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Susan S Ellenberg

Publications and source records attributed to Susan S Ellenberg.

14 recordsLinked to original sources
PubMed2005

Evaluating the safety of new vaccines: summary of a workshop.

Public concerns about the safety of vaccines arise on a regular basis. In November 2000, a workshop titled "Evaluation of New Vaccines: How Much Safety Data?" was convened by US Public Health Service agencies, including the Food and Drug Administration, the National Institutes of Health, the Centers for Disease Control and Prevention, and the Health Resources and Services Administration, to discuss appropriate methods for evaluating the safety of new vaccines. Workshop presentations addressed the current standards and approaches for new vaccine evaluation and postlicensure surveillance, as well as public views about vaccine safety and alternative approaches that could be considered. The advantages and disadvantages of conducting large controlled trials before licensure or widespread use of a new vaccine were discussed. We summarize these presentations and discussions.

Child↗
PubMed2004

Should statisticians reporting to data monitoring committees be independent of the trial sponsor and leadership?

It has long been a fundamental principle of clinical trials that interim comparative data should be kept confidential, with such data accessible only to a small number of individuals responsible for its analysis and monitoring. The rationale for keeping investigators and sponsors blinded to interim data has been extensively discussed, but the possible conflicts of interest that could arise for the statistician who performs the analysis of the interim data and presents it to a data monitoring committee has received little attention. We describe these potential conflicts, and the advantages and disadvantages of approaches that might be taken to minimize them. We have invited commentary on this issue from several statisticians with substantial experience in clinical trials and interim data monitoring.

Clinical Trials Data Monitoring Committees↗
PubMed2004

Analytical, practical and regulatory issues in prevention studies.

Prevention studies, as distinguished from studies investigating treatments for established disease, present some distinct challenges. Perhaps the most extensive experience with preventive agents is in the area of infectious diseases; vaccines have been extremely effective in preventing many such diseases. Vaccines have been, and continue to be, studied in other disease areas such as certain cancers, but as yet have not achieved success outside of infectious disease prevention. One obvious and important feature of prevention studies is that they enroll healthy individuals; thus such studies require particularly high standards for the safety of those enrolled (and those who might ultimately receive the product being tested). Prevention studies often need to be quite large, as the types of diseases most important to prevent tend to be uncommon. Large studies usually require simplified approaches; to ensure high quality of data on the key variables it may be necessary to compromise on the amount of data collected, frequency of data collection, and other aspects of trial design. The reliability of randomization and blinding may be especially important in these large studies, as bias could easily overwhelm the small effects that are usually sought. Often, biomarkers thought to indicate developing but as yet subclinical disease, will be important to evaluate; whether such markers can serve as primary endpoints in prevention studies has been a contentious issue in many contexts. Studies in older populations, such as those at risk for Alzheimer's Disease, raise challenges such as accounting for competing risks, and considering potential interactions of preventive agents with multiple medications often used by the elderly.

Clinical Trials as Topic↗
PubMed2004

A global perspective on vaccine safety and public health: the Global Advisory Committee on Vaccine Safety.

Established in 1999, the Global Advisory Committee on Vaccine Safety advises the World Health Organization (WHO) on vaccine-related safety issues and enables WHO to respond promptly, efficiently, and with scientific rigor to issues of vaccine safety with potential global importance. The committee also assesses the implications of vaccine safety for practice worldwide and for WHO policies. We describe the principles on which the committee was established, its modus operandi, and the scope of the work undertaken, both present and future. We highlight its recent recommendations on major issues, including the purported link between the measles-mumps-rubella vaccine and autism and the safety of the mumps, influenza, yellow fever, BCG, and smallpox vaccines as well as that of thiomersal-containing vaccines.

Advisory Committees↗
PubMed2003

Surveillance for safety after immunization: Vaccine Adverse Event Reporting System (VAERS)--United States, 1991-2001.

PROBLEM/CONDITION: Vaccines are usually administered to healthy persons who have substantial expectations for the safety of the vaccines. Adverse events after vaccinations occur but are generally rare. Some adverse events are unlikely to be detected in prelicensure clinical trials because of their low frequency, the limited numbers of enrolled subjects, and other study limitations. Therefore, postmarketing monitoring of adverse events after vaccinations is essential. The cornerstone of monitoring safety is review and analysis of spontaneously reported adverse events. REPORTING PERIOD COVERED: This report summarizes the adverse events reported to the Vaccine Adverse Event Reporting System (VAERS) from January 1, 1991, through December 31, 2001. DESCRIPTION OF SYSTEMS: VAERS was established in 1990 under the joint administration of CDC and the Food and Drug Administration (FDA) to accept reports of suspected adverse events after administration of any vaccine licensed in the United States. VAERS is a passive surveillance system: reports of events are voluntarily submitted by those who experience them, their caregivers, or others. Passive surveillance systems (e.g., VAERS) are subject to multiple limitations, including underreporting, reporting of temporal associations or unconfirmed diagnoses, and lack of denominator data and unbiased comparison groups. Because of these limitations, determining causal associations between vaccines and adverse events from VAERS reports is usually not possible. Vaccine safety concerns identified through adverse event monitoring nearly always require confirmation using an epidemiologic or other (e.g., laboratory) study. Reports may be submitted by anyone suspecting that an adverse event might have been caused by vaccination and are usually submitted by mail or fax. A web-based electronic reporting system has recently become available. Information from the reports is entered into the VAERS database, and new reports are analyzed weekly. VAERS data stripped of personal identifiers can be reviewed by the public by accessing http://www.vaers.org. The objectives of VAERS are to 1) detect new, unusual, or rare vaccine adverse events; 2) monitor increases in known adverse events; 3) determine patient risk factors for particular types of adverse events; 4) identify vaccine lots with increased numbers or types of reported adverse events; and 5) assess the safety of newly licensed vaccines. RESULTS: During 1991-2001, VAERS received 128,717 reports, whereas >1.9 billion net doses of human vaccines were distributed. The overall dose-based reporting rate for the 27 frequently reported vaccine types was 11.4 reports per 100,000 net doses distributed. The proportions of reports in the age groups <1 year, 1-6 years, 7-17 years, 18-64 years, and >/= years were 18.1%, 26.7%, 8.0%, 32.6%, and 4.9%, respectively. In all of the adult age groups, a predominance among the number of women reporting was observed, but the difference in sex was minimal among children. Overall, the most commonly reported adverse event was fever, which appeared in 25.8% of all reports, followed by injection-site hypersensitivity (15.8%), rash (unspecified) (11.0%), injection-site edema (10.8%), and vasodilatation (10.8%). A total of 14.2% of all reports described serious adverse events, which by regulatory definition include death, life-threatening illness, hospitalization or prolongation of hospitalization, or permanent disability. Examples of the uses of VAERS data for vaccine safety surveillance are included in this report. INTERPRETATION: As a national public health surveillance system, VAERS is a key component in ensuring the safety of vaccines. VAERS data are used by CDC, FDA, and other organizations to monitor and study vaccine safety. CDC and FDA use VAERS data to respond to public inquiries regarding vaccine safety, and both organizations have published and presented vaccine safety studies based on VAERS data. VAERS data are also used by the Advisory Committee on Immunization Practices and the Vaccine and Related Biological Products Advisory Committee to evaluate possible adverse events after vaccinations and to develop recommendations for precautions and contraindications to vaccinations. Reviews of VAERS reports and the studies based on VAERS reports during 1991-2001 have demonstrated that vaccines are usually safe and that serious adverse events occur but are rare. PUBLIC HEALTH ACTIONS: Through continued reporting of adverse events after vaccination to VAERS by health-care providers, public health professionals, and the public and monitoring of reported events by the VAERS working group, the public health system will continue to be able to detect rare but potentially serious consequences of vaccination. This knowledge facilitates improvement in the safety of vaccines and the vaccination process.

Adolescent↗
PubMed2003

Is the use of placebo controls ethically permissible in clinical trials of agents intended to reduce fractures in osteoporosis?

Substantial progress has been made in developing treatments that reduce the risk of fractures in osteoporosis. However, available treatments are only partially effective, they are not widely used, and there is need to search for more effective means of fracture prevention. Currently known effective means of reducing fractures were found using randomized placebo-controlled trials. The use of placebo controls in clinical trials has been a subject of significant controversy in recent years. The Declaration of Helsinki revision of October 2000 caused great concern among clinical investigators about the future use of placebo controls if known effective therapeutic agents are available. A working group of ethicists, clinical trial design experts, and clinical investigators examined the current state of knowledge of osteoporosis treatment and trials. They concluded that if placebo controls put subjects at substantial risk of serious outcomes, they are not ethically permissible. Placebo controls in osteoporosis trials with fracture as the measured outcome are permissible only under narrowly defined conditions. Placebo controls may be used if competent, well-informed patients refuse approved therapies for sound reasons, there is a reasonable basis for substantial disagreement or lack of consensus among professionals about whether approved treatments are better than placebos, or subjects are refractory to known effective agents. Active control trials are permissible and desirable if they can be designed and conducted in ways that overcome the interpretive difficulties often associated with such trials.

Clinical Trials as Topic↗
PubMed2002

Adverse event reports following vaccination for Lyme disease: December 1998-July 2000.

CONTEXT: The vaccine adverse event reporting system (VAERS) monitors vaccine safety post-licensure. Although events reported to VAERS are not necessarily causally associated with vaccination, VAERS reports can be used to identify possible safety concerns that occur at too low a rate to have been identified prior to licensure. OBJECTIVE: To evaluate adverse events following Lyme disease vaccination reported to VAERS during the first 19 months of the vaccine's licensure. DESIGN, SETTING, AND PARTICIPANTS: Analysis of all VAERS reports of adverse events following vaccination for Lyme disease in the US from 28 December 1998 to 31 July 2000. MAIN OUTCOME MEASURE: We evaluated reported adverse events for unexpected patterns in age, gender, time to onset, dose number, and clinical characteristics and compared them to adverse events observed in clinical trials of this vaccine. RESULTS: Over 1,400,000 doses were distributed and 905 adverse events were reported to VAERS, 440 in men and 404 in women, with ages ranging from 10 to 82 years. The majority (56%) of adverse events occurred after administration of the first dose. The most frequently reported adverse events were arthralgia (250), myalgia (195), and pain (157). There were 59 reports coded as arthritis, 34 as arthrosis, 9 as rheumatoid arthritis, and 12 as facial paralysis. Sixty-six (7.4%) events were classified as serious, involving life-threatening illness, hospitalization, prolongation of hospitalization, persistent or significant disability/incapacity, or death. Twenty-two hypersensitivity reactions were reported. CONCLUSION: Based on reporting to VAERS, we did not detect unexpected or unusual patterns of reported adverse events following Lyme disease vaccine administration, other than hypersensitivity reactions, compared with adverse events observed in clinical trials.

Adolescent↗
PubMed2002

Pediatric deaths reported after vaccination: the utility of information obtained from parents.

BACKGROUND: The federally administered Vaccine Adverse Event Reporting System (VAERS) is a passive reporting system that receives domestic and foreign reports of adverse events that occur following immunization. This investigation explored whether routinely interviewing parents for follow-up of VAERS pediatric deaths would provide additional information important to vaccine safety. METHODS: The study was designed to follow up 100 consecutive pediatric deaths reported to VAERS by interviewing a parent and a healthcare provider (HCP) for each case. Several strategies contributed to successful follow-up. A standardized questionnaire was utilized to interview HCPs and parents. Overall and specific group frequencies (HCPs and parents) were calculated for each variable. McNemar's statistical tests of exact inference were calculated to assess whether there were statistically significant differences between HCP and parent knowledge by case for various variables. RESULTS: The median age of the cases was 4 months. Approximately half of the deaths were attributed to sudden infant death syndrome. In many instances, the information was equivalent in quality. For certain variables, such as knowledge of the child's position when found in distress, more parents than HCPs indicated that they knew the answer. CONCLUSIONS: Conducting parental and HCP follow-up for pediatric deaths reported to VAERS was resource intensive. In some instances, parents were more likely than HCPs to provide information regarding some important variables about the nature of the death. None of the additional information obtained from parents, however, provided a signal or confirmation of a causal link between the vaccine and death.

Adverse Drug Reaction Reporting Systems↗
PubMed2002

Monitoring the safety of vaccines: assessing the risks.

The safety of vaccines, particularly the most widely used vaccines to which most children are exposed as infants and toddlers, has always been an extremely high priority for vaccine manufacturers and government agencies. Products intended for healthy people must be held to a high standard of safety assurance. In addition to the intense safety assessments conducted prior to licensure, post-marketing surveillance programmes are essential to identify and study possible risks that occur too rarely to have been identified in pre-licensure studies or that occur in populations not studied in pre-licensure studies. Studying rare risks of vaccines is more complex than for therapeutic products because the exposure is virtually universal for many vaccines, ensuring occurrence simply by chance of many adverse outcomes in temporal association with vaccination. In the US the Vaccine Safety Datalink (VSD), a consortium of managed care organisations, has been established to study more rigourously possible vaccine-associated risks. These risks may be identified through reports to the Vaccine Adverse Event Reporting System (VAERS), the nationwide passive surveillance programme, as well as other sources. The combination of passive surveillance and more structured case-control or cohort studies possible in the VSD has helped to both identify new vaccine risks and to provide reassuring evidence of lack of risk in other situations where concerns have been raised.

Case-Control Studies↗