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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.

Mass

3,031 total reports5.4% serious outcomes
3,031
Total Reports
16
Deaths
147
Hospitalizations
5.4
Severity Rate
% serious outcomes

About Mass Reports

Mass has been reported 3,031 times in VAERS from 1990 to 2026.

Of these reports, 16 were associated with death (0.53%) and 147 involved hospitalization.

The overall serious outcome rate (death or hospitalization) for reports mentioning Mass is 5.4%.

Understanding Mass in VAERS

Temporal association only: These reports show Mass 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 Mass. 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.

Quick Facts

Reports:3,031
Deaths:16
Hospitalizations:147
Mortality Rate:0.53%
Severity Rate:5.4%

Data Source

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