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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.
Underdose
12,134 total reports0.1% serious outcomes
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12,134
Total Reports
3
Deaths
6
Hospitalizations
0.1
Severity Rate
% serious outcomes
About Underdose Reports
Underdose has been reported 12,134 times in VAERS from 1990 to 2026.
Of these reports, 3 were associated with death (0.02%) and 6 involved hospitalization.
The overall serious outcome rate (death or hospitalization) for reports mentioning Underdose is 0.1%.
Understanding Underdose in VAERS
•Temporal association only: These reports show Underdose 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 Underdose. 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. COVID196,462
2. COVID19-21,806
3. HEP1,108
4. FLU3860
5. HEPA766
6. FLU4498
7. VARZOS318
8. UNK149
9. TDAP137
10. RV5129
Detailed Breakdowns
Quick Facts
Reports:12,134
Deaths:3
Hospitalizations:6
Mortality Rate:0.02%
Severity Rate:0.1%
Related Analysis
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Data Source
This data comes from the Vaccine Adverse Event Reporting System (VAERS), jointly managed by CDC and FDA.