The Vaccine Adverse Event Reporting System — a passive, voluntary reporting system jointly administered by the CDC and FDA for reporting adverse events following vaccination. According to Aaron Siri, VAERS is systematically used to dismiss causation claims when they are inconvenient, while being invoked selectively to claim safety — a double standard that makes it an instrument of the vaccine religion rather than a genuine safety tool.
Explanation
VAERS accepts voluntary reports from healthcare providers, vaccine manufacturers, and the public. The CDC's official position is that VAERS:
Can be used for safety signal detection (identifying patterns worth investigating)
Cannot be used to establish causation between a vaccine and an injury
Siri's observation: despite the CDC's claim that VAERS cannot establish causation, CDC officials routinely cite the absence of VAERS signals as evidence vaccines are safe — applying an asymmetric standard.
Evidence and Examples
Massive Underreporting (Harvard Study)
Between 2013 and 2018, VAERS received:
261,294 total adverse event reports
2,081 deaths
5,477 permanent disabilities
20,778 hospitalizations
These numbers are a fraction of actual events. A Harvard Pilgrim Health Care study funded by AHRQ (2006, $1 million grant) concluded that "fewer than 1% of vaccine adverse events are reported" to VAERS.
The Harvard Automated Reporting System
2006–2009: Harvard Pilgrim developed software to automatically create VAERS reports from electronic health records
Results: Over 3 years and 376,452 vaccine recipients (1.4 million doses, 45 vaccines), the system identified 35,570 possible adverse reactions
CDC response: After the system was built and validated, the CDC refused to cooperate with linking it to VAERS for automatic transmission
- CDC contacts "were no longer available" and "no longer responsive to our multiple requests"
Siri's interpretation: Automating VAERS would have provided a fixed denominator (population of known vaccine recipients), enabling true causation analysis. The CDC's refusal to cooperate was deliberate prevention of causation-capable surveillance.
CDC's Hidden PRR Analysis (Covid-19 Vaccines)
Background:
December 4, 2020: Before the first Covid-19 vaccine rollout (December 10, 2020), the CDC published its VAERS Standard Operating Procedures for Covid-19 vaccines (VAERS SOP)
The SOP stated: CDC would use Proportional Reporting Ratios (PRR) for safety signal detection; FDA would use Empirical Bayesian (EB) data mining
The Hidden Analysis:
June 30, 2022: ICAN's firm requested the PRR signal detection data from CDC via FOIA
July 29, 2022: CDC responded that it had not conducted PRR analysis — only EB analysis was performed
September 2, 2022: After pressure from Senator Ron Johnson, CDC Director admitted that "CDC performed PRR analysis between March 25, 2022, through July 31, 2022"
ICAN sued CDC based on this admission and received 51 Excel files containing PRR data
CDC's Own PRR Results (safety signal threshold: PRR ≥ 2):
Adults (sample):
Condition
PRR
Intermenstrual Bleeding
73.72
Heavy Menstrual Bleeding
63.05
Postmenopausal Haemorrhage
57.63
Pulmonary Thrombosis
52.40
Thrombectomy
28.94
Menstrual Disorder
24.99
Left Ventricular Failure
14.91
Bell's Palsy
12.37
Electric Shock Sensation
10.96
Cardiac Failure Acute
8.58
Death
6.25
Tinnitus
4.52
Additional adult signals:
Condition
PRR
Multisystem Inflammatory Syndrome
177.62
Bell's Palsy
80.74
Left Ventricular Dysfunction
48.44
Pericardial Effusion
32.29
Pericarditis
32.29
Menstrual Disorder
21.53
Menstruation Irregular
17.94
Ventricular Extrasystoles
8.97
Children ages 5–11 showed additional disturbing signals (CDC's own data, details not enumerated in text but confirmed by Siri to be similarly flagged).
CDC's Response to Exposure:
When confronted with the data it had sought to hide, the CDC announced it would no longer use PRR and would rely only on FDA's EB data mining — the method for which ICAN's FOIA and litigation to obtain the results has been ongoing for over 2.5 years with no resolution.
The Asymmetric Logic
Siri identifies VAERS as a tool used asymmetrically:
When VAERS shows a signal for a harm the CDC is willing to recognize (rare): VAERS is cited as evidence of monitoring
When VAERS shows a signal for a harm the CDC won't recognize: VAERS "cannot establish causation" — dismissed
When VAERS data is hidden entirely (PRR results): ICAN must litigate to obtain it
The CDC also developed electronic systems long ago to track every vaccine from manufacturer to point of injection and to track the vaccination status of every child in every state — yet cannot automate VAERS reporting, a system that Harvard researchers built nearly two decades ago. Siri argues this reflects deliberate intent, not technical limitation.
Significance
VAERS is the primary public-facing tool the CDC and FDA point to when claiming vaccines are safe post-licensure. Siri argues it functions as a "holy vessel" — never to be upgraded in ways that could actually detect causation, invoked selectively to affirm the religion that vaccines are safe, and suppressed when its own data contradicts that conclusion.
How do I search VAERS and what are its limitations as a safety database?
VAERS data is accessible through CDC WONDER (wonder.cdc.gov). You can search by vaccine type, adverse event, age group, and date range. The primary limitation is massive underreporting — a Harvard Pilgrim Health Care study funded by AHRQ concluded that "fewer than 1% of vaccine adverse events are reported" to VAERS. The CDC's official position is that VAERS reports cannot establish causation, yet CDC officials routinely cite the absence of VAERS signals as evidence vaccines are safe.
What percentage of vaccine adverse events are actually reported to VAERS?
A Harvard Pilgrim Health Care study funded by AHRQ ($1 million grant, 2006-2009) concluded that "fewer than 1% of vaccine adverse events are reported" to VAERS. Over 3 years and 376,452 vaccine recipients receiving 1.4 million doses, the Harvard automated system identified 35,570 possible adverse reactions. When Harvard built software to automatically transmit reports to VAERS, the CDC refused to cooperate — contacts "were no longer available" and "no longer responsive."
What did CDC's hidden PRR analysis reveal about COVID vaccine safety signals?
CDC's own Proportional Reporting Ratio analysis — hidden until ICAN's FOIA lawsuit forced disclosure — showed massive safety signals including: intermenstrual bleeding (PRR 73.72), pulmonary thrombosis (52.40), Bell's palsy (12.37-80.74), death (6.25), myocarditis/pericarditis (32.29), and multisystem inflammatory syndrome (177.62). The threshold for a safety signal was PRR of 2 or higher. After this data was exposed, the CDC announced it would stop using PRR analysis entirely.
Why did the CDC refuse to automate VAERS reporting?
Between 2006 and 2009, Harvard Pilgrim developed software that automatically identified vaccine adverse events from electronic health records. The system was built, validated, and ready for deployment. When Harvard attempted to link it to VAERS for automatic transmission, CDC contacts "were no longer available" and "no longer responsive to our multiple requests." Aaron Siri argues the CDC deliberately prevented automated reporting because it would have enabled true causation analysis by providing a fixed denominator of known vaccine recipients.
How does the CDC use VAERS asymmetrically?
When VAERS shows a signal for a harm the CDC is willing to recognize, VAERS is cited as evidence of monitoring. When VAERS shows signals for harms the CDC won't recognize, it says VAERS "cannot establish causation." When VAERS data is damaging (as with the PRR results), the CDC hides it entirely until litigation forces disclosure. The CDC can track every vaccine from manufacturer to injection point and every child's vaccination status by state, yet claims it cannot automate VAERS reporting.
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