Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.
The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.
Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

COVID-19 Vaccine Safety Reporting Systems

COVID-19 Vaccine Safety Reporting Systems
Updated Dec. 1, 2022

What You Need to Know

  • Hundreds of millions of people in the United States have safely received COVID-19 vaccinations.
  • COVID-19 vaccines have undergone the most intensive safety monitoring in U.S. history.
  • Vaccine safety monitoring uses established systems like the:
    • Vaccine Adverse Event Reporting System (VAERS)
    • Vaccine Safety Datalink (VSD)
    • Clinical Immunization Safety Assessment (CISA) Project
  • CDC’s v-safe After Vaccination Health Checker is a new smartphone-based system that was developed for COVID-19 vaccine safety monitoring. Vaccine recipients can enroll and report how they or their dependents feel after they receive a vaccine.
  • CDC provides timely updates on selected adverse events reported to VAERS after COVID-19 vaccination.

Vaccine Safety Monitoring Process

After a vaccine is authorized or approved for use, vaccine safety systems monitor adverse events (rare health conditions) and watch for potential safety problems.

  • This continued monitoring can identify adverse events that may not have been seen in clinical trials. If an unexpected adverse event is seen, experts quickly study it to assess whether it presents a safety concern.
  • Experts then decide whether changes are needed in U.S. vaccine recommendations or clinical guidance.
  • Vaccine safety monitoring is critical to help ensure that the benefits of vaccination continue to outweigh the risks for people who receive vaccines.

The U.S. Food and Drug Administration’s (FDA) COVID-19 Vaccines website includes important recommendations for ongoing safety evaluations after any COVID-19 vaccine is made available under Emergency Use Authorization (EUA) or receives full FDA approval.

In addition to scaling up existing safety monitoring systems, CDC expanded its vaccine safety surveillance through a new smartphone-based system called v-safe.

New safety monitoring system

The following system and information sources were developed during the COVID-19 pandemic. They add an additional layer of safety monitoring, giving CDC and FDA the ability to evaluate COVID-19 vaccine safety in real time and make sure COVID-19 vaccines are as safe as possible.

Existing safety monitoring systems

CDC, FDA, and other federal partners use the following systems and data sources to conduct comprehensive vaccine safety monitoring: