Polio (IPV) vaccine side effects (IPOL): VAERS data, trials and schedule
This page answers “polio vaccine side effects” with sourced pharmacovigilance data — VAERS and JADER (PMDA) reaction patterns. Counts are database reports, not proven vaccine-caused injury rates.
How to read database counts: Pharmacovigilance systems (VAERS, EudraVigilance, Yellow Card, VigiBase, Lareb, DAEN) collect spontaneous, unverified reports. A report is not a confirmed adverse event and does not prove the vaccine caused the outcome. Under-reporting, stimulated reporting, and missing denominators limit rate interpretation. Compare with trials and epidemiological studies on each page before drawing conclusions.
Gold Standard EO (Aug 10, 2026)Federal recommendation status: Recommended for all children
The August 10, 2026 Executive Order on Gold Standard Childhood Vaccine Recommendations places polio in the Recommended for all children category. The EO also expresses a preference, to the maximum extent feasible, for administering all childhood immunizations at separate medical visits.
This page summarizes published data for inactivated poliovirus vaccine (IPV) currently used in the U.S. The U.S. switched from oral polio vaccine (OPV) to IPV in 2000 due to the risk of vaccine-associated paralytic poliomyelitis (VAPP) with OPV (~1 case per 2.4 million OPV doses). This page focuses on IPV. Data are presented without interpretive language that implies the vaccine is "safe" or "unsafe."
Evidence state
For each outcome: the specific question, what controlled studies found, and how certain that evidence is on the GRADE scale (high, moderate, low, very low). Ratings are editorial judgments by the site applying GRADE to the studies in the table below — observational evidence starts at low and is rated up for large, consistent effects or a dose/age gradient, and down for inconsistency or imprecision (Methods). Where an effect is confined to a subgroup (for example young males), the question says so. "Not searched" means no controlled study has been compiled here yet; it is not a finding that the outcome is rare or caused by the vaccine.
Two sequential-surveillance studies vs historical comparators. Studies: Daley 2014, Nelson 2013.See table
Anaphylaxis
Not searched
No controlled-study result is compiled for this outcome yet.
Myocarditis or pericarditis
Not searched
No controlled-study result is compiled for this outcome yet.
Guillain-Barré syndrome
Not searched
No controlled-study result is compiled for this outcome yet.
Febrile seizure
Not searched
No controlled-study result is compiled for this outcome yet.
Immune thrombocytopenia
Not searched
No controlled-study result is compiled for this outcome yet.
1. Basic Information
Disease Protected Against
Poliomyelitis (Polio) is a enteroviral infection that can cause irreversible acute flaccid paralysis in ~1% of infections. Before vaccination, polio caused widespread epidemics. The U.S. experienced its peak epidemic in 1952 with >21,000 paralytic cases. Polio has been declared eliminated in the Americas (1994), but wild poliovirus type 1 remains endemic in Afghanistan and Pakistan. Circulating vaccine-derived polioviruses (cVDPV) from OPV use in other countries represent an ongoing global eradication challenge.
CDC Schedule (U.S., 2025)
Dose
Age
Dose 1
2 months
Dose 2
4 months
Dose 3
6–18 months
Dose 4 (booster)
4–6 years
Source: CDC ACIP, 2025 schedule. IPV is given as a standalone vaccine (IPOL®) or as part of combination vaccines (Kinrix, Quadracel, Pediarix, Pentacel, VAXELIS).
Licensed Polio (IPV) vaccine products
Each product has its own page with package-insert ingredients, side-effect data, lot lookup and comparisons with the other brands.
Structured composition for 1 branded product covered on this page,
taken from FDA-approved package inserts (DailyMed / manufacturer prescribing information).
Lists are per product — formulations differ by manufacturer and presentation.
Click an ingredient name to open its safety-context page when available.
Ingredient lists are sourced from official package inserts for the specific brands named above.
Formulations can change between lots and over time — verify against the current label before any clinical decision.
Presence of a substance does not by itself indicate harm; toxicology is dose-, route-, and context-dependent.
Browse the full ingredient database:
Vaccine Ingredients index.
Causality assessment & potential mechanisms
Conditions below combine WHO-style causality levels with potential biological mechanisms
from the site mechanism catalog
(ae_mechanisms_catalog.json).
HRSA VICP table listing (where shown) indicates a compensable temporal association under U.S. program rules —
not automatic proof of causation for every case. Mechanisms are hypothesis-level pathways with graded evidence.
Pre-existing or newly formed IgE against vaccine antigens or excipients (e.g., gelatin, egg proteins, PEG, polysorbate) triggers mast-cell and basophil degranulation with systemic mediator release.
SIRVA
0–2 days
Very likely / Probable
Evidence: High
SIRVA — incorrect injection into shoulder structures (primary · procedural)
Needle placement into the subdeltoid/subacromial bursa or joint rather than deltoid muscle causes prolonged local inflammation and restricted range of motion (procedural, not antigen-specific).
Framework: WHO causality + HRSA VICP (where applicable) + AE mechanism catalog.
Last updated: 2026-07-18.
Schema: schemas/vaccine_injury_table.schema.json
· Mechanisms: schemas/ae_mechanism.schema.json.
Not medical or legal advice.
2. Pre-Licensure Clinical Trial Data
Licensure trial design (ICAN / OpenVAERS)
The table below reproduces ICAN’s No Placebo Table rows for U.S. childhood-schedule products relevant to this page — including the control/comparator used in FDA licensing trials (not always saline placebo). OSMF presents this for transparency; it is not an endorsement of ICAN interpretations.
Vaccine
Brand
Manufacturer
Doses (schedule)
Ages injected
Control / comparator
Placebo
Safety review window
IPV
IPOL
Sanofi
4
2M 4M 6M 4Y
None
No
3 days
Source: OpenVAERS — No Placebo Table · ICAN original PDF
· Attribution: Informed Consent Action Network (ICAN) via OpenVAERS
· Last fetched: 2026-07-16.
For many trials listing '6 months' safety review, ICAN notes review was typically ~30 days post-injection with a phone call at 6 months.
The current enhanced-potency IPV (IPOL, Sanofi) was licensed in 1987 based on immunogenicity trials. Prior IPV formulations date back to the Salk vaccine (1955). The enhanced IPV formulation was developed to improve immunogenicity.
Metric
Data
Pre-licensure safety population
~2,000+ children; immunogenicity studies in ~1,500
Seroconversion (3-dose series)
~99–100% for all 3 poliovirus types
Most common reactions
Injection site pain (~5–15%), erythema (~2–5%), fever (~5–10%)
IPV has minimal reactogenicity compared to many other childhood vaccines. This is one of the least reactogenic vaccines on the pediatric schedule.
Key Limitation
IPV produces excellent humoral immunity (prevents paralysis) but induces less mucosal (intestinal) immunity than OPV. This means IPV-vaccinated individuals can still be asymptomatically infected with poliovirus and shed it in stool, though they are protected from paralysis. This is relevant for global eradication efforts.
3. Post-Licensure Safety Data
IPV has an excellent post-licensure safety record with >35 years of U.S. data. VSD and VAERS surveillance have not identified unexpected safety signals. The switch from OPV to IPV in 2000 eliminated the risk of VAPP (vaccine-associated paralytic polio), which was the primary safety concern with the prior OPV formulation. IOM (2012) did not identify safety concerns specific to IPV.
⚠ Critical Caveat
VAERS data represent unverified reports. A report to VAERS does not mean the vaccine caused the event.
VAERS reports per million doses
U.S. VAERS reports for vaccinations given 2006–2024, divided by the 345 million doses distributed in the same years (HRSA, from CDC data).
All reports
152
per million doses (151–154) · 52,468 reports
Serious reports
17.6
per million doses · 6,076 reports (death, life-threatening, hospitalised or disabled)
Reports with a death
2.77
per million doses · 953 reports
These are reporting rates: they mix real reactions, coincidental events and reports of conditions that would have happened anyway, and they depend on how actively each vaccine is watched. Doses are distributed, not administered. Combination vaccines count toward each component in both numerator and denominator. Compare with the observed-vs-expected analysis and the controlled studies above. Data: vaers_reporting_rates.json.
All vaccines, per million doses
Vaccine
All
Serious
Death
pcv
266
28.1
3.23
rotavirus
157
27.9
4.08
hpv
335
25.3
2.00
hib
126
19.7
3.25
polio
152
17.6
2.77
mmr
320
15.3
0.94
varicella
372
14.1
0.84
hepatitis-b
110
12.7
2.15
meningococcal
214
11.8
0.70
dtap
132
11.2
1.31
hepatitis-a
152
8.5
0.58
influenza
68
5.4
0.48
What controlled safety studies found
Unlike VAERS counts, these studies compare vaccinated people with a control group or control time window, so they can estimate whether a risk is raised and by how much. 2 results for polio vaccines: 0 found an increased risk of a specific outcome, 2 found no increased risk.
Bars are drawn to scale within each comparison. Disease risks are per case of the disease; vaccine risks are the excess above background per dose, from controlled studies. How likely someone is to catch the disease, without vaccination, decides how these weigh up for an individual.
No single study measured both risks in the same population for this vaccine, so no side-by-side ratio is shown; the two lists below come from different studies, eras and populations.
Serious outcomes of the disease (per million cases)
Days from vaccination to onset in U.S. VAERS reports (0–180 days). A causal reaction usually starts inside a characteristic window; but people also report what happens soon after a shot, so each event is compared with all other reports for this vaccine. The Weibull shape measures bunching (below 1 = most onsets early).
Event
Reports
Median days
In risk window
Shape (95% CI) vs others
Reading
Seizure (any)
5,818*
1
96% (others 98%)
0.71 (0.70–0.73) vs 0.76
same timing as other reports
Febrile seizure
1,280
1
98% (others 98%)
0.77 (0.74–0.82) vs 0.76
same timing as other reports
Intussusception
1,023
9
62% (others 49%)
0.84 (0.81–0.88) vs 0.76
spread later than other reports
Syncope
969
0
93% (others 78%)
0.78 (0.70–0.90) vs 0.76
same timing as other reports
Sudden infant death
853
3
75% (others 94%)
0.83 (0.80–0.88) vs 0.76
spread later than other reports
Anaphylaxis
244
0
95% (others 78%)
0.98 (0.84–1.20) vs 0.76
spread later than other reports
ADEM / encephalitis
153
5
76% (others 50%)
0.74 (0.66–0.85) vs 0.76
same timing as other reports
Immune thrombocytopenia
93
13
89% (others 50%)
0.96 (0.85–1.16) vs 0.76
spread later than other reports
Guillain-Barré syndrome
86
11.5
81% (others 50%)
0.85 (0.76–1.02) vs 0.76
same timing as other reports
Kawasaki disease
80
6.5
80% (others 50%)
0.74 (0.66–0.85) vs 0.76
same timing as other reports
Herpes zoster
63
13
57% (others 50%)
0.56 (0.48–0.67) vs 0.76
clusters earlier than other reports
Transverse myelitis
46
12
74% (others 50%)
0.86 (0.73–1.08) vs 0.76
same timing as other reports
Timing alone cannot establish causation; it can make it more or less plausible. *Fitted on a random sample of 5,000 of these reports. Data: vaers_onset.json.
VAERS Reporting Data — Halma & Varon (2025), DARE-SAFE
The DARE-SAFE paper (Halma & Varon, Pharmacoepidemiology 2025, CC BY 4.0) analyzed VAERS reports for vaccines administered in the United States from 2006–2022. The following data are extracted from Table 1 of that paper for this vaccine (IPV (Inactivated Poliovirus Vaccine)):
Metric
Value
U.S. doses administered (2006–2022)
85,815,525
Total VAERS AE reports
16,104
AE reporting rate (per 100,000 doses)
18.8
Total death reports
93
Death reporting rate (per 100,000 doses)
0.108
AE-to-Death ratio
173:1
Source: Halma, M.; Varon, J. DARE-SAFE. Pharmacoepidemiology. 2025. DOI: 10.3390/pharma4020007. CC BY 4.0. Data from Table 1.
📚 Important Interpretive Caveats (from the paper itself)
Reporting rate ≠ incidence rate. VAERS is a passive, unverified system. A report means someone submitted a claim of temporal association, not a confirmed causal event. The paper is explicit that causality cannot be inferred from these numbers alone.
Reporting behavior is not uniform. More serious, unusual, or media-salient events are reported at much higher rates than mild ones. Products receiving more public, media, legal, and clinical attention (particularly COVID-19 vaccines, which also benefited from V-safe active-surveillance prompts and CICP compensation pathways) generate more reports per dose regardless of true risk.
Age and comorbidity confounding is not adjusted. COVID-19 vaccines were disproportionately administered to elderly and comorbid populations (nursing homes, 65+, high-risk groups in early 2021) with much higher background all-cause mortality than the general child/working-age population. Some fraction of temporally-associated deaths would occur regardless of vaccination, and the paper does not perform a background-rate comparison.
Stimulated reporting is a known, documented phenomenon. Media coverage, plaintiff attorney solicitation, and advocacy campaigns — all independently inflate VAERS reporting propensity. The paper cites this literature but does not correct for it.
Small-denominator rows are unreliable. Rates computed from small denominators (e.g., monovalent measles, DT, mumps, rubella) have enormous statistical uncertainty and should not be compared to vaccines with hundreds of millions of administered doses without noting the wide confidence intervals.
Source: Halma, M.; Varon, J. DARE-SAFE: Denominator-Adjusted Rate Estimates of Substance Adverse Events Frequency Evaluation in Pharmaceuticals and Vaccines. Pharmacoepidemiology. 2025, 4, 7. DOI: 10.3390/pharma4020007. CC BY 4.0.
Passive Surveillance: AE Type Breakdown (Multi-System)
Side-by-side view of U.S. VAERS, Health Canada Canada Vigilance, Japan JADER (PMDA), EU EudraVigilance, and live-scraped international systems via SurVigilance (VigiAccess, Lareb, DAEN, DMA, Medsafe). SurVigilance panels show MedDRA PT mention totals (not individual-case counts). Category assignment uses keyword matching — approximate, not official SOC coding. VAERS files on this site are built from the public VAERS download. FAERS figures use the public quarterly FAERS files. Counts are mentions or reports, not incidence.
VAERS (United States)
Canada Vigilance (Canada)
JADER (PMDA, Japan)
EudraVigilance (EU)
No matching vaccine cases in the current EudraVigilance DAP export.
This system’s totals are not in this panel. Published counts, when this site has them, are in the surveillance section.
DMA (Denmark)
Denmark DMA interactive ADR search is currently offline (Danish Medicines Agency IT transition; public overviews frozen at 12 Mar 2024). Live product PT tables cannot be retrieved until DKMA restores the search. See DKMA notice. Denmark continues to report into EU EudraVigilance (panel above).
Medsafe (New Zealand)
VAERS (U.S., 2006–2024): 3,994 symptom mentions (4.65/100k doses). Largest share: Other / Unclassified (64%), General / Systemic (non-local) (7%), Injection-site / Local reaction (5%). Canada Vigilance (CV Online extract): 7 reaction mentions in 4 unique reports (100.0% serious (4 of 4 reports)). Largest share: Neurological (29%), Cardiac / Cardiovascular (14%), Allergic / Anaphylactic (14%). JADER (PMDA public CSV extract): 66 reaction mentions in 49 unique reports (22.4% serious (11 of 49 reports)). Largest share: Neurological (42%), Other / Unclassified (17%), General / Systemic (non-local) (11%). VigiAccess (WHO): 411,726 reaction-term mentions · search: polio. Largest share: General / Systemic (non-local) (24%), Injection-site / Local reaction (18%), Other / Unclassified (15%). Lareb (Netherlands): 17 reaction-term mentions · search: poliovirus vaccine inactivated. Largest share: General / Systemic (non-local) (29%), Injection-site / Local reaction (29%), Musculoskeletal (12%). Medsafe (New Zealand): 2,672 reaction-term mentions · search: polio. Largest share: Gastrointestinal (44%), Psychiatric / Neuropsychiatric (14%), Other / Unclassified (12%). Cross-database note: All systems are passive and unverified; reporting rates are not directly comparable across countries (different populations, reporting incentives, and lack of dose denominators for Canada/Japan/EU). top VAERS: Other / Unclassified; top Canada Vigilance: Neurological; top JADER: Neurological. SurVigilance note: VigiAccess, Lareb, DAEN, DMA, and Medsafe counts are live-scraped MedDRA PT mention totals (not deduplicated individual cases). Data via SurVigilance (GPL-3.0; pip install SurVigilance). Category assignment uses keyword matching on reported reaction terms — approximate and exploratory. Neither database establishes causality.
Pharmacovigilance Lot Signal Detection — Hypothesis-Generating Only
Multi-system context below. VAERS (U.S.) supports lot-level volume z-scores and seriousness flags by product and lot (2006–2024). Each lot links to a summary with report count, seriousness %, adverse-event pie chart, U.S. state map, and timeline. A signal flag means a statistical threshold was exceeded — not that a lot is unsafe. Full dashboard →
VAERS flags:VOL high report volume (z ≥ 3) ·
BURST clustered in <90 days ·
SER serious reports >50%.
Lot numbers are voluntary/incomplete in VAERS. Location data is U.S. state only (no postal codes in the public extract).
VAERS (United States) — all lots by product
1,147 reports with usable lot across 95 lots · 6 flagged
Loading lot tables…
Other Pharmacovigilance Systems
Lot-level analysis is only possible where reporters supply batch/lot numbers in the public extract. Canada Vigilance, JADER (PMDA, Japan), and most other national systems publish product-level spontaneous reports without lot fields.
Canada Vigilance spontaneous reports are unverified temporal associations. The public CV Online data extract does not include lot or batch numbers, so lot-level signal detection is not possible for this system — only product-level reaction patterns are shown here. No Canadian dose denominators are available. Extract 2026-03-31.
49 unique reports · 66 reaction mentions · 22.4% serious (11 of 49 reports). Top categories: Neurological (42%), Other / Unclassified (17%), General / Systemic (non-local) (11%).
JADER (Japanese Adverse Drug Event Report database) spontaneous reports are unverified temporal associations; PMDA has not assessed causality per case. The public CSV extract does not include lot or batch numbers, so lot-level signal detection is not possible — only product-level reaction patterns are shown here. Reaction terms in source data use MedDRA/J Preferred Terms. JADER CSV extract pmdacasereport202606 (2026-06). JADER reference (PDF)
Active Pharmacovigilance (Defined-Population Surveillance)
Curated findings for Inactivated polio vaccine (IPV) from active systems (not VAERS). Page inventory last reviewed: 2026-07-10.
ⓘ Active vs. passive — why this pane is separate
The VAERS / multi-system charts above are passive surveillance: spontaneous, unverified reports without a fixed denominator.
Active surveillance starts from a defined, enumerated population (EHR/claims or structured post-vaccination surveys), applies pre-specified statistical tests, and asks whether an outcome occurs
more often than expected in a risk window versus a comparison window or group.
These are not two flavors of the same evidence — active findings are the harder tier that can confirm, refute, or leave under investigation a signal first hinted in passive data.
Do not add VAERS report counts to active incidence rates.
○ No signal detected◐ Signal under investigation◑ Investigated — not confirmed● Signal confirmed (true association)– Not currently under active surveillance
CDC Vaccine Safety Datalink (VSD)
Outcome: Serious outcomes after IPV (U.S. schedule)
Tier 2○ No signal detected
U.S. use of IPV (rather than OPV) eliminated vaccine-associated paralytic poliomyelitis as a schedule risk. Active monitoring of IPV has not identified a new confirmed rare risk comparable to historical OPV VAPP.
Population
Children receiving IPV at VSD sites
Risk interval
Study-specific
Comparison
Control intervals
Evaluation period
Post-2000 U.S. exclusive IPV era
Method
Observational monitoring within pediatric schedules
Update cadence: Tier 1: check AusVaxSafety monthly when public pages update. Tier 2/3: quarterly review around ACIP meetings and PubMed/MMWR; set lastReviewed per record.
Source tiers: Tier 1 = public near-real-time dashboards (e.g. AusVaxSafety);
Tier 2 = VSD / Sentinel / PRAC-type findings released via ACIP slides, MMWR, or papers (no public VSD raw dashboard);
Tier 3 = regulator label/safety communications.
Detecting a signal and later classifying it as not confirmed is normal system behavior — not an anomaly to hide or amplify.
4. Documented Adverse Events
Rank-aggregated VAERS signal detection (rankv)
The table below lists vaccine–event pairs that were detected as disproportionality signals by all four base methods used in rankv (GPS, PRR, ROR, BCPNN) on multi-decade VAERS data, then ordered by rank aggregation (Borda average rank; related to the Spearman/GA top-list approach in the rankv paper).
Data: ~30 years of public VAERS (rankv processed tables).
Origin: precisionFDA “Gaining New Insights by Detecting Adverse Event Anomalies” challenge solution.
Caveat: Disproportionality signals are statistical associations in spontaneous reports. They do not establish causality, incidence, or product defect. Many top pairs reflect administration/product-use coding rather than clinical injury.
Injection site reactions: Mild pain (5–15%), erythema (2–5%). Strong
Low-grade fever: 5–10%. Strong
Anaphylaxis: Extremely rare (~1 per million doses). Strong
▶ Historical Note (OPV — No Longer Used in U.S.)
The OPV was associated with VAPP at a rate of ~1 per 2.4 million doses (approximately 8–10 cases/year in the U.S. when OPV was used). This was the reason for the U.S. switch to IPV in 2000. Strong (causal for OPV; not applicable to IPV)
5. Disease Prevention Benefits
Metric
Pre-Vaccine Era
Post-Vaccine Era (U.S.)
Paralytic polio (annual)
~21,000 cases (1952 peak)
0 wild-type cases since 1979; last U.S. case 1979 (imported 1993)
Global polio (1988 vs. 2023)
~350,000 cases/year
<1,000 cases/year (>99.9% reduction)
A 2022 case of paralytic polio in an unvaccinated individual in Rockland County, NY, and detection of poliovirus in wastewater, served as a reminder of ongoing risk.
Disease Burden Over Time
Reported U.S. disease burden by year. The dashed vertical line marks vaccine introduction. Hover or tap data points for values; use arrow keys when a chart has focus.
ⓘ About these charts: These are accessible SVG line charts with keyboard navigation, hover tooltips, and an underlying data table (expand below). The dashed vertical line marks the year of vaccine introduction. Reported cases undercount true incidence; case definitions, reporting practices, and diagnostic methods have changed over time. See Section 5 for additional context and pre-vs-post era comparisons.
7. Evidence Summary
IPV is one of the safest and most effective vaccines in the pediatric schedule. The safety record is extensive (>35 years), and no significant post-licensure safety signals have been identified. The primary historical safety concern (VAPP) was specific to OPV and was eliminated by the IPV switch. Evidence limitations relate primarily to the modest size of pre-licensure trials (by modern standards) and the difficulty of isolating IPV-specific safety signals when most doses are given as combination vaccines.
8. International Surveillance & Global Data
Quick links to public pharmacovigilance databases and trial registries relevant to Polio (IPV) Vaccine. Reporting counts do not establish causality.
Note: Spontaneous reports are unverified observations. Compare with epidemiological studies in Sections 3–6 before drawing conclusions.
9. Curated Adverse Event Literature
Curated peer-reviewed literature linking specific adverse events to Polio (IPV) Vaccine. Each entry is a case report, case series, or related safety publication identified via PubMed. Expand Search PubMed for additional literature below to run custom queries.
Disclaimer: Published reports describe observations and associations; they do not establish population incidence or causality.
Common questions
How long do Polio vaccine side effects last?
Most reported Polio vaccine reactions are short-lived: injection-site soreness, tiredness, and low-grade fever that typically begin within a day or two and resolve within a few days. Longer-lasting or more serious events are rarer and are the ones tracked in the post-licensure surveillance and documented adverse-event sections of this page, with report counts that are not incidence rates. Anything severe or persisting beyond a week warrants medical review.
Is the Polio vaccine given to adults, and are side effects different in adults?
Whether the Polio vaccine is recommended for adults depends on the vaccine and the person's risk factors; the schedule and product sections above describe the licensed indications and age groups. Reporting patterns in adults can differ from children, so this page's VAERS and international database breakdowns should be read with the reporting population in mind. Check the current CDC/ACIP adult schedule and the product's prescribing information for adult dosing.
10. Key References
IOM. Adverse Effects of Vaccines: Evidence and Causality. National Academies Press; 2012.