Post-Marketing Surveillance of Human Rabies Diploid Cell Vaccine (Imovax) in the Vaccine Adverse Event Reporting System (VAERS) in the United States, 1990‒2015

BACKGROUND

In 1980, human diploid cell vaccine (HDCV, Imovax Rabies, Sanofi Pasteur), was licensed for use in the United States.

OBJECTIVE

To assess adverse events (AEs) after HDCV reported to the US Vaccine Adverse Event Reporting System (VAERS), a spontaneous reporting surveillance system.

METHODS

We searched VAERS for US reports after HDCV among persons vaccinated from January 1, 1990-July 31, 2015. Medical records were requested for reports classified as serious (death, hospitalization, prolonged hospitalization, disability, life-threatening-illness), and those suggesting anaphylaxis and Guillain-Barré syndrome (GBS). Physicians reviewed available information and assigned a primary clinical category to each report using MedDRA system organ classes. Empirical Bayesian (EB) data mining was used to identify disproportional AE reporting after HDCV.

RESULTS

VAERS received 1,611 reports after HDCV; 93 (5.8%) were serious. Among all reports, the three most common AEs included pyrexia (18.2%), headache (17.9%), and nausea (16.5%). Among serious reports, four deaths appeared to be unrelated to vaccination.

CONCLUSIONS

This 25-year review of VAERS did not identify new or unexpected AEs after HDCV. The vast majority of AEs were non-serious. Injection site reactions, hypersensitivity reactions, and non-specific constitutional symptoms were most frequently reported, similar to findings in pre-licensure studies.

Post-licensure surveillance of quadrivalent inactivated influenza (IIV4) vaccine in the United States, Vaccine Adverse Event Reporting System (VAERS), July 1, 2013-May 31, 2015

BACKGROUND

Quadrivalent inactivated influenza vaccines (IIV4) were first available for use during 2013-14 influenza season for individuals aged ≥6 months. IIV4 is designed to protect against four different flu viruses; two influenza A viruses and two influenza B viruses.

METHODS

We searched the Vaccine Adverse Event Reporting System (VAERS) for US reports after IIV4 and trivalent inactivated influenza vaccine (IIV3) from 7/1/2013-5/31/2015. Medical records were requested for non-manufacturer reports classified as serious (i.e. death, hospitalization, prolonged hospitalization, life-threatening illness, permanent disability). The review included automated data analysis, clinical review of all serious reports, reports of special interest, and empirical Bayesian data mining.

RESULTS

VAERS received 1,838 IIV4 reports; 512 (28%) in persons aged 6 months-17 years of which 42 (8.2%) were serious reports; 1,265 (69%) in persons aged >18 years of which 84 (6.6%) were serious reports; two in children <6 months and 59 in persons of unknown age. Injection site erythema (24%), fever (14%) and injection site swelling (17%) were the most frequent adverse events among persons aged 6 months-17 years, while injection site pain (16%), pain (15%) and pain in extremity (13%) were the most frequent among persons aged 18-64 years given the vaccine alone. Among non-death serious reports, injection site reactions, constitutional symptoms, Guillain-Barré syndrome, seizures, and anaphylaxis were the most frequently reported adverse events. Data mining detected disproportional reporting for incorrect vaccine administration with no associated adverse events. Adverse events following IIV4 reported to VAERS were similar to those following IIV3.

CONCLUSIONS

In our review of VAERS reports, IIV4 had a similar safety profile to IIV3. Most of the reported AEs were non-serious. Our findings are consistent with data from pre-licensure studies of IIV4.

Can Natural Language Processing Improve the Efficiency of Vaccine Adverse Event Report Review?

BACKGROUND

Individual case review of spontaneous adverse event (AE) reports remains a cornerstone of medical product safety surveillance for industry and regulators. Previously we developed the Vaccine Adverse Event Text Miner (VaeTM) to offer automated information extraction and potentially accelerate the evaluation of large volumes of unstructured data and facilitate signal detection.

OBJECTIVE

To assess how the information extraction performed by VaeTM impacts the accuracy of a medical expert's review of the vaccine adverse event report.

METHODS

The "outcome of interest" (diagnosis, cause of death, second level diagnosis), "onset time," and "alternative explanations" (drug, medical and family history) for the adverse event were extracted from 1000 reports from the Vaccine Adverse Event Reporting System (VAERS) using the VaeTM system. We compared the human interpretation, by medical experts, of the VaeTM extracted data with their interpretation of the traditional full text reports for these three variables. Two experienced clinicians alternately reviewed text miner output and full text. A third clinician scored the match rate using a predefined algorithm; the proportion of matches and 95% confidence intervals (CI) were calculated. Review time per report was analyzed.

RESULTS

Proportion of matches between the interpretation of the VaeTM extracted data, compared to the interpretation of the full text: 93% for outcome of interest (95% CI: 91-94%) and 78% for alternative explanation (95% CI: 75-81%). Extracted data on the time to onset was used in 14% of cases and was a match in 54% (95% CI: 46-63%) of those cases. When supported by structured time data from reports, the match for time to onset was 79% (95% CI: 76-81%). The extracted text averaged 136 (74%) fewer words, resulting in a mean reduction in review time of 50 (58%) seconds per report.

CONCLUSION

Despite a 74% reduction in words, the clinical conclusion from VaeTM extracted data agreed with the full text in 93% and 78% of reports for the outcome of interest and alternative explanation, respectively. The limited amount of extracted time interval data indicates the need for further development of this feature. VaeTM may improve review efficiency, but further study is needed to determine if this level of agreement is sufficient for routine use.

Post-Licensure Surveillance of Trivalent Live-Attenuated Influenza Vaccine in Children Aged 2-18 Years, Vaccine Adverse Event Reporting System, United States, July 2005-June 2012

BACKGROUND

The first trivalent live-attenuated influenza vaccine (LAIV3) was licensed in 2003 for use in healthy persons 5-49 years of age. In 2007, the US Food and Drug Administration expanded its indication to healthy children 2-4 years of age.

METHODS

We searched the Vaccine Adverse Event Reporting System (VAERS) for US reports after LAIV3 from July 1, 2005 to June 30, 2012 in children aged 2-18 years. Medical records were requested for nonmanufacturer reports coded as serious (ie, death, hospitalization, prolonged hospitalization, life-threatening illness, disability). We characterized electronic data and clinically reviewed all serious reports and reports of special interest. Empirical Bayesian data mining was used to identify new or unexpected adverse events (AEs).

RESULTS

During the study period, VAERS received 2619 US LAIV3 reports for children aged 2-18 years; 197 (7.5%) reports were serious, including 5 deaths. The 2 most frequent nonfatal serious reports involved neurological and respiratory systems, with 56 (29.2%) and 43 (22.4%) reports, respectively. The most frequent neurological diagnoses were seizures and Guillain-Barré Syndrome, and the most frequent respiratory conditions were pneumonia and asthma or reactive airway disease. Data mining showed increased proportions for reports of medication errors, most commonly vaccine administration errors not associated with an AE.

CONCLUSIONS

In this VAERS analysis of reports following LAIV3, we found no new or unexpected AEs patterns. Reports of LAIV3 administration to persons, for whom it is not recommended, including children with a history of asthma or reactive airway disease or wheezing, indicate that ongoing monitoring and education in vaccine indications are needed.

Allergic reactions after egg-free recombinant influenza vaccine: reports to the US Vaccine Adverse Event Reporting System

The Vaccine Adverse Event Reporting System has received reports of allergic reactions following immunization with egg-free recombinant influenza vaccine, among patients with a self-reported egg allergy or previous allergic reaction to inactivated influenza vaccine. These results suggest that allergic reactions following influenza vaccination are not necessarily related to egg proteins.

Identifying Similar Cases in Document Networks Using Cross-Reference Structures

Our objective was to explore the creation of document networks based on different thresholds of shared information and different clustering algorithms on those networks to identify document clusters describing similar clinical cases. We created networks from vaccine adverse event report sets using seven approaches for linking reports. We then applied three clustering algorithms [visualization of similarities (VOS), Louvain, k-means] to these networks and evaluated their ability to identify known clusters. The report sets included one simulated set and three sets from the Vaccine Adverse Event Reporting System; each was split into training and testing subsets. Training subsets were used to estimate parameter values for the clustering algorithms and testing subsets to evaluate clusters. We created the networks by linking reports based on shared information in the form either of individual Medical Dictionary for Regulatory Activities Preferred Terms (PTs) or of dyads, triplets, quadruplets, quintuplets, and sextuplets of PTs; we created another network by weighting the single PT network connections by Lin's information theoretic approach to similarity. We then repeated this entire process using networks based on text mining output rather than structured data. We evaluated report clustering using recall, precision, and f-measure. The VOS algorithm outperformed Louvain and k-means in general. The best weighting scheme appeared to be related to the complexity of the known cluster. For example, singleton weighting performed best for an intussusception cluster driven by a single PT. We observed marginal differences between the code- and textual-based clustering. In conclusion, our approach supported identification of similar nodes in a document network.

Postmarketing safety of biologics and biological devices

BACKGROUND CONTEXT

Regardless of study design, the approval process of biologics and biological devices cannot identify every possible safety concern. Postmarketing safety surveillance can provide information based on real-world use of medical products in heterogeneous populations and is critical for identifying potentially serious adverse events, events that are too rare to be detected during premarketing studies, late complications, and events involving individuals or uses that were not evaluated in clinical trials.

PURPOSE

To review why adverse event reporting is important and how the information is used, with emphasis on the points that are most applicable for surgeons and other spine professionals.

METHODS

This is an overview of postmarketing safety surveillance.

RESULTS

Review of adverse event reports has resulted in safety notifications, label changes, and publications regarding the safety of biologics and biological devices, such as the risk of airway compromise after the use of recombinant human bone morphogenetic protein in cervical spine fusion, the occurrence of a fatal air embolism after the use of a fibrin sealant that had been applied with a spray device, and infections after allograft transplantation of human tissues.

CONCLUSIONS

In light of the rapid development of new biologics, postmarketing surveillance is imperative for ensuring that these products are as safe as possible. By reporting adverse events, surgeons and other health care professionals play a key role in improving and refining our understanding of the safety of biologics.

Motor palsies of cranial nerves (excluding VII) after vaccination: reports to the US Vaccine Adverse Event Reporting System

We reviewed cranial nerve palsies, other than VII, that have been reported to the US Vaccine Adverse Event Reporting System (VAERS). We examined patterns for differences in vaccine types, seriousness, age, and clinical characteristics. We identified 68 reports of cranial nerve palsies, most commonly involving the oculomotor (III), trochlear (IV), and abducens (VI) nerves. Isolated cranial nerve palsies, as well as palsies occurring as part of a broader clinical entity, were reported. Forty reports (59%) were classified as serious, suggesting that a cranial nerve palsy may sometimes be the harbinger of a broader and more ominous clinical entity, such as a stroke or encephalomyelitis. There was no conspicuous clustering of live vs. inactivated vaccines. The patient age range spanned the spectrum from infants to the elderly. Independent data may help to clarify whether, when, and to what extent the rates of cranial nerve palsies following particular vaccines may exceed background levels.

Adverse events after recombinant human BMP2 in nonspinal orthopaedic procedures

BACKGROUND

The FDA has approved recombinant human bone morphogenetic protein 2 (rhBMP-2) for treating acute, open tibial shaft fractures. However, the nature and frequency of complications after the use of rhBMP-2 in nonspinal orthopaedic surgery have not been well characterized.

QUESTIONS/PURPOSES

To determine what types of adverse events have been reported after the use of rhBMP-2, whether they were severe enough to require additional surgery, and after what types of operations these adverse events occurred.

METHODS

Adverse events reported to the FDA's Manufacturer and User Facility Device Experience database were reviewed and summarized.

RESULTS

Through December 31, 2011, the FDA has received 62 reports of adverse events involving rhBMP-2 in nonspinal orthopaedic procedures. Surgical site infections and other wound complications, heterotopic bone, pseudarthrosis, and local inflammation were among the most commonly reported adverse events. Almost half of the reports (30 reports; 48%) stated that the patients required secondary interventions to address the reported adverse events. The majority (49 reports; 79%) described adverse events occurring after unapproved uses, such as management of tibial plateau fractures, treatment of congenital pseudarthrosis of the tibia, and humeral reconstruction.

CONCLUSIONS

Serious adverse events can occur after the use of rhBMP-2 in nonspinal orthopaedic procedures and may necessitate additional surgery. Most events in this analysis occurred after off-label uses. Postmarketing review of adverse event reports remains an important approach for identifying potential safety concerns.

The contribution of the vaccine adverse event text mining system to the classification of possible Guillain-Barré syndrome reports

BACKGROUND

We previously demonstrated that a general purpose text mining system, the Vaccine adverse event Text Mining (VaeTM) system, could be used to automatically classify reports of an-aphylaxis for post-marketing safety surveillance of vaccines.

OBJECTIVE

To evaluate the ability of VaeTM to classify reports to the Vaccine Adverse Event Reporting System (VAERS) of possible Guillain-Barré Syndrome (GBS).

METHODS

We used VaeTM to extract the key diagnostic features from the text of reports in VAERS. Then, we applied the Brighton Collaboration (BC) case definition for GBS, and an information retrieval strategy (i.e. the vector space model) to quantify the specific information that is included in the key features extracted by VaeTM and compared it with the encoded information that is already stored in VAERS as Medical Dictionary for Regulatory Activities (MedDRA) Preferred Terms (PTs). We also evaluated the contribution of the primary (diagnosis and cause of death) and secondary (second level diagnosis and symptoms) diagnostic VaeTM-based features to the total VaeTM-based information.

RESULTS

MedDRA captured more information and better supported the classification of reports for GBS than VaeTM (AUC: 0.904 vs. 0.777); the lower performance of VaeTM is likely due to the lack of extraction by VaeTM of specific laboratory results that are included in the BC criteria for GBS. On the other hand, the VaeTM-based classification exhibited greater specificity than the MedDRA-based approach (94.96% vs. 87.65%). Most of the VaeTM-based information was contained in the secondary diagnostic features.

CONCLUSION

For GBS, clinical signs and symptoms alone are not sufficient to match MedDRA coding for purposes of case classification, but are preferred if specificity is the priority.

U.S. Postlicensure safety surveillance for adolescent and adult tetanus, diphtheria and acellular pertussis vaccines: 2005-2007

BACKGROUND

Pre-licensure clinical trials for two U.S. licensed tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccines did not reveal any major safety concerns. However, routine use in large adolescent and adult populations could reveal rare and potentially serious adverse events (AEs).

METHODS

To characterize reported AEs following Tdap vaccination and identify potential safety concerns warranting further evaluation, we analyzed data from the Vaccine Adverse Event Reporting System (VAERS) and assessed the frequency and proportions of AEs and reporting rates (reports per 100,000 vaccine doses distributed).

RESULTS

A total of 2090 reports (7% were serious; 55% listed Tdap alone) involving Tdap vaccines were submitted to VAERS May 2005-June 2007. The crude reporting rate was 10.2 per 100,000 vaccine doses distributed. The median age of vaccinees was 22 years, and the female to male ratio was about 2 to 1. The majority of reports described common local and systemic signs and symptoms, such as injection site reactions, fever, and headache. Rarely reported AEs included myopericarditis, demyelinating diseases of the central nervous system, Guillain-Barré Syndrome, syncope, encephalopathy/encephalitis, seizure, Bell's palsy, anaphylaxis, and thrombocytopenia.

CONCLUSIONS

Because adolescents and adults were not routinely vaccinated against pertussis in the past, this surveillance summary provides important - and reassuring - information about the use of Tdap in these age groups. Although subject to the limitations of passive surveillance, the findings of this VAERS review support the pre-licensure clinical trial data with regard to the safety of the U.S. licensed Tdap vaccines. Continued monitoring of clinically significant AEs that are temporally associated with Tdap vaccination and further assessment of such events using controlled observational studies may provide additional information about the safety of these vaccines.

Recombinant human bone morphogenetic protein-2: adverse events reported to the Manufacturer and User Facility Device Experience database

BACKGROUND CONTEXT

Adverse effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) in spinal surgery have previously been observed. However, because of its size, scope, and nature, the US Food and Drug Administration's database of postmarketing reports is useful for detecting new and unexpected safety concerns.

PURPOSE

To characterize adverse events reported to the FDA; to characterize off-label use of rhBMP-2.

STUDY DESIGN

Review of adverse events reported to the FDA after the use of rhBMP-2 (INFUSE Bone Graft) in spinal surgery.

METHODS

The Manufacturer and User Facility Device Experience database was searched for the brand name "infuse bone graft," for reports received from July 2, 2002, through August 31, 2011. Adverse events were reviewed, summarized, and classified by an MD. For each report, the most important clinical entity was identified as the principal adverse event. Off-label uses were summarized.

RESULTS

Of 834 reports, four (0.5%) described procedures in which rhBMP-2 was used in accordance with the approved indication. Nearly half of all the reports, 370 (44.4%), stated that the patient required revision surgery or other invasive interventions to address the reported adverse event. Swelling, fluid collections, osteolysis, pain/radiculopathy, heterotopic bone, pseudarthrosis, surgical site infections and other wound complications, thromboembolic events, respiratory distress, cancer, and other events were reported.

CONCLUSIONS

Because of their duration, scope, and expense, prospective studies designed to estimate the risk of rare adverse events may be impractical. Despite its imperfections, postmarketing surveillance helps to narrow the focus by revealing patterns and prioritizing topics for further research. One should not extrapolate from these results to the rhBMP-2 experience as a whole; the findings reported here might not be representative. This analysis indicates that serious adverse events can occur after the use of rhBMP-2 in spinal surgery and raises many points that surgeons may wish to consider when deciding when and how to use this product in their patients.

Vaccine adverse event text mining system for extracting features from vaccine safety reports

OBJECTIVE

To develop and evaluate a text mining system for extracting key clinical features from vaccine adverse event reporting system (VAERS) narratives to aid in the automated review of adverse event reports.

DESIGN

Based upon clinical significance to VAERS reviewing physicians, we defined the primary (diagnosis and cause of death) and secondary features (eg, symptoms) for extraction. We built a novel vaccine adverse event text mining (VaeTM) system based on a semantic text mining strategy. The performance of VaeTM was evaluated using a total of 300 VAERS reports in three sequential evaluations of 100 reports each. Moreover, we evaluated the VaeTM contribution to case classification; an information retrieval-based approach was used for the identification of anaphylaxis cases in a set of reports and was compared with two other methods: a dedicated text classifier and an online tool.

MEASUREMENTS

The performance metrics of VaeTM were text mining metrics: recall, precision and F-measure. We also conducted a qualitative difference analysis and calculated sensitivity and specificity for classification of anaphylaxis cases based on the above three approaches.

RESULTS

VaeTM performed best in extracting diagnosis, second level diagnosis, drug, vaccine, and lot number features (lenient F-measure in the third evaluation: 0.897, 0.817, 0.858, 0.874, and 0.914, respectively). In terms of case classification, high sensitivity was achieved (83.1%); this was equal and better compared to the text classifier (83.1%) and the online tool (40.7%), respectively.

CONCLUSION

Our VaeTM implementation of a semantic text mining strategy shows promise in providing accurate and efficient extraction of key features from VAERS narratives.