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Transparent access to VAERS data for informed decision-making. We present the data as-is, with appropriate context and disclaimers.

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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. Yellow Fever (YF-Vax)
  4. Gram stain negative
Yellow Fever (YF-Vax)×Gram stain negative

Gram stain negative Reports for Yellow Fever (YF-Vax)

#323 most reported symptom for this vaccine

12
Reports
0
Deaths
10
Hospitalizations
0
Mortality Rate
%
83.3
Hosp. Rate
%

Gram stain negative and Yellow Fever (YF-Vax)

Gram stain negative has been reported 12 times in association with Yellow Fever (YF-Vax) vaccination in VAERS. This represents 0.2% of all 4,996 reports for this vaccine.

Among these reports, 0 mentioned death (0.00%) and 10 involved hospitalization (83.3%).

Gram stain negative is the #323 most frequently reported symptom for Yellow Fever (YF-Vax) out of 959 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 12 reports of Gram stain negative after Yellow Fever (YF-Vax) vaccination may seem alarming, but context is critical.

The mortality rate among these reports is very low at 0.00%, suggesting most cases are non-fatal.

Important Context

•Association, not causation: These reports show Gram stain negative occurred after vaccination, not that the vaccine caused it.
•Background rates: Gram stain negative 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

Leukoencephalomyelitis12 reportsEpstein-Barr virus antibody positive12 reportsLymphocyte percentage12 reportsMonocyte percentage increased12 reports

Quick Facts

Reports:12
Deaths:0
Hospitalizations:10
% of Vaccine:0.2%
Rank:#323 of 959

Related Pages

Yellow Fever (YF-Vax) OverviewGram stain negative (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.