What Is VAERS? Why the CDC Database Is Crucial to Vaccine Safety—and How to Use It Responsibly

A lot of information is out there about the COVID-19 vaccines. You could spend days reading clinical trial data, catching up on information from the Centers for Disease Control and Prevention (CDC), and cruising social media to learn about your friends' personal experiences.

But there's one resource that's been getting a lot of attention. It's the Vaccine Adverse Event Reporting System (VAERS), a national early warning system that detects potential safety problems in vaccines licensed in the United States. VAERS didn't start with COVID-19—it's been around since 1990. Still, since the COVID-19 vaccines are relatively new, plenty of people have suddenly started caring about it.

Here's why.

What Is VAERS?

The CDC and the Food and Drug Administration (FDA) established VAERS to help detect possible safety issues with vaccines once they moved from clinical trial stages to use by the general public.

"It's meant to be very inclusive of any type of signal that may or may not relate to the vaccine," said infectious disease expert Amesh A. Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security. "It's a surveillance system used to understand what's going on with real-world usage of the vaccine."

VAERS accepts and analyzes reports of possible side effects after a person has received a vaccine, the Department of Health and Human Services (HHS) explains. Anyone can report an issue to VAERS, although healthcare professionals are required to report certain side effects, and vaccine manufacturers are required to report all side effects that they're alerted about.

As a passive reporting system, VAERS relies on people to send in information about their side effects. It's not actually designed to determine if a vaccine actually caused a health problem, but it can help pick up patterns of side effects that could potentially suggest a problem with a vaccine.

How to Use VAERS

Anyone can submit to VAERS, whether they're patients or their parents or siblings. You have two options—you can submit a report online or download a writable PDF and complete it offline before submitting it.

Here's what you'll need to provide when filling out the form:

• Date of birth
• Sex
• The brand and dosage of your vaccine
• The date, time, and location of vaccination
• Your age at the time of vaccination
• The date and time when your side effects started
• Your symptoms
• What happened with your side effects
• Medical tests and lab results, if you had them
• Your doctor's contact info, if it's relevant
• Any allergies, if you have them
• Any medications, supplements, or herbal remedies you were taking at the time of vaccination

Another way you can use VAERS is by checking out what other people have submitted. You can search the VAERS data online or download the raw data to put into a spreadsheet.

While VAERS data can be viewed by the public, information linking you to your report is not publicly available.

If You Choose to Use VAERS, Do So With Caution

Anyone can report anything to VAERS, whether it's related to the vaccine or not. So, if you happen to develop a stomachache after you get your COVID-19 vaccine, you can report it to VAERS, even though your pain may not be related to the vaccine itself. Still, the data will be recorded, and "stomachache" may be linked to the vaccine.

This is all part of the system, though, and it actually encourages you to report everything. The VAERS website even says this: "Please report clinically important adverse events that occur after vaccination of adults and children, even if you are not sure whether the vaccine caused the adverse event." So, if you're not sure if what you're experiencing after the vaccine is relevant or not, you should report it anyway.

That said, there's a disclaimer on the VAERS website that specifically warns that what issues are documented aren't proven side effects caused by the vaccine but symptoms that may be associated with it. "While very important in monitoring vaccine safety, VAERS reports alone cannot be used to determine if a vaccine caused or contributed to an adverse event or illness," says the disclaimer. "The reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable."

"VAERS is meant to pick up lots of signals, most of which are going to be noise," said Dr. Adalja. "Not everything that happens after a vaccine is caused by the vaccine."

Remember: VAERS data do not make it possible to tell whether the vaccines are actually causing the side effects that are being reported. "People forget to say that everybody is reporting everything," said Dr. Adalja. "We're also giving the vaccines to people who are high risk, and they could die of other causes. (But overall) VAERS is an important part of our safety system."

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up to date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.