Support for VAERS Follow-up Cases

VAERS accepts multiple cases for a given adverse event. The primary case is seen by normal searches, but secondary cases may follow-up, offering a history of the patient's progress. Here are some of the things you can do to examine these follow-up cases:

See Follow-ups for a Specific VAERS Case

Enter a VAERS ID number here to see the primary case and all follow-up cases that have been made. For each follow-up case, differences between it and the previous case are highlighted. See the How Differences are Shown section below for more about interpreting the results.

Find Differences between Follow-up Cases in Two Releases of the VAERS Database

Select two different VAERS releases. All follow-up cases that changed from one release to the other are displayed, and the differences described. See the How Differences are Shown section below for more about interpreting the results.

Release 1: 6/27/2025 5/30/2025 4/25/2025
Release 2: 6/27/2025 5/30/2025 4/25/2025

Find Added/Removed Follow-up Cases Between Two Releases of the VAERS Database

Select two different VAERS releases. All follow-up cases that were added or deleted between the releases will be shown.

Release 1: 6/27/2025 5/30/2025 4/25/2025
Release 2: 6/27/2025 5/30/2025 4/25/2025

Follow-up Issues

Examine the web of primary and follow-up cases, looking for gaps.

How Differences are Shown

Here is a sample case showing differences. Note the use of color coding: Red indicates something that was in the earlier report and is therefore removed. Green indicates something that is in the newer report and is therefore added. In the sample below (a fictitious case), many things have changed.

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

Changed: Vaccination Date, Onset Date, Vaccine Manufacturer, Symptoms, Hospitalized, Preexisting Conditions, Write-up

Vaccin­ation / Manu­facturer (2 vaccines)	Lot / Dose	Site / Route
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

Life Threatening?
Died?
Permanent Disability?
Recovered? Yes
ER or Doctor Visit?
Hospitalized? Yes, days: (blank)/1
Previous Vaccinations:
Other Medications: J-tan 2ml twice a day
Current Illness:
Preexisting Conditions: SGA, Hemangioma, Chiritis/Rhinitis, Term baby
Diagnostic Lab Data:
CDC 'Split Type':

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.