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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. FLU(H1N1)
  4. Presyncope
FLU(H1N1)×Presyncope

Presyncope Reports for FLU(H1N1)

#171 most reported symptom for this vaccine

40
Reports
0
Deaths
5
Hospitalizations
0
Mortality Rate
%
12.5
Hosp. Rate
%

Presyncope and FLU(H1N1)

Presyncope has been reported 40 times in association with FLU(H1N1) vaccination in VAERS.

Among these reports, 0 mentioned death (0.00%) and 5 involved hospitalization (12.5%).

Presyncope is the #171 most frequently reported symptom for FLU(H1N1) out of 993 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 40 reports of Presyncope after FLU(H1N1) 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 Presyncope occurred after vaccination, not that the vaccine caused it.
•Background rates: Presyncope 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

Tinnitus41 reportsEye pruritus40 reportsNo reaction on previous exposure to drug40 reportsContusion40 reports

Quick Facts

Reports:40
Deaths:0
Hospitalizations:5
% of Vaccine:—%
Rank:#171 of 993

Related Pages

FLU(H1N1) OverviewPresyncope (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.