Table of Contents
- Understanding the Vaccine Adverse Event Reporting System
- Who Operates VAERS and Its Role in Vaccine Safety
- Who Can Report to VAERS
- How to File a VAERS Report
- What Happens After Your Report Is Submitted
- How to Search VAERS Data
- Interpreting VAERS Reports Responsibly
- Frequently Asked Questions
Last Updated: October 14, 2026
Understanding the Vaccine Adverse Event Reporting System
The vaccine adverse event reporting system, known as VAERS, is a national program that collects and analyzes reports of health events occurring after vaccination.
VAERS gives families a pathway to document health events they believe are connected to a vaccination and contribute to ongoing safety surveillance, regardless of whether a causal relationship is established.
Operating since 1990, VAERS is a passive surveillance mechanism relying on voluntary reporting rather than active case-finding (the CDC). It casts a wide net to catch potential signals early, but reported events may not have been caused by the vaccine itself.
Who Operates VAERS and Its Role in Vaccine Safety
VAERS is jointly operated by the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA), which share responsibility for monitoring vaccine safety and responding to adverse event reports (the FDA).
The CDC manages technical infrastructure and analyzes reported data; the FDA reviews reports and coordinates with manufacturers when safety concerns emerge. Together they identify safety signals and investigate further when warranted.
VAERS works alongside other monitoring programs like the Vaccine Safety Datalink and the Clinical Immunization Safety Assessment Project, each tracking different information and populations.
The system is designed to be sensitive rather than specific, capturing many events that occur after vaccination, not just those caused by it.
Healthcare providers and vaccine manufacturers are required by law to report serious adverse events to VAERS, while the public can submit reports voluntarily online or by phone.
Who Can Report to VAERS
Anyone can file a VAERS report, including healthcare providers, parents, caregivers, vaccine recipients, and the general public. The system is intentionally accessible so reports are not missed.
Vaccine manufacturers must also forward relevant adverse event information they receive to VAERS within specific timeframes.
Patients and family members can submit reports voluntarily without waiting for a healthcare provider, which matters for those who want to document their experience and contribute to safety monitoring.
Employers, schools, and other organizations may also submit reports, though this is less common. The system accepts reports from any source.
How to File a VAERS Report
Filing a VAERS report is straightforward, but quality depends on preparation. The steps below apply whether you are a patient, caregiver, or clinician.
Step 1: Decide Whether to Report
You do not need to be certain a vaccine caused the event. VAERS accepts reports of any health event occurring after vaccination, whether or not a causal link is suspected.
People often hesitate because they are unsure whether their experience is “serious enough.” It is better to report and let analysts assess the details than to self-filter.
If you are unsure whether an event qualifies, report it anyway. VAERS is a hypothesis-generating system, not a gatekeeping one.
Step 2: Gather the Information You Will Need
Having details ready makes the form faster to complete and reduces errors. Collect the following:
About the vaccination:
- Date the vaccine was given
- Vaccine name and manufacturer
- Lot number, if it appears on the record
- Location where it was administered
- Name of the administering provider, if known
About the health event:
- Date the event began
- Description of symptoms in plain, specific language
- Whether the person was hospitalized, visited an emergency room, or required urgent care
- Any tests, diagnoses, or treatments related to the event
- Current outcome (ongoing, resolved, or fatal)
About the person’s background:
- Existing medical conditions
- Current medications
- Known allergies
- Recent illnesses or infections
- Pregnancy status, if applicable
Keep medical records, visit notes, test results, or discharge summaries nearby; the online form allows document uploads that give analysts more context.
Step 3: Submit the Report
You can file a VAERS report in two main ways:
- Online through the official VAERS website. This is the most common method and supports document uploads.
- By phone through the VAERS hotline, which is useful if you prefer to speak with someone or do not have reliable internet access.
The form asks for basic demographics, vaccination details, an event description, and medical history. If reporting for someone else, indicate your relationship to them.
Be specific when describing the event. Instead of “felt unwell,” write “fever of 103°F, body aches, and fatigue beginning about 24 hours after vaccination.” Specific descriptions help analysts compare reports and spot patterns.
If you do not know a detail, such as the lot number, leave it blank rather than guessing. Incomplete fields are acceptable; inaccurate ones are not.
Step 4: Confirmation and Report Number
After you submit, you will receive a VAERS report number. Keep this number. It is your reference if you need to follow up, provide additional information, or correct a detail later.
Step 5: What Follow-Up Looks Like
Not every report triggers follow-up, but serious reports are more likely to receive attention. Analysts may contact you to clarify medical history, timing, or symptoms; responding improves data quality.
Audience-Specific Notes
- Patients and caregivers: You can file a report yourself without a clinician’s permission.
- Healthcare providers: Serious events, including hospitalization, life-threatening illness, permanent disability, and death, are subject to mandatory reporting regardless of suspected causation.
- Vaccine manufacturers: Manufacturers must forward relevant adverse event information to VAERS within specified timeframes.
If the Reaction Is Serious, Seek Care First
Filing a report and seeking medical care are separate actions. If someone is experiencing a severe or life-threatening reaction, emergency care comes first; file the VAERS report afterward. Do not delay urgent care to complete a form.
VAERS reporting is not a substitute for medical treatment. If you are experiencing a medical emergency, contact emergency services immediately.
Privacy and Handling of Your Information
VAERS requests personal and medical details so analysts can evaluate reports, but personal identifiers are removed before public release; medical details remain in the public dataset. For specifics, consult the official privacy guidance on the VAERS website.
Official VAERS reporting portal and privacy guidance
What Happens After Your Report Is Submitted
Once submitted, your VAERS report enters the system for review and becomes part of the national safety monitoring effort.
If your report describes a serious event, analysts may contact you with follow-up questions about medical history, timing, or symptoms to understand the case more thoroughly.
Reported events enter the publicly accessible VAERS database. Personal identifiers are removed before release, but medical details remain, allowing researchers and officials to analyze the data.
The CDC and FDA use VAERS data to monitor safety trends. If a safety signal emerges, officials investigate further using other data sources and study designs.
How to Search VAERS Data
The VAERS database is publicly available online, letting you search reports for specific vaccines or look for patterns.
To search VAERS, visit the official database portal. You can filter by:
- Vaccine name
- Type of adverse event or symptom
- Age group
- Date range
- Outcome (hospitalization, death, recovery)
- Geographic location
Start with a simple search using the vaccine name and event type. The database returns matching reports you can review individually.
Remember that VAERS includes all reported events, not just those caused by the vaccine.
The database also provides summary statistics showing how many reports have been submitted for a vaccine and the most commonly reported event types.
Researchers use VAERS data to generate hypotheses and identify trends, and agencies use it to monitor safety signals.
Interpreting VAERS Reports Responsibly
VAERS is one of the most misunderstood datasets in public health. A report means someone reported a health event occurred after vaccination; it does not mean the vaccine caused it. That distinction is the foundation of responsible interpretation.
This section gives you practical tools for reading VAERS data without overstating what it can tell you.
Temporal Association Is Not Causation
Many health events happen after vaccination simply because they occur in the general population at a steady rate. When millions are vaccinated, some will experience unrelated health problems during the post-vaccination window, and VAERS captures those coincidental events alongside any genuinely linked to a vaccine.
A temporal association is a starting point for investigation, not a conclusion. Establishing causation requires controlled studies comparing outcomes between vaccinated and unvaccinated groups.
Four Questions to Ask About Any VAERS Report
When you see a VAERS report cited, run it through these filters:
- Is this event common in the general population anyway? If the same event occurs at similar rates in people who were not vaccinated, the report is unlikely to reflect a causal link.
- How close is the timing? Events occurring within a plausible biological window are more informative than events occurring months later.
- Is this a single report or a pattern? One report is a data point. Many similar reports across different locations and reporters are more meaningful.
- Is the report complete? Reports with missing medical history, unclear timing, or no follow-up are harder to interpret and may be revised or reclassified later.
Understanding Report Counts
Raw counts from VAERS can be misleading without context. Keep in mind:
- Denominator matters. A thousand reports mean something very different if ten million doses were administered versus one hundred thousand.
- Reporting is voluntary for the public. Underreporting is widely acknowledged, so reports do not equal events that occurred.
- Media coverage can stimulate reporting. When a topic gets attention, related reports often increase even if the underlying rate has not changed.
- Duplicates exist. The same event may be reported by a patient, provider, and manufacturer; analysts consolidate duplicates, but public datasets may still contain them.
Incomplete and Evolving Reports
VAERS reports are not static. A report submitted with limited information may be updated as medical records arrive or outcomes become clear, so early snapshots can differ from later, cleaned versions. Check whether a report has been updated.
What VAERS Is Good At, and What It Is Not
VAERS is well suited for:
- Detecting unusual patterns that warrant further study
- Capturing rare events that pre-licensure trials may not have been large enough to detect
- Generating hypotheses for controlled research
VAERS is not designed to:
- Prove that a vaccine caused a specific event
- Estimate how common an adverse event is
- Replace controlled studies or active surveillance systems
Treat VAERS as an early-warning radar, not a verdict. It tells you where to look, not what is true.
How Signals Move Forward
When analysts notice a pattern in VAERS, it becomes a signal for further investigation. Agencies then use tools like the Vaccine Safety Datalink and the Clinical Immunization Safety Assessment Project to test whether the signal holds up under more rigorous study designs. Only then can a causal relationship be supported or ruled out.
Reading VAERS Data in Context
If you are researching a specific vaccine or event, combine VAERS data with published studies, active surveillance reports, and clinical guidance. VAERS is a starting point for questions, not an ending point for answers. Used carefully, it is a valuable window into what people report after vaccination; used carelessly, it can be misread as proof of something it was never designed to prove.
Frequently Asked Questions
Who can submit a report to the Vaccine Adverse Event Reporting System?
Healthcare providers, vaccine manufacturers, and the public, including parents, caregivers, and vaccine recipients themselves, can submit reports to VAERS. Anyone who observes an adverse event after vaccination can file a report, whether they received the vaccine or are reporting on behalf of someone else. Reports can be submitted online, by mail, or by phone through the official VAERS website.
What information do I need to complete a VAERS report form?
You’ll need the vaccination date, vaccine name and lot number, the date the adverse event occurred, a description of what happened, any medical diagnoses, whether hospitalization was required, and current medications or medical history. If you don’t have all details, you can still submit, VAERS accepts incomplete reports. Healthcare provider contact information is helpful but not required for public submissions.
How do I search VAERS data to find reports?
The VAERS database is publicly accessible through the official website. You can search by vaccine type, adverse event, age group, or date range. The system allows filtering to find specific patterns or reports. Results show submitted reports, though remember that a report in the database does not establish causation, it documents a temporal association between vaccination and an event.
Does submitting a VAERS report mean the vaccine caused my adverse event?
No. VAERS is a passive surveillance system that collects reports of events occurring after vaccination. A report documents that an event happened after a vaccine was given, but does not prove the vaccine caused it. Investigators review reports to detect unusual patterns or safety signals that warrant further investigation. Temporal association and causation are different, VAERS captures the former to monitor for the latter.
