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.
Most Reported Symptoms
The 20 most commonly reported adverse symptoms in VAERS. Most of the top symptoms are expected immune responses — fever, headache, pain at the injection site.
What the Top Symptoms Tell Us
The most reported symptoms in VAERS are largely what you'd expect from normal immune responses:
- Pyrexia (fever): The #1 reported symptom. Fever is a sign the immune system is responding to the vaccine — exactly what it's supposed to do.
- Headache, fatigue, pain: Common side effects of almost all vaccines, usually resolving within 1-3 days.
- Injection site reactions: Redness, swelling, and pain at the injection site are among the most common and expected side effects.
The prevalence of mild, expected symptoms at the top of the list actually provides reassurance: it shows that VAERS is capturing the full spectrum of post-vaccination experiences, not just serious events.
Severity Breakdown
While most top symptoms are mild, some have significant hospitalization rates. This reflects that even common symptoms can sometimes be severe enough to require medical attention, particularly in vulnerable populations.
Top 20 Symptoms
| # | Symptom | Reports | Deaths | Hosp. | Severity |
|---|---|---|---|---|---|
| 1 | Pyrexia | 276,779 | 2,361 | 23,891 | 8.6% |
| 2 | Headache | 228,038 | 815 | 11,195 | 4.9% |
| 3 | Pain | 199,891 | 805 | 9,331 | 4.7% |
| 4 | Fatigue | 181,355 | 1,336 | 10,540 | 5.8% |
| 5 | Chills | 156,139 | 650 | 6,684 | 4.3% |
| 6 | Pain in extremity | 143,925 | 384 | 5,429 | 3.8% |
| 7 | No adverse event | 142,256 | 23 | 39 | 0.0% |
| 8 | Nausea | 135,876 | 964 | 9,042 | 6.7% |
| 9 | Injection site pain | 134,294 | 125 | 2,235 | 1.7% |
| 10 | Dizziness | 133,323 | 463 | 7,303 | 5.5% |
| 11 | Injection site erythema | 131,718 | 34 | 1,771 | 1.3% |
| 12 | Rash | 113,613 | 221 | 4,332 | 3.8% |
| 13 | COVID-19 | 97,623 | 7,316 | 35,295 | 36.2% |
| 14 | Injection site swelling | 96,522 | 28 | 1,407 | 1.5% |
| 15 | Myalgia | 95,202 | 258 | 4,011 | 4.2% |
| 16 | Erythema | 90,703 | 74 | 2,175 | 2.4% |
| 17 | Pruritus | 88,832 | 36 | 1,475 | 1.7% |
| 18 | Arthralgia | 87,171 | 191 | 3,806 | 4.4% |
| 19 | Dyspnoea | 85,976 | 4,203 | 22,749 | 26.5% |
| 20 | Vomiting | 79,547 | 1,343 | 11,544 | 14.5% |
Key Takeaways
- 1.The most commonly reported symptoms are expected immune responses (fever, headache, pain)
- 2.A single VAERS report typically lists multiple symptoms, so symptom counts exceed report counts
- 3.The dominance of mild symptoms at the top confirms VAERS captures the full spectrum of experiences