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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. Tdap (Boostrix)
  4. Haematocrit decreased
Tdap (Boostrix)×Haematocrit decreased

Haematocrit decreased Reports for Tdap (Boostrix)

#413 most reported symptom for this vaccine

47
Reports
0
Deaths
20
Hospitalizations
0
Mortality Rate
%
42.6
Hosp. Rate
%

Haematocrit decreased and Tdap (Boostrix)

Haematocrit decreased has been reported 47 times in association with Tdap (Boostrix) vaccination in VAERS. This represents 0.1% of all 52,846 reports for this vaccine.

Among these reports, 0 mentioned death (0.00%) and 20 involved hospitalization (42.6%).

Haematocrit decreased is the #413 most frequently reported symptom for Tdap (Boostrix) out of 2243 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 47 reports of Haematocrit decreased after Tdap (Boostrix) 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 Haematocrit decreased occurred after vaccination, not that the vaccine caused it.
•Background rates: Haematocrit decreased 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

Erythema multiforme47 reportsTendonitis47 reportsHaemoglobin decreased47 reportsAbortion spontaneous47 reports

Quick Facts

Reports:47
Deaths:0
Hospitalizations:20
% of Vaccine:0.1%
Rank:#413 of 2243

Related Pages

Tdap (Boostrix) OverviewHaematocrit decreased (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.