Safety Surveillance of Dietary Supplements: Importance, Challenges, and New Horizons.

Pharmacovigilance is defined as the science and activities relating to the detection, assessment, understanding, and prevention of adverse effects or any other possible drug-related problems.1 While current models of pharmacovigilance, with their tools and methodologies, were developed for prescription drugs, safety surveillance is just as important for over-the-counter health products such as dietary supplements. The practice of pharmacovigilance is challenging in itself; however, there are unique challenges associated with dietary supplements.2.

Postlicensure safety surveillance for 7-valent pneumococcal conjugate vaccine.

CONTEXT: Clinical trials evaluate a vaccine's safety before approval, but some risks may escape detection or adequate characterization until larger population exposures occur after licensure. OBJECTIVE: To summarize reports of events occurring after vaccination with 7-valent pneumococcal conjugate vaccine (PCV), including those that may warrant further investigation to assess possible causation by PCV. DESIGN: Descriptive epidemiology of reports submitted to the Vaccine Adverse Event Reporting System (VAERS), a national passive surveillance database. SETTING AND PATIENTS: United States during first 2 years after licensure of PCV (February 2000 through February 2002). Reports studied were for children younger than 18 years and vaccinated with PCV. MAIN OUTCOME MEASURES: Numbers and proportional distributions of reports. RESULTS: A total of 4154 reports of events following PCV were submitted to VAERS, for a rate of 13.2 reports per 100,000 doses distributed. Multiple vaccines were given in 74.3% of reports. The most frequently reported symptoms and signs included fever, injection site reactions, fussiness, rashes, and urticaria. Serious events were described in 14.6% of reports. There were 117 deaths, 23 reports of positive rechallenges, and 34 cases of invasive pneumococcal infections possibly representing vaccine failure. Immune-mediated events occurred in 31.3% of reports. All 14 patients with anaphylactic or anaphylactoid reactions survived. Thrombocytopenia developed in 14 patients and serum sickness in 6 others. Neurologic symptoms occurred in 38% of reports. Seizures described in 393 reports included 94 febrile seizures. CONCLUSIONS: The majority of reports to VAERS in the first 2 years after licensure of PCV described generally minor adverse events previously identified in clinical trials. The proportion of reports portraying serious events was similar to that for other vaccines. Although there are important limitations in passive surveillance data, and caution in their interpretation is necessary, symptoms experienced by a few children more than once after successive PCV doses, including allergic reactions, prolonged or abnormal crying, fussiness, dyspnea, and gastrointestinal distress, warrant continued surveillance, as do reports of rare but potentially serious events, such as seizures, anaphylactic or anaphylactoid reactions, serum sickness, and thrombocytopenia.

Recent differing expert opinions regarding the safety profile of hepatitis B vaccines: is there really a controversy?

Recent papers in Expert Opinion on Drug Safety arrived at different conclusions about the safety of hepatitis B vaccines. In one of these, review of the epidemiological literature failed to confirm the serious allegations raised with respect to vaccination. In the other, review of case reports and the authors' analytical method suggested serious adverse events are associated with the vaccine. In particular, they suggested a strong relationship with multiple sclerosis, the adverse event that has been the focus of several epidemiological investigations and has been found not to be related to vaccination. The method, using data from reported cases, attempted to compute relative and attributable risks using adult Td vaccine as a comparator. The authors made errors in assumptions about the data, including inappropriate use of controls and inappropriate application of epidemiology, rendering the conclusions invalid. Passive reporting data should be analysed with care and used only for hypothesis generation - anything more requires robust epidemiological study.

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.

Monitoring vaccine safety during measles mass immunization campaigns: clinical and programmatic issues.

In the planning and implementation of mass immunization campaigns, vaccine delivery has always been a priority. However, safety issues have gained increasingly more attention and grown in importance, and campaign planners must now take them into prime consideration. The World Health Organization has released guidelines to assist with the design and implementation of safety surveillance systems, primarily for developing countries, and these include a new monograph for measles mass campaigns. Experience in the past decade with mass campaigns (primarily in developed countries) shows that measles vaccine performs in these settings as anticipated from pre- and post-licensure studies. Serious adverse events are rare, even under the increased scrutiny extended during a campaign. The experience in developing country settings is growing. The implementation of safety surveillance for mass campaigns offers a unique opportunity for countries to avoid crisis situations and to begin vaccine safety monitoring in routine immunization programs.