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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. Polio (Oral)
  4. Injection site mass
Polio (Oral)×Injection site mass

Injection site mass Reports for Polio (Oral)

#16 most reported symptom for this vaccine

1,287
Reports
1
Deaths
34
Hospitalizations
0.08
Mortality Rate
%
2.6
Hosp. Rate
%

Injection site mass and Polio (Oral)

Injection site mass has been reported 1,287 times in association with Polio (Oral) vaccination in VAERS. This represents 4.8% of all 27,089 reports for this vaccine.

Among these reports, 1 mentioned death (0.08%) and 34 involved hospitalization (2.6%).

Injection site mass is the #16 most frequently reported symptom for Polio (Oral) out of 558 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 1,287 reports of Injection site mass after Polio (Oral) vaccination may seem alarming, but context is critical.

The mortality rate among these reports is very low at 0.08%, suggesting most cases are non-fatal.

Important Context

•Association, not causation: These reports show Injection site mass occurred after vaccination, not that the vaccine caused it.
•Background rates: Injection site mass 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

Hypotonia1,496 reportsUrticaria1,381 reportsAnorexia1,270 reportsInfection1,260 reports

Quick Facts

Reports:1,287
Deaths:1
Hospitalizations:34
% of Vaccine:4.8%
Rank:#16 of 558

Related Pages

Polio (Oral) OverviewInjection site mass (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.