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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. Hepatitis A Vaccine
5 min read
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Hepatitis A Vaccine Side Effects

Hepatitis A vaccines (Havrix, Vaqta) protect against the hepatitis A virus, which causes liver inflammation. Recommended for all children at age 1 and for adults at risk, this vaccine has an excellent safety profile with over 48,000 VAERS reports since the 1990s.

48,094
Total Reports
244
Deaths Reported
2,136
Hospitalizations
12,948
ER Visits

Most Commonly Reported Side Effects

The following symptoms are most frequently reported after hepatitis A vaccination:

#1No adverse event
7,915
#2Pyrexia
6,892
#3Injection site erythema
5,763
#4Rash
4,042
#5Injection site swelling
3,601
#6Erythema
3,422
#7Urticaria
3,132
#8Dizziness
2,671
#9Headache
2,431
#10Injection site pain
2,339
#11Vomiting
2,322
#12Product storage error
2,262

Expected Side Effects

Very common (occurring in >10% of recipients):

  • Injection site pain, tenderness, or warmth
  • Headache
  • Fatigue and malaise

Common (1-10%):

  • Fever (usually low-grade)
  • Decreased appetite
  • Injection site redness or swelling
  • Irritability (in children)

Rare:

  • Severe allergic reaction (anaphylaxis)
  • Guillain-Barré Syndrome (very rare reports)

Havrix vs Vaqta

Both Havrix (GSK) and Vaqta (Merck) are inactivated hepatitis A vaccines with similar efficacy and safety profiles. There is also Twinrix, a combination hepatitis A + B vaccine. All are given as a 2-dose series, with the second dose 6-18 months after the first.

Safety Profile Context

Hepatitis A vaccines are among the better-tolerated vaccines. The relatively low number of VAERS reports compared to the hundreds of millions of doses administered reflects a favorable safety profile. Natural hepatitis A infection, by contrast, causes weeks of illness and can be fatal in older adults and people with chronic liver disease.

Hepatitis A vaccination is routine for children at age 1 and for at-risk adults. See where it fits on the CDC vaccine schedule, review our 2026 vaccine schedule analysis, and compare with pediatric VAERS patterns.

⚠️ 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

Hepatitis A Detail →
Full VAERS profile
Hepatitis B Side Effects →
Compare with Hep B
All Side Effects →
Overview across all vaccines

2026 Safety Monitoring Update

As of mid-2026, the hepatitis A vaccine continues to be monitored through VAERS and complementary surveillance systems including the Vaccine Safety Datalink (VSD) and the Clinical Immunization Safety Assessment (CISA) project. No new safety signals have been identified in recent data that would change the established safety profile of this vaccine.

The HHS administration's announced development of AI-powered VAERS analysis tools may provide additional insights into hepatitis A vaccine adverse event patterns. These tools aim to detect subtle signals that traditional statistical methods might miss, though their implementation timeline and methodology remain under development.

It's worth noting that VAERS reporting for routine vaccines like hepatitis A has remained stable through the post-pandemic period. While COVID-19 vaccine reports surged and then declined, reporting patterns for established childhood and adult vaccines have been remarkably consistent, suggesting that the VAERS system continues to function as designed for ongoing safety surveillance.

Understanding VAERS Data for hepatitis A

When interpreting VAERS data for hepatitis A vaccines, several key principles apply:

  • Reports ≠ Causation: A VAERS report means an event occurred after vaccination. It does not establish that the vaccine caused the event. Many reported symptoms are common health occurrences that would happen regardless of vaccination.
  • No denominator: VAERS does not track the number of doses administered. Without knowing how many people received the vaccine, raw report counts cannot be used to calculate risk rates or compare safety across vaccines.
  • Co-administration: Many vaccines are given at the same visit. When a VAERS report lists multiple vaccines, it's impossible to determine which vaccine (if any) was responsible for the reported adverse event.
  • Reporting variability: Healthcare provider awareness, media attention, and public concern all influence how many reports are filed. Changes in report volume may reflect changes in reporting behavior rather than changes in actual safety.

How to Use This Data Responsibly

VAERS data is most useful as a starting point for conversation with your healthcare provider, not as a basis for medical decisions. If you're concerned about hepatitis A vaccine side effects:

  • Discuss your specific risk factors with your doctor or pharmacist
  • Ask about the relative risks of the disease the vaccine prevents vs. the vaccine itself
  • Consider your age, health status, and any previous vaccine reactions
  • Remember that clinical trials and post-market studies provide much stronger safety evidence than VAERS alone

For the most up-to-date safety information, consult the CDC's vaccine information pages or speak with a qualified healthcare professional.

More Resources

When Do Side Effects Start?
73% occur within 3 days of vaccination
Serious vs Non-Serious Outcomes
The full severity spectrum in VAERS
Report an Adverse Event
How to file a VAERS report
Our Methodology
How we process VAERS data

2026 Safety Monitoring Update

As of mid-2026, the hepatitis A vaccine continues to be monitored through VAERS and complementary surveillance systems including the Vaccine Safety Datalink (VSD) and the Clinical Immunization Safety Assessment (CISA) project. No new safety signals have been identified in recent data that would change the established safety profile of this vaccine.

The HHS administration's announced development of AI-powered VAERS analysis tools may provide additional insights into hepatitis A vaccine adverse event patterns. These tools aim to detect subtle signals that traditional statistical methods might miss, though their implementation timeline and methodology remain under development.

It's worth noting that VAERS reporting for routine vaccines like hepatitis A has remained stable through the post-pandemic period. While COVID-19 vaccine reports surged and then declined, reporting patterns for established childhood and adult vaccines have been remarkably consistent, suggesting that the VAERS system continues to function as designed for ongoing safety surveillance.

Understanding VAERS Data for hepatitis A

When interpreting VAERS data for hepatitis A vaccines, several key principles apply:

  • Reports ≠ Causation: A VAERS report means an event occurred after vaccination. It does not establish that the vaccine caused the event. Many reported symptoms are common health occurrences that would happen regardless of vaccination.
  • No denominator: VAERS does not track the number of doses administered. Without knowing how many people received the vaccine, raw report counts cannot be used to calculate risk rates or compare safety across vaccines.
  • Co-administration: Many vaccines are given at the same visit. When a VAERS report lists multiple vaccines, it's impossible to determine which vaccine (if any) was responsible for the reported adverse event.
  • Reporting variability: Healthcare provider awareness, media attention, and public concern all influence how many reports are filed. Changes in report volume may reflect changes in reporting behavior rather than changes in actual safety.

How to Use This Data Responsibly

VAERS data is most useful as a starting point for conversation with your healthcare provider, not as a basis for medical decisions. If you're concerned about hepatitis A vaccine side effects:

  • Discuss your specific risk factors with your doctor or pharmacist
  • Ask about the relative risks of the disease the vaccine prevents vs. the vaccine itself
  • Consider your age, health status, and any previous vaccine reactions
  • Remember that clinical trials and post-market studies provide much stronger safety evidence than VAERS alone

For the most up-to-date safety information, consult the CDC's vaccine information pages or speak with a qualified healthcare professional.

More Resources

When Do Side Effects Start?
73% occur within 3 days of vaccination
Serious vs Non-Serious Outcomes
The full severity spectrum in VAERS
Report an Adverse Event
How to file a VAERS report
Our Methodology
How we process VAERS data

More Side Effect Guides

Hepatitis B Side Effects
Engerix-B data
COVID-19 Side Effects
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Full Dashboard
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