Vaccine Adverse Event Reporting System

Vaccine Adverse Event Reporting System
Name	Vaccine Adverse Event Reporting System
Abbreviation	VAERS
Formation	1990
Jurisdiction	United States
Parent agency	Centers for Disease Control and Prevention and Food and Drug Administration
Website	https://vaers.hhs.gov/

Vaccine Adverse Event Reporting System. It is a national early warning system in the United States designed to detect potential safety problems with vaccines licensed for use. Co-managed by the Centers for Disease Control and Prevention and the Food and Drug Administration, its primary purpose is to collect reports of adverse events following immunization. The system accepts submissions from healthcare providers, manufacturers, and the general public to aid in ongoing post-marketing surveillance.

Overview and purpose

The system serves as a critical component of the nation's comprehensive vaccine safety infrastructure, operating alongside other surveillance systems like the Clinical Immunization Safety Assessment network and the Vaccine Safety Datalink. Its fundamental objective is to provide a mechanism for the passive reporting of any clinically significant health concern occurring after the administration of any vaccine, without requiring proof of causation. This allows public health officials at the Centers for Disease Control and Prevention and the Food and Drug Administration to rapidly identify unusual or unexpected patterns of reports that may signal a potential safety issue requiring further scientific investigation. The data contributes to informed policy decisions by bodies like the Advisory Committee on Immunization Practices.

History and establishment

The system was established in 1990 following the passage of the National Childhood Vaccine Injury Act of 1986. This landmark legislation was a direct response to liability concerns from pharmaceutical companies and lawsuits related to vaccines like the whole-cell pertussis vaccine. The act mandated the creation of a centralized reporting system to improve the monitoring of vaccine safety. The operational responsibility was jointly assigned to the Centers for Disease Control and Prevention and the Food and Drug Administration, building upon earlier, less coordinated reporting efforts. Its creation coincided with the establishment of the National Vaccine Injury Compensation Program, which provides a no-fault alternative to the traditional tort system for those found to be injured by certain vaccines.

How VAERS works

The system operates as a passive surveillance program, relying on voluntary submissions from a variety of sources. Medical professionals, pharmaceutical companies, and vaccine recipients or their family members can all file reports, which can be submitted online or via a paper form. Reports are screened for completeness and entered into a publicly accessible database managed by the Centers for Disease Control and Prevention. While manufacturers are legally required to report any adverse events they become aware of, there is no similar mandate for individual physicians or patients. Each report typically includes information on the administered vaccine, the details of the adverse event, and the demographic information of the recipient, but the quality and detail of these reports can vary significantly.

Data analysis and limitations

Scientists and epidemiologists from agencies like the Centers for Disease Control and Prevention and the Food and Drug Administration employ sophisticated data mining techniques, such as proportional reporting ratio analyses, to identify reporting patterns that exceed expected background rates. A fundamental and critical limitation is that reports to the system alone cannot establish that a vaccine caused an adverse event; temporal association is not proof of causation. The data are subject to several biases, including under-reporting, stimulated reporting during media attention, and inconsistent report quality. Furthermore, there are no unvaccinated control groups for comparison within the database itself, necessitating confirmation of any signals through controlled studies in systems like the Vaccine Safety Datalink.

Role in vaccine safety monitoring

The system functions as an essential initial signal detection tool within a larger multi-layered safety framework. When a potential signal is identified, it triggers more rigorous scientific investigation using other resources. These may include formal epidemiological studies using the Vaccine Safety Datalink, which utilizes electronic health records from integrated healthcare organizations like Kaiser Permanente, or clinical reviews by the Clinical Immunization Safety Assessment network. Findings from these investigations inform updates to vaccine recommendations by the Advisory Committee on Immunization Practices and may lead to regulatory action by the Food and Drug Administration, such as updates to a vaccine's labeling or, in rare cases, changes to its authorized use.

Notable reports and controversies

The system has been central to several important vaccine safety discussions throughout its history. It played a key role in investigating early reports of intussusception following the first rotavirus vaccine in 1999, leading to its withdrawal from the United States market. During the 2009 swine flu pandemic, reports of narcolepsy following the use of the Pandemrix vaccine in Europe heightened scrutiny, though the signal was not replicated with vaccines used in North America. In the COVID-19 pandemic, the system received an unprecedented volume of reports for vaccines from Pfizer-BioNTech, Moderna, and Johnson & Johnson, including reports of myocarditis and thrombosis with thrombocytopenia syndrome. These signals were promptly assessed and confirmed through other surveillance systems, leading to updated risk communication and, in the case of the Johnson & Johnson vaccine, a revised Emergency Use Authorization. The system's data has also been frequently misinterpreted and misused by anti-vaccination activists and politicians to incorrectly allege widespread vaccine harm, highlighting the challenges of communicating the system's purpose and limitations to the public.

Category:Vaccine safety Category:Centers for Disease Control and Prevention Category:Food and Drug Administration Category:Health in the United States