Institute for Vaccine Safety

Baltimore, MD, United States

Institute for Vaccine Safety

Baltimore, MD, United States
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Gessner B.D.,Agence de Medecine Preventive AMP | Halsey N.,Institute for Vaccine Safety
Vaccine | Year: 2016

A new dengue vaccine was associated with increased risk of hospitalized virologically-confirmed disease during year 3 of follow-up among children age 2-5. years. Among hypotheses to explain this finding, we could not distinguish definitively between antibody dependent enhancement, waning immunity, or chance occurrence. However, any theory must account for the following: (a) the signal occurred mainly because of decreased dengue among controls rather than increased dengue among vaccinees; (b) among 48 data points, a statistically significant increase in hospitalization among vaccinated children occurred for only one age group, during one year, and in one region; (c) cumulative risk was similar for vaccinated vs. control children age 2-5. years at the end of year 5 and lower for vaccinated vs. control children among older age groups; (d) the protective effect of vaccine against hospitalization decreased from years 1-2 to years 3-5 of follow-up for all age groups and regions. © 2017 The Author(s).


Halsey N.A.,Institute for Vaccine Safety
Journal of the Pediatric Infectious Diseases Society | Year: 2017

Public trust can be improved by learning from past mistakes, by establishing a standing forum for review of new concerns as they arise, and by maintaining a robust vaccine safety system. Developing standard guidelines for reporting causality assessment in case reports would help educate physicians and prevent future unnecessary concerns based on false assumptions of causal relationships. © The Author 2016. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved.


Salmon D.A.,Institute for Vaccine Safety | Dudley M.Z.,Institute for Vaccine Safety | Glanz J.M.,Kaiser Permanente | Omer S.B.,Emory University
American Journal of Preventive Medicine | Year: 2015

Vaccine hesitancy reflects concerns about the decision to vaccinate oneself or one's children. There is a broad range of factors contributing to vaccine hesitancy, including the compulsory nature of vaccines, their coincidental temporal relationships to adverse health outcomes, unfamiliarity with vaccine-preventable diseases, and lack of trust in corporations and public health agencies. Although vaccination is a norm in the U.S. and the majority of parents vaccinate their children, many do so amid concerns. The proportion of parents claiming non-medical exemptions to school immunization requirements has been increasing over the past decade. Vaccine refusal has been associated with outbreaks of invasive Haemophilus influenzae type b disease, varicella, pneumococcal disease, measles, and pertussis, resulting in the unnecessary suffering of young children and waste of limited public health resources. Vaccine hesitancy is an extremely important issue that needs to be addressed because effective control of vaccine-preventable diseases generally requires indefinite maintenance of extremely high rates of timely vaccination. The multifactorial and complex causes of vaccine hesitancy require a broad range of approaches on the individual, provider, health system, and national levels. These include standardized measurement tools to quantify and locate clustering of vaccine hesitancy and better understand issues of trust; rapid, independent, and transparent review of an enhanced and appropriately funded vaccine safety system; adequate reimbursement for vaccine risk communication in doctors' offices; and individually tailored messages for parents who have vaccine concerns, especially first-time pregnant women. The potential of vaccines to prevent illness and save lives has never been greater. Yet, that potential is directly dependent on parental acceptance of vaccines, which requires confidence in vaccines, healthcare providers who recommend and administer vaccines, and the systems to make sure vaccines are safe. © 2015 by American Journal of Preventive Medicine and Elsevier Ltd. All rights reserved.


Salmon D.A.,Office of the Assistant Secretary for Health | Salmon D.A.,Institute for Vaccine Safety | Proschan M.,U.S. National Institutes of Health | Forshee R.,U.S. Food and Drug Administration | And 8 more authors.
The Lancet | Year: 2013

Background The influenza A (H1N1) 2009 monovalent vaccination programme was the largest mass vaccination initiative in recent US history. Commensurate with the size and scope of the vaccination programme, a project to monitor vaccine adverse events was undertaken, the most comprehensive safety surveillance agenda in the USA to date. The adverse event monitoring project identified an increased risk of Guillain-Barré syndrome after vaccination; however, some individual variability in results was noted. Guillain-Barré syndrome is a rare but serious health disorder in which a person's own immune system damages their nerve cells, causing muscle weakness, sometimes paralysis, and infrequently death. We did a meta-analysis of data from the adverse event monitoring project to ascertain whether influenza A (H1N1) 2009 monovalent inactivated vaccines used in the USA increased the risk of Guillain-Barré syndrome. Methods Data were obtained from six adverse event monitoring systems. About 23 million vaccinated people were included in the analysis. The primary analysis entailed calculation of incidence rate ratios and attributable risks of excess cases of Guillain-Barré syndrome per million vaccinations. We used a self-controlled risk-interval design. Findings Influenza A (H1N1) 2009 monovalent inactivated vaccines were associated with a small increased risk of Guillain-Barré syndrome (incidence rate ratio 2·35, 95% CI 1·42-4·01, p=0·0003). This finding translated to about 1·6 excess cases of Guillain-Barré syndrome per million people vaccinated. Interpretation The modest risk of Guillain-Barré syndrome attributed to vaccination is consistent with previous estimates of the disorder after seasonal influenza vaccination. A risk of this small magnitude would be difficult to capture during routine seasonal influenza vaccine programmes, which have extensive, but comparatively less, safety monitoring. In view of the morbidity and mortality caused by 2009 H1N1 influenza and the effectiveness of the vaccine, clinicians, policy makers, and those eligible for vaccination should be assured that the benefits of inactivated pandemic vaccines greatly outweigh the risks. Funding US Federal Government. © 2013 Elsevier Ltd.


Tozzi A.E.,Bambino Gesu Childrens Hospital | Balakrishnan M.R.,World Health Organization | Halsey N.A.,Institute for Vaccine Safety | Law B.,Public Health Agency of Canada | Zuber P.L.F.,World Health Organization
Vaccine | Year: 2013

Serious illnesses or even deaths may rarely occur after childhood vaccinations. Public health programs are faced with great challenges to establish if the events presenting after the administration of a vaccine are due to other conditions, and hence a coincidental presentation, rather than caused by the administered vaccines. Given its priority, the Global Advisory Committee for Vaccine Safety (GACVS) commissioned a group of experts to review the previously published World Health Organization (WHO) Adverse Event Following Immunization (AEFI) causality assessment methodology and aide-memoire, and to develop a standardized and user friendly tool to assist health care personnel in the processing and interpretation of data on individual events, and to assess the causality after AEFIs. We describe a tool developed for causality assessment of individual AEFIs that includes: (a) an eligibility component for the assessment that reviews the diagnosis associated with the event and identifies the administered vaccines; (b) a checklist that systematically guides users to gather available information to feed a decision algorithm; and (c) a decision support algorithm that assists the assessors to come to a classification of the individual AEFI. Final classification generated by the process includes four categories in which the event is either: (1) consistent; (2) inconsistent; or (3) indeterminate with respect of causal association; or (4) unclassifiable. Subcategories are identified to assist assessors in resulting public health decisions that can be used for action. This proposed tool should support the classification of AEFI cases in a standardized, transparent manner and to collect essential information during AEFI investigation. The algorithm should provide countries and health officials at the global level with an instrument to respond to vaccine safety alerts, and support the education, research and policy decisions on immunization safety. © 2013 Elsevier Ltd.


Halsey N.A.,Institute for Vaccine Safety | Edwards K.M.,Vanderbilt University | Dekker C.L.,Stanford University | Klein N.P.,Kaiser Permanente | And 5 more authors.
Vaccine | Year: 2012

Assessing individual reports of adverse events following immunizations (AEFI) can be challenging. Most published reviews are based on expert opinions, but the methods and logic used to arrive at these opinions are neither well described nor understood by many health care providers and scientists. We developed a standardized algorithm to assist in collecting and interpreting data, and to help assess causality after individual AEFI. Key questions that should be asked during the assessment of AEFI include: Is the diagnosis of the AEFI correct? Does clinical or laboratory evidence exist that supports possible causes for the AEFI other than the vaccine in the affected individual? Is there a known causal association between the AEFI and the vaccine? Is there strong evidence against a causal association? Is there a specific laboratory test implicating the vaccine in the pathogenesis? An algorithm can assist with addressing these questions in a standardized, transparent manner which can be tracked and reassessed if additional information becomes available. Examples in this document illustrate the process of using the algorithm to determine causality. As new epidemiologic and clinical data become available, the algorithm and guidelines will need to be modified. Feedback from users of the algorithm will be invaluable in this process. We hope that this algorithm approach can assist with educational efforts to improve the collection of key information on AEFI and provide a platform for teaching about causality assessment. © 2012 Elsevier Ltd.


Vadaparampil S.T.,Moffitt Cancer Center | Kahn J.A.,Cincinnati Childrens Hospital Medical Center | Salmon D.,Office of Public Health and Science | Lee J.-H.,Moffitt Cancer Center | And 8 more authors.
Vaccine | Year: 2011

Objective: The purpose of this study was to determine the prevalence of physician recommendation of human papillomavirus (HPV) vaccination in early (ages 11-12), middle (13-17), and late adolescent/young adult (18-26) female patients by physician specialty, and to identify factors associated with recommendation in early adolescents. Methods: A 38-item survey was conducted April 2009 through August 2009 among a nationally representative random sample of 1538 Family Physicians, Pediatricians, and Obstetricians and Gynecologists obtained from the American Medical Association Physician Masterfile. A multivariable model was used to assess factors associated with frequency of physician recommendation of HPV vaccination (" always" = 76-100% of the time vs. other = 0-75%) within the past 12. months. Results: Completed surveys were received from 1013 physicians, including 500 Family Physicians, 287 Pediatricians, and 226 Obstetricians and Gynecologists (response rate = 67.8%). Across the specialties, 34.6% of physicians reported they " always" recommend the HPV vaccine to early adolescents, 52.7% to middle adolescents, and 50.2% to late adolescents/young adults. The likelihood of " always" recommending the HPV vaccine was highest among Pediatricians for all age groups (P< 0.001). Physician specialty, age, ethnicity, reported barriers, and Vaccines for Children provider status were significantly associated with " always" recommending HPV vaccination for early adolescents. Conclusions: Findings suggest missed clinical opportunities for HPV vaccination, and perceived barriers to vaccination may drive decisions about recommendation. Results suggest the need for age and specialty targeted practice and policy level interventions to increase HPV vaccination among US females. © 2011 Elsevier Ltd.


Vadaparampil S.T.,Moffitt Cancer Center | Vadaparampil S.T.,Center for Infection Research in Cancer | Vadaparampil S.T.,University of South Florida | Malo T.L.,Moffitt Cancer Center | And 13 more authors.
American Journal of Preventive Medicine | Year: 2014

Background Physician recommendation is a key predictor of human papillomavirus (HPV) vaccine uptake. Understanding factors associated with recommendation is important for efforts to increase current suboptimal vaccine uptake. Purpose This study aimed to examine physician recommendations to vaccinate female patients aged 11-26 years, in 2009 and 2011, at 3 and 5 years postvaccine licensure, respectively. A second aim was to identify trends in factors associated with vaccine recommendation for ages 11 and 12 years. Methods Nationally representative samples of physicians practicing family medicine, pediatrics, and obstetrics and gynecology were randomly selected from the American Medical Association Physician Masterfile (n=1538 in 2009, n=1541 in 2011). A mailed survey asked physicians about patient and clinical practice characteristics; immunization support; and frequency of HPV vaccine recommendation ("always" ≥75% of the time vs other). Analyses were conducted in 2012. Results Completed surveys were received from 1013 eligible physicians (68% response rate) in 2009 and 928 (63%) in 2011. The proportion of physicians who reported always recommending HPV vaccine increased significantly from 2009 to 2011 for patients aged 11 or 12 years (35% vs 40%, respectively; p=0.03), but not for patients aged 13-17 years (53% vs 55%; p=0.28) or 18-26 years (50% vs 52%; p=0.52). Physician specialty, age, and perceived issues/barriers to vaccination were associated with vaccine recommendation for patients aged 11 or 12 in both years. Conclusions Results suggest a modest increase in recommendations for HPV vaccination of girls aged 11 or 12 years over a 2-year period; however, recommendations remain suboptimal for all age groups despite national recommendations for universal immunization. © 2014 American Journal of Preventive Medicine.


Griffioen M.,University of Maryland, Baltimore | Halsey N.,Institute for Vaccine Safety
Public Health Nursing | Year: 2014

Objective: To examine published studies of immediate hypersensitivity reactions (IHS) following vaccination and to determine whether women are at an increased risk of developing IHS after vaccination. Design and Sample: PubMed was reviewed for vaccine articles reporting IHS by gender through June 2012. Data were abstracted on type of study, vaccine, hypersensitivity reaction, and statistic reported. Measures: Articles were included if they described experimental, quasi-experimental, correlational or descriptive studies and IHS was reported by gender. Results: Of 847 articles found in PubMed, 11 met the inclusion criteria. In eight studies, more women than men reported IHS, in two studies more men than women reported IHS and in one study the count was even. Conclusion: Limited data from these studies suggest that women may have higher rates of IHS reactions following vaccination than men. Limitations to the available data include the lack of denominator data and that the definition of IHS was not consistent across the studies. Large-scale population-based studies are indicated to determine if there are differences in rates by gender and biologic basis for these differences. © 2013 Wiley Periodicals, Inc.


Phadke V.K.,Emory University | Bednarczyk R.A.,Emory University | Salmon D.A.,Institute for Vaccine Safety | Omer S.B.,Emory University
JAMA - Journal of the American Medical Association | Year: 2016

IMPORTANCE Parents hesitant to vaccinate their children may delay routine immunizations or seek exemptions from state vaccine mandates. Recent outbreaks of vaccine-preventable diseases in the United States have drawn attention to this phenomenon. Improved understanding of the association between vaccine refusal and the epidemiology of these diseases is needed. OBJECTIVE To review the published literature to evaluate the association between vaccine delay, refusal, or exemption and the epidemiology of measles and pertussis, 2 vaccine-preventable diseases with recent US outbreaks. EVIDENCE REVIEW Search of PubMed through November 30, 2015, for reports of US measles outbreaks that have occurred since measles was declared eliminated in the United States (after January 1, 2000), endemic and epidemic pertussis since the lowest point in US pertussis incidence (after January 1, 1977), and for studies that assessed disease risk in the context of vaccine delay or exemption. FINDINGS We identified 18 published measles studies (9 annual summaries and 9 outbreak reports), which described 1416 measles cases (individual age range, 2 weeks-84 years; 178 cases younger than 12 months) and more than half (56.8%) had no history of measles vaccination. Of the 970 measles cases with detailed vaccination data, 574 cases were unvaccinated despite being vaccine eligible and 405 (70.6%) of these had nonmedical exemptions (eg, exemptions for religious or philosophical reasons, as opposed to medical contraindications; 41.8%of total). Among 32 reports of pertussis outbreaks, which included 10 609 individuals for whom vaccination status was reported (age range, 10 days-87 years), the 5 largest statewide epidemics had substantial proportions (range, 24%-45%) of unvaccinated or undervaccinated individuals. However, several pertussis outbreaks also occurred in highly vaccinated populations, indicating waning immunity. Nine reports (describing 12 outbreaks) provided detailed vaccination data on unimmunized cases; among 8 of these outbreaks from 59%through 93%of unvaccinated individuals were intentionally unvaccinated. CONCLUSIONS AND RELEVANCE A substantial proportion of the US measles cases in the era after elimination were intentionally unvaccinated. The phenomenon of vaccine refusal was associated with an increased risk for measles among people who refuse vaccines and among fully vaccinated individuals. Although pertussis resurgence has been attributed to waning immunity and other factors, vaccine refusal was still associated with an increased risk for pertussis in some populations. Copyright 2016 American Medical Association. All rights reserved.

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