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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 (Flublok Quadrivalent)
  4. Muscular weakness
Influenza, Seasonal (Flublok Quadrivalent)×Muscular weakness

Muscular weakness Reports for Influenza, Seasonal (Flublok Quadrivalent)

#51 most reported symptom for this vaccine

34
Reports
2
Deaths
10
Hospitalizations
5.88
Mortality Rate
%
29.4
Hosp. Rate
%

Muscular weakness and Influenza, Seasonal (Flublok Quadrivalent)

Muscular weakness has been reported 34 times in association with Influenza, Seasonal (Flublok Quadrivalent) vaccination in VAERS. This represents 1.0% of all 3,407 reports for this vaccine.

Among these reports, 2 mentioned death (5.88%) and 10 involved hospitalization (29.4%).

Muscular weakness is the #51 most frequently reported symptom for Influenza, Seasonal (Flublok Quadrivalent) out of 377 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 34 reports of Muscular weakness after Influenza, Seasonal (Flublok Quadrivalent) vaccination may seem alarming, but context is critical.

The 5.88% mortality rate among these reports is elevated, but this reflects the severity of the condition itself rather than vaccine causation.

Important Context

•Association, not causation: These reports show Muscular weakness occurred after vaccination, not that the vaccine caused it.
•Background rates: Muscular weakness 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

Neck pain35 reportsInjection site reaction34 reportsInsomnia33 reportsSleep disorder33 reports

Quick Facts

Reports:34
Deaths:2
Hospitalizations:10
% of Vaccine:1.0%
Rank:#51 of 377

Related Pages

Influenza, Seasonal (Flublok Quadrivalent) OverviewMuscular weakness (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.