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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 & Varicella (Proquad)
  4. Abnormal behaviour
Measles, Mumps, Rubella & Varicella (Proquad)×Abnormal behaviour

Abnormal behaviour Reports for Measles, Mumps, Rubella & Varicella (Proquad)

#101 most reported symptom for this vaccine

75
Reports
0
Deaths
13
Hospitalizations
0
Mortality Rate
%
17.3
Hosp. Rate
%

Abnormal behaviour and Measles, Mumps, Rubella & Varicella (Proquad)

Abnormal behaviour has been reported 75 times in association with Measles, Mumps, Rubella & Varicella (Proquad) vaccination in VAERS. This represents 0.3% of all 23,562 reports for this vaccine.

Among these reports, 0 mentioned death (0.00%) and 13 involved hospitalization (17.3%).

Abnormal behaviour is the #101 most frequently reported symptom for Measles, Mumps, Rubella & Varicella (Proquad) out of 936 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 75 reports of Abnormal behaviour after Measles, Mumps, Rubella & Varicella (Proquad) 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 Abnormal behaviour occurred after vaccination, not that the vaccine caused it.
•Background rates: Abnormal behaviour 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

Contusion76 reportsLip swelling76 reportsVaccination site swelling74 reportsFeeling hot73 reports

Quick Facts

Reports:75
Deaths:0
Hospitalizations:13
% of Vaccine:0.3%
Rank:#101 of 936

Related Pages

Measles, Mumps, Rubella & Varicella (Proquad) OverviewAbnormal behaviour (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.