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Data source: VAERS (Vaccine Adverse Event Reporting System)

Data through 2026 · Updated quarterly

Built by TheDataProject.ai · © 2026 VaccineWatch

Important: VAERS accepts reports of adverse events following vaccination. For any given report, there is no certainty that the reported event was caused by the vaccine. Reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable. Most reports to VAERS are voluntary, which means they are subject to biases. This data cannot be used to determine if vaccines cause or contribute to adverse events.

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Important: VAERS reports alone cannot determine if a vaccine caused an adverse event. Reports may contain incomplete, inaccurate, or unverified information. Correlation does not equal causation.

  1. Home
  2. Vaccines
  3. Influenza, Seasonal (Fluvirin)
  4. Underdose
Influenza, Seasonal (Fluvirin)×Underdose

Underdose Reports for Influenza, Seasonal (Fluvirin)

#131 most reported symptom for this vaccine

599
Reports
0
Deaths
0
Hospitalizations
0
Mortality Rate
%
0
Hosp. Rate
%

Underdose and Influenza, Seasonal (Fluvirin)

Underdose has been reported 599 times in association with Influenza, Seasonal (Fluvirin) vaccination in VAERS. This represents 0.5% of all 119,695 reports for this vaccine.

Among these reports, 0 mentioned death (0.00%) and 0 involved hospitalization (0.0%).

Underdose is the #131 most frequently reported symptom for Influenza, Seasonal (Fluvirin) out of 3021 total symptoms.

Disclaimer: VAERS reports describe events that occurred after vaccination but do not establish that the vaccine caused the event. Many reported symptoms may be coincidental or related to underlying conditions.

What This Means

Seeing 599 reports of Underdose after Influenza, Seasonal (Fluvirin) vaccination may seem alarming, but context is critical. With 119,695 total reports for this vaccine (representing many millions of doses), Underdose appears in only 0.5% of reports.

The mortality rate among these reports is very low at 0.00%, suggesting most cases are non-fatal.

Important Context

•Association, not causation: These reports show Underdose occurred after vaccination, not that the vaccine caused it.
•Background rates: Underdose may occur naturally at baseline rates in the population, unrelated to vaccination.
•Anyone can report: VAERS accepts reports from anyone — patients, parents, healthcare providers — without requiring medical verification.
•Denominator missing: VAERS counts reports, not rates per dose. Without knowing how many doses were given, raw counts can be misleading. Learn more →

Similarly Ranked Symptoms

X-ray606 reportsPharyngitis601 reportsProduct storage error597 reportsInjection site urticaria591 reports

Quick Facts

Reports:599
Deaths:0
Hospitalizations:0
% of Vaccine:0.5%
Rank:#131 of 3021

Related Pages

Influenza, Seasonal (Fluvirin) OverviewUnderdose (All Vaccines)Why Raw Numbers MisleadTop Symptoms Analysis

Data Source

This data comes from the Vaccine Adverse Event Reporting System (VAERS), jointly managed by CDC and FDA.