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Transparent access to VAERS data for informed decision-making. We present the data as-is, with appropriate context and disclaimers.

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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. COVID-19 Bivalent (Moderna)
  4. Underdose
COVID-19 Bivalent (Moderna)×Underdose

Underdose Reports for COVID-19 Bivalent (Moderna)

#14 most reported symptom for this vaccine

1,780
Reports
0
Deaths
0
Hospitalizations
0
Mortality Rate
%
0
Hosp. Rate
%

Underdose and COVID-19 Bivalent (Moderna)

Underdose has been reported 1,780 times in association with COVID-19 Bivalent (Moderna) vaccination in VAERS. This represents 4.1% of all 42,946 reports for this vaccine.

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

Underdose is the #14 most frequently reported symptom for COVID-19 Bivalent (Moderna) out of 2434 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 1,780 reports of Underdose after COVID-19 Bivalent (Moderna) vaccination may seem alarming, but context is critical.

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

Oropharyngeal pain2,014 reportsChills1,992 reportsMalaise1,730 reportsDizziness1,647 reports

Quick Facts

Reports:1,780
Deaths:0
Hospitalizations:0
% of Vaccine:4.1%
Rank:#14 of 2434

Related Pages

COVID-19 Bivalent (Moderna) 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.