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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.

⚠️

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. Vaccine Side Effects
  3. Varicella (Chickenpox) Vaccine
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Varicella (Chickenpox) Vaccine Side Effects

The varicella vaccine (Varivax) protects against chickenpox and is given as two doses in childhood. With over 93,000 VAERS reports, it's one of the most-reported childhood vaccines — largely reflecting its widespread use since FDA approval in 1995.

116,688
Total Reports
353
Deaths Reported
3,868
Hospitalizations
33,689
ER Visits

Most Commonly Reported Side Effects

The following symptoms are most frequently reported after varicella vaccination:

#1No adverse event
15,409
#2Pyrexia
14,829
#3Injection site erythema
12,411
#4Rash
10,701
#5Infection
8,519
#6Drug ineffective
8,148
#7Injection site swelling
7,919
#8Erythema
6,875
#9Dermatitis bullous
5,952
#10Product storage error
5,701
#11Pruritus
5,292
#12Incorrect product storage
5,193

Varivax vs ProQuad (MMRV)

Varicella protection is available as standalone Varivax or combined with MMR as ProQuad (MMRV). ProQuad has a slightly higher rate of febrile seizures in children 12-23 months compared to giving MMR and varicella separately, which is why the CDC allows either approach for the first dose.

Expected Side Effects

Common (occurring in >10% of recipients):

  • Pain, redness, or swelling at injection site
  • Fever (usually mild, within 42 days)
  • Mild varicella-like rash (about 4% of children) — usually just a few spots

Less common:

  • Irritability
  • Upper respiratory symptoms
  • Headache and fatigue

Rare:

  • Febrile seizures (slightly higher with MMRV vs separate vaccines)
  • Herpes zoster (shingles) from vaccine-strain virus — much rarer than from natural chickenpox
  • Pneumonia, encephalitis (extremely rare)
  • Severe allergic reaction

Important Context

Before the varicella vaccine, chickenpox caused about 100 deaths and 10,000+ hospitalizations per year in the U.S. Since routine vaccination began in 1995, chickenpox cases have declined by over 90%. The vaccine's benefits in preventing natural chickenpox complications far exceed the risks of reported adverse events.

Many VAERS reports for varicella involve co-administered vaccines (given at the same visit), making it difficult to attribute symptoms to any single vaccine.

⚠️ Remember: VAERS reports show correlation, not causation. A report filed after vaccination doesn't mean the vaccine caused the reported event. Always consult your healthcare provider for medical advice.

Explore This Data

Varicella Vaccine Detail →
Full VAERS profile
MMRV (ProQuad) →
Combined vaccine data
All Side Effects →
Overview across all vaccines

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