all vaccines, all ages) in Chinese studies were consistent with those from similar international studies elsewhere, but there was substantial heterogeneity in regional reporting rates in China (range 2.3–37.8/100,000 doses). The highest AEFI reporting rates were for diphtheria–tetanus–pertussis whole-cell (DTwP) and acellular (DTaP) vaccines (range 3.3–181.1/100,000 doses for DTwP; range 3.5–92.6/100,000 doses for DTaP), with higher median rates for DTwP than DTaP, and higher than expected rates for DTaP vaccine. Similar higher rates for DTwP and DTaP containing vaccines, and relatively lower rates for vaccines against hepatitis B virus, poliovirus, and Japanese encephalitis virus were found in China and elsewhere in the world.

Conclusions

Overall AEFI reporting rates in China were consistent with similar post-marketing surveillance systems in other countries. Sources of regional heterogeneity in AEFI reporting rates, and their relationships to differing vaccine manufacturers versus differing surveillance practices, require further exploration.     

Vaccination of adults 65 years of age and older with tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine (Boostrix(®)): results of two randomized trials

Background

Pertussis can cause significant morbidity in elderly patients, who can also transmit this disease to infants and young children. There is little data available on the use of acellular pertussis vaccines in recipients ≥65 years of age.

Methods

Two studies examined the safety and immunogenicity of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine (Boostrix^®) in healthy ≥65 year olds. In Study A subjects received single doses of Tdap and seasonal influenza vaccine either co-administered or given one month apart. In Study B subjects received either Tdap or tetanus-diphtheria (Td) vaccine. Antibodies were measured before and one month after vaccination. Reactogenicity and safety were actively assessed using diary cards.

Results

A total of 1104 subjects 65 years of age and older received a Tdap vaccination in the two studies. In study A, no differences in immune responses to Tdap or influenza vaccine were observed between co-administered or sequentially administered vaccines. In study B, Tdap was non-inferior to Td with respect to diphtheria and tetanus seroprotection, and anti-pertussis GMCs were non-inferior to those observed in infants following a 3-dose diphtheria, tetanus and acellular pertussis (DTaP) primary vaccination series, in whom efficacy against pertussis was demonstrated. Reports of adverse events were similar between Tdap and Td groups.

Conclusions

Tdap was found to be immunogenic in subjects ≥65 years, with a safety profile comparable to US-licensed Td vaccine. Tdap and influenza vaccine may be co-administered without compromise of either the reactogenicity or immunogenicity profiles of the two vaccines.     

Laboratory investigation of immune responses to acellular pertussis vaccines when used for boosting adolescents after primary immunisation with whole cell pertussis vaccines: a comparison with data from clinical study

The lack of unequivocal immunological correlates of human protection and an absence of a validated animal model for acellular pertussis vaccines, compounded by limited opportunity to undertake efficacy studies in humans and laboratory evaluation side by side, has made it difficult to compare vaccines and formulations. In the present study, the effect on the booster response to pertussis in adolescents primed in infancy with whole cell pertussis vaccine, of three low dose acellular pertussis/diphtheria/tetanus toxoid (TdPa) formulations with or without inactivated poliomyelitis vaccine (IPV) components, was investigated. To assess the relationship between laboratory vaccine evaluation and clinical trial performance, parallel evaluation of the same TdPa vaccines were carried out in a mouse booster model with whole cell pertussis vaccine priming. Prior to boosting, the clinical subjects had low cell mediated immune responses (CMI) responses to pertussis vaccine components. After boosting, all TdPa formulations stimulated CMI responses to the pertussis vaccine components assessed. The booster responses to the pertussis antigens remained skewed towards Th1 type even though acellular pertussis vaccines were used. In general the antibody and CMI responses to pertussis antigens in the mouse model followed the trend seen in the human subjects. Protection against aerosol challenge with virulent Bordetella pertussis was related to the magnitude of the antibody and CMI responses in the mouse model. As in the human subjects, the responses remained skewed towards Th1 type.     

School-age children and adolescents suspected of having been to be infected with pertussis in Japan

Many countries including Japan have adapted acellular pertussis vaccines combined with diphtheria and tetanus toxoids (DTaP). DTaP vaccine coverage is approximately >90%, but pertussis re-emergence has been observed since 2000 in Japan. In the present study, anti-pertussis antibodies were investigated among school-age children and adolescents from 2013 to 2015. The positive rate of anti-pertussis toxin (PT) antibodies was higher among children aged 12–13 years (60.0%. 95%CI; 56.0–63.9%) in 2014 and 18–19 years (73.0%. 95%CI; 61.4–82.6%) in 2013, compared with 6–7 years (47.1%. 95%CI; 40.7–53.6%). The mean PT antibody titer was higher among children aged 12–13 years (23.8 EU/ml. 95%CI; 21.9–25.8) in 2014 and 18–19 years (29.3 EU/ml. 95%CI; 23.0–35.6) in 2013, compared with 6–7 years (18.3 EU/ml. 95%CI; 15.5–21.2). Distributions of pertussis antibodies and mean titers at their same grade of school-age were similar from 2013 to 2015. Although school-age children were immunized with 4 doses of DTaP, the data suggested the decay of vaccine-acquired immunity and possibility of asymptomatic infection in school age, indicating the additional DTaP vaccination before the entry of elementary school, preventing household contact.     

Immunogenicity and safety of the quadrivalent meningococcal vaccine MenACWY-TT co-administered with a combined diphtheria-tetanus-acellular pertussis vaccine versus their separate administration in adolescents and young adults: A phase III,randomized study

BackgroundThis study evaluated the immunogenicity and safety of quadrivalent meningococcal conjugate vaccine using tetanus (T) toxoid as carrier protein (MenACWY-TT) co-administered with combined diphtheria-tetanus-acellular pertussis vaccine (Tdap) versus their separate administration in adolescents and young adults.MethodsIn this phase III, randomized, partially-blind study (NCT01767376), healthy 11–25-year-olds (N = 660) were randomized (1:1:1) to receive MenACWY-TT and Tdap at Month 0 (Co-ad group), MenACWY-TT at Month 0 and Tdap at Month 1 (ACWY_Tdap group) or Tdap at Month 0 and MenACWY-TT at Month 1 (Tdap_ACWY group). Immune responses to MenACWY-TT were measured by serum bactericidal assay using rabbit complement (rSBA). Anti-diphtheria (D), anti-tetanus (T), anti-pertussis toxin (PT), anti-filamentous hemagglutinin (FHA) and anti-pertactin (PRN) antibody concentrations were assessed using enzyme-linked immunosorbent assays. Non-inferiority of immunogenicity was assessed using pre-defined clinical criteria. Safety was also evaluated.ResultsNon-inferiority of immunogenicity of MenACWY-TT and Tdap when co-administered versus their separate administration was demonstrated in terms of rSBA geometric mean titers (GMTs) for 4 meningococcal serogroups and of the percentage of participants with antibody concentrations >1 IU/ml for D and T. Among the pertussis antigens, non-inferiority criteria for geometric mean concentrations (GMCs) were reached for PT, but not met for FHA and PRN. Across all groups, ≥93.2% of participants had vaccine responses to each meningococcal serogroup, ≥99.1% were seroprotected against T and D, and ≥85.5% had booster responses to each pertussis antigen. Robust increases in antibody GMTs/GMCs were observed for all antigens between pre-and post-vaccination. Both vaccines had clinically acceptable safety profiles.ConclusionImmune responses to MenACWY-TT and to the T and D antigens from Tdap were not impacted by their co-administration. The lower antibody concentrations observed against the pertussis components may be of limited clinical relevance since robust anti-pertussis booster responses were observed. This study supports concurrent administration of the 2 vaccines in adolescents.     

Transiently increased IgE responses in infants and pre-schoolers receiving only acellular Diphtheria–Pertussis–Tetanus (DTaP) vaccines compared to those initially receiving at least one dose of cellular vaccine (DTwP) – Immunological curiosity or canary in the mine?

BackgroundSeveral previous studies have highlighted the strong Th2-polarising and IgE-promoting activity of the DTaP vaccine, but there is no evidence that this has pathological consequences and accordingly there is no current interest amongst vaccine developers in reformulating DTaP to attenuate these properties. In light of an apparent resurgence in pertussis in many countries, and emerging evidence from other areas of paediatric immunology of IgE-mediated interference with host defence mechanisms, this issue requires more detailed clarification.MethodsWe have re-evaluated the impact of DTaP-only versus mixed DTwP/DTaP vaccination on Th2-dependent “bystander” IgE responses in three cohorts of children under different priming conditions, encompassing both vaccine-targeted and unrelated antigens including food allergens.ResultsWe confirm the generalised IgE-trophic activity of the DTaP vaccine in pre-schoolers and demonstrate similar (albeit transient) effects in infants. We additionally demonstrate that use of an alternative mixed infant priming schedule encompassing an initial dose of DTwP significantly attenuates this property.InterpretationCentral to our interpretation of these findings are studies demonstrating: (i) mixed DTwP/DTaP priming improves resistance to pertussis disease and attenuates the IgE-stimulatory component of long term vaccine-specific memory; (ii) IgE-mediated mechanisms can interfere with innate antiviral immunity and accordingly exacerbate airway symptoms in infected children. These observations, taken together with the data presented here, suggest a plausible mechanistic link between baseline pertussis-specific IgE titres in DTaP vaccinees and susceptibility to pertussis disease, which merits testing. Retrospective IgE analyses on sera collected from children at the time of presentation with pertussis could resolve this issue.     

CpG 1018® adjuvant enhances Tdap immune responses against Bordetella pertussis in mice

Bordetella pertussis is the causative agent of whooping cough (pertussis), a severe respiratory disease that can be fatal, particularly in infants. Despite high vaccine coverage, pertussis remains a problem because the currently used DTaP and Tdap vaccines do not completely prevent infection or transmission. It is well established that the alum adjuvant is a potential weakness of the acellular vaccines because the immunity provided by it is short-term. We aimed to evaluate the potential of CpG 1018® adjuvant to improve antibody responses and enhance protection against B. pertussis challenge in a murine model. A titrated range of Tdap vaccine doses were evaluated in order to best identify the adjuvant capability of CpG 1018. Antibody responses to pertussis toxin (PT), filamentous hemagglutinin (FHA), or the whole bacterium were increased due to the inclusion of CpG 1018. In B. pertussis intranasal challenge studies, we observed improved protection and bacterial clearance from the lower respiratory tract due to adding CpG 1018 to 1/20th the human dose of Tdap. Further, we determined that Tdap and Tdap + CpG 1018 were both capable of facilitating clearance of strains that do not express pertactin (PRN^-), which are rising in prevalence. Functional phenotyping of antibodies revealed that the inclusion of CpG 1018 induced more bacterial opsonization and antibodies of the Th1 phenotype (IgG2a and IgG2b). This study demonstrates the potential of adding CpG 1018 to Tdap to improve immunogenicity and protection against B. pertussis compared to the conventional, alum-only adjuvanted Tdap vaccine.     

Vaccination coverage among adolescents aged 13-17 years - United States, 2007

Three new vaccines have been recommended for adolescents by the Advisory Committee for Immunization Practices (ACIP) since 2005: meningococcal conjugate vaccine (MCV4; 1 dose), tetanus, diphtheria, acellular pertussis vaccine (Tdap; 1 dose), and quadrivalent human papillomavirus vaccine (HPV4; 3 doses). ACIP also recommends that adolescents should receive recommended vaccinations that were missed during childhood. Since 2006, CDC has conducted the National Immunization Survey-Teen (NIS-Teen) to estimate vaccination coverage from a national sample of adolescents aged 13-17 years. This report describes the findings from NIS-Teen 2007, which indicated substantial increases in receipt of new adolescent vaccinations compared with 2006, including Tdap (from 10.8% to 30.4%) and MCV4 (from 11.7% to 32.4%), and increases in coverage with childhood vaccinations, including measles, mumps, and rubella (MMR), hepatitis B (HepB), and varicella (VAR) (among those without disease history). An assessment of HPV4 coverage, which is reported for the first time, showed that 25.1% of adolescent females initiated the vaccine series (>/=1 dose) in 2007. To improve vaccination coverage among adolescents, health-care providers should take advantage of every health-care visit as an opportunity to evaluate vaccination status and administer vaccines when needed.     

Vaccine hesitancy among parents of adolescents and its association with vaccine uptake

BackgroundAddressing parental vaccine hesitancy may increase adolescent vaccination acceptance. However, no validated measure exists to identify parents hesitant toward adolescent vaccines.ObjectiveTo determine if a modified version of the Parent Attitudes about Childhood Vaccines (PACV) survey, a previously validated tool to identify parental hesitancy toward vaccines in infants, predicts adolescent vaccine uptake at office visits.MethodsWe modified the PACV for use in the adolescent setting and distributed it to a convenience sample of parents of adolescents aged 11 to 17 presenting for care at a diverse group of six pediatric practices in Oklahoma and South Carolina. We determined the vaccination status of the parents’ adolescents for 3 vaccines (Tetanus–diphtheria–acellular pertussis [Tdap], meningococcal conjugate [MCV4], and human papillomavirus [HPV] vaccines). We used Fisher's exact tests to compare vaccination status with each survey item and with an overall general hesitancy scale that we constructed.ResultsWe analyzed 363 surveys. At the time of the visit, vaccination coverage was 84% for Tdap, 73% for MCV, and 45% for any dose of HPV. Thirty-nine percent of parents expressed concern about vaccine efficacy and 41% expressed concern about side effects. Forty-five percent of parents disagreed with the statement that “teens can get all of the vaccines that are due at a single visit.” Two individual items were associated with not receiving a dose of HPV vaccine that was due. The overall modified PACV score failed to predict adolescent vaccine uptake at an office visit.ConclusionSeveral individual items were associated with vaccine uptake. The cumulative modified PACV, a general measure of vaccine hesitancy, was not associated with vaccination status despite illuminating parental hesitancy. We need to better understand vaccine-specific concerns for the adolescent population.     

MenACWY-TT is immunogenic when co-administered with Tdap and AS04-HPV16/18 in girls and young women: Results from a phase III randomized trial

BackgroundCo-administration of vaccines in adolescents may improve coverage. We assessed co-administration of quadrivalent meningococcal serogroups A, C, W and Y tetanus toxoid-conjugate vaccine (MenACWY-TT), human papillomavirus 16/18 AS04-adjuvanted vaccine (AS04-HPV16/18) and tetanus-diphtheria-acellular pertussis vaccine (Tdap) in girls and young women.MethodsIn this phase IIIb study (NCT01755689), 1300 healthy 9–25-year-old females were randomized (1:1:1:1:1) to receive: MenACWY-TT at month (M) 0 and AS04-HPV16/18 at M1, M2, M7; MenACWY-TT and AS04-HPV16/18 at M0 and AS04-HPV16/18 at M1, M6; AS04-HPV16/18 at M0, M1, M6; MenACWY-TT, Tdap and AS04-HPV16/18 at M0 and AS04-HPV16/18 at M1, M6; Tdap and AS04-HPV16/18 at M0 and AS04-HPV16/18 at M1, M6. Immunogenicity, safety and reactogenicity were evaluated.ResultsImmunogenicity of MenACWY-TT and AS04-HPV16/18 when co-administered was non-inferior to that of the 2 vaccines given separately. Co-administration of MenACWY-TT, AS04-HPV16/18 and Tdap was non-inferior to MenACWY-TT administered alone or to Tdap co-administered with AS04-HPV16/18 in terms of immunogenicity for all vaccine components, except pertussis antigens. Post-vaccination, ≥89.5% of participants reached antibody levels above the pre-specified threshold for all antigens. No safety concerns were identified.ConclusionOur data support co-administration of MenACWY-TT with Tdap and AS04-HPV16/18 vaccines in adolescents.     

National and state vaccination coverage among adolescents aged 13 through 17 years--United States, 2010

The Advisory Committee on Immunization Practices (ACIP) recommends that adolescents routinely receive meningococcal conjugate (MenACWY, 2 doses); tetanus, diphtheria, acellular pertussis (Tdap, 1 dose); and human papillomavirus (HPV, 3 doses) vaccines (influenza vaccine is recommended annually for all persons aged 6 months and older). CDC tracks vaccination coverage among adolescents aged 13 through 17 years through the National Immunization Survey--Teen (NIS-Teen). To provide updated vaccination coverage estimates, CDC analyzed 2010 NIS-Teen data and compared results with 2009 NIS-Teen estimates. This report summarizes the results of that analysis, which found that coverage increased for all three of the routinely administered adolescent vaccines: Tdap from 55.6% to 68.7%, MenACWY from 53.6% to 62.7%, (among females) ≥1 dose of HPV from 44.3% to 48.7%, and ≥3 doses of HPV from 26.7% to 32.0%. Vaccination coverage varied widely among states; three states (Massachusetts, Rhode Island, and Washington) had coverage of >65% for ≥1 dose of all three vaccines (Tdap, MenACWY, and HPV). Continued evaluation of vaccination-promoting initiatives, including state vaccination-financing policies, is needed to understand their impact on adolescent vaccination and to promote effective practices.     

Duration of protection against Bordetella pertussis infection elicited by whole-cell and acellular vaccine priming in Polish children and adolescents

BackgroundIn the context of reported resurgence of pertussis in the last decade, researchers hypothesized that acellular (aP) pertussis vaccines elicit a shorter-lived protection compared to whole-cell (wP) pertussis vaccines. However, in the studies seeking to demonstrate this hypothesis, exposure to each vaccine type was not concurrent, and contradictory epidemiologic modeling questioned its validity. The context of pertussis vaccination history in Poland, with both vaccine types used concurrently in comparable proportions, provided an opportunity to investigate this hypothesis. We sought to compare waning of protection by primary series vaccine type by measuring anti-pertussis toxin antibody concentrations as proxy for recent infection.Materials and methodsSerological samples from 2,745 children and adolescents aged ≥5 years and <16 years and with completed 5-dose pertussis vaccination series were tested by ELISA for pertussis toxin (PT) antibodies. Participants were stratified by type of priming vaccine (wP or aP). Vaccination timeliness and priming-specific trends in anti-PT antibody levels by time since last vaccine dose were analyzed.ResultsA total of 1,161 (42.5%) children received wP vaccines, and 1,314 (48.1%) received aP vaccines for their primary series and toddler booster. Overall, 53.57% of the subjects received doses 2–4 in a timely manner, while only 41.52% received all 5 doses at the recommended intervals. Using GMCs or seropositivity measures, both priming groups showed a re-increase in anti-PT antibody levels signing infection in recent years from 8 years after the school-entry booster onward. Comparisons did not show any significant differences between the two groups in the timing or intensity of this re-increase.ConclusionOur results clearly confirm that vaccine-elicited immunity against pertussis wanes among adolescents even after a complete infant, toddler and school-entry vaccination series. The timing and intensity of the waning of protection appear similar with whole-cell as with acellular pertussis vaccines.     

Comparison of acellular pertussis-based combination vaccines by Japanese control tests for toxicities and laboratory models for local reaction

Two batches each of diphtheria–tetanus–acellular pertussis vaccine (DTaP) and that combined with inactivated polio vaccine purchased from the U.S.A., European and Asian markets were compared with Japanese DTaPs by Japanese control tests for DTaP and laboratory models for local reaction. All the imported vaccines met Japanese criteria for toxicities of acellular pertussis vaccine except for the toxicity to mouse weight gain (body weight decreasing (BWD) toxicity). When injecting into mouse footpad, rabbit back skin and mouse quadriceps muscle, the imported vaccines induced much severer inflammation and tissue injury comparing to Japanese DTaPs irrespective of animal species, injection site and injection volume suggesting that these vaccines may induce stronger local reactogenicity.     

A randomized,blinded, placebo-controlled trial comparing antibody responses to homeopathic and conventional vaccines in university students

BackgroundHomeopathic vaccines are licensed in many countries but scientific data to support their use are sparse. The goal of this study was to compare the antibody response of homeopathic and conventional vaccines and placebo in young adults. We hypothesized that there would be no significant difference between homeopathic vaccines and placebo, while there would be a significant increase in antibodies in those received conventional vaccines.MethodsA randomized blinded placebo-controlled trial was conducted where 150 university students who had received childhood vaccinations were assigned to diphtheria, pertussis, tetanus, mumps, measles homeopathic vaccine, placebo, or conventional diphtheria, pertussis, tetanus (Tdap) and mumps, measles, rubella (MMR) vaccines. The primary outcome was a ≥ two-fold increase in antibodies from baseline following vaccination as measured by ELISA. Participants, investigators, study coordinator, data blood drawers, laboratory technician, and data analyst were blinded.ResultsNone of the participants in either the homeopathic vaccine or the placebo group showed a ≥ two-fold response to any of the antigens. In contrast, of those vaccinated with Tdap, 68% (33/48) had a ≥ two-fold response to diphtheria, 83% (40/48) to pertussis toxoid, 88% (42/48) to tetanus, and 35% (17/48) of those vaccinated with MMR had a response to measles or mumps antigens (p < 0.001 for each comparison of conventional vaccine to homeopathic vaccine or to placebo). There was a significant increase in geometric mean titres of antibody from baseline for conventional vaccine antigens (p < 0.001 for each), but none for the response to homeopathic antigens or placebo.ConclusionsHomeopathic vaccines do not evoke antibody responses and produce a response that is similar to placebo. In contrast, conventional vaccines provide a robust antibody response in the majority of those vaccinated.Trial Registry: NCT 02825368.     

Effect of injection site on reactogenicity and immunogenicity of acellular and whole-cell pertussis component diphtheria-tetanus-pertussis vaccines in infants

The effect of injection site on reactogenicity and specific immunogenicity was assessed in participants in a pertussis vaccine efficacy trial. The percent of DTwP and DTaP recipients with any reaction was slightly lower in subjects injected in the buttock compared with those injected in the thigh. This finding was most common in DTwP recipients. Geometric mean antibody values to pertactin, filamentous hemagglutinin and fimbriae (Bordetella pertussis antigens) were lower in DTaP vaccinees when buttock was utilized as the injection site. Our findings present evidence against the use of the buttock as the site of immunization for DTaP vaccines since the benefit with regards to reactogenicity is minimal and the immunologic response to an important antigen of B. pertussis, pertactin, is decreased.