Data Mining in the US using the Vaccine Adverse Event Reporting System

New exploration of signal detection of Regional Risks from the perspective of data mining: a pharmacovigilance analysis based on spontaneous reporting data in Zhenjiang, China

BACKGROUND

This study aimed to adopt the conventional signal detection methods to explore a new way of risk identification and to mine important drug risks from the perspective of big data based on Zhenjiang Adverse Event Reporting System (ZAERS).

RESEARCH DESIGN AND METHODS

Data were extracted from ZAERS database between 2012 and 2022. The risks of all the reported drug event combinations were identified at the preferred term level and the standardized MedDRA query level using disproportionality analysis. Then, we conducted signal assessment according to the descriptions of drug labels.

RESULTS

In total 41,473 ADE were reported and there were 12 risky signals. Signal assessment indicates the suspected causal associations in clindamycin-taste and smell disorders, valsartan-hepatic enzyme increased and valsartan-edema peripheral; the specific manifestations of allergic reactions triggered by clindamycin, cefotaxime, cefazodime, ShexiangZhuanggu plaster, ShexiangZhuifeng plaster, and Yanhuning need to be refined in drug labels. In addition, the drug labels of NiuHuangShangQing tablet/capsule, Fuyanxiao capsule, and BiYanLing tablet should be improved.

CONCLUSIONS

In this study, we attempted a new way to find potential drug risks using small spontaneous reporting data. Our findings also suggested the need for more precise identification of allergic risks and the improvement of traditional Chinese medicine labels.

Real-world evidence of autoimmune hepatitis following COVID-19 vaccination: A population-based pharmacovigilance analysis

Objective: Autoimmune hepatitis (AIH) has occasionally been reported after administration of Coronavirus Disease 2019 (COVID-19) vaccine. The present study aimed to investigate the reported rate and disproportionality of AIH following COVID-19 vaccination. Methods: The Centers for Disease Control (CDC) COVID Data Tracker and the Vaccines Adverse Event Reporting System (VAERS) were queried between 11 December 2020 and 15 March 2022. Reported rates were calculated by cases of AIH divided by the number of vaccinated people. Disproportionate pattern of AIH for COVID-19 vaccination was accessed based on the reporting odds ratio and empirical bayes geometric mean (ROR and EBGM, respectively). Results: A total of 53 reports of AIH were identified after administration of COVID-19 vaccine during the study period. The overall reported rate of COVID-19 vaccination-related AIH was 0.21 (95% CI 0.16-0.27) per million people. The results found no disproportionate reporting of AIH following COVID-19 vaccination in the VAERS (overall: ROR 1.43, 95% CI 0.52-3.96; EBGM05 0.37. mRNA: ROR 1.42, 95% CI 0.51-3.94; EBGM05 0.37. Virus vector: ROR 1.57, 95% CI 0.42-5.85; EBGM05 0.34). Conclusion: COVID-19 vaccine did not increase the risk of AIH. The number of AIH cases reported to VAERS does not suggest a safety concern attributable to COVID-19 vaccine at this time.

Booster dose of COVID-19 mRNA vaccine does not increase risks of myocarditis and pericarditis compared with primary vaccination: New insights from the vaccine adverse event reporting system

Background

Despite the likely association between coronavirus 2019 (COVID-19) mRNA vaccines and cases of myocarditis/pericarditis, the benefit–risk assessment by the Centers for Disease Control (CDC) still showed a favorable balance for the primary series of COVID-19 mRNA vaccinations. Since August 2021, a full-scale booster vaccination in certain recipients has been recommended. Great concerns about whether the COVID-19 mRNA booster vaccination could increase the risks of myocarditis/pericarditis have been raised since then. The present study aimed to compare the incidence rates and risks of myocarditis/pericarditis between booster and primary vaccination programs.

Methods

The CDC COVID Data Tracker and the Vaccines Adverse Event Reporting System (VAERS) were queried between December 11, 2020 and March 15, 2022. Incidence rates were calculated by cases of myocarditis/pericarditis divided by the number of vaccinated people or the total doses of COVID-19 mRNA vaccines. Disproportionality patterns for myocarditis/pericarditis of different COVID-19 mRNA vaccinations were accessed based on the reporting odds and proportional reporting ratios (ROR and PRR, respectively).

Results

A total of 2,588 reports of myocarditis/pericarditis were identified after administration of primary-series COVID-19 mRNA vaccination and 269 after the booster dose program during the study period. The incidence of myocarditis/pericarditis following booster COVID-19 mRNA vaccination was lower than that of primary series. The results showed significantly high reporting of myocarditis/pericarditis following the administration of primary COVID-19 mRNA vaccination, whereas the disproportional level was lower in the booster-dose vaccination.

Conclusion

This study found that the booster dose of COVID-19 mRNA vaccination when compared with primary series course did not lead to an increase in the risks of myocarditis/pericarditis.

Improvement in the Analysis of Vaccine Adverse Event Reporting System Database

As a national public health surveillance resource, Vaccine Adverse Event Reporting System (VAERS) is a key component in ensuring the safety of vaccines. Numerous methods have been used to conduct safety studies with the VAERS database. These efforts focus on the downstream statistical analysis of the vaccine and adverse event associations. In this paper, we primarily focus on processing the raw data in VAERS before the analysis step, which is also an important part of the signal detection process. Due to the semi-annual update in the Medical Dictionary for Regulatory Activities (MedDRA) coding system, adverse event terms that describe the same symptom might change in VAERS; therefore, we identify these terms and combine them to increase the signal detection power. We also consider the uncertainty of the vaccine and adverse event pairs that arise from reports with multiple vaccines. Finally, we discuss four commonly used statistics in assessing the vaccine and adverse event associations, and propose to use the statistics that are robust to the reporting bias in VAERS and adjust for potential confounders of the vaccine and adverse event association to increase signal detection accuracy.

Challenges in evaluating post-licensure vaccine safety: observations from the Centers for Disease Control and Prevention

Introduction: Vaccination is one of the most successful and cost-effective public health interventions. Although vaccines undergo extensive safety and efficacy evaluations prior to licensure, vaccine safety assessment post-licensure is essential for detecting rare and longer-term adverse events (AEs) and maintaining public confidence in vaccines and recommended immunization programs. Despite the proven effect of vaccines to save lives and prevent disease and overwhelming evidence of vaccines' safety and societal benefit, like any drug, no vaccine can be considered as completely safe and completely effective. New vaccines continue to be introduced and require rapid safety assessment post-licensure through pharmacovigilance reports as well as epidemiologic studies to investigate any potential safety signals.Areas covered: We discuss selected challenges for conducting pharmacovigilance and epidemiologic studies of AEs after vaccination in the United States using the post-licensure safety surveillance infrastructure of the Centers for Disease Control and Prevention (CDC).Expert opinion: The availability of specific post-licensure surveillance systems to monitor and study AEs after vaccination, such as the Vaccine Adverse Event Reporting System, the Vaccine Safety Datalink, and the Clinical Immunization Safety Assessment Project, each with its unique set of strengths and limitations, provide a harmonized and supportive approach to meet several of these barriers.

Post-marketing safety surveillance for inactivated and live-attenuated Japanese encephalitis vaccines in China, 2008-2013

INTRODUCTION

Two types of Japanese encephalitis (JE) vaccines, inactivated JE vaccine (JE-I) and live-attenuated JE vaccine (JE-L), are available and used in China. In particular, one JE-L, produced by a domestic manufacturer in China, was prequalified by WHO in 2013. We assessed the safety of JE vaccines in China during 2008-2013 using the Chinese National Adverse Events Following Immunization Information System (CNAEFIS) data.

METHODS

We retrieved AEFI reporting data about JE vaccines from CNAEFIS, 2008-2013, examined demographic characteristics of AEFI cases, and used administrative data on vaccine doses as denominator to calculate and compare crude reporting rates. We also used disproportionality reporting analysis between JE-I and JE-L to assess potential safety signals.

RESULTS

A total of 34,879 AEFIs related with JE-I and JE-L were reported, with a ratio of male to female as 1.3:1; 361 (1.0%) cases were classified as serious. JE vaccines were administered concurrently with one or more other vaccines in 13,592 (39.0%) of cases. The overall AEFI reporting rates were 214.4 per million vaccination doses for JE-L and 176.9 for JE-I (rate ratio [RR]: 1.2, 95% confidence interval [CI]: 1.1-1.3) in 2010-2013. Febrile convulsions (FC) following JE-I was found as a signal of disproportionate reporting (SDR). However, there was no significant difference between the reporting rates of FC of JE-I and JE-L (0.3 per million vaccination doses for JE-L, 0.4 for JE-I, p=0.05).

CONCLUSIONS

While our analysis did not find apparent safety concern of JE vaccines in China, further study should consider JE-I vaccines and febrile convulsion, and taking more sensitive methods to detect signals.

Differential Adverse Event Profiles Associated with BCG as a Preventive Tuberculosis Vaccine or Therapeutic Bladder Cancer Vaccine Identified by Comparative Ontology-Based VAERS and Literature Meta-Analysis

M. bovis strain Bacillus Calmette–Guérin (BCG) has been the only licensed live attenuated vaccine against tuberculosis (TB) for nearly one century and has also been approved as a therapeutic vaccine for bladder cancer treatment since 1990. During its long time usage, different adverse events (AEs) have been reported. However, the AEs associated with the BCG preventive TB vaccine and therapeutic cancer vaccine have not been systematically compared. In this study, we systematically collected various BCG AE data mined from the US VAERS database and PubMed literature reports, identified statistically significant BCG-associated AEs, and ontologically classified and compared these AEs related to these two types of BCG vaccine. From 397 VAERS BCG AE case reports, we identified 64 AEs statistically significantly associated with the BCG TB vaccine and 14 AEs with the BCG cancer vaccine. Our meta-analysis of 41 peer-reviewed journal reports identified 48 AEs associated with the BCG TB vaccine and 43 AEs associated with the BCG cancer vaccine. Among all identified AEs from VAERS and literature reports, 25 AEs belong to serious AEs. The Ontology of Adverse Events (OAE)-based ontological hierarchical analysis indicated that the AEs associated with the BCG TB vaccine were enriched in immune system (e.g., lymphadenopathy and lymphadenitis), skin (e.g., skin ulceration and cyanosis), and respiratory system (e.g., cough and pneumonia); in contrast, the AEs associated with the BCG cancer vaccine mainly occurred in the urinary system (e.g., dysuria, pollakiuria, and hematuria). With these distinct AE profiles detected, this study also discovered three AEs (i.e., chills, pneumonia, and C-reactive protein increased) shared by the BCG TB vaccine and bladder cancer vaccine. Furthermore, our deep investigation of 24 BCG-associated death cases from VAERS identified the important effects of age, vaccine co-administration, and immunosuppressive status on the final BCG-associated death outcome.

Surveillance systems and methods for monitoring the post-marketing safety of influenza vaccines at the Centers for Disease Control and Prevention

INTRODUCTION

Annual influenza vaccine safety monitoring is an important component of the influenza vaccination program in the United States to ensure that vaccines are safe, which is important for maintaining public trust in the national vaccination program. This is specially the case for influenza vaccines since the antigen composition of the viruses of which the vaccine is made often changes from one season to the next, based on the circulating strain of influenza virus.

AREAS COVERED

This review describes the two surveillance systems used by the Centers for Disease Control and Prevention (CDC) to monitor the safety of influenza vaccines: 1) the Vaccine Adverse Event Reporting System (VAERS); and 2) the Vaccine Safety datalink (VSD).

EXPERT OPINION

VAERS and VSD are used routinely to monitor the safety of influenza vaccines in the United States, and over the years they have demonstrated their value in monitoring vaccine safety since their implementation in 1990. Both systems, although different, complemented each other well to study febrile seizures in young children following influenza vaccination during the 2010-2011 influenza season. Other examples of potential safety concerns after influenza vaccines are also presented and discussed.

Influenza immunization during pregnancy: Benefits for mother and infant

The serious consequences of influenza infection during pregnancy have been recognized for almost a century. In this article, we reviewed the evidence on the immunogenicity, safety and impact of maternal influenza immunization for both mother and child. After vaccination, pregnant women have similar protective titers of anti-influenza antibodies as non-pregnant women, demonstrating that pregnancy does not alter the trivalent inactivated influenza vaccine immune response. Studies from the United States, Europe and resource-constrained regions demonstrate that maternal vaccination is associated with increased anti-influenza antibody concentrations and protection in the newborn child as well as the immunized mother. Given the acceptable safety profile of influenza vaccines and the World Health Organization's recommendation for its use in pregnant women, maternal vaccination with inactivated influenza vaccine is a cost-effective approach to decrease influenza disease in newborns. However, as seen for influenza immunization in the elderly, the protective efficacy of current inactivated vaccines in protection of newborns is 50% at best, indicating significant room for vaccine improvement, which could potentially be achieved by addition of a safe and effective adjuvant. Thus, global deployment of inactivated influenza immunization during pregnancy would have substantial and measurable health benefits for mothers and their newborns.

Thimerosal-Preserved Hepatitis B Vaccine and Hyperkinetic Syndrome of Childhood

(1) BACKGROUND: Hyperkinetic syndrome of childhood (HKSoC) is an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9) category in which the majority of the children are also diagnosed under the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR), where the umbrella term is "Attention-Deficit and Disruptive Behavior Disorders". The diagnostic criteria for HKSoC are developmentally inappropriate inattention, hyperactivity, and impulsivity. Some studies have implicated mercury (Hg) exposure as a risk factor. (2) METHODS: This hypothesis testing study; using the Vaccine Safety Datalink; assessed the toxicological effects of bolus exposure to organic-Hg from Thimerosal-containing vaccines (TCVs) by examining the relationship between Thimerosal-preserved hepatitis B vaccines (TM-HepB) given at varying levels and at specific intervals in the first six months after birth and the risk of a child being diagnosed with HKSoC. (3) RESULTS: Children diagnosed with HKSoC were significantly more likely to be exposed to increased organic-Hg from TM-HepB doses given within the first month (odds ratio = 1.45; 95% confidence interval (CI) = 1.30-1.62); within the first two months (odds ratio = 1.43; 95% CI = 1.28-1.59); and within the first six months (odds ratio = 4.51; 95% CI = 3.04-6.71) than controls. (4) CONCLUSION: The results indicate that increasing organic-Hg exposure from TCVs heightens the risk of a HKSoC diagnosis.

Rational design of small molecules as vaccine adjuvants

Adjuvants increase vaccine potency largely by activating innate immunity and promoting inflammation. Limiting the side effects of this inflammation is a major hurdle for adjuvant use in vaccines for humans. It has been difficult to improve on adjuvant safety because of a poor understanding of adjuvant mechanism and the empirical nature of adjuvant discovery and development historically. We describe new principles for the rational optimization of small-molecule immune potentiators (SMIPs) targeting Toll-like receptor 7 as adjuvants with a predicted increase in their therapeutic indices. Unlike traditional drugs, SMIP-based adjuvants need to have limited bioavailability and remain localized for optimal efficacy. These features also lead to temporally and spatially restricted inflammation that should decrease side effects. Through medicinal and formulation chemistry and extensive immunopharmacology, we show that in vivo potency can be increased with little to no systemic exposure, localized innate immune activation and short in vivo residence times of SMIP-based adjuvants. This work provides a systematic and generalizable approach to engineering small molecules for use as vaccine adjuvants.

Thimerosal-containing hepatitis B vaccination and the risk for diagnosed specific delays in development in the United States: a case-control study in the vaccine safety datalink

Background:

Within the first 3 years of life, the brain develops rapidly. Its development is characterized by critical developmental periods for speech, vision, hearing, language, balance, etc.; and alteration in any of the processes occurring in those critical periods can lead to specific delays in development.

Aims:

The present study evaluated the potential toxic effects of organic-mercury exposure from Thimerosal (49.55% mercury by weight) in childhood vaccines and its hypothesized possible relationship with specific delays in development.

Materials and Methods:

A hypothesis testing case-control study was undertaken to evaluate the relationship between exposure to Thimerosal-containing hepatitis B vaccines administered at specific intervals in the first 6 months among cases diagnosed with specific delays in development and controls born between 1991-2000, utilizing data in the Vaccine Safety Datalink database.

Results:

Cases were significantly more likely than controls to have received increased organic-mercury from Thimerosal-containing hepatitis B vaccine administered in the first, second, and sixth month of life.

Conclusion:

Though routine childhood vaccination may be an important public health tool to reduce the morbidity and mortality associated with infectious diseases, the present study supports an association between increasing organic-mercury exposure from Thimerosal-containing childhood vaccines and the subsequent risk of specific delays in development among males and females.

A smart medication recommendation model for the electronic prescription

BACKGROUND

The report from the Institute of Medicine, To Err Is Human: Building a Safer Health System in 1999 drew a special attention towards preventable medical errors and patient safety. The American Reinvestment and Recovery Act of 2009 and federal criteria of 'Meaningful use' stage 1 mandated e-prescribing to be used by eligible providers in order to access Medicaid and Medicare incentive payments. Inappropriate prescribing has been identified as a preventable cause of at least 20% of drug-related adverse events. A few studies reported system-related errors and have offered targeted recommendations on improving and enhancing e-prescribing system.

OBJECTIVE

This study aims to enhance efficiency of the e-prescribing system by shortening the medication list, reducing the risk of inappropriate selection of medication, as well as in reducing the prescribing time of physicians.

METHOD

103.48 million prescriptions from Taiwan's national health insurance claim data were used to compute Diagnosis-Medication association. Furthermore, 100,000 prescriptions were randomly selected to develop a smart medication recommendation model by using association rules of data mining.

RESULTS AND CONCLUSION

The important contribution of this model is to introduce a new concept called Mean Prescription Rank (MPR) of prescriptions and Coverage Rate (CR) of prescriptions. A proactive medication list (PML) was computed using MPR and CR. With this model the medication drop-down menu is significantly shortened, thereby reducing medication selection errors and prescription times. The physicians will still select relevant medications even in the case of inappropriate (unintentional) selection.

Did narcolepsy occur following administration of AS03-adjuvanted A(H1N1) pandemic vaccine in Ontario, Canada? A review of post-marketing safety surveillance data

A vaccine safety signal and association between new onset of narcolepsy and AS03-adjuvanted pandemic influenza A(H1N1) vaccine (Pandemrix, GlaxoSmithKline) in children and young adults has been reported in several European countries. In Ontario, Canada, AS03-adjuvanted pandemic A(H1N1) vaccine (Arepanrix, GlaxoSmithKline) was the primary vaccine administered in 2009/10, with 4.8 million doses distributed. We assessed post-marketing safety surveillance data by extracting adverse events following immunisation (AEFIs) associated with this vaccine from the integrated Public Health Information System. Reports were screened for key terms related to narcolepsy and further limited to children and young adults four to 29 years of age. Of 1,604 AEFIs reported in Ontario, 53 reports met the search criteria. Individual assessment by a nurse consultant for additional context suggestive of narcolepsy yielded five reports for secondary medical review. None of the five reports proved consistent with a possible narcolepsy diagnosis based on the available information. We present the first post-marketing assessment from Canada of narcolepsy reports following receipt of Arepanix. Continued investigation of differences between Arepanrix and Pandemrix and subsequent risk of narcolepsy is indicated. In light of the limitations of passive surveillance to detect a signal in this instance, validation using other data sources is prudent.

A dose-response relationship between organic mercury exposure from thimerosal-containing vaccines and neurodevelopmental disorders

A hypothesis testing case-control study evaluated concerns about the toxic effects of organic-mercury (Hg) exposure from thimerosal-containing (49.55% Hg by weight) vaccines on the risk of neurodevelopmental disorders (NDs). Automated medical records were examined to identify cases and controls enrolled from their date-of-birth (1991–2000) in the Vaccine Safety Datalink (VSD) project. ND cases were diagnosed with pervasive developmental disorder (PDD), specific developmental delay, tic disorder or hyperkinetic syndrome of childhood. In addition, putative non-thimerosal-related outcomes of febrile seizure, failure to thrive and cerebral degenerations were examined. The cumulative total dose of Hg exposure from thimerosal-containing hepatitis B vaccine (T-HBV) administered within the first six months of life was calculated. On a per microgram of organic-Hg basis, PDD (odds ratio (OR) = 1.054), specific developmental delay (OR = 1.035), tic disorder (OR = 1.034) and hyperkinetic syndrome of childhood (OR = 1.05) cases were significantly more likely than controls to receive increased organic-Hg exposure. By contrast, none of the non-thimerosal related outcomes were significantly more likely than the controls to have received increased organic-Hg exposure. Routine childhood vaccination may be an important public health tool to reduce infectious disease-associated morbidity/mortality, but the present study significantly associates organic-Hg exposure from T-HBV with an increased risk of an ND diagnosis.

Data mining for prospective early detection of safety signals in the Vaccine Adverse Event Reporting System (VAERS): a case study of febrile seizures after a 2010-2011 seasonal influenza virus vaccine

BACKGROUND

Reports of data mining results as an initial indication of a prospectively detected safety signal in the US Vaccine Adverse Event Reporting System (VAERS) have been limited. In April 2010 a vaccine safety signal for febrile seizures after Fluvax(®) and Fluvax(®) Junior was identified in Australia without the aid of data mining. In order to refine Northern Hemisphere influenza vaccine safety surveillance, VAERS data mining analyses based on vaccine brand name were initiated during the 2010-2011 influenza season.

OBJECTIVE

We describe the strategies that led to the finding of a novel safety signal using empirical Bayesian data mining.

METHODS

The primary US VAERS analysis calculated an empirical Bayesian geometric mean (EBGM), which was adjusted for age group, sex and year received. A secondary age-stratified analysis calculated a separate EBGM for 11 pre-defined age subsets. These bi-weekly analyses were generated with database restrictions that separated live and inactivated vaccines as well as with the US VAERS database. A cutoff of 2.0 at the fifth percentile of the confidence interval (CI) for the EBGM, the EB05, was used to identify vaccine adverse event combinations for further evaluation. Examination of potential interactions among concomitantly administered vaccines is based on the Interaction Signal Score (INTSS), which is a relative measure of how much excess disproportionality is present in the three-dimensional combination of two vaccines and one adverse event term. An INTSS >1 indicates that the CI for the three-dimensional analysis is larger than and does not overlap with the CI from the highest two-dimensional analysis. We subsequently examined the possibility of masking by removing all 2,095 Fluzone(®) 2010-2011 reports from the 10 December 2010 version of the VAERS database. In addition, we calculated relative reporting ratios to observe the relative contribution of adjustment and the Multi-Item Gamma Poisson Shrinker (MGPS) algorithm to EBGM values.

RESULTS

On 10 December 2010, US VAERS analyses we found an EB05 >2 for Fluzone(®) 2010-2011 and the Medical Dictionary for Regulatory Activities (MedDRA(®)) term "febrile seizure". MedDRA(®) terminology is the medical terminology developed under the auspices of the International Conference on Harmonization of technical requirements for Registration of Pharmaceuticals for Human Use (ICH). No other vaccine products had independent vaccine-febrile seizure combinations with an EB05 >2. Three-dimensional analyses to examine possible interactions among vaccine products concomitantly administered with Fluzone(®) 2010-2011 yielded Interaction Signal Score values <1. Removal of all Fluzone(®) 2010-2011 reports from the VAERS database failed to demonstrate a previously masked vaccine adverse event pair with an EB05 >2. The inactivated vaccine database restriction resulted in a 41 % reduction in background VAERS reports and a 24 % reduction in foreground VAERS reports.

CONCLUSION

Empirical Bayesian data mining in VAERS prospectively detected the safety signal for febrile seizures after Fluzone(®) 2010-2011 in young children. The EB05 threshold, database restrictions, adjustment and baseline data mining were strategies adopted a priori to enhance the specificity of the 2010-2011 influenza vaccine data mining analyses. A database restriction used to separate live vaccines resulted in a reduced EB05. Adjustment of data mining analyses had a larger effect on estimates of disproportionality than the MGPS algorithm. Masking did not appear to influence our findings. This case study illustrates the value of VAERS data mining for vaccine safety monitoring.

Epidemiological and clinical reasons for vaccination against pertussis and influenza in pregnant women

Vaccinations in pregnancy are an important aspect of prenatal care for improving both maternal health and neonatal outcomes. Despite the fact that protection against some infectious diseases for pregnant women can be easily provided through immunizations, current coverage rates are low. Two vaccines are notably recommended during pregnancy: influenza and the combined tetanus, diphtheria and acellular pertussis (Tdap) vaccine. In this review the authors discuss current recommendations for vaccination against pertussis and influenza in pregnant women in terms of epidemiological, clinical, and immunological reasons, taking into account safety and effectiveness. Promoting patients' awareness about pertussis and influenza and encouraging general practitioners, nurses and obstetricians to recommend the pertussis booster and influenza vaccine will hopefully increase the number of pregnant women who choose to become vaccinated.

A two-phase study evaluating the relationship between Thimerosal-containing vaccine administration and the risk for an autism spectrum disorder diagnosis in the United States

Background

Autism spectrum disorder (ASD) is defined by standardized criteria of qualitative impairments in social interaction, qualitative impairments in communication, and restricted and stereotyped patterns of behavior, interests, and activities. A significant number of children diagnosed with ASD suffer a loss of previously-acquired skills, which is suggestive of neurodegeneration or a type of progressive encephalopathy with an etiological pathogenic basis occurring after birth. To date, the etiology of ASD remains under debate, however, many studies suggest toxicity, especially from mercury (Hg), in individuals diagnosed with an ASD. The present study evaluated concerns about the toxic effects of organic-Hg exposure from Thimerosal (49.55% Hg by weight) in childhood vaccines by conducting a two-phased (hypothesis generating/hypothesis testing) study with documented exposure to varying levels of Thimerosal from vaccinations.

Methods

A hypothesis generating cohort study was undertaken to evaluate the relationship between exposure to organic-Hg from a Thimerosal-containing Diphtheria-Tetanus-acellular-Pertussis (DTaP) vaccine in comparison to a Thimerosal-free DTaP vaccine administered, from 1998 through 2000, for the risk of ASD as reported in the Vaccine Adverse Event Reporting System (VAERS) database (phase I). A hypothesis testing case–control study was undertaken to evaluate the relationship between organic-Hg exposure from Thimerosal-containing hepatitis B vaccines administered at specific intervals in the first six months of life among cases diagnosed with an ASD and controls born between 1991 through 1999 in the Vaccine Safety Datalink (VSD) database (phase II).

Results

In phase I, it was observed that there was a significantly increased risk ratio for the incidence of ASD reported following the Thimerosal-containing DTaP vaccine in comparison to the Thimerosal-free DTaP vaccine. In phase II, it was observed that cases diagnosed with an ASD were significantly more likely than controls to receive increased organic-Hg from Thimerosal-containing hepatitis B vaccine administered within the first, second, and sixth month of life.

Conclusions

Routine childhood vaccination is an important public health tool to reduce the morbidity and mortality associated with infectious diseases, but the present study provides new epidemiological evidence supporting an association between increasing organic-Hg exposure from Thimerosal-containing childhood vaccines and the subsequent risk of an ASD diagnosis.

A probabilistic model for reducing medication errors

Background

Medication errors are common, life threatening, costly but preventable. Information technology and automated systems are highly efficient for preventing medication errors and therefore widely employed in hospital settings. The aim of this study was to construct a probabilistic model that can reduce medication errors by identifying uncommon or rare associations between medications and diseases.

Methods and Finding(s)

Association rules of mining techniques are utilized for 103.5 million prescriptions from Taiwan’s National Health Insurance database. The dataset included 204.5 million diagnoses with ICD9-CM codes and 347.7 million medications by using ATC codes. Disease-Medication (DM) and Medication-Medication (MM) associations were computed by their co-occurrence and associations’ strength were measured by the interestingness or lift values which were being referred as Q values. The DMQs and MMQs were used to develop the AOP model to predict the appropriateness of a given prescription. Validation of this model was done by comparing the results of evaluation performed by the AOP model and verified by human experts. The results showed 96% accuracy for appropriate and 45% accuracy for inappropriate prescriptions, with a sensitivity and specificity of 75.9% and 89.5%, respectively.

Conclusions

We successfully developed the AOP model as an efficient tool for automatic identification of uncommon or rare associations between disease-medication and medication-medication in prescriptions. The AOP model helps to reduce medication errors by alerting physicians, improving the patients’ safety and the overall quality of care.

Tracking vaccine-safety inquiries to detect signals and monitor public concerns

BACKGROUND

The Centers for Disease Control and Prevention frequently receives inquiries from health care providers, public health officials, and the general public seeking data or guidance on vaccine-safety issues. Past inquiries to public health authorities identified potential problems including viscerotropic illness rarely associated with yellow fever vaccination.

OBJECTIVE

To systematically describe vaccine-safety inquiries received at the Centers for Disease Control and Prevention.

METHODS

External and internal inquiries were recorded in a database from May 1, 2002 to May 31, 2009. Key variables analyzed included the source of the question, the type of information being sought, and the vaccine type(s) associated with the inquiry.

RESULTS

A total of 983 vaccine-safety inquiries were answered and analyzed. Health care workers were the source of 43% of the questions, and the general public accounted for 19% of the questions. Nearly half of the requests (49%) concerned information about the Vaccine Adverse Event Reporting System, and nearly one-fourth (21%) were requests from providers for clinical guidance. The most frequent specific topics of inquiry and vaccines involved were neurologic adverse events (AEs) temporally associated with vaccination (17%) and safety of all vaccines or childhood vaccines (20%), respectively.

CONCLUSIONS

Questions about rare but potentially serious AEs and general concerns about vaccine safety were encountered relatively frequently. The substantial number of clinically focused inquiries may indicate a need for more provider support tools and resources. Tracking of inquiries can supplement information received through vaccine AE reporting and contribute to an enhanced scientific and communications response to vaccine-safety concerns.

An automated technique for identifying associations between medications, laboratory results and problems

BACKGROUND

The patient problem list is an important component of clinical medicine. The problem list enables decision support and quality measurement, and evidence suggests that patients with accurate and complete problem lists may have better outcomes. However, the problem list is often incomplete.

OBJECTIVE

To determine whether association rule mining, a data mining technique, has utility for identifying associations between medications, laboratory results and problems. Such associations may be useful for identifying probable gaps in the problem list.

DESIGN

Association rule mining was performed on structured electronic health record data for a sample of 100,000 patients receiving care at the Brigham and Women's Hospital, Boston, MA. The dataset included 272,749 coded problems, 442,658 medications and 11,801,068 laboratory results.

MEASUREMENTS

Candidate medication-problem and laboratory-problem associations were generated using support, confidence, chi square, interest, and conviction statistics. High-scoring candidate pairs were compared to a gold standard: the Lexi-Comp drug reference database for medications and Mosby's Diagnostic and Laboratory Test Reference for laboratory results.

RESULTS

We were able to successfully identify a large number of clinically accurate associations. A high proportion of high-scoring associations were adjudged clinically accurate when evaluated against the gold standard (89.2% for medications with the best-performing statistic, chi square, and 55.6% for laboratory results using interest).

CONCLUSION

Association rule mining appears to be a useful tool for identifying clinically accurate associations between medications, laboratory results and problems and has several important advantages over alternative knowledge-based approaches.

Vaccine safety: current systems and recent findings

PURPOSE OF REVIEW

An understanding of vaccine safety is important for all immunization providers, who have responsibilities to identify, report, and prevent adverse events.

RECENT FINDINGS

New analytic methods can provide more rapid information on adverse events compared with traditional observational studies. Some adverse events following vaccination are preventable. Syncope is increasingly recognized postvaccination and may be associated with severe injury or death. Both human and system factors should be addressed to prevent vaccine administration errors. Ongoing basic science and clinical research is critical to improved understanding of vaccine safety. A recent study suggests that many cases of encephalopathy following whole-cell pertussis vaccine were due to severe myoclonic epilepsy of infancy, a severe seizure disorder associated with mutations of the sodium channel gene SCN1A.

SUMMARY

Vaccine safety requires prelicensure evaluation, postlicensure surveillance and investigation, addressing preventable adverse events, reconsideration of vaccine policy as understanding of risks and benefits changes, and ongoing research to better understand the response to vaccination and the pathogenesis of adverse events.

Comorbidity study of ADHD: applying association rule mining (ARM) to National Health Insurance Database of Taiwan

OBJECTIVE

This paper intends to apply association rule mining (ARM) to explore the labyrinthian network of ADHD comorbidity, and to examine the practicality of ARM in comorbidity studies using clinic databases.

METHODS

From clinic records of enrollees of Taiwan National Health Insurance (NHI), 18,321 youngsters aged 18 or less with diagnosis of ADHD in 2001 were recruited as case group in this study. And all their clinic diagnoses made from 2000 to 2002, as comorbidity, were categorized according to "The International Classification of Disease, 9th Revision, Clinical Modification" (ICD-9-CM) diagnosis system. For comparison, fourfold non-ADHD controls were recruited from 2001s NHI enrollees on a random base but matched gender and age of cases. ARM was done with Apriori algorithm to examine the strengths of associations among those diagnoses. The support and confidence values of ARM results were examined. Comorbidity rates and relative risk (RR) ratios of both groups of each diagnosis were compared one another.

RESULTS

ADHD case group has apparently higher risk of comorbidity with psychiatric comorbidity than with other physical illnesses. From results of ARM, developmental delay (DD) appears as an important node between ADHD and anxiety disorder (support: 5.12%, confidence: 97.42%), mild mental retardation (support: 4.42%, confidence: 92.09%) and autism (support: 6.49%, confidence: 94.93%).

CONCLUSIONS

The finding of this study, an important role of DD between ADHD and other psychiatric comorbidity, supports neurological findings in developmental delay of ADHD children's front cortex, as well as some epidemiology findings. This study also demonstrated the practicality of ARM in comorbidity studies using enormous clinic databases like NHIRD.

Global safety of vaccines: strengthening systems for monitoring, management and the role of GACVS

Vaccines have contributed enormously in reducing the impact of many infectious diseases, and the expanded use of new and existing vaccines provides unprecedented potential for further reducing the global burden of infectious diseases. Yet, as with the deployment of other technologies, their use may also sometimes be associated with undesirable effects that need to be identified rapidly, understood and minimized. In this article, we review the models and systems that have been developed to monitor and respond to concerns regarding vaccine safety and we give illustrative examples of real or perceived vaccine safety issues. The Global Advisory Committee on Vaccine Safety (GACVS) was set up 10 years ago and charged to provide the WHO with independent advice on vaccine safety issues. The role of the GACVS is both to analyze and to interpret reports of the adverse effects of vaccines that impact on global vaccination programs and strategies, and to foster the development of improved surveillance systems to detect any adverse effects of vaccines, particularly in low- and middle-income countries. It also monitors the development of new vaccines during clinical testing and advises on the safe use of vaccines in immunization programs. As success is achieved with reducing the burden of vaccine-preventable diseases, there will be increasing attention focused on potential adverse effects, on the development of effective surveillance systems to detect adverse effects, and on improved methods to manage and control any harmful consequences of vaccination.

Serious adverse events rarely reported after trivalent inactivated influenza vaccine (TIV) in children 6-23 months of age

In October 2003 the Advisory Committee on Immunization Practices (ACIP) recommended influenza vaccination for all children ages 6-23 months. We evaluated the safety of this recommendation by querying the Vaccine Adverse Events Reporting System (VAERS) for serious adverse events (SAE) reported between July 1, 2003 and June 30, 2006 in 6-23 month old infants after trivalent inactivated influenza vaccine (TIV). Cases were reviewed and the causal relationship with vaccine assessed. One hundred and four SAE were reported; median time from vaccination to SAE onset was one day. The two most commonly reported SAE disease categories were fever (N=52) and seizure (N=35). Causality assessment revealed that none of the SAE was definitely related to TIV. Although the number of SAE increased over time, the most common types of events remained unchanged with no new or unexpected safety concerns identified with expanded TIV use.

Regional and national health care data repositories

Efforts are underway to define a national framework for secondary analysis of health-related data. In the meantime, regional health databases have been constructed using insurance claims data, clinical data from single large health care providers, clinical data from multiple collaborating health care providers, and public health data. Large-scale survey data also are available in government databases. Clinical laboratory results are an important component of all these databases because they can provide validation for manually assigned diagnostic and procedure codes and can support inference of key information not provided by coding, such as severity of disease and prevalence of risk factors.

Safety review of the purified chick embryo cell rabies vaccine: Data from the Vaccine Adverse Event Reporting System (VAERS), 1997–2005

On October 20, 1997, the U.S. Food and Drug Administration (FDA) licensed Purified Chick Embryo Cell (PCEC, RabAvert) vaccine against rabies in humans following clinical trials demonstrating safety and efficacy. From October 1997 through December 2005, the Vaccine Adverse Event Reporting System (VAERS) received 336 reports of adverse events (AEs) following vaccination with PCEC vaccine in the U.S.; there were no death reports. Serious events, including 20 hospitalizations and 13 neurological events, were described in 24 (7%) reports. There was no pattern among the 13 neurological AEs suggesting a plausible relationship to vaccination. A total of 20 AEs, 3 serious, were classified as possible anaphylaxis. There were 312 non-serious AEs (93%). Nineteen reports (6%) described that the vaccination series was discontinued because of non-serious AEs. Most reported AEs are non-serious and consistent with pre-licensure safety data. The rabies risk must be carefully considered before vaccine discontinuation.

A comparative assessment of immunization records in the Defense Medical Surveillance System and the Vaccine Adverse Event Reporting System

We compared immunization data in the Defense Medical Surveillance System (DMSS) and immunization data for service members with an anthrax vaccine-associated adverse event reported to the Vaccine Adverse Event Reporting System (VAERS) during January 1998 through December 2004. Our main measure of agreement was sensitivity of the DMSS conditional on an immunization record(s) occurring in VAERS. The sensitivity of DMSS was 73% for all vaccines and 74% for the anthrax vaccine on the VAERS index immunization date. Our study is the first to quantify the agreement between immunization records in VAERS and DMSS. Our data suggest the immunization information in military VAERS reports and the DMSS is similar for anthrax and non-anthrax immunizations.