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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. Meningococcal Vaccine
5 min read
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Meningococcal Vaccine Side Effects

Meningococcal vaccines protect against bacterial meningitis — a rare but potentially fatal infection. Routinely given to adolescents at ages 11-12 and 16, and required by many colleges for dorm residents. VAERS contains over 36,000 reports across all meningococcal vaccine types.

39,923
Total Reports
185
Deaths Reported
2,247
Hospitalizations
10,749
ER Visits

Most Commonly Reported Side Effects

The following symptoms are most frequently reported after meningococcal vaccination:

#1Injection site erythema
5,010
#2Dizziness
4,859
#3Headache
4,552
#4Syncope
4,126
#5Pyrexia
4,055
#6Injection site swelling
3,971
#7Erythema
3,408
#8No adverse event
3,334
#9Nausea
3,017
#10Injection site pain
2,838
#11Pallor
2,560
#12Loss of consciousness
2,414

Types of Meningococcal Vaccines

There are two main categories:

  • MenACWY (conjugate): Menactra, Menveo, MenQuadfi — protects against serogroups A, C, W, Y. This is the routine adolescent vaccine.
  • MenB (serogroup B): Bexsero, Trumenba — protects against serogroup B. Recommended for teens/young adults at increased risk or during outbreaks.

MenB vaccines tend to have more local side effects (injection site pain) than MenACWY vaccines, which is reflected in VAERS reporting patterns.

Expected Side Effects

Very common:

  • Injection site pain (up to 50%+ for MenB)
  • Fatigue and malaise
  • Headache
  • Muscle pain

Common:

  • Fever
  • Nausea
  • Joint pain

Rare:

  • Guillain-Barré Syndrome (Menactra specifically monitored for this)
  • Severe allergic reaction
  • Syncope (fainting) — common in adolescents after any injection, not vaccine-specific

Fainting in Adolescents

A notable portion of meningococcal vaccine VAERS reports involve syncope (fainting). This is not specific to meningococcal vaccines — adolescents faint after any injection at much higher rates than other age groups. The CDC recommends a 15-minute observation period after vaccinating adolescents for this reason.

Why It Matters

Meningococcal disease is rare (about 300-400 cases/year in the U.S.) but devastating — 10-15% of cases are fatal, and up to 20% of survivors have permanent complications like limb amputation, hearing loss, or brain damage. The vaccine has dramatically reduced cases in the age groups most at risk.

MenACWY is routine at ages 11-12 with a booster at 16. See where meningococcal vaccines fit on the CDC vaccine schedule and our 2026 vaccine schedule analysis.

⚠️ 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

Menactra Detail →
Full VAERS profile
Pediatric Analysis →
Youth vaccine data
All Side Effects →
Overview across all vaccines

2026 Safety Monitoring Update

As of mid-2026, the meningococcal 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 meningococcal 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 meningococcal 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 meningococcal

When interpreting VAERS data for meningococcal 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 meningococcal 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 meningococcal 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 meningococcal 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 meningococcal 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 meningococcal

When interpreting VAERS data for meningococcal 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 meningococcal 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

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