Methods of ensuring vaccine safety

Safety surveillance of meningococcal group B vaccine (Bexsero®), Vaccine Adverse Event Reporting System, 2015-2018

BACKGROUND

Bexsero® (GlaxoSmithKline) is a four-component Neisseria meningitidis serogroup B vaccine (MenB-4C). It was licensed in the United States in 2015 for use among individuals ages 10-25 years. We aimed to assess the post-licensure safety profile of MenB-4C by examining reports received in the Vaccine Adverse Event Reporting System (VAERS).

METHODS

VAERS is a national passive surveillance system for adverse events (AEs) following immunization that uses the Medical Dictionary for Regulatory Activities to code reported AEs and the Code of Federal Regulations to classify reports by seriousness. In this case series, we analyzed U.S. reports involving MenB-4C received between January 23, 2015 through December 31, 2018. We used Empirical Bayesian data mining to identify MenB-4C/AE combinations reported at least twice as often as expected.

RESULTS

VAERS received 1,867 reports following MenB-4C administration, representing 332 reports per million doses distributed. Most reports were for females (59%), with a median age of 17 years (interquartile range: 16-18 years); 40% of reports described simultaneous administration of other vaccines. The majority of reports were classified as non-serious (96%). The most commonly reported AEs were injection site pain (22%), pyrexia (16%), and headache (16%). Data mining identified disproportionate reporting for "injected limb mobility decreased" secondary to injection site reactions, including extensive swelling of the vaccinated limb and injection site pain.

CONCLUSIONS

Analysis of passive surveillance data from over 5.6 million doses of MenB-4C distributed in the United States did not reveal new safety concerns. The large majority of reports were classified as non-serious and the reported AEs were generally consistent with the safety experience described in clinical studies and the product's package insert. While our results are reassuring, continued post-marketing surveillance is warranted.

Adverse events reported to the U.S. Food and Drug Administration Adverse Event Reporting System for tisagenlecleucel

The U.S. Food and Drug Administration (FDA) approved the first chimeric antigen receptor T-cell therapy, tisagenlecleucel, in August 2017. We sought to describe adverse events (AEs) reported to the FDA Adverse Event Reporting System (FAERS) for tisagenlecleucel in the post-marketing period. We searched FAERS reports to identify U.S. patients treated with tisagenlecleucel between August 30, 2017-August 31, 2019. We reviewed individual reports, calculated AE frequencies and reporting rates (RRs), and used Empirical Bayesian Geometric Mean methods to identify disproportionate reporting. We identified 646 de-duplicated reports with a median age at AE of 18 (interquartile range: 11-56) years. The overall RR was 81.0%, and more than 95% of reports described a serious outcome. Cytokine release syndrome (CRS) was the most frequently reported AE (51.1%) with a RR of 41.4%; neurotoxicity was reported less frequently (21.2%), with a RR of 17.2%. Most disproportionately reported AEs were listed on the package insert or confounded by indication. We identified 13 subsequent neoplasms (SPN), the majority occurring within 6 months of tisagenlecleucel administration, and none reporting evidence of insertional mutagenesis. A total of 165 reports (26%) described a death outcome; most deaths occurred >30 days after treatment. The majority of deaths (64%) were due to progression of the underlying lymphoid neoplasm, and few (<5%) were attributed to CRS or neurotoxicity. We did not identify new safety concerns reported for tisagenlecleucel in the post-marketing period. Reporting rates for CRS and neurotoxicity were lower than identified in the prelicensure clinical trials.

Monitoring the safety of high-dose, trivalent inactivated influenza vaccine in the vaccine adverse event reporting system (VAERS), 2011 - 2019

BACKGROUND

On 12/23/2009 a new high-dose trivalent inactivated influenza vaccine (IIV3-HD) was licensed for adults aged ≥65 years. We assessed the post-licensure safety data for IIV3-HD in the Vaccine Adverse Event Reporting System (VAERS) during 2011-2019.

METHODS

We searched VAERS for reports after IIV3-HD during 1/1/2011-06/30/2019 in persons aged ≥65 years. Medical records were reviewed for all death reports and for certain pre-specified conditions (e.g. Guillain Barré Syndrome [GBS], anaphylaxis). We also reviewed certain groups who received IIV3-HD erroneously (e.g. pregnant women, children). Empirical Bayesian data mining was used to identify disproportional reporting.

RESULTS

VAERS received 12,320 reports after IIV3-HD;723 reports (5.9%) were serious. The most common adverse events (AEs) among serious reports were pyrexia (30.2%), asthenia (28.9%), and dyspnea (24.9%), and among non-serious reports were injection site erythema (16.8%), pain in extremity (15.8%), and injection site pain (14.2%). Among 55 death reports, the most common causes of death were diseases of the circulatory system (n = 23;41.8%). Based on medical record review, there were 61 reports of GBS and 13 of anaphylaxis. There were 13 reports of pregnant-women who inadvertently received IIV3-HD; three reports described arm pain or local reactions, and 10 did not report any AE. Among 59 reports of children who erroneously received IIV3-HD, 31 experienced an AE (most commonly injection site or constitutional reactions) and the remaining 28 reports did not describe any AE.

CONCLUSIONS

Post-licensure safety data of IIV3-HD during 9 influenza seasons revealed no new or unexpected safety concerns among individuals ≥65 years. Inadvertent administration of IIV3-HD to children or pregnant women was observed, although with no serious AEs reported. Training and education of providers in vaccine recommendations and groups for whom the vaccine is indicated may help in preventing these vaccine administration errors. This review provides baseline information for future monitoring of the quadrivalent-high-dose influenza vaccine.

Adverse Events Associated With the Use of Sipuleucel-T Reported to the US Food and Drug Administration's Adverse Event Reporting System, 2010-2017

IMPORTANCE

Sipuleucel-T was the first therapeutic cancer vaccine approved by the US Food and Drug Administration (FDA) in 2010. Although almost a decade has passed since its approval for the treatment of asymptomatic or minimally symptomatic castration-resistant prostate cancer (CRPC), there remains a paucity of literature describing safety data in the postmarketing period.

OBJECTIVE

To describe the postmarketing safety experience for sipuleucel-T.

DESIGN, SETTING, AND PARTICIPANTS

In this case series study, US reports for sipuleucel-T submitted to the FDA's Adverse Event Reporting System were searched and reviewed between April 29, 2010, and December 31, 2017. This system is a spontaneous safety surveillance database for drug and therapeutic biologic products. The analysis of 3216 reports and select case reviews were undertaken between February and November 2018.

MAIN OUTCOMES AND MEASURES

Descriptive statistics were used to assess adverse event reports for sipuleucel-T. Empirical Bayes Geometric Means (EBGM) and their 90% confidence intervals (CIs) were computed to identify disproportionate (ie, at least twice the expected) reporting of sipuleucel-T-event pairs. Selected adverse events and death reports were individually reviewed.

RESULTS

In total, 3216 reports were identified for sipuleucel-T, of which 2014 (62.6%) were serious. For all included reports, the patients' median (interquartile range) age was 73 (67-79) years, and 3149 were specified to be males. Chills (n = 318), malaise (n = 196), pyrexia (n = 189), culture positive (n = 184), fatigue (n = 180), and nausea (n = 173) were among the most commonly reported adverse events. Infusion-related reactions (EBGM, 12.1; 90% CI, 9.4-15.3), infections, vascular events, and transient ischemic attacks (EBGM, 2.9; 90% CI, 2.2-3.9) were reported disproportionately. Among 249 deaths for which relevant dates were available, 128 (51.4%) were reported within 30 days of a sipuleucel-T infusion, of which 81.2% included a specified cause of death; of these 104 deaths, there were 37 neoplasms (35.6%), 25 cardiac disorders (24.0%), 18 nervous system disorders (17.3%), and 9 infections (8.7%).

CONCLUSIONS AND RELEVANCE

Reported adverse events were generally consistent with the safety experience observed in prelicensure studies and described in the sipuleucel-T package insert. Off-label use among overtly symptomatic men with CRPC, reporting bias, or lack of product effectiveness may have influenced the reporting of deaths within 30 days of treatment initiation. With this overview of sipuleucel-T experience, the present study serves as a resource for health care professionals and patients as they weigh the risks and benefits of treatment in the context of all available therapeutic options for CRPC.

Safety Surveillance of Diphtheria and Tetanus Toxoids and Acellular Pertussis (DTaP) Vaccines

OBJECTIVE

To assess the safety of currently licensed diphtheria-tetanus-acellular pertussis (DTaP) vaccines in the United States by using data from the Vaccine Adverse Event Reporting System (VAERS), a spontaneous reporting surveillance system.

METHODS

We searched VAERS for US reports of DTaP vaccinations occurring from January 1, 1991, through December 31, 2016, and received by March 17, 2017. We reviewed available medical records for all death reports and a random sample of reports classified as nondeath serious. We used Empirical Bayesian data mining to identify adverse events that were disproportionally reported after DTaP vaccination.

RESULTS

VAERS received 50 157 reports after DTaP vaccination; 43 984 (87.7%) of them reported concomitant administration of other vaccines, and 5627 (11.2%) were serious. Median age at vaccination was 19 months (interquartile range 35 months). The most frequently reported events were injection site erythema (12 695; 25.3%), pyrexia (9913; 19.8%), injection site swelling (7542; 15.0%), erythema (5599; 11.2%), and injection site warmth (4793; 9.6%). For 3 of the DTaP vaccines, we identified elevated values for vaccination errors using Empirical Bayesian data mining.

CONCLUSIONS

No new or unexpected adverse events were detected. The observed disproportionate reporting for some nonserious vaccination errors calls for better education of vaccine providers on the specific indications for each of the DTaP vaccines.

Improving vaccines by incorporating immunological coadjuvants

While vaccination continues to be the most successful interventionist health policy to date, infectious disease remains a significant cause of death worldwide. A primary reason that vaccination is not able to generate effective immunity is a lack of appropriate adjuvants capable of initiating the desired immune response. Adjuvant combinations can potentially overcome this problem; however, the possible permutations to consider, which include the route and kinetics of vaccination, as well as combinations of adjuvants, are practically limitless. This review aims to summarize the current understanding of adjuvants and related immunological processes and how this knowledge can and has been applied to the strategic selection of adjuvant combinations as components of vaccines against human infectious disease.

Considerations for controlling invasive meningococcal disease in high income countries

The development of conjugate vaccines has enabled the prevention and control of Neisseria meningitidis caused by serogroups A, C, W-135 and Y. Vaccines that provide protection against a broad number of serogroup B strains likely will be available soon to enable greater control of meningococcal disease in high income countries. We present an argument for adequate post-marketing surveillance to monitor epidemiological shifts and to provide a context for the safety and reactogenicity of serogroup B vaccines, including the newer recombinant vaccines. We also offer a series of recommendations to address possible concerns about vaccine safety.

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.

A process for sentinel case review to assess causal relationships between smallpox vaccination and adverse outcomes, 2003-2004

The US Department of Defense requested that the Advisory Committee on Immunization Practices-Armed Forces Epidemiological Board joint Smallpox Vaccine Safety Working Group define the likelihood that smallpox vaccination played a causal role in the fatal illness of an Army reservist. Reported serious adverse events for which there was no a priori reason to discount the existence of a causal association with smallpox vaccine were reviewed to assess whether they were signals of constellations of vaccine-associated adverse events. A causal relationship between the immunization experience and the index patient's death was favored, but the implication of an individual vaccine was precluded. No new smallpox vaccine-associated clinical syndromes were identified. The data supported neutrality regarding the hypothesis that dilated cardiomyopathy was causally associated with smallpox vaccine-induced myocarditis. This review of sentinel cases augmented the ongoing safety review process and was transparent, but it shares limitations with other case-based causality-assessment methods.

Neurological adverse events of immunization: experience with an aluminum adjuvanted meningococcal B outer membrane vesicle vaccine

Throughout the history of vaccination, vaccines have been accused of harmful side effects. Adverse events following immunization may be caused by the active antigen in the vaccine or other constituents, such as adjuvants, or may merely be coincidental. Possible neurological side effects have always obtained high attention. However, the risk of serious events caused by existing vaccines or aluminum adjuvants is very small. Currently, there are several new vaccines and adjuvants in the pipeline. Of these vaccines, many will be offered mainly to adolescents or adults. When taken into general use, some of them will probably be associated with serious adverse events. Although coincidence will be the most probable explanation in most cases, causality will have to be discussed in many situations. Preparing to address the causes of these adverse events is important.

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

The US Vaccine Adverse Event Reporting System (VAERS), which is charged with vigilance for detecting vaccine-related safety issues, faces an increasingly complex immunisation environment. Since 1990, steady increases in vaccine licensing and distribution have resulted in increasing numbers of reports to VAERS. Prominent features of current reports include more routine vaccine co-administration and frequent reports of new postvaccination clinical syndromes. Data-mining methods, based on disproportionality analyses, are one strategy being pursued by VAERS researchers to increase the utility of its complex database. The types of analyses used include proportional reporting ratios, association rule discovery, and various 'historic limits' methods that compare observed versus expected event counts. The use of such strategies in VAERS has been primarily supplemental and retrospective. Signals for inactivated influenza, typhoid and tetanus toxoid-containing vaccines have been successfully identified. Concerns flagged through data mining should always be subject to clinical case review as a first evaluation step. Persistent issues should be subject to formal hypothesis testing in large linked databases or other controlled-study settings. Automated data-mining techniques for prospective use are currently undergoing development and evaluation within VAERS. Their use (as one signal-detection tool among many) by trained medical evaluators who are aware of system limitations is one legitimate approach to improving the ability of VAERS to generate vaccine-safety hypotheses. Such approaches are needed as more new vaccines continue to be licensed.

Understanding vaccine safety information from the Vaccine Adverse Event Reporting System

The Vaccine Adverse Event Reporting System (VAERS) is administered by the Food and Drug Administration and CDC and is a key component of postlicensure vaccine safety surveillance. Its primary function is to detect early warning signals and generate hypotheses about possible new vaccine adverse events or changes in frequency of known ones. VAERS is a passive surveillance system that relies on physicians and others to voluntarily submit reports of illness after vaccination. Manufacturers are required to report all adverse events of which they become aware. There are a number of well-described limitations of such reporting systems. These include, for example, variability in report quality, biased reporting, underreporting and the inability to determine whether a vaccine caused the adverse event in any individual report. Strengths of VAERS are that it is national in scope and timely. The information in VAERS reports is not necessarily complete nor is it verified systematically. Reports are classified as serious or nonserious based on regulatory criteria. Reports are coded by VAERS in a uniform way with a limited number of terms using a terminology called COSTART. Coding is useful for search purposes but is necessarily imprecise. VAERS is useful in detecting adverse events related to vaccines and most recently was used for enhanced reporting of adverse events in the national smallpox immunization campaign. VAERS data have always been publicly available. However, it is essential for users of VAERS data to be fully aware of the strengths and weaknesses of the system. VAERS data contain strong biases. Incidence rates and relative risks of specific adverse events cannot be calculated. Statistical significance tests and confidence intervals should be used with great caution and not routinely. Signals detected in VAERS should be subjected to further clinical and descriptive epidemiologic analysis. Confirmation in a controlled study is usually required. An understanding of the system's defined objectives and inherent drawbacks is vital to the effective use of VAERS data in vaccine safety investigations.

Postmarketing safety surveillance for typhoid fever vaccines from the Vaccine Adverse Event Reporting System, July 1990 through June 2002

Vaccines against Salmonella enterica serotype Typhi are used for prophylaxis of international travelers and have potential use as counterbioterrorism agents. The Vaccine Adverse Event Reporting System (VAERS) cannot usually establish causal relationships between vaccines and reported adverse events without further research but has successfully detected unrecognized side effects of vaccine. We reviewed reports to VAERS for US-licensed typhoid fever vaccines for the period of July 1990 through June 2002. We received 321 reports for parenteral Vi capsular polysaccharide vaccine and 345 reports for live, oral, attenuated Ty21a vaccine, with 7.5% and 5.5%, respectively, describing death, hospitalization, permanent disability, or life-threatening illness. Unexpected frequently reported symptoms included dizziness and pruritus for Vi vaccine and fatigue and myalgia for Ty21a vaccine. Gastroenteritis-like illness after receipt of Ty21a vaccine and abdominal pain after receipt of Vi vaccine, which are previously recognized events, occasionally required hospitalization. Nonfatal anaphylaxis was reported after both vaccines. VAERS reports do not indicate any unexpected serious side effects that compromise these vaccines' use for travelers' prophylaxis.