What is VAERS?

According to the HHS, VAERS is “a national early warning system to detect possible safety problems in U.S.-licensed vaccines.” It was created in 1990 and is co-managed by the U.S. Centers for Disease Control and Prevention (CDC) and the FDA. 

According to the Department of Health and Human Services, VAERS is utilized for seven primary purposes:

  1. Detect new, unusual, or rare vaccine adverse events.
  2. Monitor increases in known adverse events.
  3. Identify potential patient risk factors for particular types of adverse events.
  4. Assess the safety of newly licensed vaccines.
  5. Determine and address possible reporting clusters by geographically localized, temporally specific, or product-/batch-/lot-specific adverse events.
  6. Recognize persistent issues with administration or safe-use.
  7. Provide a national safety monitoring system that extends to the entire general population for response to public health emergencies, such as a large-scale pandemic influenza vaccination program.

The CDC and FDA both use VAERS to great effect in detecting sharp spikes in a particular set of adverse events in specific regions, populations, and products.

What Are the Benefits and Limitations of VAERS?

The biggest benefit of VAERS is also its greatest limitation: the reporters. VAERS is open to the public and anyone can report an adverse event. Additionally, healthcare providers have certain adverse events they are required to report. Adverse vaccine events and vaccine manufacturers are required to report all adverse events they are aware of.

This can be a benefit to consumers because it offers a large reporting population sharing their unfiltered experiences without concern about potential interference from manufacturers or interest groups. Additionally, by allowing individuals to report adverse events themselves, it turns every consumer into an investigator for the FDA and CDC.

One issue with this approach is that due to the volume of reports, there is no moderation whatsoever. The VAERS website is forthcoming with noting that none of the reports that the database contains are verified for accuracy or relevance. The effects of this range from spelling errors or repetitions in the entries, to the reporting of events wholly unrelated to the vaccine itself. Similar to the FDA Adverse Events Reporting System (FAERS) and Manufacturer and User Device Experience (MAUDE) database, the side effects reported may have very little to do with the actual product or device being used

The Department of Human Services states on their FAQ page that consumers should keep in mind while they browse VAERS that:

  • It is generally not possible to find out from VAERS data if a vaccine caused the adverse event.
  • Reports submitted to VAERS often lack details and sometimes contain errors.
  • Serious adverse events are more likely to be reported than non-serious events.
  • Numbers of reports may increase in response to media attention and increased public awareness.
  • VAERS data cannot be used to determine rates of adverse events.

These limitations are important to note, but there are uses for VAERS.

How Can VAERS Be Used To Protect Consumers?

VAERS exists chiefly to scan for large numbers of unexpected, serious, negative vaccine adverse effects. An example of this type of correlated data action would be when the Johnson & Johnson vaccine was pulled after a number of people reported having blood clots. 

Even though the data may be inaccurate, the CDC and FDA can take those potentially flawed reports and begin conducting rigorous scientific inquiries into the vaccine in question to determine whether these side effects are a coincidence or causally related to the vaccine itself. For consumers searching VAERS, there are some things to keep in mind to get the most use out of the database.

  • VAERS data is the beginning of an inquiry, not the end. Consumers who find a concerning side effect linked to a vaccine should then look into whether a scientific study has been conducted to audit whether the vaccine caused this side effect or whether this side effect is likely just a coincidence.
  • The more people report an adverse effect, the more likely it may be that this adverse event may be connected to the vaccine itself. 

As an example, the CDC Wonder database has 190 reports for the cholera vaccine. Of those, 18 patients, or 9.47%, reported chills. It would be reasonable to assume the chills may be caused by the cholera vaccine. By comparison, one person, 0.53%, reported that the cholera vaccine gave them asthma. This isn’t impossible, but it’s not probable and should not be an assumed consequence of receiving the vaccine without significant scientific data backing that conclusion.

By keeping these principles in mind, consumers can continue to utilize all available tools to discern rational skepticism from misinformation.