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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. Measles, Mumps & Rubella (MMR II)
  4. Loss of consciousness
Measles, Mumps & Rubella (MMR II)×Loss of consciousness

Loss of consciousness Reports for Measles, Mumps & Rubella (MMR II)

#103 most reported symptom for this vaccine

514
Reports
1
Deaths
46
Hospitalizations
0.19
Mortality Rate
%
8.9
Hosp. Rate
%

Loss of consciousness and Measles, Mumps & Rubella (MMR II)

Loss of consciousness has been reported 514 times in association with Measles, Mumps & Rubella (MMR II) vaccination in VAERS. This represents 0.6% of all 89,976 reports for this vaccine.

Among these reports, 1 mentioned death (0.19%) and 46 involved hospitalization (8.9%).

Loss of consciousness is the #103 most frequently reported symptom for Measles, Mumps & Rubella (MMR II) out of 2292 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 514 reports of Loss of consciousness after Measles, Mumps & Rubella (MMR II) vaccination may seem alarming, but context is critical.

The mortality rate among these reports is very low at 0.19%, suggesting most cases are non-fatal.

Important Context

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

Full blood count545 reportsCondition aggravated527 reportsIncorrect route of product administration514 reportsImmediate post-injection reaction503 reports

Quick Facts

Reports:514
Deaths:1
Hospitalizations:46
% of Vaccine:0.6%
Rank:#103 of 2292

Related Pages

Measles, Mumps & Rubella (MMR II) OverviewLoss of consciousness (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.