Reactogenicity and immunogenicity of a booster dose of a combined diphtheria, tetanus, and tricomponent acellular pertussis vaccine at fourteen to twenty-eight months of age

Review of scientific evidence to support recommendations of the full-dose DTaP-IPV vaccination in pre-school age children in Italy

INTRODUCTION

Two vaccine formulations are available to prevent diphtheria, tetanus, pertussis, and poliomyelitis: the pediatric full-dose (DTaP-IPV) and the reduced dose formulation (dTap-IPV). Different immunization schedules are internationally recommended for the pre-school booster dose.

AREAS COVERED

International and Italian recommendations, scientific evidence on immunogenicity and safety of DTaP/dTap vaccines to support the full dose as a pre-school booster and Italian vaccination coverage (VC) up to adolescence.

EXPERT OPINION

The WHO recommends a '3+1' schedule with DTaP vaccine for primary immunization, followed by a pre-school booster with DTaP or dTap vaccine. In Italy, a '2+1' schedule, with no booster in the second year, and a pre-school booster dose are recommended with DTPa-IPV vaccines. Studies showed a non-inferior immunogenicity in dTap vaccinees in pre-school age; nevertheless, the antibody titers were usually greater in children vaccinated with DTaP, while lower frequencies of adverse events were recorded in children receiving dTap. Italian VCs for pre-school and adolescent boosters have not been satisfactory, which further reduced during the COVID-19 period. In Italy, the pre-school booster offers the last chance to receive a full dose of DTaP vaccine, thus, representing the most suitable intervention to provide lasting protection in children.

Diagnosis and management of hypersensitivity reactions to vaccines

INTRODUCTION

Many countries in Europe now recommend and enforce mandatory vaccinations to improve vaccination coverage. Thus, the number of adverse events following immunization (AEFI) may show an increase. Among these events, severe hypersensitivity reactions to vaccines are rare. However, it is important that they be identified and recognized so that they may be adequately managed.

AREAS COVERED

The literature search was undertaken through PubMed and Embase to identify English-language papers focusing on hypersensitivity to vaccines.

EXPERT OPINION

Hypersensitivity reactions following vaccinations are rare and are classified according to their chronology and extension: immediate when they occur within the first 4 hours following administration and non-immediate when they occur later. Local reactions are the most common adverse event following injection of vaccines and generally do not require any allergy workup. Immediate reactions, however, are potentially IgE-mediated and require an allergy workup. In general, a previously known food allergy (i.e., egg or milk) is not a contraindication to immunizations. Patients with a known allergy to gelatin, yeast, latex, antibiotics, or other specific components of vaccines require an allergy workup before administration of the vaccine.

A phase 2 study of a combined diphtheria-tetanus-acellular pertussis vaccine with a Sabin-derived inactivated poliovirus vaccine in children

Background: With the goal of global eradication of poliomyelitis due to wild-type viruses within sight, WHO now recommends that infants receive at least one dose of trivalent inactivated poliovirus vaccine (IPV) with bivalent OPV (types 1 and 3) replacing trivalent OPV. Limited manufacturing capacity and new regulations on manufacturers' use of wild-type viruses is driving the development of IPV based on attenuated Sabin type polioviruses. Takeda are developing a Sabin-based IPV (sIPV) to augment global capacity and supply. Methods: This study was performed to evaluate three dosages (low, medium and high) of the sIPV when administered as a combination vaccine with diphtheria-tetanus-acellular pertussis antigens (DTaP-sIPV) as a three dose primary series or as booster dose in Japanese infants and toddlers. Results: All formulations were immunogenic and well-tolerated with no safety concerns in either infants or toddlers. There was a dosage-dependent induction of neutralizing antibodies against Sabin polioviruses, the only statistically significant differences being between the low-dose and medium- and high-dose sIPVs. There was good correlation of neutralizing antibodies against Sabin and wild-type polioviruses. No sIPV dose had an observable effect on immune responses to DTaP components or the reactogenicity profile of the combined vaccine. Conclusion: When administered as a DTaP-sIPV combination, Takeda's sIPV vaccine was well-tolerated and highly immunogenic in infant and toddler schedules. The medium-dose formulation offers the optimal balance between immunogenicity and potential dose-sparing to provide a new source of sIPV to enhance the global supply, while mitigating the environmental risks associated with manufacturing vaccines with wild-type viruses.

Pertussis: Microbiology, Disease, Treatment, and Prevention

Pertussis is a severe respiratory infection caused by Bordetella pertussis, and in 2008, pertussis was associated with an estimated 16 million cases and 195,000 deaths globally. Sizeable outbreaks of pertussis have been reported over the past 5 years, and disease reemergence has been the focus of international attention to develop a deeper understanding of pathogen virulence and genetic evolution of B. pertussis strains. During the past 20 years, the scientific community has recognized pertussis among adults as well as infants and children. Increased recognition that older children and adolescents are at risk for disease and may transmit B. pertussis to younger siblings has underscored the need to better understand the role of innate, humoral, and cell-mediated immunity, including the role of waning immunity. Although recognition of adult pertussis has increased in tandem with a better understanding of B. pertussis pathogenesis, pertussis in neonates and adults can manifest with atypical clinical presentations. Such disease patterns make pertussis recognition difficult and lead to delays in treatment. Ongoing research using newer tools for molecular analysis holds promise for improved understanding of pertussis epidemiology, bacterial pathogenesis, bioinformatics, and immunology. Together, these advances provide a foundation for the development of new-generation diagnostics, therapeutics, and vaccines.

Vaccine allergy

Overdiagnosis of vaccine allergy is considered a major public health problem. This article discusses the different types of allergic reactions after immunization based on the timing (immediate vs nonimmediate) and the extent of the reaction (local vs systemic). The vaccine components potentially responsible for an allergic reaction are discussed, as well as the management of patients with a history of reaction to a specific vaccine and those with a history of allergy to one of the vaccine components.

Managing a child with possible allergy to vaccine

Similarly to other medications, vaccines may be responsible for allergic reactions. Although IgE-mediated allergies to vaccine are extremely rare, they are clearly overdiagnosed. Indeed, accurate diagnosis of vaccine allergy is important not only to prevent serious or even life-threatening reactions, but also to avoid unnecessary vaccine restriction. Systematic approaches have been proposed and, if implemented, will likely reduce the number of children being inappropriately labeled as allergic to vaccine. In diagnosis of vaccine allergy, the patient's history is central although not sufficient. In case of suspicion of an allergy, the child should be referred to an allergist in order to perform a complete allergy workup, based primarily on skin tests and/or specific IgE. Highlighting the most recent literature, this article will address the management of children with a possible allergy to vaccine.

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.

Combination vaccines

The combination of diphtheria, tetanus, and pertussis vaccines into a single product has been central to the protection of the pediatric population over the past 50 years. The addition of inactivated polio, Haemophilus influenzae, and hepatitis B vaccines into the combination has facilitated the introduction of these vaccines into recommended immunization schedules by reducing the number of injections required and has therefore increased immunization compliance. However, the development of these combinations encountered numerous challenges, including the reduced response to Haemophilus influenzae vaccine when given in combination; the need to consolidate the differences in the immunization schedule (hepatitis B); and the need to improve the safety profile of the diphtheria, tetanus, and pertussis combination. Here, we review these challenges and also discuss future prospects for combination vaccines.

Review of 8 years of experience with Infanrix hexa (DTPa-HBV-IPV/Hib hexavalent vaccine)

Combination vaccines that include multiple antigens within one formulation are now widely accepted as an effective means of eliciting protection against several diseases at the same time. Owing to improvements in quality and convenient modes of administration, they have become part of routine pediatric practice. Hexavalent vaccines, including diphtheria, tetanus, pertussis, hepatitis B, polio and Haemophilus influenzae type b antigens represent the latest advance in the development of combination vaccines. Over 8 years since its first licensure, this review looks at the immunogenicity, efficacy and safety profile of the only hexavalent pediatric vaccine currently in use--Infanrix hexa (diphtheria, tetanus, acellular pertusis-hepatitis B virus-inactivated poliovirus vaccine/Haemophilus influenzae type b vaccine [DTPa-HBV-IPV/Hib]; GlaxoSmithKline Biologicals, Rixensart, Belgium)--through published clinical trials and postmarketing surveillance data. These data show DTPa-HBV-IPV/Hib to be highly immunogenic and well tolerated across a range of different primary and booster vaccination schedules, as well as when administered concomitantly with other licensed vaccines (e.g., pneumococcal conjugate vaccine). Additional issues surrounding the use of hexavalent vaccines are also reviewed.

Kinrix: a new combination DTaP-IPV vaccine for children aged 4-6 years

Combination vaccines allow the administration of multiple vaccine antigens without the need for multiple injections. Recently, a combined diphtheria toxoid, tetanus toxoid, acellular pertussis and inactivated poliomyelitis vaccine (DTaP-IPV), Kinrix, has been licensed in the USA for use as the fifth DTaP dose and fourth IPV dose in children 4-6 years of age. Clinical trials have shown Kinrix to be immunogenic in 4-6-year-old children, with a safety profile comparable with that of separate DTaP and IPV vaccination. The use of Kinrix reduces by one the number of injections required to provide this age group with all recommended immunizations. Strategies such as the use of combined vaccines can help to maintain high levels of coverage against diphtheria, tetanus, pertussis and poliomyelitis diseases.

Tetanus-diphtheria-acellular pertussis vaccination of adults in the USA

Pertussis is an important cause of morbidity and mortality, and its incidence has been increasing in adolescents and adults over the past two decades. Waning immunity in adolescents and adults may be partially responsible. Adults can suffer significant illness from pertussis and its complications, such as pneumonia, rib fractures and syncope. Moreover, adults serve as a source of disease for infants, who are more vulnerable to severe complications and even death. The economic burden of pertussis is substantial, in terms of both medical and nonmedical costs. Fortunately, the burden of pertussis disease can now be safely and effectively reduced by vaccinating adults with tetanus-diphtheria-acellular pertussis (Tdap) vaccine. Further research is needed to elucidate the role of vaccination in pregnant women and those over 65 years of age, and also to determine whether further booster doses of Tdap are needed.

Safety of a fifth dose of diphtheria and tetanus toxoid and acellular pertussis vaccine in children experiencing extensive, local reactions to the fourth dose

Extensive local reactions have been reported after booster doses of diphtheria and tetanus toxoid and acellular pertussis vaccine, but few data are available on revaccination after these reactions. Of 20 children with extensive local reactions after dose 4, only 4 experienced entire upper arm swelling and 7 had swelling >5 cm after dose 5. These reactions were well tolerated and support revaccination.

Neonatal vaccination with an acellular pertussis vaccine accelerates the acquisition of pertussis antibodies in infants

OBJECTIVES

Because young infants are at highest risk of pertussis complications, this study assessed whether neonatal acellular pertussis (aP) vaccination could provide earlier immunity.

STUDY DESIGN

Neonates (n = 121) were randomly assigned (1:1) to receive either aP or hepatitis B vaccine (HBV) (controls) vaccine at birth, followed by vaccination with DTaP-HBV-IPV/Hib at 2, 4 and 6 months. Immune responses were measured. Reactogenicity was assessed for 7 days after each dose.

RESULTS

The aP birth dose was followed by few adverse events. Reactogenicity of subsequent vaccine doses did not differ between groups. Seven serious adverse events were reported from each group; none were related to the study vaccines. At 3 months of age, vaccination with aP at birth had induced significantly higher antibody responses to the 3 pertussis antigens compared with controls. At 7 months, geometric mean/concentrations of antibodies against pertussis antigens were similar in both groups, and all subjects had reached "seroprotective" antibody concentrations against diphtheria, tetanus, and poliovirus types 1, 2, and 3. Geometric mean/concentrations of antibodies to haemophilus influenzae type b (Hib) and HBV were significantly lower in the aP group.

CONCLUSIONS

Early neonatal immunization with aP was safe, well tolerated, and resulted in earlier antibody responses, seen after the first dose of a DTaP combination vaccine. Birth dose of aP did not induce immunologic tolerance to pertussis antigens but appear to dampen responses to Hib and HBV vaccines.

Pertussis booster vaccination in HIV-infected children receiving highly active antiretroviral therapy

OBJECTIVE

Our goal was to evaluate the immunogenicity and safety of pertussis booster vaccination in children infected with HIV on highly active antiretroviral therapy (HAART).

PATIENTS AND METHODS

HIV-infected children on stable HAART for > or = 3 months with plasma HIV-RNA concentrations of < 30,000 to 60,000 copies per mL who previously received > or = 4 doses of diphtheria-tetanus-pertussis (DTP)-containing vaccine were eligible. Diphtheria-tetanus-acellular pertussis (DTaP) vaccine was administered to subjects 2 to < 7 years old who had 4 previous DTP-containing vaccines, subjects 2 to < 7 years old who had > or = 5 previous DTP-containing vaccines and negative tetanus antibody, and subjects > or = 7 to < or = 13 years old who had negative tetanus antibody. Pertussis toxin and filamentous hemagglutinin antibodies were measured before and 8, 24, and 72 weeks after DTaP vaccine.

RESULTS

Ninety-two subjects received DTaP vaccine and met criteria for analysis. Antibody concentrations were low at entry: pertussis toxin geometric mean concentration at 4.8 enzyme-linked immunosorbent assay units (EU) per mL and filamentous hemagglutinin geometric mean concentration at 4.1 EU/mL. Pertussis toxin and filamentous hemagglutinin geometric mean concentrations rose to 22.3 and 77.0 EU/mL, respectively, 8 weeks after the study DTaP vaccine. Antibody concentrations fell by 24 weeks after vaccination but remained higher than before vaccination. Predictors of response 8 weeks after DTaP vaccine included the concentration of homologous antibody, lower HIV-RNA level, and higher CD4 percentage at entry. One vaccinated subject experienced erythema and induration of > or = 25 mm.

CONCLUSIONS

A DTaP vaccine booster was well tolerated by children on HAART and induced increases in antibodies. Antibody concentrations after vaccination were lower than those reported in populations uninfected by HIV. Although comparison among studies must be made with caution, these data suggest that children infected with HIV may be deficient in immunologic memory from previous DTP-containing vaccination and/or that immune reconstitution with HAART may be incomplete for pertussis antigens.

Safety and immunogenicity of a fully liquid vaccine containing five-component pertussis-diphtheria-tetanus-inactivated poliomyelitis-Haemophilus influenzae type b conjugate vaccines administered at two, four, six and 18 months of age

OBJECTIVE

The safety, immunogenicity and lot consistency of a fully liquid, five-component acellular pertussis combination vaccine, comprised of diphteria, tetanus and acellular pertussis, inactivated polio vaccine, Haemophilus influenzae type b (DTaP-IPV-Hib [Pediacel, sanofi pasteur, Canada]) were assessed and compared with that of Hib vaccine reconstituted with the five-component acellular pertussis combination vaccine (DTaP-IPV//Hib, Pentacel [sanofi pasteur, Canada]).

METHODS

Infants were recruited at vaccine study centres in Montreal, Quebec; Simon Fraser Health Region, British Columbia, and southern Alberta after the protocol had been approved by the relevant institutional ethics committees. Written informed consent was obtained from the parents or guardians of all subjects. At two months of age, the infants were randomly assigned to receive one of three consecutive production lots of DTaP-IPV-Hib by intramuscular injection. Reactions to vaccinations were assessed by parental observation and through telephone interviews conducted by study nurses. Blood samples were obtained at two, six, seven, 18 and 19 months of age for measurement of antibodies to vaccine antigens.

RESULTS

Most injection site and systemic reactions were mild or moderate, and of brief duration. All infants were protected against tetanus, diphtheria and all three polio serotypes after both primary and booster vaccinations. Antibody responses to pertussis antigens were similar to those observed in Swedish infants, in whom the five-component vaccine was shown to be 85% effective. Proportions of infants with antipolyribosylribitol phosphate antibody of 0.15 mug/mL or greater and 1.0 mug/mL or greater, were 97.9% and 88.9%, respectively, following primary immunization, and 100% and 99% following booster vaccination. Safety and immunogenicity results with both reconstituted and fully liquid combination vaccines were comparable.

CONCLUSIONS

The fully liquid combination vaccine was comparable in terms of safety and immunogenicity with the reconstituted combination vaccine.

Booster immunization with a hexavalent diphtheria, tetanus, acellular pertussis, hepatitis B, inactivated poliovirus vaccine and Haemophilus influenzae type b conjugate combination vaccine in the second year of life: safety, immunogenicity and persistence of antibody responses

The immunogenicity and reactogenicity of booster vaccination with GSK Biologicals' hexavalent DTPa-HBV-IPV/Hib vaccine was assessed in toddlers aged 12-18 months previously primed with the same combination (N=341), or with DTPa-IPV/Hib and HBV administered separately (N=102; Trials 217744/059 and 217744/096). Antibody persistence at age 4-6 years was also assessed in children who had received a 4th consecutive dose of DTPa-HBV-IPV/Hib vaccine or separate DTPa-IPV/Hib and HBV vaccines in this study and in another study conducted under similar conditions in Germany. Prior to booster vaccination in the second year of life, antibody concentrations and seroprotection rates were similar irrespective of the primary vaccine used. One month after boosting with DTPa-HBV-IPV/Hib, substantial antibody increases were observed against all vaccine antigens indicative of previous immune priming. Seropositivity and booster response rates against all antigens were 97.4-100%. Reactogenicity following booster vaccination with DTPa-HBV-IPV/Hib was similar regardless of the primary regimen used. Three to four years after administration of the 4th DTPa-HBV-IPV/Hib dose, >90% vaccinees had persistent protective antibody concentrations against diphtheria, hepatitis B, Hib and the three poliovirus types. Anti-tetanus antibody concentrations were > or = 0.1 IU/ml in 76.4% subjects and seropositivity for pertussis antibodies ranged from 34.5% for PT to 98.9% for FHA. In conclusion, the combined hexavalent DTPa-HBV-IPV/Hib vaccine is immunogenic and safe when used for boosting in the second year of life, regardless of the primary vaccine used, and offers sustained protection during early childhood and beyond.

Reactogenicity and immunogenicity profiles of a novel pentavalent diphtheria-tetanus-whole cell pertussis-hepatitis B and Haemophilus influenzae type B vaccine: a randomized dose-ranging trial of the Hib tetanus-conjugate content

BACKGROUND

Combined vaccines containing diphtheria-tetanus-pertussis whole-cell (DTPw), Haemophilus influenzae type b (Hib), and hepatitis-B vaccines are essential for the continuing success of vaccination programs in developing nations. This randomized, dose-ranging study assessed the immunogenicity and reactogenicity of primary and booster vaccination with pentavalent DTPw-HBV/Hib vaccines containing 10, 5 or 2.5 microg of polyribosylribitol phosphate (PRP) conjugated to tetanus toxoid (trials Hib-052/064).

METHODS

Six hundred eighty infants were randomized to receive one of 5 vaccine combinations at 6, 10, and 14 weeks of age. Of these, 351 received the same vaccine at 15-24 months of age. The immune response was evaluated on blood samples collected 1 month after the 3-dose primary course and before and 6 weeks after the booster dose. Reactogenicity was assessed during a 4-day period after each vaccine dose using diary cards.

RESULTS

After primary vaccination, all subjects had seroprotective anti-PRP antibody concentrations (> or = 0.15 microg/mL) and > 95% had concentrations > or = 1.0 microg/mL, irrespective of the PRP dose administered. Anti-PRP antibody avidity after primary vaccination and antibody persistence until the second year of life were similar among groups. The booster dose induced marked increases in anti-PRP antibody GMCs and antibody avidity, indicative of effective priming and the presence of immune memory. All vaccination regimens elicited good immune responses and comparable antibody persistence to the other vaccine antigens, with significant increases in all antibody concentrations observed after boosting. All vaccination regimens were safe, with similar overall reactogenicity profiles.

CONCLUSION

Hib conjugate vaccines containing reduced amounts of PRP can be effectively combined with the licensed DTPw-HBV vaccine to provide protection against 5 major childhood pathogens in a single injection.

Assessment of nine candidate DTP-vaccines with reduced amount of antigen and/or without adjuvant as a fourth (booster-) dose in the second year of life

BACKGROUND

The incidence of local reactions to diphtheria-, tetanus and acellular pertussis (DTaP-) vaccines in infants and toddlers increases with each subsequent dose, and entire thigh swellings (ETS) have been reported. Lowering the amount of antigen or of adjuvant may decrease the reactogenicity of DTaP while maintaining a protective immune response.

OBJECTIVES

Following priming with three doses of a DTaP vaccine during infancy, the safety, reactogenicity and immunogenicity of nine different candidate DTaP-vaccines with reduced amounts of antigen and/or adjuvant given as fourth (booster) dose were evaluated.

METHODS

Study participants were healthy infants aged 15-27 months at the time of booster vaccination. Each participant had received three doses of a DTaP vaccine (Infanrixtrade mark, GlaxoSmithKline, Rixensart, Belgium; "reference DTaP") at age 3, 4, and 5 months as part of a previous clinical trial. More than 20,000 children were eligible for participation in the current study protocol at the time. In a first phase at a University hospital-based vaccination study center, nine sequential cohorts of 63-119 study subjects received one of nine different candidate vaccines. Patients and study personal were blinded with regard to which vaccine was currently in use. Reactogenicity was solicited from parents using diary cards. Blood was drawn prior to and 4 weeks after vaccination and immediately centrifuged. The serum was stored at -20 degrees C until serology was performed by ELISA tests. As soon as the first candidate vaccine with adequate reactogenicity and immunogenicity profile was identified in the first study phase, a second study phase was initiated in parallel, to evaluate the safety and reactogenicity of the respective candidate vaccine in private practices in large cohorts (1613-2095 study subjects per group).

RESULTS

In the first study phase, DTaP with no aluminum induced the highest frequency of ETS and fever. All other candidate vaccines caused lower rates of local and general reactions than the reference DTaP. As a general rule, vaccines with less antigen induced fewer reactions, although there was no strict dose-response effect and the difference, e.g. between a one-tenth and a one-fifth DTaP dose (DTaP 1/5; DTaP 1/10) was not clinically relevant. Separate injections of Td and aP caused fewer general reactions than the respective TdaP combination and local reactions were higher at the aP than at the Td injection site. Again, as a general rule, reduced amounts of antigen induced lower antibody concentrations, although all vaccines induced "protective" anti-tetanus and anti-diphtheria antibody responses. A total of 92-100% of children showed seroresponses to pertussis antigens even when vaccinated with reduced amounts of the respective pertussis antigen. Elimination of aluminum from DTaP vaccine induced higher anti-tetanus-antibody concentrations and so did a reduction of the amount of diphtheria antigen. Additional examples for antigen interaction were increased antibody concentrations, observed with injection of Td and aP into different limbs. In the second study phase, all three vaccines evaluated (one with a reduced amount of diphtheria antigen, TdaP; one with reduced amounts of all antigens, tdap; and one with a fifth dose of the reference vaccine (DTaP 1/5)) were safe and had an acceptable reactogenicity profile in a total of 4871 study subjects.

CONCLUSIONS

Local reactions due to DTaP booster doses in the second year of life can be reduced by reducing the amount of antigen in the respective vaccine while an adequate immunogenicity is maintained. Aluminum-free vaccines induced ETS and fever most commonly. Any changes in vaccine composition should lead to a full evaluation of the new product.

Extensive swelling reaction associated with diphtheria and tetanus toxoids and acellular pertussis vaccine

Although extensive swelling reactions in the injected limb after the administration of diphtheria-tetanus toxoid-acellular pertussis vaccine have been reported previously, to our knowledge, computerized tomography images of this entity have not been published. A 4-year-old boy with extensive swelling after vaccination with diphtheria-tetanus toxoid-acellular pertussis vaccine is presented.

Safety and immunogenicity of a combined DTPa–IPV vaccine administered as a booster from 4 years of age: A review

A combined DTPa-IPV booster vaccine was administered as a 4th or 5th dose after DTPa or DTPw priming. Over 99% vaccines developed antibody levels considered to be protective to diphtheria, tetanus and poliovirus, and >95% mounted a response to acellular pertussis antigens. Rectal temperature >39.5 degrees C was observed in at most 3.2% of vaccinees. Swelling >50 mm occurred in 24% of DTPa-primed compared to 5.5% of DTPw-primed children. Large swelling involving the entire upper arm (extending to involve the elbow joint) was reported for up to 1.2% of DTPa-primed subjects, which is consistent with literature reports for other DTPa vaccines.

Immunogenicity and reactogenicity of a reduced-antigen-content diphtheria-tetanus-acellular pertussis vaccine in healthy Taiwanese children and adolescents

PURPOSE

Disease caused by Bordetella pertussis is increasingly being identified among older children and adults in immunized populations, indicating a waning of the vaccine-induced immunity. These findings suggest the need for booster immunization of older children and adults. Modern acellular reduced-antigen-content vaccines have been developed, which can be given as a booster in individuals more than 4 years of age. This study was to assess the immunogenicity and reactogenicity of Boostrix, GlaxoSmithKline Biologicals' reduced-antigen-content diphtheria-tetanus acellular pertussis (dTpa) vaccine, when administered as a booster in healthy subjects previously primed with DTP vaccine.

METHODS

Healthy Taiwanese children and adolescents aged 6-8 years and 15-20 years, previously primed with DTP vaccine, were enrolled. All received one dose of Boostrix. Two blood samples were taken from each of them, one before vaccination and one at 1 month after vaccination. Serum antibodies to diphtheria and tetanus toxoids and immunoglobulin G (IgG) antibodies against the pertussis components PT, FHA and PRN were measured by enzyme-linked immunosorbent assay (ELISA) technique. Adverse reactions following vaccination were recorded.

RESULTS

A total of 180 subjects were recruited. The vaccine response rates to the pertussis antigens ranged between 89.0-100%. There were no serious adverse events reported during the study period.

CONCLUSIONS

The results of this study suggest that Boostrix may be safely and effectively administered as a booster dose to children previously primed with DTP vaccine.

Acellular pertussis vaccines for adolescents

BACKGROUND

The epidemiology of pertussis is changing, with a clear increase in the number of cases diagnosed in adolescents and adults. This development has spurred studies and anticipated licensure of safer diphtheria, tetanus, acellular pertussis combined (Tdap) vaccines for this older population.

METHODS

Literature review.

RESULTS

Tdap vaccines are safe and immunogenic when administered to adolescents and adults. Correlates of immunity to pertussis after Tdap vaccination have not been established, but various combinations of antibody to pertussis antigens (pertussis toxin, filamentous hemagglutinin, pertactin, and fimbriae) provide protection. The importance of the number of antigens in Tdap vaccines for protection against mild pertussis disease is unclear. Pertussis vaccination establishes herd immunity after sufficient uptake within communities and countries. As experience with TdaP vaccines has accumulated, a 1-2% occurrence of large, local injection-site reactions with all TdaP vaccine products have been observed for booster doses in children 4-6 years of age. The frequency of large local reactions appears lower in adolescents and adults. The pathophysiologic mechanisms for the local reactions are not established, but a majority appears to be immunoglobulin E-mediated-reactive edema, and a minority appears to be immunoglobulin G-mediated Arthus-type reactions.

CONCLUSIONS

Tdap vaccines appear safe and immunogenic. The economic impact of pertussis provides a cost-benefit justification for widespread use of Tdap vaccine boosting in adolescents.

Molecular pathogenesis, epidemiology, and clinical manifestations of respiratory infections due to Bordetella pertussis and other Bordetella subspecies

Bordetella respiratory infections are common in people (B. pertussis) and in animals (B. bronchiseptica). During the last two decades, much has been learned about the virulence determinants, pathogenesis, and immunity of Bordetella. Clinically, the full spectrum of disease due to B. pertussis infection is now understood, and infections in adolescents and adults are recognized as the reservoir for cyclic outbreaks of disease. DTaP vaccines, which are less reactogenic than DTP vaccines, are now in general use in many developed countries, and it is expected that the expansion of their use to adolescents and adults will have a significant impact on reducing pertussis and perhaps decrease the circulation of B. pertussis. Future studies should seek to determine the cause of the unique cough which is associated with Bordetella respiratory infections. It is also hoped that data gathered from molecular Bordetella research will lead to a new generation of DTaP vaccines which provide greater efficacy than is provided by today's vaccines.

Booster vaccination with hexavalent DTPa-HBV-IPV/Hib vaccine in the second year of life is as safe as concomitant DTPa-IPV/Hib + HBV administered separately

The safety and reactogenicity of a booster dose of GSK Biologicals' hexavalent DTPa-HBV-IPV/Hib vaccine (N=4725) was compared with the separate administration of GSK Biologicals' DTPa-IPV/Hib and HBV vaccines (N=4474) in two open, randomized multicenter studies (A and B). Solicited symptoms occurring within 4 days of vaccination were recorded on diary cards and serious adverse events (SAEs) were collected throughout the study period. In Study A (N=1149), incidences of solicited symptoms were similar in both groups; there were no SAEs either reported within 4 days of vaccination or considered to be causally related to vaccination. In study B (N=8050), where fever was the only solicited symptom, rectal temperature > or =39.5 degrees C was observed in 2.5% and 2.8% of the subjects, respectively. Fever > or =40.0 degrees C was rare (0.6%), and only two cases of febrile convulsions were recorded during the 4 days following vaccination both in the control group. Large swelling reactions (defined as local injection site swelling with diameter >50 mm, noticeable diffuse injection site swelling or noticeable increased circumference of the injected limb) were reported following 2.3% of the booster vaccine doses, regardless of the vaccine used. Extensive swelling reactions involving an adjacent joint were reported in 0.1% of the subjects. Two SAEs, both reported after booster doses of DTPa-IPV/Hib and HBV vaccines administered separately, were considered by the investigators to be related to vaccination. Both resolved completely without sequelae. The hexavalent DTPa-HBV-IPV/Hib vaccine and the DTPa-IPV/Hib and HBV vaccines administered separately have similar good reactogenicity and safety profiles when given as booster doses in the second year of life.

Acellular Pertussis Vaccine Safety and Efficacy in Children, Adolescents and Adults

This review offers a perspective on the acellular pertussis vaccine efficiency trials concluded in the 1990s and presents the main conclusions of a meta-analysis of 52 studies that assessed the safety and efficacy of the diphtheria-tetanus (DT)-whole cell pertussis (DTwP) and DT-acellular pertussis (DTaP) vaccines administered to children. A clear serological correlate of immunity to pertussis following DTaP vaccination was not identified despite an intensive analysis. It can be speculated that this may be because various combinations of antibody to agglutinogens (pertussis toxin, filamentous haemagglutinin, pertactin and fimbriae) provide protection, or because serum antibody levels and responses do not uniformly reflect mucosal IgA antibody levels.Long-term efficacy following DTaP vaccination is becoming characterised and cell-mediated immunity (T-cell memory) may have importance. DTaP vaccination appears to establish herd immunity after sufficient uptake within communities and countries. As experience with DTaP vaccine safety has accumulated, a 1-2% occurrence of large, local injection reactions with all products has been defined for booster doses. The pathophysiological mechanisms for the reactions are not established but a majority appear likely to be IgE-mediated reactive oedema and a minority to be IgG-mediated reactive Arthus-type reactions. DTwP and DTaP combinations with other vaccines have been studied and licensed; the most controversial combination products are the DTaP/Haemophilus influenzae type B polysaccharide conjugate vaccines. Pertussis epidemiology is changing with a clear increase in occurrence in adolescents and adults. This development has spurred studies and licensure of safer DTaP vaccines for this older population. The economic impact of pertussis and transmission from adults to vulnerable infants provides a cost-benefit justification for widespread use of DTaP vaccines in all age groups with routine boosting every 10 years.

Mycoplasma pneumoniae and Legionella pneumophila in community-acquired lower respiratory tract infections among hospitalized children: diagnosis by real time PCR

Mycoplasma pneumoniae and Legionella pneumophila are increasingly recognized as important agents of community-acquired lower respiratory tract infections (LRTI). Mycoplasma pneumoniae has been also recognized as a cause of nosocomial infections. The aim of this study was to investigate the role of real time polymerase chain reaction (PCR) for the rapid diagnosis of these infections among hospitalized children with community-acquired LRTI. During 2001, 65 children were prospectively studied. Microbiological investigation consisted of capillary PCR with a LightCycler for M. pneumoniae and L. pneumophila in induced sputum or throat swab specimens, IgM enzyme immunoassay for M. pneumoniae and immunofluorescence for L. pneumophila in paired sera. Serology testing showed acute M. pneumoniae infection in 18 (27.5%) patients and L. pneumophila in 1 (1.5%). M. pneumoniae was also detected in sputum specimen by capillary PCR in 9 (50%) serologically diagnosed cases, including 4 (22%) with non-diagnostic IgM levels in the acute phase. Capillary PCR and IgM enzyme immunoassay diagnosed together 15 (83%) M. pneumoniae cases in the acute phase. It is concluded that M. pneumoniae is an important cause of LRTI necessitating hospitalization among children in Greece. Capillary PCR in sputum may diagnose M. pneumoniae LRTI in the acute setting and direct therapy and isolation of patients.

Antibody persistence against diphtheria, tetanus, pertussis, poliomyelitis and Haemophilus influenzae type b (Hib) in 5–6-year-old children after primary vaccination and first booster with a pentavalent combined acellular pertussis vaccine: immunogenicity and tolerance of a tetravalent combined acellular pertussis vaccine given as a second booster

The main objective of this study was to assess in 5-6-year-old French children (n=234) the persistence of antibodies induced by a primary series vaccination (at 2-4 months of age) and a first booster (at 12-16 months of age) with a pentavalent two-component acellular pertussis combined vaccine (DTacP-IPV-Hib; Pentavac). The second objective was to evaluate in these 5-6-year-old French children the safety and the immunogenicity of a tetravalent acellular pertussis combined vaccine (DTacP-IPV; Tetravac) given as second booster.

RESULTS

Seroprotective antibody levels against diphtheria, tetanus, types 1-3 poliomyelitis and PRP were maintained 4-5 years after primary-vaccination and first booster with Pentavac. As expected, anti-PT antibodies levels were low, suggesting that children were not colonised by Bordetella pertussis. The second booster with Tetravac was well tolerated and elicited a strong booster response for all antigens.

CONCLUSION

acellular pertussis combined vaccine, used in primary-vaccination, could be considered as having the same priming effect and the same efficacy as whole cell pertussis vaccine.

Local reactions after the fourth dose of acellular pertussis vaccine in South Australia

OBJECTIVE

To assess the reported rate of local reactions after administration of acellular pertussis vaccine (DTPa) according to dose number and type of pertussis vaccine (whole-cell or acellular) used for the primary course, and to document the severity and outcome of fourth-dose local reactions.

DESIGN AND SETTING

Retrospective review. Reports of adverse events after vaccination in South Australia between 1 January 1997 and 31 December 2000 were reviewed, and a questionnaire administered to all parents who reported a local reaction after the fourth dose of DTPa.

MAIN OUTCOME MEASURES

The number, and rate per 100 000 administered doses, of local reactions following the primary and booster doses of DTPa, and of local reactions after the fourth-dose in cohorts of children whose primary vaccinations were with either DTPw or DTPa. Redness and/or swelling at the injection site as reported by parents.

RESULTS

Of 581 reported adverse events after vaccination, 138 were local reactions after a pertussis-containing vaccine. Primary vaccinations with DTPa was a significant risk factor for a fourth-dose local reaction (relative risk, 6.7; 95% CI, 2.4-18.5). Parental questionnaires were completed for 45 of the 71 children (63%) with reported local reactions after the fourth dose of DTPa; extensive limb swelling was reported in 8 children (18%) and all except one child had recovered by the time of review.

CONCLUSIONS

Parents should be informed that children receiving booster doses of DTPa vaccine, after primary doses with DTPa, are at increased risk of local reactions (which tend to resolve spontaneously) but not of systemic effects. Studies should be initiated to investigate the pathogenesis and the risk of recurrence of local reactions to further improve vaccination schedules.

Extensive swelling reactions occurring after booster doses of diphtheria-tetanus-acellular pertussis vaccines

Extensive local reactions are recognized to occur after administration of the fourth and fifth booster doses of diphtheria-tetanus-acellular pertussis (DTaP) vaccines. The incidence of these reactions is being delineated by prospective studies. Retrospective evaluations suggest that entire proximal limb swelling occurs in 2 to 6 percent of children given booster doses of DTaP vaccines. The reactions subside without sequelae, but they may be misdiagnosed as cellulitis and lead to unnecessary medical intervention. The pathogenesis of these reactions probably is multifactorial. Evidence suggests that both antigen content and prevaccination immunity have roles. Important, unanswered questions are the safety of revaccinating a child who previously has had an extensive local reaction and the safety of introducing further DTaP boosters into the adolescent and adult populations.

Nature, evolution, and appraisal of adverse events and antibody response associated with the fifth consecutive dose of a five-component acellular pertussis-based combination vaccine

We performed a randomized, controlled clinical trial to characterize the evolution of the adverse events associated with the fifth consecutive dose of an acellular pertussis vaccine, and to assess the level of discomfort associated with the injection and the attitude of parents concerning these events. A total of 505 children who had received either four doses of acellular pertussis vaccine or whole-cell pertussis vaccine were given a fifth dose of one of the two vaccines. Adverse events were monitored by parents and collected by telephone or home visit at 4, 8, 12, 24, 48 and 72 h, and 7 and 28 days after immunization. Rates of injection site redness >or=50mm were similar in recipients of five doses of acellular pertussis vaccine (32.8%) or five doses of whole-cell pertussis vaccine (43.3%). Injection site swelling, tenderness, and decreased arm movement were all more frequent in children who received five doses of whole-cell pertussis vaccine. Antibody levels before or after immunization did not predict those children who had increased injection site reactions. The children rated the injection site reactions as significantly more severe after five consecutive doses of whole-cell vaccine. Parent satisfaction was higher after the acellular vaccine. We conclude that a fifth consecutive dose of a whole-cell pertussis vaccine is associated with high rates of tender redness and swelling at the injection site, in contrast to a fifth consecutive dose of an acellular pertussis vaccine which is associated with high rates of non-painful redness. However, parents will still need to be aware of the high rates of injection site reactions expected after a fifth dose of acellular pertussis vaccine.

Development and clinical testing of multivalent vaccines based on a diphtheria-tetanus-acellular pertussis vaccine: difficulties encountered and lessons learned

The widespread use of whole-cell pertussis vaccines in the second half of the 20th century have reduced the incidence of the disease significantly. However, in some countries, concerns about the reactogenicity and potential neurological damage associated with whole-cell vaccines led to a decrease in vaccine acceptance and an increase in morbidity and mortality of pertussis in several countries. This prompted the development of less reactogenic acellular pertussis vaccines combined with diphtheria and tetanus toxoids, initially in Japan and later in other countries. In Europe, the improved diphtheria, tetanus and acellular pertussis (DTPa) vaccine was first introduced in March 1994. The pertussis component of this DTPa vaccine, developed by Glaxo SmithKline, consists of pertussis toxoid, filamentous haemagglutinin and pertactin. The vaccine is well tolerated, with a lower incidence of adverse reactions than after administration of whole-cell vaccines. The long-lasting efficacy and effectiveness of DTPa vaccines have been extensively documented and these are now the cornerstone of a large range of combined vaccines including DTPa-hepatitis B (HBV), DTPa-inactivated polio (IPV) and DTPa-HBV-IPV. A lyophilised Haemophilus influenzae type b (Hib) vaccine can be reconstituted with all of these liquid combinations. The introduction of well-tolerated and efficacious DTPa vaccines and their more polyvalent combinations has improved the acceptance and simplified the implementation of childhood immunisation. This paper is a review of the technical and scientific difficulties encountered and the lessons learned over the 10-year period that it took to develop and introduce six multivalent vaccines using the Glaxo SmithKline DTPa as a building block.

Which strategy for pertussis vaccination today?

Pertussis (whooping cough) remains an epidemic disease responsible for infant and child morbidity and mortality, and is perceived as a serious public health problem. Since the widespread use of whole-cell pertussis vaccines in the 1940s, vaccination programs have varied greatly between countries. National specificity is a function of several factors. The most important are: vaccine efficacy and tolerability;vaccine coverage and distribution; and vaccine acceptance by parents and professionals. During the 1970s, Sweden, England, Wales and Japan provided contrasting examples of the attitude of health authorities to the use of whole-cell vaccines. The increase in pertussis incidence was noted as a consequence of active opposition to this vaccine. The re-emergence of pertussis in the 1990s, in countries with high vaccination coverage and increased incidence of disease in individuals >15 years and <6 months of age, has drawn attention to the role of booster doses of pertussis vaccines and their introduction into regular vaccination programs. The use of acellular vaccines for booster doses for adolescents and adults would seem unambiguous because of their decreased reactogenicity, although the exact schedule has yet to be established. The choice between the two kinds of vaccines is more difficult for primary courses, where safety and efficacy profiles are similar, and the attitude towards acellular vaccines varies from country to country. In this case, the strategy adopted results from the national history of pertussis infection and from the quality of the available whole-cell vaccine. Two contrasting examples are the US, where acellular vaccines were licensed for the primary series in the 1990s, and the UK, where whole-cell vaccines are exclusively used for primary immunization. The changing epidemiology of pertussis, and its local diversification, would suggest that at present it is difficult to define a single worldwide strategy with only one kind of vaccine and one schedule. In order to control pertussis incidence, each country should continue to determine the best national vaccination program established in very close relation to the past and present epidemiological situation and available healthcare resources.

Retrospective population-based assessment of medically attended injection site reactions, seizures, allergic responses and febrile episodes after acellular pertussis vaccine combined with diphtheria and tetanus toxoids

BACKGROUND

Since 1997 diphtheria-tetanus toxoids-acellular pertussis (DTaP) vaccines have been recommended for the five dose pertussis vaccination series. To assess rates of medically attended injection site reactions (ISRs), seizures, allergic responses and febrile episodes after Tripedia DTaP vaccine administered in the context of routine care, we conducted a retrospective assessment among the population of Group Health Cooperative from 1997 through 2000.

METHODS

Administrative databases were used to identify medical visits linked with diagnostic codes potentially indicative of ISRs, seizures, allergic responses and febrile episodes after DTaP vaccine. Outcomes were confirmed by medical record review.

RESULTS

During the study period 76 133 doses of DTaP were administered. Of the 26 ISRs identified, 6 followed DTaP given as the fourth dose and 18 followed DTaP given as the fifth dose, for rates of 1 per 2779 and 1 per 900 vaccinations, respectively. During the study period nearly all children receiving DTaP as the fifth dose had received whole cell pertussis vaccine for their primary series, and all of the fifth dose ISRs were among that group. Four of those reactions involved the entire upper arm. The rate of febrile seizures within 2 days of DTaP among children <2 years of age was 1 per 19 496 vaccinations.

CONCLUSIONS

The low rate of febrile seizures and other serious events confirms the safety of DTaP vaccine. The risk of medically attended ISRs was highest with DTaP given as the fifth dose, and whole arm reactions were reported, but medically attended ISRs were relatively uncommon and were self-limited.

Comparative trial to assess the reactogenicity of the diphtheria-tetanus-acellular pertussis (DTPa) vaccine plus Haemophilus influenzae type B (Hib) conjugate vaccine and that of the diphtheria-tetanus-whole cell pertussis (DTPw) vaccine plus Hib conjugate vaccine, administered in single injection a

BACKGROUND

The diphtheria-tetanus-whole-cell pertussis (DTPw) vaccine is being replaced in Western countries,and in several Spanish Autonomous Communities, by the diphtheria-tetanus-acellular pertussis (DTPa) vaccine. Although the administration of booster doses of DTPw or DTPa and Haemophilus influenzae type b conjugate (Hib) vaccines to toddlers is a current practice ina number of countries, there are few data comparing the reactogenicity profiles of their administration as a single injection.

SUBJECTS AND METHOD

An open,prospective, randomised, multicentre trial was conducted to compare the reactogenicity profile of a single injection of DTPa and Hib vaccines (DTPa/Hib) with that of a single injection of DTPw and Hib vaccines (DTPw/Hib) as booster doses to toddlers--previously primed with DTPw and Hib vaccines. 200 children (15.1 +/-1.0 months-old) were randomised to receive DTPa/Hib (group 1;n = 101) or DTPw/Hib (group 2; n = 99) and followed up to 30 days post-vaccination. All subjects received the oral polio vaccine concomitantly. Local and general symptoms were recorded by parents on diary cards.

RESULTS

Incidences of any local reaction and any general symptom <<probably related>>/<<suspected>>to vaccination were reported more frequently in group 2 than in group 1 (p < 0.0001). Pain at the injection site was reported by 29% and 66% of subjects in groups 1 and 2, respectively (p< 0.0001). Pain such that the child cried when limb was moved was also more frequently recorded in group 2 (15%) than in group 1 (1%) (p < 0.0001). Differences in prevalence of any swelling(16% in group 1, 30% in group 2) and swelling > 20 mm reached statistical significance (p (3/4) 0.012). Fever (rectal temperature>= 38 degrees C) was reported by 17% and 41 % in groups 1 and 2 subjects, respectively (p < 0.0001). Fussiness, loss of appetite and restlessness were also more frequently reported in DTPw/Hib subjects and reached statistical significance (at least p = 0.015).Analgesics/antipyretics were prescribed as a prophylactic treatment in only 14% of cases (9 and 19 subjects in groups 1 and 2, respectively;p = 0.0424). Antipyretic treatment after vaccination was significantly more prescribed in group 2 (27 cases) than in group 1 (8) (p <0.015).

CONCLUSION

The administration of DTPa/Hib as a single injection leads to a better reactogenicity profile than the administration of DTPw/Hib, also as a single injection, as booster doses to toddlers primed with DTPw and Hib vaccines.

Large scale safety study of a liquid hexavalent vaccine (D-T-acP-IPV-PRP--T-HBs) administered at 2, 4, 6 and 12-14 months of age

A study was conducted to assess the safety of a new, liquid hexavalent vaccine (Hexavac, Aventis Pasteur MSD, Lyon, France) in a large population of 1783 children in Germany vaccinated at 2, 4, 6 and 12-14 months of age. Immediate reactions, local and systemic reactions, and serious adverse events (SAEs) were monitored. The frequencies of redness > or = 2 cm and swelling > or = 2 cm were 6.7 and 7.1% after all doses of the primary series combined and 13.4 and 12.0% following the booster dose, respectively. Transient swelling of the entire thigh was reported in seven infants after all doses of the primary series (0.1%) and in four children after the booster dose (0.2%). The most frequent systemic adverse events within 3 days after vaccination were irritability (19.3% after primary series and 13.2% after booster) and fever > or = 38.0 degrees C (15.4% after primary series and 28.5% after booster). Fever above 40.0 degrees C was reported in 0.1% of the infants post-primary series and in 0.9% of the children after the booster immunization. Only 3 of 144 SAE were considered to be vaccine related and were seen to resolve spontaneously and without sequelae. The liquid hexavalent vaccine was generally well tolerated when given to children as a primary immunization series at 2, 4 and 6 months and as a booster dose at 12-14 months.

Safety and immunogenicity of Biken acellular pertussis vaccine in combination with diphtheria and tetanus toxoid as a fifth dose at four to six years of age. Munich Vaccine Study Group

OBJECTIVES

To evaluate the safety and immunogenicity of Biken acellular pertussis vaccine in combination with diphtheria and tetanus toxoid (Biken DTaP) vaccine administered to children 4 to 6 years of age who had previously received four doses of Biken DTaP.

METHODS

580 children were enrolled to receive one dose of Biken DTaP. Local and systemic reactions were collected by parent diary for all subjects within 3 days after vaccination and in a subset for 14 days. All adverse events occurring within 30 days after vaccination were recorded.

RESULTS

Any redness and swelling occurred in 59.8 and 61.4%, respectively. Redness or swelling larger than 5 cm/10 cm occurred in 31%/6.1% and 25%/6.5% of the children, respectively. Any pain was reported in 58.8%, but clinically significant pain occurred in 2.1% of the children. Fever >38.0 degrees C occurred in 3.8% of the children. Fussiness, drowsiness, anorexia and vomiting were experienced by 19.7, 15.5, 7.3 and 2.2%, respectively. Sixty-three of 247 adverse events (25%) occurring within 30 days after vaccination were assessed to possibly be vaccine-related. Fifty-eight of the 63 possibly related events (92%) were caused by local reactions as redness, swelling or itchiness. The remaining 5 events included hematoma, headache, stomachache and sleep disturbance. All local and systemic reactions and adverse events resolved without sequelae. Immunogenicity analysis showed a 4-fold antibody increase to pertussis toxin in 97% of subjects and to filamentous hemagglutinin in 82%. All subjects had postvaccination antibody titers of 0.1 IU/ml or greater against diphtheria and tetanus. Higher prevaccination antibody titers against diphtheria toxoid, pertussis toxin and filamentous hemagglutinin were associated with a higher frequency of large local reactions.

CONCLUSION

In comparison with a fourth dose of Biken DTaP administered at 18 to 24 months of age in the same population, the rate of local reactions increased after the fifth dose, whereas systemic reactions remained similarly low or decreased.

Effectiveness of a single dose of acellular pertussis vaccine to prevent pertussis in children primed with pertussis whole cell vaccine

We estimated the protection given by one booster dose of acellular pertussis vaccine (aP) given at 18 months or before school entry to children already primed with whole cell vaccine (wP). Case-control studies were conducted in these two age groups. In children who received or were eligible to receive their 18 months booster, the risk of pertussis was 1.4 and 3.6 times higher for those with 4 and 3 wP, respectively, compared to those with 3 wP + 1 aP. In 5 and 6 yr old children, the risk of pertussis among the subjects with 5 and 4 wP, was 1.4 and 2.1 times higher respectively than in those who received 4 wP + 1 aP. A single dose of aP increased the protection against pertussis and this protection was greater than that obtained with a wP booster.

Primary vaccination of infants with diphtheria-tetanus-acellular pertussis-hepatitis B virus- inactivated polio virus and Haemophilus influenzae type b vaccines given as either separate or mixed injections

OBJECTIVE

The aim of this open, multicenter, randomized trial was to evaluate the immunogenicity and reactogenicity of a candidate combined diphtheria-tetanus-acellular pertussis-hepatitis B virus-inactivated polio virus (DTaP-HBV-IPV) vaccine when given as either a mixed or as separate concomitant injections with Haemophilus influenzae type b (Hib) vaccine.

STUDY DESIGN

A total of 359 subjects were randomized to receive either DTaP-HBV-IPV/Hib (mixed administration - 180 subjects) or DTaP-HBV-IPV + Hib (separate administration in opposite limbs - 179 subjects) at 2, 3, and 4 months of age.

RESULTS

After vaccination, seroprotective antibody concentrations against diphtheria, tetanus, hepatitis B, and polio viruses and a high (> or = 97%) pertussis vaccine response were seen in almost all study participants. All subjects except one in the mixed administration group had postvaccination Hib anti-PRP antibody concentrations > or = 0.15 microg/mL. Of subjects in the mixed and separate group, 77.2% (geometric mean antibody concentration, 2. 62 microg/mL) and 88.6% (geometric mean antibody concentration, 4.45 microg/mL) had Hib anti-PRP concentrations > or = 1 microg/mL, respectively. The addition of the Hib component to the 5-component vaccine did not increase the incidence of local or general reactions.

CONCLUSION

Both administrations of the candidate vaccine were found to be safe, immunogenic, and well tolerated. Although anti-PRP geometric mean antibody concentrations and the percent of subjects achieving the 1 microg/mL seroprotective level were lower after the mixed administration, they were in the range seen with monovalent Hib vaccines or with other DTaP-based/Hib combinations licensed in some European countries. Therefore both administrations have the potential to simplify childhood immunization.

[Tolerance of acellular pertussis vaccine booster injection in 15-20-month-old children]

Severe reactions to whole cell pertussis vaccine are the main reason for the poor adhesion of parents and practitioners to pertussis vaccine booster injections in children, leading to a poor immunization in the population, particularly in young adults. The acellular pertussis vaccine appears to be better tolerated while keeping a good immunogenicity. In a randomized multicentric study on pertussis vaccine booster injection tolerance in 386 15-20 month-old children, we confirmed the better local and general tolerance of the acellular vaccine as compared with the whole cell vaccine. This should help to develop a positive opinion toward pertussis vaccine among parents and practitioners, and to improve the level of active pertussis immunization among children, adolescents, and young adults.

Safety and immunogenicity of combined Dtpa-IPV vaccine for primary and booster vaccination

This study evaluated the safety and immunogenicity of combined diphtheria, tetanus, acellular pertussis, inactivated poliomyelitis vaccine (DTPa-IPV) given as primary immunization at ages 3, 4.5 and 6 months and a booster dose between the ages of 18 and 27 months to healthy children. The acellular pertussis tricomponent vaccine contains pertussis toxoid (PT), filamentous haemaglutinin (FHA) and 69 kDa outer membrane protein (PRN). Serum immune responses to the administered antigens were measured before and after the primary and the booster vaccination series. The safety of the vaccine was evaluated based on diary cards completed by parents within 4 d following each vaccination. A total of 237 and 150 children completed the primary and booster vaccination series, respectively. A total of 483 (66.5%) and 111 (74%) local and 317 (43.7%) and 98 (65.3%) general adverse events were reported after 726 doses of the primary series and 150 of the booster doses, respectively. Compared with primary vaccination, the incidence of all adverse symptoms was greater after the booster dose and a previous severe reaction was a risk factor for a severe reaction after the booster dose (OR = 5.11). All but 1 child, who failed to have antibodies to diphtheria toxoid after the booster dose, responded to all administered antigens with antibody titres greater than the assay cut-off points. The combined DTPa-IPV used for primary and booster immunization induced good immunity, but was associated with large local reactions in 21.3% of children after the booster dose.

Extensive swelling after booster doses of acellular pertussis-tetanus-diphtheria vaccines

BACKGROUND

Diphtheria and tetanus toxoid combined with acellular pertussis (DTaP) vaccines are less reactogenic than diphtheria and tetanus toxoid combined with whole cell pertussis (DTwP) vaccines. However, local reactions increase in rate and severity with each successive DTaP dose, and swelling of the entire injected limb has been reported after booster doses.

METHODS

We reviewed reports of swelling of the entire thigh or upper arm after the fourth and fifth dose, respectively, of DTaP vaccines administered in the National Institutes of Health multicenter comparative DTaP studies. Relationships were explored among reports of severe swelling, rates of other reactions, quantity of vaccine contents, and prevaccination and postvaccination antibody levels to pertussis toxin, tetanus toxin, and diphtheria toxin.

RESULTS

Entire thigh swelling was an unsolicited reaction reported in 20 (2%) of the 1015 children who received 4 consecutive doses of the same DTaP vaccine. The reaction was associated with 9 of the 12 DTaP vaccines evaluated. Although there were no reports of swelling of the entire upper arm in 121 children given a fifth dose of the same DTaP, 4 (2.7%) of 146 recipients of 5 doses of a mixed schedule of DTaP vaccines experienced such swelling. Rates of other reactions were higher in children with entire thigh swelling than in those without. Of the children with entire thigh swelling, 60% had local pain, and 60% had erythema. All swelling subsided spontaneously without sequelae. There was a significant linear association between the rates of entire thigh swelling after dose 4 and diphtheria toxoid content in the DTaP products. Lesser degrees of swelling (>50 mm but less than entire limb) correlated with pertussis toxoid content after dose 4 and aluminum content after dose 5. No relationship was established between levels of serum antibody to diphtheria, tetanus, or pertussis toxin and rates of swelling of the whole thigh.

CONCLUSIONS

Booster doses of DTaP vaccines can cause entire limb swelling, which is usually associated with redness and pain. Our data suggest that this extensive swelling reaction may be more common with vaccines containing high diphtheria toxoid content.

Acellular vaccines containing reduced quantities of pertussis antigens as a booster in adolescents

OBJECTIVE

To evaluate the immunogenicity and reactogenicity of an acellular pertussis vaccine (pa) either formulated with diphtheria and tetanus toxoids (dTpa) or administered consecutively with a licensed tetanus and diphtheria vaccine (Td) as a 5th dose in adolescents.

METHODS

A total of 510 healthy children 10 to 13 years of age were assigned randomly, using a single-blind design, to receive either the dTpa vaccine or the Td vaccine with the pa vaccine 1 month later. The quantities of 3 pertussis antigens (pertussis toxin, filamentous hemagglutinin, and pertactin) in the dTpa and the pa vaccines were one third of those of the Infanrix vaccine (SmithKline Beecham Biologicals, Rixensart, Beligium) licensed for use in infants. For enzyme-linked immunosorbent assay measurement of serum immunoglobulin G antibodies and proliferation assay of peripheral blood mononuclear cells, blood samples were obtained before and 1 month after immunization. Local and systemic reactions were recorded on diary cards for 15 days after immunization.

RESULTS

After immunization with dTpa or pa, significant and comparable rises in geometric mean values of antibodies (12- to 46-fold) and proliferations (8- to 18-fold) to each of the pertussis antigens were noted. After immunization with dTpa or Td, significant rises in geometric mean values of antidiphtheria and antitetanus antibodies (35- to 76-fold) were noted, and all subjects had values of these antibodies >/=.1 international units/mL. The dTpa and pa vaccines were at least as well tolerated as the licensed Td vaccine.

CONCLUSIONS

Booster immunization of adolescents with an acellular vaccine containing reduced quantities of pertussis antigens in addition to diphtheria and tetanus toxoids induces good responses in both arms of the immune system without an increase in adverse reactions.

Comparison of a fifth dose of a five-component acellular or a whole cell pertussis vaccine in children four to six years of age

BACKGROUND AND OBJECTIVES

Acellular pertussis vaccines are now preferred for all five childhood immunization doses; however, there are few data on the safety and immunogenicity of five consecutive doses. This study compared a fifth dose of an acellular and a whole cell pertussis vaccine in 4- to 6-year-old children previously immunized with four doses of acellular or whole cell pertussis vaccine.

STUDY DESIGN

In a double blind, multicenter study, 366 healthy children were randomly allocated to receive a single injection of a 5-component acellular or a whole cell pertussis vaccine, each combined with diphtheria and tetanus toxoids and inactivated poliovirus vaccine.

RESULTS

Although injection site redness > or =50 mm and swelling > or =50 mm were common in children who had received five doses of acellular (50% and 48.1%, respectively) or whole cell (66.2% and 59.7%) pertussis vaccine, limb soreness and limitation of motion were less frequently reported after acellular (1.9% and 0%) than after whole cell (49.2% and 36.3%; P < 0.0001) pertussis vaccine. Pre-fifth dose antipertussis antibody titers were higher in children who previously had received four doses of acellular pertussis vaccine. Postimmunization antibody titers against pertussis toxin, filamentous hemagglutinin, pertactin and tetanus toxin were higher in recipients of five doses of acellular pertussis vaccine, whereas antibody titers to diphtheria toxin, pertussis fimbriae and poliovirus serotypes were higher in recipients of five doses of the whole cell pertussis vaccine (P < 0.05 for all comparisons).

CONCLUSIONS

A regimen consisting of five doses of a five-component acellular pertussis combination vaccine is safe and immunogenic in pre-school children. Local adverse reactions are common but are less painful and activity-limiting than a regimen of five doses of a whole cell pertussis vaccine.

Immunogenicity and reactogenicity of HbOC vaccine administered simultaneously with acellular pertussis vaccine (DTaP) into either arms or thighs of infants

To evaluate the reactogenicity and immunogenicity of a Haemophilus influenzae type b conjugate vaccine (HbOC) and of a tricomponent acellular pertussis vaccine (DTaP) when injected simultaneously into either contralateral arms or into contralateral thighs, 110 infants were enrolled to receive three doses of DTaP at 3, 4, and 5 months and two HbOC doses at 3 and 5 months of age. Administration of either of the two vaccines into arms was associated with significantly more local side effects than administration into thighs. There was no difference in geometric mean concentration (GMC) values for any of the four vaccine antigens between subjects who had been vaccinated into arms or thighs. After immunization, all children had protective antibody titers to diphtheria toxin. While post vaccination the mean anti-tetanus toxoid GMC was > or = 1.25 IU/ml, there was no significant rise as compared to the GMC before vaccination. GMCs of antibodies against the various pertussis antigens were similar to those observed before with the same DTaP vaccine. The simultaneous administration of DTaP and HbOC was safe and immunogenic irrespective of the site of vaccine administration, but significantly more local reactions occurred when vaccines were injected into arms.