Hypotonic-hyporesponsive episodes reported to the Vaccine Adverse Event Reporting System (VAERS), 1996-1998

DTaP-IPV-HB-Hib vaccine (Hexaxim): an update 10 years after first licensure

INTRODUCTION

Hexaxim® is fully liquid, hexavalent, combination vaccine that provides immunization against diphtheria, tetanus, pertussis (whooping cough), polio, hepatitis B, and invasive diseases caused by Haemophilus influenzae type b. Combination vaccines such as Hexaxim reduce the number of injections needed, improving both vaccination compliance and operational efficiency.

AREAS COVERED

Safety and immunogenicity data were reviewed from >25 clinical trials involving approximately 7200 infants/toddlers, identified using PubMed searches to April 2023. These trials have evaluated a diverse range of primary series and booster schedules, including antibody persistence, co-administration of Hexaxim with other routine pediatric vaccines, and specific populations (born to Tdap-vaccinated women, preterm, and immunocompromised infants). Lastly, post-marketing surveillance and real-world effectiveness data were assessed.

EXPERT OPINION

An extensive program of clinical development prior to licensure demonstrated favorable vaccine safety and good immunogenicity of each antigen, and Hexaxim was first approved for use in 2012. In the 10 years since licensure, Hexaxim has been adopted widely, with more than 180 million doses distributed worldwide. The widespread use of this hexavalent vaccine is a crucial tool in the ongoing and future control of six pediatric infectious diseases globally.

Surveillance of adverse events following immunization of 13-valent pneumococcal conjugate vaccine among infants, in Zhejiang province, China

OBJECTIVES

To evaluate the safety of 13-valent pneumococcal conjugate vaccine (PCV13) after its licensure.

METHODS

Review and describe the AEFI reported to national adverse event following immunization surveillance system (NAEFISS) in Zhejiang province from 2017 to 2020. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories. The data mining algorithm used in this study was reporting odds ratio (ROR). A value of ROR-1.96SE >1 (standard error [SE]) was considered as the positive signal.

RESULTS

NAEFISS received 3332 AEFI cases following PCV13, with a reporting rate of 17.58/10000 doses. Of the reported AEFI, 652 were serious AEFI cases and the reporting rate was 3.44 for serious AEFI. The reporting rate of fever was the highest among all the clinical diagnosis (7.39/10000 doses). The positive signals were obtained for injection site reaction (ROR-1.96SE: 1.55), hypotonic hyporesponsive episode (HHE) (ROR-1.96SE: 1.62) and febrile seizure (ROR-1.96SE: 1.52).

CONCLUSION

The present results supported previous observations that the PCV13 administered as the four-dose schedule was generally well tolerated in Chinese infants as we did not identify any new/unexpected safety concern from the NAEFISS during a four-year time period.

Hypotonic-hyporesponsive Episodes After Diphtheria, Tetanus and Acellular Pertussis Vaccination

BACKGROUND

Hypotonic-hyporesponsive episode (HHE) after whole cell pertussis vaccination is a known adverse event. Less is known about the risk of HHE after administration of acellular pertussis vaccines.

METHODS

Using parental interviews, this study actively surveyed for HHE among infants after doses 1 and 2 of acellular pertussis vaccine.

RESULTS

We interviewed the parents of 52,531 infants. HHE was reported at a rate of 22.8 per 100,000 doses (95% CI: 11.8-39.9) of acellular pertussis vaccine, approximately 45 episodes per 100,000 children.

CONCLUSIONS

These rates are lower than HHE rates reported after whole cell pertussis vaccines and within the range of HHE rates reported in other studies of acellular pertussis vaccines.

How were DTP-related adverse events reduced after the introduction of an acellular pertussis vaccine in Chile?

Chile has a passive surveillance system of adverse events following immunization (AEFI) that allows monitoring and evaluating the safety profile of the vaccines administered. Between 2018 and 2019, the National Immunization Program (NIP) changed from a pentavalent whole-cell pertussis vaccine (wP) to a hexavalent (DTaP-IPV-HepB-Hib) acellular pertussis vaccine (aP) for children <2 years.

Autonomic dysfunction and HPV immunization: an overview

This article reviews the case series reported from several countries describing patients with suspected severe side effects to the HPV vaccines. The described symptom clusters are remarkably similar and include disabling fatigue, headache, widespread pain, fainting, gastrointestinal dysmotility, limb weakness, memory impairment episodes of altered awareness, and abnormal movements. This constellation of symptoms and signs has been labeled with different diagnoses such as complex regional pain syndrome (CRPS), postural orthostatic tachycardia syndrome (POTS), small fiber neuropathy (SFN), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), or fibromyalgia. It is known that autoimmunity and autoantibodies are present in a subset of patients with CRPS, POTS, SFN, ME/CFS, and fibromyalgia. This article proposes that vaccine-triggered, immune-mediated autonomic dysfunction could lead to the development of de novo post-HPV vaccination syndrome possibly in genetically susceptible individuals. Being cognizant that a temporal relationship between vaccination and symptom onset does not necessarily equate to causality, mounting evidence of case series calls for well-designed case-control studies to determine the prevalence and possible causation between these symptom clusters and HPV vaccines. Since personalized medicine is gaining momentum, the use of adversomics and pharmacogenetics may eventually help identify individuals who are predisposed to HPV vaccine adverse events.

[Postvaccinal complications and management of suspected cases]

In all developed countries there is the possibility to protect oneself from vaccine-preventable diseases. However, not all individuals make use of this option. It is precisely in highly developed countries where a trend to vaccination hesitancy is noticeable, i. e. reluctance to get oneself or one's children vaccinated. The reasons why this is so are many, but the most important reason is the fear of postvaccinal complications, especially of those that imply sequelae or those with fatal outcomes.Whereas there are some proven associations between vaccination and adverse drug reaction, for example febrile seizures after the measles-mumps-rubella (MMR) vaccination, other hypotheses can be refuted, for example autism after the MMR vaccination. On one hand, this article gives an overview of known postvaccinal complications with indication of a causal association with vaccination and on the other hand addresses hypotheses of potential adverse drug reactions that have been refuted by pharmacoepidemiological studies.Only the scientific debate of these hypotheses, which are repeatedly discussed, especially on social media, can contribute to corroborating or refuting a potential causal association. If evidence for a causal association grows, e. g. intussusception, the relevant authorities (e.g. Paul Ehrlich Institute, European Medicines Agency) will take risk-minimizing measures. If studies and meta-analyses do not reveal any evidence of a causal association, a targeted information strategy will be required in order to prevent myths from circulating, vaccination coverages from declining, and infectious diseases from spreading.

Rate of Recurrence of Adverse Events Following Immunization: Results of 19 Years of Surveillance In Quebec, Canada

BACKGROUND

While adverse events following immunization (AEFI) are frequent, there are limited data on the safety of reimmunizing patients who had a prior AEFI. Our objective was to estimate the rate and severity of AEFI recurrences.

METHODS

We analyzed data from the AEFI passive surveillance system in Quebec, Canada, that collects information on reimmunization of patients who had a prior AEFI. Patients with an initial AEFI reported to the surveillance system between 1998 and 2016 were included. Rate of AEFI recurrence was calculated as number of patients with recurrence/total number of patients reimmunized.

RESULTS

Overall, 1350 patients were reimmunized, of which 59% were 2 years of age or younger. The AEFI recurred in 16% (215/1350) of patients, of whom 18% (42/215) rated the recurrence as more severe than the initial AEFI. Large local reactions extending beyond the nearest joint and lasting 4 days or more had the highest recurrence rate (67%, 6/9). Patients with hypotonic hyporesponsive episodes had the lowest rate of recurrence (2%, 1/50). Allergic-like events recurred in 12% (76/659) of patients, but none developed anaphylaxis. Of 33 patients with seizures following measles mumps rubella with/without varicella vaccine, none had a recurrence. Compared with patients with nonserious AEFIs, those with serious AEFIs were less often reimmunized (60% versus 80%; rate ratio: 0.8; 95% confidence interval: 0.66-0.86).

CONCLUSIONS

Most patients with a history of mild or moderate AEFI can be safely reimmunized. Additional studies are needed in patients with serious AEFIs who are less likely to be reimmunized.

Prevention of Pertussis, Tetanus, and Diphtheria with Vaccines in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP)

This report compiles and summarizes all recommendations from CDC's Advisory Committee on Immunization Practices (ACIP) regarding prevention and control of tetanus, diphtheria, and pertussis in the United States. As a comprehensive summary of previously published recommendations, this report does not contain any new recommendations and replaces all previously published reports and policy notes; it is intended for use by clinicians and public health providers as a resource. ACIP recommends routine vaccination for tetanus, diphtheria, and pertussis. Infants and young children are recommended to receive a 5-dose series of diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccines, with one adolescent booster dose of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine. Adults who have never received Tdap also are recommended to receive a booster dose of Tdap. Women are recommended to receive a dose of Tdap during each pregnancy, which should be administered from 27 through 36 weeks’ gestation, regardless of previous receipt of Tdap. After receipt of Tdap, adolescents and adults are recommended to receive a booster tetanus and diphtheria toxoids (Td) vaccine every 10 years to assure ongoing protection against tetanus and diphtheria.

Use of electronic immunization registry in the surveillance of adverse events following immunization

OBJECTIVE

To describe adverse events following vaccination (AEFV) of children under two years old and analyze trend of this events from 2000 to 2013, in the city of Araraquara (SP), Brazil.

METHODS

This is a descriptive study conducted with data of the passive surveillance system of AEFV that is available in the electronic immunization registry (EIR) of the computerized medical record of the municipal health service (Juarez System). The study variables were: age, gender, vaccine, dose, clinical manifestations and hospitalization. We estimated rates using AEFV as numerator and administered doses of vaccines as denominator. The surveillance sensitivity was estimated by applying the method proposed by the Centers for Disease Control and Prevention. We used Prais-Winsten regression with a significance level of 5.0%.

RESULTS

The average annual rate of AEFV was 11.3/10,000 administered doses, however without a trend in the study period (p=0.491). Most cases occurred after the first dose (41.7%) and among children under one year of age (72.6%). Vaccines with pertussis component, yellow fever and measles-mumps-rubella were the most reactogenic. We highlighted the rates of hypotonic-hyporesponsive episodes and convulsion that were 4.1/10,000 and 1.5/10,000 doses of vaccines with pertussis component, respectively, most frequently in the first dose; 60,0% of cases presented symptoms in the first 24 hours after vaccination, however, 18.6% showed after 96 hours. The sensitivity of surveillance was 71.9% and 78.9% for hypotonic-hyporesponsive episodes and convulsion, respectively.

CONCLUSIONS

The EIR-based AEFV surveillance system proved to be useful and highly sensitive to describe the safety profile of vaccines in a medium-sized city. It was also shown that the significant increase of the vaccines included in the basic vaccination schedule in childhood in the last decade did not alter the high safety standard of the National Immunization Program.

Hypotonic-hyporesponsive episodes after administration of hexavalent DTP-based combination vaccine: A description of 12 cases

Hypotonic-hyporesponsive (HHE) episodes are known and recognized phenomena, which typically occur within 48 hours of immunisation..Our aim is to describe 12 cases of HHE brought to the Center of Pediatric Sleep Medicine, with attention to the clinical features of the episode and their follow-up. Medical charts of infants visited between 2005-2015 were reviewed. Twelve infants showed a HHE using HHE using Brighton Collaboration Criteria. All infants received a Hexavalent diphtheria -tetanus -pertussis acellular component -hepatitis B-,inactivated poliovirus- Haemophilus influenzae type-b conjugate vaccine. Five out of 12 were brought to Emergency Department, where 2 were symptomatic (one was hyporeactive, the other had fever). No infant died during the episode, or the follow-up, nor developed neurological disease after subsequent vaccinations. HHE are confirmed as benign events, even after administration of hexavalent vaccination, devoid of negative neuropsychomotor outcome.

Surveillance of adverse events following the introduction of 13-valent pneumococcal conjugate vaccine in infants, and comparison with adverse events following 7-valent pneumococcal conjugate vaccine, in Victoria, Australia

The 13-valent pneumococcal vaccine (PCV13) replaced the 7-valent vaccine (PCV7) on the Australian National Immunization Program (NIP) in 2011. Post-marketing surveillance of adverse events following immunization (AEFI) is crucial for detecting potential safety signals and maintaining confidence in the NIP. This study describes all AEFI reported to Surveillance of Adverse Events following Vaccination in the Community (SAEFVIC), Melbourne, Australia, following both the primary series of PCV13 (children <7 months) and the catch-up dose (12 months-35 months) in its first year of inclusion on the NIP. AEFI reporting rates per 100,000 doses of vaccine administered were compared for the PCV13 primary series and PCV7 primary series in the previous year. SAEFVIC received 229 reports describing 406 AEFI following PCV13 vaccine in the 12 months post introduction. There was no difference in the total number of AEFI cases reported between the vaccines but 7 AEFI categories were reported at a significantly higher rate following PCV13 compared with PCV7. No difference in reporting rate was observed for serious AEFI (p = 0.25). Post-hoc analysis of a further 12 months of PCV13 data revealed that all 7 AEFI categories that were initially reported at a significantly higher rate following PCV13 compared to PCV7 in the first 12 months post introduction, were no longer significantly increased in the 13-24 month period. The initial high reporting rate for several common AEFI post PCV13 compared to PCV7 may be explained by heightened awareness of the new vaccine. There were no safety signals detected for rare or serious AEFI that would require further investigation at this time.

Iatrogenic neurology

Iatrogenic disease is one of the most frequent causes of hospital admissions and constitutes a growing public health problem. The most common type of iatrogenic neurologic disease is pharmacologic, and the central and peripheral nervous systems are particularly vulnerable. Despite this, iatrogenic disease is generally overlooked as a differential diagnosis among neurologic patients. The clinical picture of pharmacologically mediated iatrogenic neurologic disease can range from mild to fatal. Common and uncommon forms of drug toxicity are comprehensively addressed in this chapter. While the majority of neurologic adverse effects are listed and referenced in the tables, the most relevant issues are further discussed in the text.

Safety and immunogenicity of an investigational fully liquid hexavalent DTaP-IPV-Hep B-PRP-T vaccine at two, four and six months of age compared with licensed vaccines in Latin America

OBJECTIVE

This trial assessed the safety of a fully liquid investigational hexavalent DTaP-IPV-Hep B-PRP-T vaccine containing 10 μg Hansenula polymorpha-derived recombinant hepatitis B (hep B) antigen for primary vaccination of infants at 2, 4 and 6 months of age compared with licensed comparators.

METHODS

Participants received the DTaP-IPV-Hep B-PRP-T vaccine (group 1, N = 1422) or licensed DTwP-Hep B//Hib (Tritanrix-Hep B/Hib) and oral poliovirus vaccines (group 2, N = 711). The incidence of severe fever (≥ 39.6°C rectal equivalent) in the 2 groups was compared statistically; reactogenicity was evaluated from parental reports. Anti-Hep B antibody titers were measured in a subset of participants (no hepatitis B vaccination at birth) 1 month after dose 3.

RESULTS

The investigational vaccine was well tolerated. After any dose, fever (rectal equivalent temperature ≥ 38°C) was observed in 74.8% and 92.7% of participants in groups 1 and 2; severe fever was observed in 4.0% and 5.5% of participants. Solicited injection site and systemic reactions were numerically less frequent in group 1 than group 2, although this difference was not assessed statistically. In both groups, all participants included in the immunogenicity analysis achieved anti-Hep B ≥ 10 mIU/mL and ≥ 96.2% of participants achieved anti-Hep B ≥ 100 mIU/mL, although geometric mean titer was approximately 3-fold lower for the investigational vaccine.

CONCLUSION

This new, fully liquid acellular pertussis hexavalent vaccine demonstrated less reactogenicity than the licensed comparator whole cell pertussis vaccine and was highly immunogenic for the new Hep B valence.

Avaliação do sistema brasileiro de vigilância de eventos adversos pós-vacinação

OBJETIVOS: Descrever e avaliar o Sistema brasileiro de vigilância passiva de eventos adversos pós-vacinação (SPVEAPV). MÉTODOS: A descrição e avaliação do SPVEAPV fundamentaram-se nas notificações de eventos adversos pós-vacina Tetravalente ou DTwP/Hib - vacina adsorvida difteria, tétano, pertussis e Haemophilus influenzae b (conjugada) - (EAPV-T), durante o período de 2002 a 2005. Empregou-se a metodologia proposta pelo Centers for Disease Control and Prevention. RESULTADOS: O SPVEAPV apresenta abrangência nacional, tem por objetivos identificar e padronizar condutas frente a casos de eventos adversos pós-vacinação (EAPV) e identificar lotes reatogênicos. A vigilância é útil, simples e flexível, sua sensibilidade é baixa, superestima os eventos mais graves, mas descreve de forma consistente os EAPV-T, identificando a convulsão, a febre e o episódio hipotônico-hiporresponsivo como os mais frequentes, apontando a maior proporção de EAPV na primeira dose (49,7%) e nas primeiras seis horas após a vacinação (72,8%); é útil ao subsidiar decisões e investigações complementares; 46,1% das notificações são feitas até 10 dias após a vacinação; sua completude varia de 70% a 90%, conforme o item. CONCLUSÕES: O SPVEAPV mostra-se útil no monitoramento da segurança da vacina DTwP/Hib, sendo, porém, recomendável a incorporação de novas metodologias como a de municípios e/ou hospitais sentinelas e a de sistemas informatizados de registros de imunização com a finalidade de elevar sua sensibilidade.

Update on available vaccines in India: report of the APPA VU 2010: I

The Asia Pacific Pediatric Association Vaccinology Update 2010 was held in Mumbai on November 13-14, 2010 to discuss the latest information on burden of infectious diseases, recent developments in vaccines and their impact on immunization practices against infectious diseases occurring in Indian children. During the conference the importance of including conjugate Haemophilus influenzae type b vaccine and anti-rabies vaccines in routine immunization was stressed. Also, the need for giving a second dose of measles mumps rubella vaccine at school entry; and the need for a two-dose varicella vaccine regimen (first dose at 12-15 months of age and a second dose at age 4-6 years) was elucidated. Information related to vaccines which have become available in India in recent years, namely, inactivated poliovirus vaccine; diphtheria, tetanus, acellular pertussis (DTaP) vaccine; conjugate pneumococcal vaccine; rotavirus vaccines; H1N1 vaccines; live attenuated hepatitis A virus vaccine; oral cholera vaccine; tetanus, reduced-dose diphtheria, acellular pertussis (Tdap) vaccine; and human papillomavirus vaccines were discussed.

Post-licensure comparison of the safety profile of diphtheria/tetanus/whole cell pertussis/haemophilus influenza type b vaccine and a 5-in-1 diphtheria/tetanus/acellular pertussis/haemophilus influenza type b/polio vaccine in the United Kingdom

General practitioner consultation data were used to compare the reactogenicity in infants of a 5-in-1 acellular pertussis vaccine (DTaP(5)/Hib/IPV) introduced in the United Kingdom in 2004 to the 4-in-1 whole cell-pertussis vaccine (DTwP/Hib) that it replaced. For each vaccine the incidence in the week following vaccination was compared to other periods to obtain a relative incidence. A lower relative incidence of crying, fever and local reactions was seen with DTaP(5)/Hib/IPV than DTwP/Hib. Although there were no other significant differences between vaccines the relative incidence was significantly above one on the day of vaccination for convulsions following DTwP/Hib and for apnoea/collapse following DTaP(5)/Hib/IPV.

Performance of the Brighton collaboration case definition for hypotonic–hyporesponsive episode (HHE) on reported collapse reactions following infant vaccinations in the Netherlands

We reviewed collapse (sudden onset of pallor, limpness and hyporesponsiveness) following the first infant (DPTP+Hib) vaccination reported to the enhanced passive surveillance system of the Netherlands in 1994-2003. All 1303 reports identified by the current RIVM (National Institute for Public Health and Environment) case definition were captured by the Brighton Collaboration (BC) case definition, with in 17 (1.3%) reports insufficient information. Over the years the proportion of the highest level of diagnostic certainty (level 1) increased due to more complete data from 70% to over 90%. We checked the BC case definition also on a sample of cases (with pallor or hyporesponsiveness) not meeting RIVM's case definition for collapse at the time. Sixty out of 200 cases were captured by BC but again rejected by RIVM. The sensitivity BC levels 2 and 3 appeared too high. We recommend a more restrict case definition by the Brighton Collaboration with certain exclusion criteria to make it more specific. Furthermore a change in the specifications for levels 2 and 3 will increase specificity and accommodate for the loss of sensitivity.

An adolescent and adult formulation combined tetanus, diphtheria and five-component pertussis vaccine

Pertussis causes substantial morbidity among adolescents and adults, as well as other persons in contact with affected individuals. In the context of widespread childhood immunization, vaccination of adolescents and adults is a relatively new strategy for reducing the disease in all age groups. ADACEL is a tetanus-diphtheria-acellular pertussis combination vaccine (incorporating pertussis toxoid, filamentous hemagglutinin, pertactin and fimbriae type 2 and 3 antigens) formulated for use in adolescents and adults based on similar products designed for infants and children. ADACEL vaccine is approved for use in Australia, Canada, Germany and the USA, and has been demonstrated to induce robust immune responses and acceptable levels of reactogenicity in clinical trials. Surveillance data from Canada, where ADACEL vaccine has been used in adolescents and adults in conjunction with ongoing childhood vaccination for several years, indicate an enhanced overall reduction in pertussis disease.

Vaccination-related adverse events

Vaccine-related adverse events are uncommon and typically mild. Children may experience conditions such as rashes, fevers, syncope, protracted crying, or seizures shortly after receiving their routine immunizations. When children are brought to the emergency department or clinic to be evaluated for one of these conditions, the health care provider may be called upon to determine the likelihood that it was caused by a recently administered set of vaccines. This determination has substantial implications for medical care, including the safety of administering future vaccines. This article reviews the current understanding of vaccine-related adverse events. Using this information, clinicians should be able to identify those events likely to be related to vaccine administration and those that are not. The appropriate management of vaccine-related adverse events is also discussed.

Hepatitis B immunisation for newborn infants of hepatitis B surface antigen-positive mothers

BACKGROUND

Hepatitis B vaccine and hepatitis B immunoglobulin are considered for newborn infants of HBsAg-positive mothers to prevent hepatitis B infection.

OBJECTIVES

To assess the beneficial and harmful effects of hepatitis B vaccines and hepatitis B immunoglobulin in newborn infants of HBsAg-positive mothers.

SEARCH STRATEGY

Trials were identified through The Cochrane Neonatal Group Controlled Trials Register, The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, and EMBASE (until February 2004), authors of trials, and pharmaceutical companies.

SELECTION CRITERIA

Randomised clinical trials comparing: plasma-derived vaccine (PDV) or recombinant vaccine (RV) versus no intervention, placebo, or other active vaccines; hepatitis B immunoglobulin versus no intervention, placebo, or other control immunoglobulin; as well as PDV or RV plus hepatitis B immunoglobulin versus no intervention, placebo, or other control vaccines or immunoglobulin.

DATA COLLECTION AND ANALYSIS

Outcomes are assessed at maximal follow-up. The primary outcome measure was hepatitis B occurrence, based on a blood specimen positive for HBsAg, HBeAg, or antibody to hepatitis B core antigen (anti-HBc). Binary outcomes are reported as relative risks (RR) with 95% confidence interval (CI). Subgroup analyses were performed with regard to methodological quality of the trial, mother's HBe-Ag status, and time of immunisation after birth.

MAIN RESULTS

We identified 29 randomised clinical trials, five of which were considered high quality. Only three trials reported inclusion of hepatitis B e-antigen negative mothers. Compared with placebo/no intervention, vaccine reduced hepatitis B occurrence (RR 0.28, 95% confidence interval (CI) 0.20 to 0.40, 4 trials). No significant differences of hepatitis B occurrence were found comparing recombinant vaccine (RV) versus plasma-derived vaccine (PDV) (RR 1.00, 95% CI 0.71 to 1.42, 4 trials) and high-dose versus low-dose vaccine (PDV: RR 0.97, 95% CI 0.55 to 1.68, 3 trials; RV: RR 0.78, 95% CI 0.31 to 1.94, 1 trial). Compared with placebo/no intervention, hepatitis B immunoglobulin or the combination of vaccine plus hepatitis B immunoglobulin reduced hepatitis B occurrence (hepatitis B immunoglobulin: RR 0.50, 95% CI 0.41 to 0.60, 1 trial; PDV plus hepatitis B immunoglobulin: RR 0.08, 95% CI 0.03 to 0.17, 3 trials). Compared with vaccine, vaccine plus hepatitis B immunoglobulin reduced hepatitis B occurrence (RR 0.54, 95% CI 0.41 to 0.73, 10 trials). Hepatitis B vaccine and hepatitis B immunoglobulin seem safe, but few trials reported on adverse events.

AUTHORS' CONCLUSIONS

Vaccine, hepatitis B immunoglobulin, and vaccine plus hepatitis B immunoglobulin prevent hepatitis B occurrence in newborn infants of HBsAg positive mothers.

Effect of hepatitis B immunisation in newborn infants of mothers positive for hepatitis B surface antigen: systematic review and meta-analysis

OBJECTIVE

To evaluate the effects of hepatitis B vaccine and immunoglobulin in newborn infants of mothers positive for hepatitis B surface antigen.

DESIGN

Systematic review and meta-analysis of randomised clinical trials.

DATA SOURCES

Electronic databases and hand searches.

REVIEW METHODS

Randomised clinical trials were assessed for methodological quality. Meta-analysis was undertaken on three outcomes: the relative risks of hepatitis B occurrence, antibody levels to hepatitis B surface antigen, and adverse events.

RESULTS

29 randomised clinical trials were identified, five of which were considered high quality. Only three trials reported inclusion of mothers negative for hepatitis B e antigen. Compared with placebo or no intervention, vaccination reduced the occurrence of hepatitis B (relative risk 0.28, 95% confidence interval 0.20 to 0.40; four trials). No significant difference in hepatitis B occurrence was found between recombinant vaccine and plasma derived vaccine (1.00, 0.71 to 1.42; four trials) and between high dose versus low dose vaccine (plasma derived vaccine 0.97, 0.55 to 1.68, three trials; recombinant vaccine 0.78, 0.31 to 1.94, one trial). Compared with placebo or no intervention, hepatitis B immunoglobulin or the combination of plasma derived vaccine and hepatitis B immunoglobulin reduced hepatitis B occurrence (immunoglobulin 0.50, 0.41 to 0.60, one trial; vaccine and immunoglobulin 0.08, 0.03 to 0.17, three trials). Compared with vaccine alone, vaccine plus hepatitis B immunoglobulin reduced hepatitis B occurrence (0.54, 0.41 to 0.73; 10 trials). Hepatitis B vaccine and hepatitis B immunoglobulin seem safe, but few trials reported adverse events.

CONCLUSION

Hepatitis B vaccine, hepatitis B immunoglobulin, and vaccine plus immunoglobulin prevent hepatitis B occurrence in newborn infants of mothers positive for hepatitis B surface antigen.

Hypotonic-hyporesponsive episode in a 7-month-old infant after receipt of multiple vaccinations

A 7-month-old boy became difficult to arouse, was limp and had blue extremities 8 hours after immunization with intravenous poliovirus, diphtheria-tetanus toxoids-acellular pertussis, Haemophilus influenzae type b-hepatitis B virus and pneumococcal vaccines. The hypotonic-hyporesponsive episode had resolved by the time the infant was seen in an emergency department 1 hour later. The report describes hypotonic-hyporesponsive episode, encourages reporting of vaccine-associated adverse events and discusses prognosis and implications for subsequent immunization.

Acellular pertussis vaccines for use among infants and young children

Pertussis is still one of the most common vaccine-preventable childhood diseases in developed countries. Infants, particularly those < 6 months, are the most susceptible and those who suffer the greatest disease burden and mortality. In the 1970s, concerns about the reactogenicity of whole-cell vaccines led to a decrease in vaccine coverage and later the re-emergence of the disease in many countries. The advent of acellular vaccines in recent years has constituted an important advance in the acceptance of this immunisation and consequently the control of the disease. The efficacy of acellular pertussis vaccines is approximately 59 - 93%, similar to whole-cell vaccines, but all available data confirm the substantial improvement in safety of the new vaccines. With the licensure of acellular pertussis vaccines and combined vaccines containing them, pertussis immunisation has become significantly developed. Furthermore, the possibility of continuing to vaccinate adolescents and adults with new diphtheria, tetanus, and pertussis (dTap) vaccines is an important step in achieving control and elimination of the disease.

Update on side effects from common vaccines

Vaccines have had a tremendous impact on public health by reducing morbidity and mortality from a variety of virulent pathogens. However, unintended side effects continue to pose a potential risk that may outweigh the vaccine's protective attributes. In this review, we discuss recent articles and controversies pertaining to vaccine-associated adverse events. Included in the discussion are influenza, hepatitis B, measles-mumps-rubella, diphtheria-tetanus-pertussis, polio, Haemophilus influenzae type b, and rotavirus vaccines. The importance and contribution of vaccine constituents (such as thimerosal) to side effects is also reviewed.

An evaluation of serious neurological disorders following immunization: a comparison of whole-cell pertussis and acellular pertussis vaccines

Serious neurological disorders reported following whole-cell pertussis in comparison to acellular pertussis vaccines were evaluated. The Vaccine Adverse Events Reporting System (VAERS) was analyzed for Emergency Department (ED) visits, life-threatening reactions, hospitalizations, disabilities, deaths, seizures, infantile spasms, encephalitis/encephalopathy, autism, Sudden Infant Death Syndrome (SIDS) and speech disorders reported with an initial onset of symptoms within 3 days following whole-cell pertussis and acellular pertussis vaccines among those residing in the US from 1997 to 1999. Controls were employed to evaluate potential biases in VAERS. Evaluations as to whether whole-cell and acellular vaccines were administered to populations of similar age and sex were undertaken because these factors might influence the study's results. Statistical increases were observed for all events examined following whole-cell pertussis vaccination in comparison to acellular pertussis vaccination, excepting cerebellar ataxia. Reporting biases were minimal in VAERS, and whole-cell and acellular pertussis vaccines were administered to populations of similar age and sex. Biologic mechanisms for the increased reactogenicity of whole-cell pertussis vaccines may stem from the fact that whole-cell pertussis vaccines contain 3,000 different proteins, whereas DTaP contains two to five proteins. Whole-cell pertussis vaccine contains known neurotoxins including: endotoxin, pertussis toxin and adenylate cyclase. Our results, and conclusions by the US Institute of Medicine, suggest an association between serious neurological disorders and whole-cell pertussis immunization. In light of the presence of a safer and at least equally efficacious acellular pertussis vaccine alternative, the Japanese and US switch to using acellular pertussis vaccine seems well justified. Other countries using whole-cell pertussis-containing vaccines should consider following suite in the near future.

Safety, reactogenicity and immunogenicity of a combined hexavalent tetanus, diphtheria, acellular pertussis, hepatitis B, inactivated poliovirus vaccine and Haemophilus influenzae type b conjugate vaccine, for primary immunization of infants

Safety, reactogenicity and immunogenicity of GSK Biologicals' hexavalent DTPa-HBV-IPV/Hib vaccine (Infanrix)hexa) was assessed when used for primary vaccination at 3, 4 and 5 months of age (N = 2163), compared to the separate administration of DTPa-IPV/Hib and HBV vaccines (N = 720). A similar safety and reactogenicity profile was demonstrated for both vaccine regimens, as well as a good immune response for all antigen components. By offering protection against six diseases in a series of single injections, the hexavalent DTPa-HBV-IPV/Hib vaccine was shown to be a safe, well tolerated and immunogenic alternative to primary immunization with licensed separately administered vaccines.

Decrease in hospital admissions for febrile seizures and reports of hypotonic-hyporesponsive episodes presenting to hospital emergency departments since switching to acellular pertussis vaccine in Canada: a report from IMPACT

OBJECTIVE

Acellular pertussis vaccines were introduced with the promise of an improved safety profile compared with whole-cell vaccines. In 1997-1998, Canada adopted 1 combination acellular pertussis vaccine, having previously used 1 particular combination whole-cell pertussis vaccine. We hypothesized that the change would result in a decrease in hospitalization rates for seizures and reports of hypotonic-hyporesponsive episodes (HHEs) temporally related to pertussis vaccination.

METHODS

Active surveillance was performed between 1995 and 2001 by the Immunization Monitoring Program-Active monitors at 12 hospitals using standard case definitions. Seizures had to occur within 72 hours after immunization with a pertussis-containing vaccine or 5 to 30 days after immunization with measles-mumps-rubella vaccine. HHE episodes had to occur within 48 hours of receipt of a pertussis-containing vaccine. Poisson regression models were used to compare the average number of monthly admissions for seizures and HHEs before and after introduction of the acellular pertussis vaccine.

RESULTS

We found a 79% decrease in febrile seizures associated with receipt of pertussis vaccine but no significant decrease in febrile seizures temporally related to measles-mumps-rubella between 1995-1996 and 1998-2001. There was a 60% to 67% reduction in HHEs associated with pertussis-containing vaccines between the same time periods, depending on case definition.

CONCLUSIONS

The risks of febrile seizures and HHEs after pertussis-containing vaccine declined significantly with the introduction of acellular pertussis vaccine in Canada. Active surveillance systems are important for detecting trends in uncommon adverse events after routine immunizations.

Immunization Monitoring Program, Active: a model of active surveillance of vaccine safety

In Canada since 1993 the nation's passive system for reporting postimmunization adverse events has been supplemented by the active surveillance of inpatients at 10 to 12 pediatric referral centers, a system referred to as the Immunization Monitoring Program, Active. Participating centers are located from coast-to-coast and receive referrals from every province and territory. Approximately 20 percent of the population aged 0 to 12 years lives in the immediate vicinity of these centers. Nurse monitors at each center search for numerous target conditions, including postimmunization adverse events and vaccine-preventable infections. Vaccine safety observations have included (1) a substantial decrease in the risk of the development of febrile seizures and hypotonic-hyporesponsive episodes since the country switched from whole-cell to acellular pertussis-containing vaccines, (2) no evidence for encephalopathy resulting from the latter vaccines, (3) a generally benign outcome with postimmunization thrombocytopenia cases, and (4) an unexpectedly high rate of disseminated bacille Calmette-Guérin infections among aboriginal infants. Concomitant disease surveillance has been important for sustaining the surveillance system because few postimmunization adverse events require hospital admission.

EMLA cream and oral glucose for immunization pain in 3-month-old infants

The objective of this study is to determine whether use of lidocaine-prilocaine 5% cream (EMLA) and oral glucose decreases pain associated with diphteria-pertussis-tetanus (DPT) immunization in 3-month-old infants.

DESIGN

randomized, double-blind, controlled trial in outpatient paediatric practice in northern Sweden. EMLA or placebo was applied to the infant's lateral region of the right thigh and covered with an occlusive dressing 1h before the immunization. In addition, 1 ml of glucose (300 mg/ml) or placebo (water) was instilled on the baby's tongue within 2 min before the DPT-injection. Forty-five infants received EMLA and glucose and 45 infants placebo cream and water. ECG was recorded and stored in a computer and the procedure was videotaped. The parents and the nurse assessed the infants' pain on a visual analogue scale (VAS) after the immunization. Heart rate and heart rate variability pre- and post-injection were calculated. From the videotapes, the modified behavioural pain scale (MBPS) was used to assess pain scores during baseline and after immunization. The latency of the first cry and total crying time were measured. The parents and the nurse scored the infants' pain on the VAS significantly lower in the treatment group than in the placebo group. The infants' responses to the immunization measured as the difference in MBPS scores pre- and post-injection were significantly lower in the EMLA-glucose group compared with the placebo group. More infants cried after the immunization in the placebo group compared with the EMLA-glucose group and the latency of the first cry after the injection was shorter in the placebo group. A biphasic transient heart rate response with a marked deceleration followed by a subsequent acceleration was seen more frequently in the placebo group compared to the EMLA-glucose group. EMLA and glucose alleviate immunization pain in 3-month-old infants.

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.

Pertussis: persistent pathogen, imperfect vaccines

Routine use of pertussis vaccines has diminished the incidence of this disease but has not eliminated the pathogen. Pertussis remains a significant cause of disease in both very young infants and in the adolescent and adult populations. Acellular pertussis vaccines have fewer adverse reactions compared with whole-cell pertussis vaccines. Although efficacious against severe disease, current vaccines may not be as efficacious against milder forms of infection. New methodologies for understanding disease pathogenesis, immune responses and vaccine development are needed to effectively interrupt continued transmission of this pathogen.

Development of case definitions for acute encephalopathy, encephalitis, and multiple sclerosis reports to the vaccine: Adverse Event Reporting System

The Vaccine Adverse Event Reporting System (VAERS), administered by the FDA and CDC, is the U.S. system for surveillance of vaccine adverse events (AE). Acute encephalopathy age <18 months (EO < 18), age > or =18 months (EO > or = 18), encephalitis (EI), and multiple sclerosis (MS) after vaccination have been reported to VAERS, but reports often contain insufficient information to validate diagnoses. Standardized case definitions would enhance the utility of VAERS reports for AE surveillance. We developed practical case definitions for classification of VAERS reports, and three neurologists independently applied the definitions to reports submitted in 1993. Inter-observer agreement was assessed, and non-concordant classifications were reviewed in a follow-up conference call. Reports of EO < 18 (n = 8), EO > or = 18 (n = 20), EI (n = 15), and MS (n = 16) were classified as "definite" in 7% to 30% of the cases, while 26% to 51% of reports were thought to have insufficient information to make a classification. Agreement among reviewers was good to excellent, (kappa: 0.65 to 0.85) except for EO < 18 m for which it was marginal (kappa: 0.37). It is possible to develop reproducible case definitions for acute encephalopathy, encephalitis, and multiple sclerosis using a standardized approach. Application of standardized case definitions to VAERS reports documents the limited information in many reports, specifies data for supplemental collection, and indicates that VAERS reports should be cautiously interpreted. Development and application of case definitions for other adverse events reported after vaccination should enhance the value of vaccine safety databases. Published by Elsevier Science Inc.

Hypotonic-hyporesponsive episodes following pertussis vaccination: a cause for concern?

Vaccine safety has become a major community concern and of particular importance for parents, vaccine recipients and vaccine providers. A hypotonic-hyporesponsive episode (HHE) is a sudden and unexpected episode of loss of tone, unresponsiveness and colour change which uncommonly affects infants and children after vaccination. Although any vaccine may be associated with this adverse event, HHE usually follows administration of a pertussis containing vaccine. There has been renewed interest in this adverse event in the light of community concerns regarding vaccine safety. The focus of this interest has been to formulate an acceptable case definition, to document possible risk factors and to better define the outcome of HHE. In addition, studies have documented the outcome of revaccination of children who have had an HHE. Although much remains to be learnt about HHE it would appear that there are no long-term sequelae and that children who have had an HHE can be revaccinated. Parents should be provided with the available information such that they can make an assessment of the risks and benefits of pertussis vaccination. The benefits of pertussis vaccination still outweigh the risk and universal childhood pertussis vaccination should continue to be advocated.

Neurological adverse events associated with vaccination

Public tolerance to adverse reactions is minimal. Several reporting systems have been established to monitor adverse events following immunization. The present review summarizes data on neurologic complications following vaccination, and provides evidence that indicates whether they were directly associated with the vaccines. These complications include autism (measles vaccine), multiple sclerosis (hepatitis B vaccine), meningoencephalitis (Japanese encephalitis vaccine), Guillain-Barré syndrome and giant cell arteritis (influenza vaccine), and reactions after exposure to animal rabies vaccine. Seizures and hypotonic/hyporesponsive episodes following pertussis vaccination and potential risks associated with varicella vaccination, as well as vaccine-associated paralytic poliomyelitis following oral poliovirus vaccination, are also described. In addition, claims that complications are caused by adjuvants, preservatives and contaminants [i.e. macrophagic myofasciitis (aluminium), neurotoxicity (thimerosal), and new variant Creutzfeldt-Jakob disease (bovine-derived materials)] are discussed.

Pertussis: an old disease that is still with us

Our knowledge of pathogenesis, clinical presentation and prevention of pertussis has improved substantially over recent years. We now better understand the function of long-known virulence factors for Bordetella pertussis, and genome sequencing has identified a multitude of new proteins; their functions are yet to be elucidated. Furthermore, improved diagnostic tools have revealed the broad spectrum of disease, and new insights into the host's immune response have been gained. Finally, the development, evaluation, licensing and implementation of several new acellular pertussis vaccines with high acceptance have changed the epidemiology of pertussis in many countries (i.e. a shift towards an increasing burden of disease in adolescent persons and adults). These developments are likely to have great impact on the daily practice not only of paediatricians, but also of general practitioners, internists, gynaecologists and many other specialists in adolescent and adult medicine. The present review provides an update on recent progress.