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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
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  3. Platelet count decreased

Platelet count decreased

4,498 total reports71.0% serious outcomes
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Platelet count decreased appears in 4,498 VAERS reports across all vaccines. Of these, 304 reports also mentioned death and 2,891 involved hospitalization. The severity rate (deaths + hospitalizations as a percentage of reports) is 71.0%. The top vaccines associated with this symptom are COVID-19, MMR, Chickenpox (Varivax). Remember: VAERS reports show temporal association, not causation.

4,498
Total Reports
304
Deaths
2,891
Hospitalizations
71
Severity Rate
% serious outcomes

About Platelet count decreased Reports

Platelet count decreased has been reported 4,498 times in VAERS from 1990 to 2026.

Of these reports, 304 were associated with death (6.76%) and 2,891 involved hospitalization.

The overall serious outcome rate (death or hospitalization) for reports mentioning Platelet count decreased is 71.0%.

Understanding Platelet count decreased in VAERS

•Temporal association only: These reports show Platelet count decreased occurred after vaccination, not necessarily because of vaccination.
•Background rates matter: Many symptoms occur naturally at baseline rates in the population, unrelated to vaccination.
•Reporting variability: Medical terminology may be used differently by various healthcare providers and over time.
•Investigation needed: High-frequency reports may trigger further epidemiological studies to determine causation.

What This Data Shows

Most Associated Vaccines: The vaccines most frequently mentioned in reports with Platelet count decreased. This may reflect usage patterns, not causation.
Severity Patterns: The percentage of reports that involve serious outcomes can help prioritize safety investigations.
Reporting Trends: Changes in reporting frequency over time may reflect increased awareness, media attention, or actual safety signals.

Most Associated Vaccines

1. COVID-195,017
2. MMR364
3. Chickenpox (Varivax)250
4. Flu (Trivalent)234
5. HPV (Gardasil)203
6. Pneumococcal (PCV7)183
7. Hib172
8. Hepatitis A160
9. Shingles (Zostavax)126
10. Flu (Quadrivalent)109
View all vaccines →

Detailed Breakdowns

Platelet count decreased × COVID-19 →Platelet count decreased × MMR →Platelet count decreased × Chickenpox (Varivax) →

Quick Facts

Reports:4,498
Deaths:304
Hospitalizations:2,891
Mortality Rate:6.76%
Severity Rate:71.0%

Related Analysis

Most Common Symptoms Analysis →Serious Outcomes Analysis →When Do Side Effects Start? →Recovery Rates Analysis →

Explore Further

Compare with Other SymptomsRead Symptoms Analysis

Data Source

This data comes from the Vaccine Adverse Event Reporting System (VAERS), jointly managed by CDC and FDA.