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Current Trends Vaccine Adverse Event Reporting System -- United States

Since 1988, health-care providers and vaccine manufacturers have been required by law to report to the U.S. Department of Health and Human Services (DHHS) certain suspected adverse events following specific immunizations (1,2) (Table 1). On November 1, 1990, the new DHHS Vaccine Adverse Event Reporting System (VAERS) will become fully operational. VAERS will accept all reports of suspected adverse events after the administration of any vaccine, including but not limited to those listed in Table 1. VAERS will serve as a single system for monitoring such reports, replacing CDC's Monitoring System for Adverse Events Following Immunization and the Food and Drug Administration's (FDA) Adverse Reaction Reporting System for publicly and privately purchased vaccines (3).

The new VAERS report form (Figure 1) is preaddressed and postage-paid. Health-care providers should complete a VAERS report form whenever they treat a patient for a possible vaccine adverse event (Table 1) and judge the event warrants reporting. Submission of a report does not necessarily denote that the vaccine caused the adverse event. Vaccine manufacturers should forward reports of vaccine adverse events directly to VAERS instead of FDA. Although lay persons may also report to VAERS, they are encouraged to obtain the assistance of a health professional in completing the form.

All VAERS patient-identifying information will be kept confidential as provided in the Privacy Act (4) and the National Childhood Vaccine Injury Compensation Act (1). All persons who submit the form will receive written notification that the report has been received by VAERS. VAERS staff will contact these persons for follow-up of the patient's condition at 60 days and at 1 year after report of serious adverse events.

Copies of the VAERS form and Table 1 have been mailed to physicians in the specialities of pediatrics, family practice, general practice, internal medicine, emergency medicine, and obstetrics/gynecology. Reporting forms and information about reporting requirements or completion of the form can be obtained through a toll-free number for VAERS ((800) 822-7967). Reported by: National Vaccine Program, Office of the Assistant Secretary of Health. Office of Biological Product Review, Center for Biologics Evaluation and Research, Food and Drug Administration. Div of Immunization, Center for Prevention Svcs, CDC.

Editorial Note

Editorial Note: The goal of immunization programs is to protect the public from vaccine-preventable diseases while minimizing the occurrence of adverse events following immunizations. The incidence rates of vaccine-preventable diseases in the United States have decreased dramatically since the mid-1950s, primarily because of the availability and widespread public acceptance of effective vaccines (5). During the initial period following introduction of a vaccine, the occurrence of adverse events may be overshadowed by the higher frequency of complications due to natural disease. As immunization efforts and coverage with a specific vaccine increase, disease incidence is substantially reduced and, for some diseases, is virtually eliminated (e.g., poliomyelitis). Because awareness about the public health benefits of a vaccine and its impact on disease then declines, adverse events following use of the vaccine may receive greater attention. Consequently, concerns about potential adverse events may lead to reductions in vaccine coverage and recurrence of epidemic disease (6,7).

Because immunity to a given vaccine-preventable disease can be acquired only by natural infection or by immunization, immunization of a substantial proportion of each birth cohort will be needed until the disease is eradicated. Continuous monitoring of vaccine safety is therefore necessary to 1) evaluate the benefits and risks of immunization, 2) develop policies that maximize the beneficial impact of the vaccine on public health, and 3) determine the potential needs for further vaccine improvement.

Before licensure, vaccines are evaluated extensively for immunogenicity, safety, and efficacy in animals and in human volunteers through controlled clinical trials. Because of the relatively small sample sizes of most prelicensure trials, rare adverse events are unlikely to be detected. Therefore, postlicensure or postmarketing surveillance (i.e., the continued monitoring of vaccine safety in the general population after licensure) is critical for identifying and evaluating rare or uncommon adverse events.

Postmarketing surveillance by a passive system, such as VAERS, detects "spontaneous" reports from health-care providers after an adverse event occurs. However, because passive surveillance systems are not linked to unimmunized comparison groups, these systems generally cannot be used to assess whether a reported adverse event occurs more often than expected. This limitation complicates assessment of a specific vaccine's role in causing a given adverse event. Other methods used for postmarketing surveillance, such as case-control studies or analysis of data bases that link immunization and outcome (e.g., hospital discharge) records, provide comparison groups but may not be timely or practical for ongoing surveillance (8). Based on these considerations, DHHS expects that VAERS may 1) provide a means for detecting new or previously unreported vaccine-related adverse events associated with existing and new vaccines (9), 2) assist in determining the number of adverse events reported nationwide, 3) permit collection and analysis of vaccine-specific adverse event information, and 4) assist in the assessment of potential risk factors for adverse events.


  1. The National Childhood Vaccine Injury Act of 1986. Public Health Service Act *** 2125. (42 U.S.C. *** 300aa-25 (Supp. 1987)).

  2. CDC. National Childhood Vaccine Injury Act: requirements for permanent vaccination records and for reporting of selected events after vaccination. MMWR 1988;37:197-200.

  3. Stetler HC, Mullen JR, Brennan JP, Livengood JR, Orenstein WA, Hinman AR. Monitoring system for adverse events following immunization. Vaccine 1987;5:169-74.

  4. The Privacy Act. 5 U.S.C. *** 552a.

  5. Hinman AR. Public health considerations. In: Plotkin SA, Mortimer EA, eds. Vaccines. Philadelphia: WB Saunders, 1988:587-611.

  6. Kimura M, Kuno-Sakai H. Epidemiology of pertussis in Japan. Tokai J Exp Clin Med 1988;13(suppl):1-7.

  7. Cherry JD. The epidemiology of pertussis and pertussis vaccine in the United Kingdom and the United States: a comparative study. Curr Probl Pediatr 1984;14:1-78.

  8. Strom BL. Choosing among the available approaches for pharmacoepidemiologic studies. In: Strom BL, ed. Pharmacoepidemiology. New York: Churchill Livingston, 1989:245-56.

  9. Brown F. From Jenner to genes--the new vaccines. Lancet 1990;335:587-90.

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