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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
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  3. Measles, Mumps & Rubella (MMR II)
  4. Brain stem syndrome
Measles, Mumps & Rubella (MMR II)×Brain stem syndrome

Brain stem syndrome Reports for Measles, Mumps & Rubella (MMR II)

#1326 most reported symptom for this vaccine

8
Reports
1
Deaths
6
Hospitalizations
12.5
Mortality Rate
%
75
Hosp. Rate
%

Brain stem syndrome and Measles, Mumps & Rubella (MMR II)

Brain stem syndrome has been reported 8 times in association with Measles, Mumps & Rubella (MMR II) vaccination in VAERS. This represents 0.0% of all 89,976 reports for this vaccine.

Among these reports, 1 mentioned death (12.50%) and 6 involved hospitalization (75.0%).

Brain stem syndrome is the #1326 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 8 reports of Brain stem syndrome after Measles, Mumps & Rubella (MMR II) vaccination may seem alarming, but context is critical.

The 12.50% 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 Brain stem syndrome occurred after vaccination, not that the vaccine caused it.
•Background rates: Brain stem syndrome 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

Laryngeal oedema8 reportsOral candidiasis8 reportsHyperlipidaemia8 reportsExtrasystoles8 reports

Quick Facts

Reports:8
Deaths:1
Hospitalizations:6
% of Vaccine:0.0%
Rank:#1326 of 2292

Related Pages

Measles, Mumps & Rubella (MMR II) OverviewBrain stem syndrome (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.