Through decades of research, testing and development, vaccines have proven to be an effective way to prevent many infectious diseases and their effects, including serious illness, hospitalization and death. Vaccines are held to a high safety standard, undergoing thorough testing before they are licensed, and are constantly monitored for safety throughout all stages of use.

Most people do not experience serious side effects from vaccines. Some mild side effects can occur on occasion, including pain or swelling at the injection site, and often these side effects are signs that a body is effectively building a healthy immune response and protection.

Getting multiple vaccinations at once has been shown to be safe.

Vaccine Adverse Event Reporting System (VAERS)

Vaccine Adverse Event Reporting System (VAERS)

On rare occasion, an adverse event (possible side effect) can occur after a person receives a vaccine dose. The cause of these adverse events can be difficult to identify, and often are from an unrelated cause, not the vaccine. Safety monitoring is important for scientists to look for immunization response trends or unusual patterns of adverse events. Vaccine Adverse Event Reporting System (VAERS) is used by the Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) to collect reports of side effects that happen after vaccination. The system relies on individuals to report adverse health events following vaccination – anyone can and should report adverse events to VAERS (

VAERS logo


How VAERS Works


How is Vaccine Safety Monitored in the U.S.?

The success of vaccination programs depends not only on vaccines’ effectiveness but also on their safety. Because vaccines are given to millions of healthy people each year, they are held to a very high standard and are continuously monitored for safety. The U.S. has one of the most advanced systems in the world for assessing vaccine safety. This includes a coordinated and overlapping approach using state-of-the-art technologies and systems working together. Each of the "gears," or systems, supplies a different type of data for researchers to analyze. Together, they work as a well-oiled machine to help provide a comprehensive picture of vaccine safety in the U.S. Click here for more.


How to Report an Adverse Event to VAERS

Created in 1990 by the US Department of Health and Human Services, VAERS is a database for the collection of adverse events following vaccines. It is operated and monitored by the CDC and the FDA to detect whether any vaccines are associated with higher than expected rates of adverse events.

Anyone can report to VAERS. This can be vaccine recipients themselves, caregivers of vaccine recipients (parents, guardians) or health care providers. Any clinically significant or unexpected events following a vaccine administration should be reported to VAERS. See VAERS Table of Reportable Events Following Vaccination (PDF).

Adverse events that follow vaccines are rare. Most adverse events that follow vaccines are manageable by health care providers that administer vaccines and will occur within hours of administration. Some extremely rare events can occur within six months of vaccine administration. People with conditions known to make them more vulnerable to these events should talk to their health care provider before receiving a vaccine. Some adverse events and their expected timeline after vaccination are listed here: Vaccine Injury Table Effective for Claims Filed on or After 1-3-2022 (

North Dakota Health and Human Services (NDHHS) does not maintain the VAERS database but does regularly review reports made by or on behalf of North Dakotans. To contact the NDHHS Immunization Unit for assistance with or questions about VAERS, please contact

VAERS: Online Reporting Demonstration


The Vaccine Life Cycle

Vaccine Safety Process

View Full Size (PDF)


Questions? Contact Us

NDHHS Disease Control — Immunization Unit
600 E. Boulevard Avenue, Dept. 325
Bismarck, ND 58505-0200

Phone: (701) 328-3386
Toll-Free: (800) 472-2180
TTY: 711