Sudden and unexpected deaths after the administration of hexavalent vaccines (diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B, Haemophilius influenzae type b): is there a signal?

Rare cases of Guillain-Barré syndrome after COVID-19 vaccination, Germany, December 2020 to August 2021

BackgroundGuillain-Barré syndrome (GBS) has been associated with vaccination against COVID-19.AimWe aimed to compare clinical characteristics and analyse excess GBS cases following administration of different COVID-19 and influenza vaccines in Germany versus the expected numbers estimated from pre-pandemic background incidence rates.MethodsWe analysed safety surveillance data reported to the German national competent authority between 27 December 2020 and 31 August 2021. GBS cases were validated according to Brighton Collaboration (BC) criteria. We conducted observed vs expected (OvE) analyses on cases fulfilling BC criteria levels 1 to 4 for all four European Medicines Agency-approved COVID-19 vaccines and for influenza vaccines.ResultsA total of 214 GBS cases after COVID-19 vaccination had been reported, of whom 156 were eligible for further analysis. Standardised morbidity ratio estimates 3-42 days after vaccination were 0.34 (95% confidence interval (CI): 0.25-0.44) for Comirnaty, 0.38 (95% CI: 0.15-0.79) for Spikevax, 3.10 (95% CI: 2.44-3.88) for Vaxzevria, 4.16 (95% CI: 2.64-6.24) for COVID-19 Vaccine Janssen and 0.60 (95% CI: 0.35-0.94) for influenza vaccines. Bilateral facial paresis was reported in 19.7% and 26.1% of the 156 GBS cases following vaccination with Vaxzevria and COVID-19 Vaccine Janssen, respectively, and only in 6% of cases exposed to Comirnaty.ConclusionThree and four times more GBS cases than expected were reported after vaccination with Vaxzevria and COVID-19 Vaccine Janssen, respectively, therefore GBS might be an adverse event of vector-based vaccines. Bifacial paresis was more common in cases with GBS following vaccination with vector-based than mRNA COVID-19 vaccines.

Non-immunization associated with increased risk of sudden unexpected death in infancy: A national case-control study

OBJECTIVE

In the context of vaccine scepticism, our study aimed to analyse the association between immunization status and the occurrence of sudden unexpected death in infancy (SUDI).

STUDY DESIGN

A multi-centre case-control study was conducted between May 2015 and June 2017 with data from the French national SUDI registry (OMIN) for 35 French regional SUDI centres. Cases were infants under age 1 year who died from SUDI and who were registered in OMIN. Controls, matched to cases by age and sex at a 2:1 ratio, were infants admitted to Nantes University Hospital. All immunization data for diphtheria (D), tetanus (T), acellular pertussis (aP), inactivated poliovirus (IPV), Haemophilus influenzae b (Hib), hepatitis B (HB) and 13-valent pneumococcal conjugate vaccine (PCV13) were collected by a physician. Cases and controls were considered immunized if at least one dose of vaccine was administered.

RESULTS

A total of 91 cases and 182 controls were included. The median age was 131 days (interquartile range 98-200.0) and the sex ratio (M/F) was about 1.1. For all vaccines combined (D-T-aP-IPV-Hib and PCV13), 22 % of SUDI cases versus 12 % of controls were non-immunized, which was significantly associated with SUDI after adjustment for potential adjustment factors (adjusted odds ratio 2.01 [95 % confidence interval 1.01-3.98, p = 0,047]).

CONCLUSIONS

Non-immunization for D-T-aP-IPV-Hib-HB and PCV13 was associated with increased risk of SUDI. This result can be used to inform the general public and health professionals about this risk of SUDI in case of vaccine hesitancy.

Vaccines and sudden infant death: An analysis of the VAERS database 1990-2019 and review of the medical literature

Although there is considerable evidence that a subset of infants has an increased risk of sudden death after receiving vaccines, health authorities eliminated "prophylactic vaccination" as an official cause of death, so medical examiners are compelled to misclassify and conceal vaccine-related fatalities under alternate cause-of-death classifications. In this paper, the Vaccine Adverse Event Reporting System (VAERS) database was analyzed to ascertain the onset interval of infant deaths post-vaccination. Of 2605 infant deaths reported to VAERS from 1990 through 2019, 58 % clustered within 3 days post-vaccination and 78.3 % occurred within 7 days post-vaccination, confirming that infant deaths tend to occur in temporal proximity to vaccine administration. The excess of deaths during these early post-vaccination periods was statistically significant (p < 0.00001). A review of the medical literature substantiates a link between vaccines and sudden unexplained infant deaths. Several theories regarding the pathogenic mechanism behind these fatal events have been proposed, including the role of inflammatory cytokines as neuromodulators in the infant medulla preceding an abnormal response to the accumulation of carbon dioxide; fatal disorganization of respiratory control induced by adjuvants that cross the blood-brain barrier; and biochemical or synergistic toxicity due to multiple vaccines administered concurrently. While the findings in this paper are not proof of an association between infant vaccines and infant deaths, they are highly suggestive of a causal relationship.

What Matters to Parents Regarding Immunization of Their Children: Systematic Analysis of Expert Advice to Parents in an Internet Forum

BACKGROUND

World Health Organization announced vaccine hesitancy among the top 10 threats to global health in 2019. While the number of persons looking for information on health topics on the internet is increasing, information regarding immunization on the internet is often inaccurate and misleading. We aimed to determine the kind of information parents seek on the internet for decision-making regarding immunizations for their children.

METHODS

We investigated threads of an internet vaccine forum, where parents can get personalized advice from a vaccine expert, with regard to the types of vaccines and content of the questions. One thousand six hundred twenty consultations (4896 questions) between September 2001 and December 2018 were examined. Of these, 1386, including 4000 questions, were related to immunizations of the user's child. Date of consultation, user gender and country of residence, age of the child; kind of vaccine(s), and topic of the question according to the following categories were analyzed: Vaccination schedule, safety, effectiveness, necessity, vaccine application, serology, exchangeability of different vaccine types and brands, maternally acquired immunity, reimbursement, and vaccine product related.

RESULTS

Most questions concerned infants (47.7%) and regarded measles-component (28.9%) and diphtheria-tetanus-pertussis combination vaccines (25.3%). Parents were mainly interested in vaccination schedule (33.8%), safety (26.6%), and effectiveness (17.8%) of vaccines. Over time, safety-related questions decreased, and effectiveness related questions increased. Disease outbreaks or newly introduced vaccines and vaccinations temporarily raised interest. From 2011 onwards, most questions regarded measles-component vaccines.

CONCLUSIONS

Our findings will assist health care professionals and policy makers in preparing targeted information campaigns to address questions and counteract vaccine hesitancy.

Sudden Infant Death After Vaccination: Survey of Forensic Autopsy Files

Sudden infant deaths might be attributable to adverse reaction to vaccination, but separating them from coincidental occurrences is difficult. This study retrospectively investigated vaccination-related details and postmortem findings for 57 cases of sudden death in children 2 years or younger. Data were extracted from autopsy files at the Department of Forensic Medicine, Tokai University School of Medicine. Vaccination histories were available in 50 cases based on the maternity passbook. Of the 32 cases in which any vaccines were administered, 7 infants (21.9%) had received immunization within 7 days of death. The most frequent vaccine cited as the last immunization before death was Haemophilus influenzae B. Although a temporal association of vaccines with sudden death was present for two 3-month-old and one 14-month-old infants in whom death occurred within 3 days of receiving the H. influenzae type b and other vaccinations, a definitive relationship between the vaccine and death could not be identified. Histopathological examinations revealed pneumonia and upper respiratory infection as contributing to death in their cases. Moreover, all 3 cases showed hemophagocytosis in the spleen and lymph nodes, which are similar features to hemophagocytic lymphohistiocytosis. Judgment of the disorders as truly related to vaccination is difficult, but suspicious cases do exist. Forensic pathologists must devote more attention to vaccination in sudden infant death cases.

Vaccination and anaphylaxis: a forensic perspective

Aim

To review the available literature pertaining to fatalities following vaccine administration and, in particular, cases of vaccine-related fatal anaphylaxis.

Method

The MEDLINE database was systematically searched up to March 2016 to identify all relevant articles pertaining to fatal cases of anaphylaxis following vaccine administration.

Results

Six papers pertaining to fatal anaphylaxis following vaccination were found relevant. Mast cell tryptase and total IgE concentration was assessed exclusively in one case. Laryngeal edema was not detected in any of these cases, whereas eosinophil or mast cell infiltration was observed in lymphoid organs. In one case, immunohistochemical investigations using anti-tryptase antibodies allowed pulmonary mast cells and degranulating mast cells with tryptase-positive material outside to be identified.

Conclusion

In any suspected IgE-mediated fatal anaphylactic cases, biochemical investigations should be systematically performed for forensic purposes. Splenic tissue should be routinely sampled for immunohistochemical investigations in all suspected anaphylaxis-related deaths and mast cell/eosinophil infiltrations should be systematically sought out in the spleen, myocardium, and coronary artery wall. The hypothesis of fatal anaphylaxis following vaccination should be formulated exclusively when circumstantial data, available medical records, laboratory investigations, and autopsy or histology findings converge in a consistent pattern. The reasonable exclusion of alternative causes of death after all postmortem investigations is also imperative in order to establish or rule out a cause-and-effect relationship between vaccine administration and any presumptive temporarily-related death.

Rotavirus vaccination: a risk factor for intussusception?

Recently published pharmacoepidemiological studies associate the currently authorized Rotavirus (RV) vaccines with intussusception (IS). We aimed at investigating whether, in Germany, there are excess IS cases in RV vaccinees compared with the background incidence before market authorization in 2006. Suspected cases of IS following receipt of RV vaccines reported to the Paul-Ehrlich-Institut (PEI) from 2006 to 2010 were reviewed and validated against the criteria of the Brighton Collaboration's definition for IS. An observed-versus-expected analysis was conducted using standardized morbidity ratio (SMR) methods based on age-specific incidence rates for IS ranging from 19.2 to 98.5 per 100,000 person-years. A total of 27 cases of suspected IS in RV vaccinees were reported to the PEI. No excess of IS cases could be detected 1-7 days after receipt of either RV vaccine after any dose in the first year of life; however, in infants aged 3-5 months, a significantly increased SMR for IS was found in a risk window of 1-7 days after the first dose of either RV vaccine [SMRs: Rotarix® 4.6 (95% CI 1.5-10.7); RotaTeq® 5.8 (95% CI 1.2-17.1)]. A significantly increased risk of IS in a risk window of 1-7 days after RV vaccination was not found when the first dose was administered earlier. Therefore, it is recommended to start the vaccination course at 6-12 weeks of age.

Sensorimotor polyneuropathy after hexavalent vaccination

New vaccines in infants are generally well tolerated and serious adverse events are rare. We present a patient who developed severe sensorimotor polyneuropathy 2 weeks after the first immunization with hexavalent routine vaccine (INFANRIX hexa). Through intense physiotherapy the infant made a complete recovery.

Combined hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus-Haemophilus influenzae type B vaccine; Infanrix™ hexa: twelve years of experience in Italy

Infant vaccination using 2-dose priming at 3 and 5 mo of age with a booster at 11–12 mo of age was pioneered in Italy. The 3-5-11 schedule is now used in a growing number of European countries. Infanrix™ hexa (DTPa-HBV-IPV/Hib, GlaxoSmithKline Vaccines) was first licensed for use in 2000 and has been the only pediatric hexavalent vaccine available since 2005. We reviewed available clinical trial data describing the immunogenicity of DTPa-HBV-IPV/Hib when administered at 3, 5, and 11 mo of age, and conducted an analysis of safety using global and Italian post-marketing surveillance data. In Italy, DTPa-HBV-IPV/Hib has a demonstrated safety record extending over a decade of use, it has been associated with record levels of vaccine coverage, and with sustained disease control in vaccinated cohorts. Hexavalent vaccines will continue to contribute to high vaccine coverage in Italy and across Europe.

[Sonographic screening of basilar arteries reduces the risk of sudden infant death]

Sudden infant death syndrome (SIDS) is the most frequent cause of death in the first year of life. The causes of SIDS remain unclear although multiple theories have been published in recent decades. However, some important risk factors associated with SIDS, such as prone sleeping have been validated. Over 85% of all SIDS victims were found in a prone position but it is unclear why the prone sleeping position is more dangerous than the supine sleeping position. A possible cause of SIDS is hypoperfusion of the brain stem during head rotation. Some infants show compression of the vertebral arteries at the craniocervical junction during head rotation, especially in the prone position and this may lead to a subsequent decrease of brain stem perfusion. If compression lasts for a longer time hypoperfusion of the brainstem and central apnea and bradycardia result, which can lead to SIDS. The decrease in brainstem perfusion occurs more often and is more pronounced in the prone position as the head is more rotated in the prone than in the supine position. Doppler sonographic flow measurements of the flow in the basilar artery through the open fontanel, allow the detection of patients at risk of position-dependent hypoperfusion of the brain. Flow measurements are obtained in a neutral position (head in midline) and during head rotation. In the vast majority of infants (98.7%) the flow in the basilar artery is independent of head rotation and body position. In rare cases (1.3%) flow velocities drop to below 50% of the initial value during head rotation. A pathological biphasic or even retrograde flow can be found during head rotation in only 0.3% of infants and these infants may have an increased risk for SIDS. To prevent SIDS head rotation which leads to an abnormal or pathological flow decrease during head rotation should be avoided. Additionally these infants should be monitored until blood flow in the basilar artery has returned to normal, which usually occurs during the first year of life. This approach reduced the incidence of SIDS in our patients from 1% to 0.04‰.

DTPa-HBV-IPV/Hib vaccine (Infanrix hexa™): a guide to its use in infants

Infanrix hexa™, a diphtheria, tetanus, acellular pertussis, hepatitis B, inactivated poliomyelitis, and Haemophilus influenzae type b (Hib) conjugate vaccine, is indicated for primary and booster vaccination of infants. Available clinical data from more than a decade of experience with the vaccine indicate that primary and booster vaccination with Infanrix hexa™ is a safe and useful option for providing protection against the common childhood diseases of diphtheria, tetanus, poliomyelitis, pertussis, hepatitis B, and disease caused by Hib.

Reanalyses of case-control studies examining the temporal association between sudden infant death syndrome and vaccination

In this paper we examine different time periods after vaccinations and investigate whether the risk of sudden infant death is different during the post-vaccination period than at other times. Three already published case-control studies are re-examined in this context. Several evaluation approaches are presented. The recently developed self-controled case series (SCCS) method for terminal events, which only takes the cases into account, is used in addition. There is no increased or reduced risk of sudden infant death during the period after the vaccination. The previously reported protective effect seen in case contol studies is based on the inclusion of unvaccinated cases. The results of the case-control analysis of one study is affected by two confounders. The SCCS method for terminal events, in which all time-independent confounders are eliminated, is an alternative to case-control analysis when it comes to the temporal association between exposed time periods and SIDS after vaccination.

Sudden unexpected deaths and vaccinations during the first two years of life in Italy: a case series study

BACKGROUND

The signal of an association between vaccination in the second year of life with a hexavalent vaccine and sudden unexpected deaths (SUD) in the two days following vaccination was reported in Germany in 2003. A study to establish whether the immunisation with hexavalent vaccines increased the short term risk of SUD in infants was conducted in Italy.

METHODOLOGY/PRINCIPAL FINDINGS

The reference population comprises around 3 million infants vaccinated in Italy in the study period 1999-2004 (1.5 million received hexavalent vaccines). Events of SUD in infants aged 1-23 months were identified through the death certificates. Vaccination history was retrieved from immunisation registries. Association between immunisation and death was assessed adopting a case series design focusing on the risk periods 0-1, 0-7, and 0-14 days after immunisation. Among the 604 infants who died of SUD, 244 (40%) had received at least one vaccination. Four deaths occurred within two days from vaccination with the hexavalent vaccines (RR = 1.5; 95% CI 0.6 to 4.2). The RRs for the risk periods 0-7 and 0-14 were 2.0 (95% CI 1.2 to 3.5) and 1.5 (95% CI 0.9 to 2.4). The increased risk was limited to the first dose (RR = 2.2; 95% CI 1.1 to 4.4), whereas no increase was observed for the second and third doses combined.

CONCLUSIONS

The RRs of SUD for any vaccines and any risk periods, even when greater than 1, were almost an order of magnitude lower than the estimates in Germany. The limited increase in RRs found in Italy appears confined to the first dose and may be partly explained by a residual uncontrolled confounding effect of age.

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.

Vaccination safety update

INTRODUCTION

In Germany, a large number of biased reports against vaccination have recently been published in all of the news media, and particularly on the internet. This paper discusses the safety profile of modern vaccines and their continuous surveillance and shows why the current criticism of vaccination on safety grounds is unjustified.

METHODS

The authors have performed a selective literature search to enable a proper distinction to be drawn between scientifically justified and unjustified reports on the potential adverse effects of vaccination.

RESULTS

At present, the safety of a new vaccine must be demonstrated in large-scale clinical trials before the product is licensed. After licensing, the safety of new vaccines is constantly monitored, and the results of monitoring are published.

DISCUSSION

An examination of these data reveals that the expressed doubts about the safety of vaccines are unjustified.

Adverse events following immunization: perception and evidence

PURPOSE OF REVIEW

The aim of this article is to highlight the evidence on new and ongoing vaccine safety concerns in the light of several vaccines recently licensed and others made available and recommended more widely.

RECENT FINDINGS

There is increasingly convincing epidemiologic and laboratory evidence against a causal relation of several alleged adverse events following immunization. The scientific framework to detect and investigate adverse events following immunization is increasingly robust.

SUMMARY

Currently available vaccines are safe in immunocompetent individuals and there is no evidence to deviate from current immunization schedules.

Recommendations for sudden infant death syndrome prevention: a discussion document

This article reviews the evidence for the current UK Department of Health recommendations for prevention of sudden infant death syndrome (SIDS) and suggests other factors that should be considered. The wording of the Department of Health recommendations for SIDS prevention has changed over the past 6 years, but the specific recommendations are largely consistent with the scientific evidence. The emphasis on thermal and illness factors and immunisation could be reduced. Bed sharing and sharing the parental bedroom should be given more emphasis. Two major recommendations need to be discussed in greater detail: (1) breast feeding and (2) pacifier use. Meta-analyses or reviews looking at each risk factor or a combination of risk factors are required. Further, it is recommended that a committee is established that reviews the recommendations and publishes the evidence that leads to these recommendations, as is done by the American Academy of Pediatrics Taskforce on Sudden Infant Death Syndrome.

Sudden infant death syndrome: No increased risk after immunisation

BACKGROUND

Although previous studies have shown either no association between immunisation and SIDS or even a decreased risk of SIDS, adverse effects, including death, from immunisations continue to cause concern, especially when a new vaccine is introduced.

METHODS

A large case control study with immunisation data on 307 SIDS cases and 971 controls.

RESULTS

SIDS cases were immunised less frequently and later than controls. Furthermore there was no increased risk of SIDS in the 14 days following immunisation. There was no evidence to suggest the recently introduced hexavalent vaccines were associated with an increased risk of SIDS.

CONCLUSIONS

This study provides further support that immunisations may reduce the risk of SIDS.

Safety of DTaP–IPV–HIb–HBV hexavalent vaccine in very premature infants

OBJECTIVES

To assess the clinical safety of DTaP-IPV-HIb-HBV hexavalent immunization in very premature infants and to verify if the first administration of vaccine is by itself a reason for close monitoring hospitalized VLBW infants born at less than 31 weeks' gestation.

PATIENTS AND METHODS

Eighty-one preterm newborns less than 31 weeks' gestational age, admitted in the NICU, were eligible to be immunized with hexavalent vaccine under close monitoring, including pre-and post-immunization continuous monitoring of heart rate, oxygen saturation, respiratory rate, resistance index at the anterior cerebral artery and ECG cQT interval.

RESULTS

Of the 81 eligible premature newborns, 36 were graduated from the NICU before the least date for immunization, at 7 weeks of age. The other 45 were vaccinated in the NICU and entered the study. Twenty-three of them were under medical treatment for chronic disease at the time of the immunization while 22 were healthy and stable. Five infants (11%) had apnoea/bradycardia/desaturation, related to vaccine administration and required medical support. All five infants were in the group of newborns with chronic disease (21.7% prevalence of adverse reactions in this group). No significant variation of cQT or RI before and after the immunization was observed either in the whole groups of patients or in the five infants who showed cardio-respiratory events related to vaccination.

CONCLUSIONS

Hexavalent DTaP-IPV-HIb-HBV immunization is not associated with cardiac electric activity and cerebral blood flow variations in both stable and unstable very premature infants. However, it can cause apnoea/bradycardia/desaturation in premature babies with chronic disease. Therefore, if the baby is in the NICU for chronic diseases at 2 months post-birth, it should be monitored for apnoea, bradycardia and desaturation in association with vaccination. Hospitalized healthy preterm infants without chronic disease and therapy seem to be less vulnerable to cardio-respiratory adverse reactions. Nevertheless, it is advisable to immunize and monitor them at 8 weeks before discharge instead of possibly delaying immunization for several weeks and not monitor them.