Each month, the U.S. Government publishes a new release of its VAERS database. Most of the differences between releases consist of new VAERS reports that were introduced since the previous release. But the government never closes a VAERS report, and may make changes to any report at any time. Sometimes reports are even deleted.

The VAERS Wayback Machine has a collection of old releases of the VAERS database, starting in 2003. It allows you to examine the government data more carefully and observe how the data changes over time. Here are some of the things that you can do with the VAERS Wayback Machine:

Enter a VAERS ID number here to see all changes that have been made to that report since 2003. You can find out when the report first appeared, how it was modified, and if applicable, when it was deleted. See the How Differences are Shown section below for more about interpreting the results.

Select two different VAERS releases to compare them. All VAERS reports that are in just one of the two releases will be listed.

Select two different VAERS releases to compare them. All VAERS reports that are found in both releases will be examined and the differences described. Because this report can be very large, only 400 reports are shown (the earliest 200 and the latest 200). See the How Differences are Shown section below for more about interpreting the results.

Do a search of an older VAERS database.

Here is a sample report showing differences. Note the use of color coding: Red indicates something that was in the older release and is therefore removed. Green indicates something that is in the newer release and is therefore added.

In the sample report below (a fictitious report), the date of vaccination and onset has changed, the manufacturer of the Flu vaccine has changed, the number of days in the hospital was entered (was previously blank), four symptoms have been removed, and the write-up and preexisting conditions were edited.

Differences between 8/31/2010 and 10/5/2010:

VAERS ID: 274544/274544   Vaccinated: 2005-11-29/2006-11-30 Age: 1.0   Onset: 2005-11-29/2006-11-30 Gender: Male   Submitted: 2006-12-04 Location: Louisiana   Entered: 2006-12-04	Life Threatening Illness? Died? Disability? Recovered? Yes ER or Doctor Visit? Hospitalized? Yes, days: (blank)/1     Extended hospital stay? Current Illness: Diagnostic Lab Data: Previous Vaccinations: Other Medications: J-tan 2ml twice a day Preexisting Conditions: SGA, Hemangioma, Chiritis/Rhinitis, Term baby CDC 'Split Type':
Vaccination Manufacturer Lot Dose Route Site FLU: INFLUENZA (SEASONAL) (FLUZONE) AVENTIS PASTEUR/SANOFI PASTEUR U2174KA 0 IM LL HEPA: HEP A (HAVRIX) MERCK & CO. INC. 0560R 0 IM RL
Administered by: Public     Purchased by: Public Symptoms: Anaphylactic reaction, Angioneurotic oedema, Dyspnoea, Eye swelling, Swelling face, Vaccination complication, Wheezing Write-up:Administration to a child <4 yold. Initial case report received from a pediatrician via agency on 04 NOV 2009. A 1-year-old male patient was accidentally vaccinated with FLUVIRIN 2009/2010 i.m. on 30 OCT 2009. No adverse effect was reported. Company assessment: Seriousness criterion: not serious. Causality: not applicable. No measures necessary.