Immunogenicity and safety of a tetanus toxoid,reduced diphtheria toxoid and three-component acellular pertussis vaccine in adults 19–64 years of age

Purpose

This study was conducted to assess the immunogenicity and safety of a tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine containing three pertussis antigens (Boostrix^®, Tdap3v), currently licensed in the US for use in adolescents 10–18 years of age, in adults 19–64 years of age.

Methods

2284 healthy adults, aged 19–64 years, were randomized to receive a single dose of Tdap vaccine, either Tdap3v or a five-pertussis component Tdap vaccine (Adacel^®, Tdap5v) licensed for adult use in the US. Blood samples were taken before and 1 month after vaccination. Reactogenicity was assessed for 15 days after vaccination.

Results

Tdap3v was comparable to Tdap5v in eliciting seroprotective levels of antibodies to diphtheria and tetanus toxoids, with >98% of subjects having post-vaccination seroprotective antibody levels (≥0.1 IU/mL) against diphtheria or tetanus toxoids. The pertussis components of Tdap3v were shown to be immunogenic in adults, with booster responses to pertussis toxoid (PT), filamentous hemagglutinin (FHA), and pertactin (PRN) observed in 77.2%, 96.9%, and 93.2%, respectively, of Tdap3v recipients, and in 47.1%, 94.0%, and 91.7%, respectively, of Tdap5v recipients. Anti-pertussis antibody GMCs in Tdap3v recipients exceeded those observed in infants following primary DTaP vaccination, in whom efficacy against pertussis disease was subsequently demonstrated. Injection site reactions (pain, redness, and swelling) and fever ≥37.5 °C (99.5 °F) were reported significantly more often (p < 0.05) by Tdap5v recipients than by Tdap3v recipients. Fatigue preventing normal daily activities was reported by a small but significantly greater percentage of Tdap3v recipients (2.5%) than Tdap5v recipients (1.2%, p < 0.05).

Conclusion

In adult recipients, Tdap3v was comparable to an approved Tdap vaccine in providing seroprotection against diphtheria and tetanus, and produced immune responses to pertussis antigens consistent with protection against disease. The overall safety profile of Tdap3v was generally comparable to that of Tdap5v [NCT #106316].     

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.     

A randomised, double-blind, non-inferiority clinical trial on the safety and immunogenicity of a tetanus, diphtheria and monocomponent acellular pertussis (TdaP) vaccine in comparison to a tetanus and diphtheria (Td) vaccine when given as booster vaccinations to healthy adults

Background

Increasing incidence of pertussis in adolescents and adults has stimulated the development of safe and immunogenic acellular pertussis vaccines for booster vaccination of adolescents and adults.

Purpose

To obtain clinical documentation of the safety and immunogenicity of a tetanus, diphtheria and monocomponent acellular pertussis combination vaccine (TdaP), when given as a booster vaccination to adults.

Methods

The trial was double-blind, controlled and randomised. 802 healthy adults, aged 18–55 years who had completed childhood vaccination with diphtheria, tetanus and whole cell pertussis vaccine (DTwP), were booster vaccinated with TdaP or Td. Blood samples were taken before and one month after the vaccination for serological analysis and adverse events were recorded during the one-month-follow-up period.

Results

The monocomponent acellular pertussis vaccine (aP) in the TdaP vaccine was immunogenic in adults with 92.0% of TdaP vaccinated subjects obtaining an anti-pertussis toxin (anti-PT) antibody booster response. TdaP was non-inferior to Td in eliciting seroprotective anti-tetanus and diphtheria antibody concentrations with more than 98% of subjects obtaining post-vaccination seroprotective concentrations (≥0.1 IU/mL). T and d booster response rates were 93.0% and 97.5%, respectively.The frequencies of solicited local adverse reactions were low and comparable between TdaP and Td vaccinees. In the TdaP group, 30.7% reported pain, 4.2% swelling and 2.0% erythema at the injection site. The most frequent solicited general symptoms were headache (20.4%), fatigue (17.0%) and myalgia (10.0%). In the Td group, 35.7% reported pain, 2.5% swelling and 3.2% erythema at the injection site, whereas headache, fatigue and myalgia were reported by 15.7%, 14.5% and 12.5%, respectively.In conclusion, TdaP Vaccine SSI was safe and immunogenic when given as a booster vaccination to adults. ClinicalTrials.gov registration number: NCT01033877.     

U.S. Postlicensure safety surveillance for adolescent and adult tetanus,diphtheria and acellular pertussis vaccines: 2005–2007

Background

Pre-licensure clinical trials for two U.S. licensed tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccines did not reveal any major safety concerns. However, routine use in large adolescent and adult populations could reveal rare and potentially serious adverse events (AEs).

Methods

To characterize reported AEs following Tdap vaccination and identify potential safety concerns warranting further evaluation, we analyzed data from the Vaccine Adverse Event Reporting System (VAERS) and assessed the frequency and proportions of AEs and reporting rates (reports per 100,000 vaccine doses distributed).

Results

A total of 2090 reports (7% were serious; 55% listed Tdap alone) involving Tdap vaccines were submitted to VAERS May 2005–June 2007. The crude reporting rate was 10.2 per 100,000 vaccine doses distributed. The median age of vaccinees was 22 years, and the female to male ratio was about 2 to 1. The majority of reports described common local and systemic signs and symptoms, such as injection site reactions, fever, and headache. Rarely reported AEs included myopericarditis, demyelinating diseases of the central nervous system, Guillain–Barré Syndrome, syncope, encephalopathy/encephalitis, seizure, Bell's palsy, anaphylaxis, and thrombocytopenia.

Conclusions

Because adolescents and adults were not routinely vaccinated against pertussis in the past, this surveillance summary provides important – and reassuring – information about the use of Tdap in these age groups. Although subject to the limitations of passive surveillance, the findings of this VAERS review support the pre-licensure clinical trial data with regard to the safety of the U.S. licensed Tdap vaccines. Continued monitoring of clinically significant AEs that are temporally associated with Tdap vaccination and further assessment of such events using controlled observational studies may provide additional information about the safety of these vaccines.     

Barriers to early uptake of tetanus, diphtheria and acellular pertussis vaccine (Tdap) among adults-United States, 2005-2007

Background

The tetanus, diphtheria and acellular pertussis vaccine (Tdap) was recommended by the Advisory Committee on Immunization Practices (ACIP) for U.S. adults in 2005. Our objective was to identify barriers to early uptake of Tdap among adult populations.

Methods

The 2007 National Immunization Survey (NIS)-Adult was a telephone survey sponsored by the Centers for Disease Control and Prevention (CDC). Immunization information was collected for persons aged ≥18 years on all ACIP-recommended vaccines. A weighted analysis accounted for the complex survey design and non-response.

Results

Overall, 3.6% of adults aged 18-64 years reported receipt of a Tdap vaccination. Of unvaccinated respondents, 18.8% had heard of Tdap, of which 9.4% reported that a healthcare provider had recommended it. A low perceived risk of contracting pertussis was the single most common reason for either not vaccinating with Tdap or being unwilling to do so (44.7%). Most unvaccinated respondents (81.8%) indicated a willingness to receive Tdap if it was recommended by a provider.

Conclusions

During the first two years of availability, Tdap uptake was likely inhibited by a low collective awareness of Tdap and a low perceived risk of contracting pertussis among U.S. adults, as well as a paucity of provider-to-patient vaccination recommendations. Significant potential exists for improved coverage, as many adults were receptive to vaccination.     

Tetanus,diphtheria and acellular pertussis (Tdap) vaccination among healthcare personnel—United States, 2011

Background

Health-care personnel (HCP) are at risk for exposure to and possible transmission of vaccine-preventable diseases. Receiving recommended vaccines is an essential prevention practice for HCP to protect themselves and their patients. The tetanus, diphtheria and acellular pertussis vaccine (Tdap) was recommended by the Advisory Committee on Immunization Practices (ACIP) for HCP in 2006 for protection against pertussis. We assessed the recent compliance of U.S. HCP in receiving Tdap vaccination.

Methods

To estimate Tdap vaccination coverage among HCP, we analyzed data from the 2011 National Health Interview Survey (NHIS). Multivariable logistic regression and predictive marginal models were performed to identify factors independently associated with vaccination among HCP.

Results

Overall, Tdap vaccination coverage was 26.9% among HCP aged 18–64 years (95% confidence interval (CI) = 24.3%, 29.7%), which was significantly higher compared with non-HCP among the same age group (11.1%; 10.5–11.8%). Overall, vaccination coverage was significantly higher among physicians (41.5%) compared with nurses (36.5%) and other types of HCP (range 11.7–29.9%). Vaccination coverage was significantly higher among HCP aged 18–49 years compared with those 50–64 years (30.0% vs. 19.2%, respectively). Characteristics independently associated with an increased likelihood of Tdap vaccination among HCP were: younger age, higher education, living in the western United States, being hospitalized within past year, having a place for routine health care in clinic or health center, and receipt of influenza vaccination in the previous year. Marital status of widowed, divorced, or separated was independently associated with a decreased likelihood of Tdap vaccination among HCP.

Conclusions

By 2011, Tdap vaccination coverage was only 26.9% among HCP. Vaccination coverage varied widely by types of HCP and demographic characteristics. Emphasizing the benefits of HCP vaccination for staff and patients, providing vaccinations in the workplace and other non-traditional settings, and providing Tdap at no charge may help increase Tdap vaccination among HCP in all health-care settings.     

Economic impact of the introduction of an acellular pertussis vaccine in Canada: A 6-year analysis

Background

Between July 1997 and April 1998, Canadian public health agencies switched from the whole cell vaccine to the acellular vaccine for pertussis immunization. The acellular vaccine provided better efficacy and fewer adverse events than the whole cell vaccine did.

Objective

To determine the economic impact of replacing the whole cell vaccine with an acellular vaccine in Canada.

Methods

A decision analytic model was developed comparing costs and outcomes of pertussis vaccination for Canadian children born in the years 1991–2004. Effectiveness was measured as number of avoided pertussis cases as well as the number of avoided hospital admissions. Incremental costs per avoided pertussis case and per avoided hospital admission were calculated for Ministry of Health (MoH) and societal (SOC) perspectives. Various one-way sensitivity analyses as well as a Monte Carlo simulation were performed by varying key model parameters.

Results

The switch in immunization programs resulted in an incremental cost to the MoH of CAD $108 per pertussis case avoided (CAD $0.96 per child-year). From the SOC perspective, there was a savings of CAD $184 per pertussis case avoided (CAD $0.13 per child-year). The one-way sensitivity analyses provided incremental cost-effective ratios (ICERs) ranging from an incremental cost of CAD $1034 per avoided pertussis case from the MoH perspective to a saving of CAD $1583 per avoided case from the SOC perspective. The Monte Carlo simulation confirmed the robustness of these results.

Conclusions

Pertussis vaccination with AcE was cost-saving from the societal perspective and cost-effective from the Ministry of Health perspective.     

Pharmacist-led Tdap vaccination of close contacts of neonates in a women's hospital

Background

Pertussis can cause severe illness and death in infants. Immunization of family members with the tetanus toxoid, reduced diphtheria toxoids, and acellular pertussis (Tdap) vaccine can decrease risk of pertussis infection among infants. A community pharmacy on a women's hospital campus implemented a Tdap vaccination pilot program.

Objective

To investigate the rate of Tdap vaccination among close contacts of neonates in a women's hospital pharmacy and to assess the impact of a coordinated pharmacy and hospital Tdap vaccination program.

Methods

The intervention entailed education from hospital staff who explained the risks of pertussis, advocated the benefits of vaccination, and encouraged family members to be vaccinated. In the on-site clinic or in the pharmacy, pharmacists administered vaccine to eligible patients. Rates of Tdap vaccinations in the intervention pharmacy with in-hospital vaccination were compared to comparison pharmacies without Tdap interventions.

Results

In the pre-study period (December 2008–November 2010), there were 31 Tdap vaccinations administered at the intervention pharmacy (mean = 1.3/month); during the study period (December 2010–November 2012), 2045 Tdap vaccinations were administered (mean = 85.2/month). In four comparison hospital-campus pharmacies, there were 77 vaccinations (mean = 0.8/month) during the pre-study period and 817 vaccinations (mean = 8.5/month) during the study period. There were 155 vaccinations administered in 44 area-community pharmacies (mean = 0.1/month) during the pre-study period and 2930 (mean = 2.8/month) during the study period. The intervention pharmacy had the highest average monthly rate of change in Tdap volume from pre-study to study period (83.9), compared to comparison hospital-campus pharmacies (7.7, p < .001) and area-community pharmacies (2.7, p < .001). During the study period, the estimated Tdap vaccination coverage per live births was 8.1% in the intervention pharmacy versus 5.5% in the comparison hospital-campus pharmacies (p < .001).

Conclusions

Tdap vaccination rates increased after implementation of the intervention program. This project illustrates how health systems and community pharmacists can collaborate to improve patient care.     

Knowledge,attitudes and vaccination coverage of healthcare workers regarding occupational vaccinations

Objectives

Immunization of healthcare workers (HCWs) is a major issue for infection control in healthcare facilities. The aim of this study was to evaluate knowledge regarding occupational vaccinations, HBV, varicella and influenza vaccination rates and attitudes towards influenza vaccine among HCWs.

Design and setting

A cross-sectional survey was conducted in two wards (Medicine and Paediatrics) of a 1182-bed teaching hospital in Paris, France.

Methods

A standardized, anonymous, self-administered questionnaire was used.

Results

Of 580 HCWs, 395 (68%) completed the questionnaire. Knowledge about the occupational vaccinations of HCWs was low. HBV (69%), tuberculosis (54%) and influenza (52%) were the most cited vaccinations. Paediatric staff was more aware of influenza and pertussis immunizations (p < .05). HBV vaccination rate was 93%, among whom 65% were aware of their immune status. Influenza vaccination rate for 2006–2007 was 30% overall, ranging from 50% among physicians to 20% among paramedical staff (p < .05). Physicians based their refusal on doubts about vaccine efficacy, although paramedics feared side effects. Influenza vaccination was associated with knowledge of vaccine recommendations [OR = 1.75, 95% CI: 1.13–2.57] and contact with patients [OR = 3.05, 95% CI: 1.50–5.91].

Conclusions

Knowledge of recommended occupational vaccinations is insufficient in HCWs, except for HBV and influenza. Although the HBV vaccine coverage of HCWs is satisfactory, a large proportion of them is unaware of immune status. Influenza vaccine coverage remains low, especially among paramedical staff because of fear of side effects. As vaccine coverage is associated with knowledge, educational campaigns should be strengthened to increase the adhesion of HCWs to vaccinations.     

Cost–benefit analysis of hospital based postpartum vaccination with combined tetanus toxoid,reduced diphtheria toxoid,and acellular pertussis vaccine (Tdap)

Objective

To assess the economic benefits associated with hospital-based postpartum Tdap (combined tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccination.

Methods

A decision tree model was constructed to calculate the potential cost–benefit of this strategy from both a health care system and a societal perspective. Probabilities and costs were derived from published literature, data reported to Centers for Disease Control and Prevention, and recommendations from expert panels. The maternal vaccination protection period for infants was defined as 7 months, and 10 years of waning immunity following Tdap for birth mothers was estimated in the model. All cost estimates were inflated to year 2012 US dollars and discounted at a 3% annual discount rate.

Results

In the base case from a societal perspective, the expected costs per vaccinated and unvaccinated mother were estimated at $129.27 and $187.97, respectively, suggesting an expected net benefit of $58.70 per vaccinated mother. The overall societal benefits in the cohort of 3.6 million U.S. birth mothers ranged from $52.8–126.8 million, depending on the vaccination coverage level. If including direct medical costs only, the strategy would not generate net savings from a health care system perspective. Annual incidence of pertussis in birth mothers and Tdap efficacy exhibited substantial impact on the model as shown in one-way and two-way sensitivity analyses.

Conclusions

Although postpartum Tdap vaccination is not cost-beneficial from a health care system perspective in the base case, this strategy is likely to generate net benefits from a societal perspective.     

Changes in Tdap and MCV4 Vaccine Coverage Following Enactment of a Statewide Requirement of Tdap Vaccination for Entry Into Sixth Grade

Objectives. We evaluated changes in tetanus toxoid, reduced diptheria toxoid, acellular pertussis (Tdap), and tetravalen meningococcal (MCV4) vaccine coverage following enactment of a New York State mandate requiring Tdap before entering sixth grade.Methods. Using data from a hospital-based immunization registry, we measured Tdap and MCV4 coverage among youths aged 11 to 14 years in New York City at 3 time points: premandate, mandate year 1, and mandate year 2.Results. Among overlapping cohorts of 4316 (premandate), 4131 (mandate year 1), and 3639 (mandate year 2) youths, Tdap coverage increased steadily over time (29%, 58%, and 83%, respectively). Increases were observed among all ages. Across the same time points, MCV4 coverage also increased (10%, 30%, and 60%, respectively). Most adolescents did not receive MCV4 during the same visit they received Tdap.Conclusions. A Tdap school-entry mandate was associated with substantial increases in immunization coverage, even in age groups not directly affected by the mandate. At the postmandate time points, MCV4 coverage remained lower than Tdap coverage. Provider education should emphasize the importance of reviewing vaccine records and administering all recommended vaccines at every clinical encounter.In recent years, new vaccines against pertussis¹ and meningitis² have been introduced to the routine immunization schedule for children and adolescents. Both are recommended for youths aged 11 to 12 years, with catch-up vaccination for older adolescents. Pertussis is a highly contagious infection, often causing school or community outbreaks. Among healthy adolescents, pertussis is usually a self-limited illness characterized by a prolonged cough. However, secondary complications can occur, and adolescents serve as an important reservoir for transmission to infants, for whom infection can lead to pneumonia, respiratory failure, apnea, and even death.³ The tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine has been shown to be 92% effective in preventing culture-confirmed pertussis.⁴Adolescents, and specifically those in crowded living conditions, have been shown to be at increased risk for N. meningitides infection.⁵ N. meningitides is highly contagious and can cause meningitis, septicemia, and death. The tetravalent meningococcal polysaccharide-protein conjugate (MCV4) vaccine has been shown to be safe and highly immunogenic in protecting against N. meningitides infection.⁶Although the Tdap and MCV4 vaccines hold great promise, achieving high immunization coverage among adolescents remains a challenge. Barriers to adolescent immunization include failure to present for medical services, missed immunization opportunities, and scattered immunization records.⁷ Few adolescents report the receipt of annual preventive health visits,⁸ so reviewing immunization status and immunizing at every clinical encounter is key to increasing vaccine coverage in this population. Results of the 2008 National Immunization Survey–Teen indicate that among adolescents aged 13 to 17 years, nationwide coverage for Tdap and MCV4 remains low (41% and 42%, respectively).⁹Mandates requiring immunization prior to school entry have been highly effective in increasing immunization coverage.^10–14 In 1 study, hepatitis B immunization rates increased from 13% to 71% following implementation of a middle school mandate.¹⁵ Mandates were initially used to promote the uptake of vaccines for highly contagious infectious diseases and thus to prevent school-based outbreaks, but today many states mandate vaccines for diseases that are not communicable (tetanus) or that are communicable primarily through sexual or blood exposures (hepatitis B). Recent controversy regarding mandates for the human papillomavirus vaccine has resulted in significant backlash against mandates,^16–18 highlighting the need for states to be judicious in their decisions to implement new mandates.Although mandates are known to rapidly increase vaccine coverage in their target population, there is little evidence of any carryover benefits. No studies to date have evaluated whether a new mandate will result in improved vaccine coverage for nonmandated age groups or for other nonmandated, age-appropriate vaccines. In the fall of 2007, New York State became one of the first states to require Tdap prior to entering sixth grade. This situation provided a unique opportunity to observe postmandate changes in coverage for Tdap (the mandated vaccine) and MCV4 (a nonmandated, recommended vaccine) across multiple age groups.     

Effectiveness and cost-effectiveness of different immunization strategies against whooping cough to reduce child morbidity and mortality

Introduction

In the last years there has been a significant increase in reported cases of pertussis in developed countries, in spite of high rates of childhood immunization. Health institutions have recommended different vaccination strategies to reduce child morbidity and mortality: vaccination of adolescents and adults, pregnant women, people in contact with the newborn (cocoon strategy) and health care workers. The aim of this paper is to review the scientific evidence supporting these recommendations.

Methods

Systematic review on the effectiveness and cost-effectiveness of the above strategies for the reduction of morbidity and mortality from pertussis in infants under 12 months. The electronic databases Medline, PreMedline, Embase, CRD, Cochrane Central, and Trip Database were consulted from 1990 to October 2012. The evidence was assessed using the GRADE system.

Results

There were eight studies on the efficacy or safety of the strategies analyzed, and 18 economic evaluations. Direct evidence on the efficacy of these strategies is scarce. Economic evaluations suggest that vaccination of adolescents and adults would be cost-effective, although there is major uncertainty over the parameters used.

Conclusions

From the perspective of health technology assessment, there is insufficient evidence to recommend the vaccination strategies evaluated.     

Tolerability and antibody response in adolescents and adults revaccinated with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine adsorbed (Tdap) 4-5 years after a previous dose

Background

Although decennial adult boosters of tetanus and diphtheria toxoids are recommended in Canada and the United States, a second dose of pertussis vaccine is not currently recommended for adults.

Methods

This open-label, postmarketing, multicenter study evaluated the tolerability and immunogenicity of a second dose of an adult formulation of tetanus, diphtheria, and pertussis vaccine (Tdap) in adolescents and adults 5 years after a first dose.

Results

A total of 545 participants from previous Tdap vaccine studies, ranging in age from 15 to 69 years, participated in this study. Of these participants, 94.2% had at least one solicited adverse event after the booster dose such as injection-site erythema (28.6%), swelling (25.6%), or pain (87.6%) or a systemic adverse event such as myalgia (61.0%), headache (53.2%), malaise (38.2%), or fever (6.5%). These adverse events were slightly more frequent than after the initial dose. Postvaccination, 100% of participants had a tetanus antibody level ≥0.10 IU/mL and 95% had a diphtheria antibody level ≥0.10 IU/mL. For pertussis, 82.1% (pertussis toxoid), 96.7% (filamentous hemagglutinin), 95.6% (pertactin), and 99.8% (fimbriae) had a postvaccination antibody threshold of ≥50 EU/mL.

Conclusion

A second dose of Tdap vaccine 5 years after the initial dose was well tolerated and immunogenic in adolescents and adults.     

Humoral immunity 10 years after booster immunization with an adolescent and adult formulation combined tetanus, diphtheria, and 5-component acellular pertussis vaccine

Persistence of antibodies after a single dose of Tdap vaccine (tetanus, diphtheria, and 5-component acellular pertussis vaccine) was evaluated in a follow-up study of adolescents (N=324) and adults (N=644) who had received Tdap in earlier clinical trials. Outcome measures were seroprotection (tetanus and diphtheria) or seropositivity (pertussis) and geometric mean concentrations. Humoral immune responses to all antigens were robust 1 month after initial immunization, decreased at subsequent measurements, but continued to exceed pre-immunization levels 1, 3, 5, and 10 years later. Protective levels of diphtheria and tetanus antitoxin persisted in 99.3% of adolescents 10 years after a booster dose of Tdap. Seropositivity to 1 or more pertussis antigens also persisted in most adolescents for 10 years. Although tetanus antitoxin responses were similar in adults to those observed in adolescents, diphtheria antitoxin titers were lower, reflecting the fact that a smaller proportion of adults had received diphtheria toxoid in the previous 10 years compared to adolescents. These data will contribute to the selection of the optimal interval for repeat doses of Tdap.     

Humoral immunity 5 years after booster immunization with an adolescent and adult formulation combined tetanus, diphtheria, and 5-component acellular pertussis vaccine

Persistence of antibodies following a single dose of Tdap vaccine (tetanus, diphtheria, and five-component acellular pertussis vaccine for use in individuals past childhood) was evaluated in a follow-up of adolescents (N=324) and adults (N=644) who had received Tdap in earlier clinical trials. Outcome measures were seroprotection (tetanus and diphtheria) or seropositivity (pertussis) and geometric mean titers. Humoral immune responses to all antigens were robust 1 month after initial immunization; antibodies exceeded pre-immunization levels 1, 3, and 5 years later. These data will contribute to selecting the optimal interval for booster doses of Tdap.     

The impact of adolescent pertussis immunization, 2004-2009: lessons from Australia

Objective

To compare the impact of three strategies for delivering a booster dose of adult-formulated tetanus–diphtheria–pertussis (Tdap) vaccine to adolescents in Australia. These comprise: (i) administering Tdap to: a one-year age cohort; (ii) administering Tdap to the entire high school and to subsequent entrant cohorts; and (iii) administering Tdap to the entire high school but without continuing to immunize entrant cohorts.

Methods

A series of ecologic analyses of pertussis notifications during epidemic periods in relevant age cohorts were conducted. The primary outcome measure was the incidence rate ratio (IRR), calculated by dividing pertussis incidence after the introduction of Tdap delivery programmes by pertussis incidence during the most recent pre-programme epidemic.

Findings

During the epidemic period of 2008–2009, the national-level IRR among age cohorts targeted for Tdap was 0.6 (95% confidence interval, CI: 0.6–0.7), but among other age cohorts it was 1.1 (95% CI: 1.1–1.2). Only the jurisdiction that implemented strategy 2 (Western Australia) experienced sustained decreases in pertussis notifications in both adolescents and infants under 6 months of age (IRR: 0.4; 95% CI: 0.3–0.6) until 2009.

Conclusion

If confirmed by longer experience in Australia and elsewhere, a broad school-based catch-up programme followed by immunization of school entrants may be the optimum strategy for the implementation of adolescent Tdap programmes.     

Pregnant women's intention to take up a post-partum pertussis vaccine,and their willingness to take up the vaccine while pregnant: A cross sectional survey

Introduction

Post-partum vaccination of new mothers is currently recommended in Australia to reduce pertussis infection in infants. Internationally, vaccination recommendations now include pregnant women in some countries. Understanding the awareness of pertussis vaccination recommendations among pregnant women, and their willingness to have the vaccine while pregnant is important for informing vaccine program implementation.

Objective

To determine awareness and intentions toward current recommendations for post-partum pertussis vaccination among Australian pregnant women, and their willingness to accept pertussis vaccine during pregnancy, should it be recommended in Australia in the future.

Design

Quantitative self-administered survey, using a non-random stratified sampling plan based on representative proportions by age, parity and region of residence.

Participants and setting

Pregnant women receiving antenatal care through three large, demographically diverse referral hospitals in metropolitan, urban and rural New South Wales, Australia.

Results

The response rate was 815/939 (87%). Most women (80%) reported willingness to have the pertussis vaccine during pregnancy, should it be recommended. Thirty four per cent of women intended to receive a pertussis vaccine post-partum, 17% had received it previously, while 45% had never heard of pertussis vaccine, had not thought about it, or were undecided about having it. Compared with those who had not received a recommendation to have the vaccine post-partum, women who had received a recommendation were 7 times more likely (95% CI 4–14) to report intention to have the vaccine.

Conclusions

Health care provider recommendation is paramount to raising awareness of pertussis vaccination recommendations among pregnant women. Women's willingness to have the vaccine while pregnant is encouraging, and indicates the potential for high pertussis vaccine coverage among pregnant women, should it be recommended in Australia.     

Connaissance et application des recommandations vaccinales concernant la coqueluche par la médecine du travail des établissements de santé de Paris

Objective

A questionnaire was used on 44 public and private hospital physicians in Paris to evaluate their knowledge of and adherence to Vaccination Guidelines, three years after their introduction.

Results

Eighty per cent of the physicians answered and 92.5% were aware of the vaccination guidelines but only 2 out of 4 respected the targeted vaccination in young adults even when the vaccine was available. A policy of pertussis vaccination was applied only in 12 institutions, but even in these, the rate of vaccinated healthcare workers remained low or was not documented.

Conclusion

Pertussis is a potential risk to newborns not or partially vaccinated in France. Even if the vaccine is available, adherence to pertussis vaccination guidelines must be improved. Efforts should be made to better publicize and apply pertussis vaccination guidelines.