Guillain-Barré Syndrome, Part II: Where the Table Ends

A claim that a vaccine caused Guillain-Barré syndrome is not decided the way a negligence case is decided, and some of these claims never reach the question a lay reader expects to be central: whether the vaccine caused the patient's disease. The federal Vaccine Injury Table (the regulation that lists covered vaccines, the injuries presumed to follow them, and the time window for each) lists Guillain-Barré after seasonal influenza vaccine when the first symptom appears between day 3 and day 42. A claim that fits that entry does not have to prove causation at all. Every other Guillain-Barré claim in the federal program does. Guillain-Barré after a tetanus-containing or pneumococcal conjugate vaccine, or after an influenza vaccine with a first symptom on day 2 or day 50, must establish causation in fact, meaning proof that the vaccine actually caused the illness in this person. That is a different case, in which causation becomes one of the facts the petitioner must prove, under a test set out in 2005 by the federal appeals court that hears vaccine cases. The record sorts a file into one kind or the other, chiefly with dates, and several of those dates take a neurologist to establish from the chart.

Part I covered the disease itself and the tests that are often normal early in it. Guillain-Barré syndrome is an acute immune attack on the peripheral nerves and their roots, producing weakness that reaches its worst point within weeks and then plateaus and recovers, often incompletely. Part II concerns its cause.

The Program, Briefly

The National Childhood Vaccine Injury Act of 1986 created the Vaccine Injury Compensation Program (VICP, a no-fault federal compensation scheme for injuries from covered vaccines) and placed it in front of the ordinary courts. For a covered vaccine, a civil suit for damages against the manufacturer or the person who gave it cannot go forward until a Program petition has been decided and the petitioner has formally rejected the result, or has withdrawn the petition after the statutory deadlines for a decision have passed. Petitions are heard in the United States Court of Federal Claims by special masters (judicial officers appointed by that court to decide vaccine petitions), with the Secretary of Health and Human Services as respondent.

Several provisions shape a Guillain-Barré petition before any medicine is argued. The injured person must have suffered residual effects for more than six months after the vaccination, or died from it, or undergone both inpatient hospitalization and surgical intervention. In a disease from which recovery can be incomplete, whether residual effects lasted beyond six months is a clinical question, and the answer depends on what the later examinations recorded. An injury petition must be filed within 36 months of the first symptom or manifestation of onset, which is measured from the symptom onset rather than from the vaccination or the diagnosis; a death petition must be filed within 24 months of the death and no more than 48 months after the first symptom (§ 300aa-16(a)(2), (3)). The Program pays reasonable attorney fees on a successful petition, and may pay them on an unsuccessful one brought in good faith with a reasonable basis.

Coverage is its own threshold. The Program applies only to vaccines listed in the Table. According to the Health Resources and Services Administration (HRSA, the agency that administers the Program), a category of vaccines is covered only if it is recommended for routine administration to children or pregnant women, subject to the excise tax that funds the Program, and added by the Secretary. A vaccine recommended only for adults can therefore fall outside the Program, so coverage is the first thing to confirm. COVID-19 vaccines are not on the Table. Injuries from them fall under the Countermeasures Injury Compensation Program (CICP, a separate federal program for countermeasures covered by a declaration under the Public Readiness and Emergency Preparedness Act), where a request must be filed within one year of the vaccination itself rather than of the first symptom, and no court reviews the decision (42 U.S.C. § 247d-6e; 42 C.F.R. § 110.42(a)). According to HRSA, the CICP pays no attorney fees. A Guillain-Barré claim therefore belongs to one of three kinds: a Table claim, an off-Table claim inside the Program, or a claim the Program does not reach.

The Table Defines the Disease It Compensates

The Table entry is short. Under seasonal influenza vaccines, item D lists Guillain-Barré syndrome with an onset interval of "3-42 days (not less than 3 days and not more than 42 days)." It is the only Guillain-Barré entry in the Table. No other vaccine carries one.

What the entry compensates for is defined in the regulation's qualifications and aids to interpretation (the paragraphs that state what each listed condition means for Table purposes), and that definition is narrower than the clinical label (42 C.F.R. § 100.3(c)(15)). It recognizes four subtypes: acute inflammatory demyelinating polyneuropathy (AIDP, the form in which the immune attack strips the insulating myelin from the nerve), the two axonal forms that damage the nerve fiber itself, and Miller Fisher syndrome (the variant presenting with eye-movement paralysis, unsteadiness and absent reflexes rather than limb weakness). For the limb-weakness forms, it requires bilateral flaccid weakness (limp, with loss of muscle tone) with reduced or absent reflexes in the weak limbs, a monophasic course (a single episode rather than a relapsing one), an interval from first symptom to the worst point of weakness of between 12 hours and 28 days, a plateau afterward, and no more likely alternative diagnosis. Conditions that do not meet those terms "are not within the Table" (§ 100.3(a)).

The definition therefore runs a second clock, and an argument confined to the first can miss it. The Table window runs from vaccination to the first symptom. The definition then runs a separate interval from the first symptom to the nadir (the point of maximum weakness), and a separate rule for what follows: treatment-related fluctuations are accepted within nine weeks of onset, and recurrence after that "would not be consistent with GBS." An ultimate diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP, the related immune neuropathy that keeps progressing or relapses) is the first named exclusion, and the list ends by stating that it is not exhaustive. Part I described the small group of patients whose acute illness turns out to be chronic. Under the regulation, that course takes the claim off the Table even where the first symptom fell on day 10. The regulation's nine-week limit is also not the same as the eight-week point after which, according to the clinical guideline described in Part I, a change of diagnosis to the chronic form should be considered.

One sentence in the definition carries over directly from Part I. Spinal fluid findings and nerve conduction studies are "supportive, but not required," and the regulation states that both "are frequently normal in the first week of illness in otherwise typical cases of GBS" (§ 100.3(c)(15)(iv)). The four-subtype scheme is a regulatory taxonomy written for compensation purposes, and an expert should not present it as the state of the neurological art.

A Presumption, and What Rebuts It

Inside the Table, the petitioner proves a covered vaccine, an illness meeting the definition, and a first symptom inside the window. Those facts, together with the severity requirement and the statute's other threshold conditions, are sufficient for compensation unless the respondent proves another cause. The law then treats causation as established, without the petitioner having to prove it.

The respondent can rebut by showing, by a preponderance of the evidence (more likely than not), that the illness was "due to factors unrelated to the administration of the vaccine" (§ 300aa-13(a)(1)(B)). Two limits make that hard in this disease. The statute excludes from those factors anything "idiopathic, unexplained, unknown, hypothetical, or undocumentable" (§ 300aa-13(a)(2)(A)), so an illness whose cause was never identified is not thereby rebutted. And it describes a qualifying alternative cause as one documented in the record, with "no known relation to the vaccine involved," and "shown to have been the agent or agents principally responsible" (§ 300aa-13(a)(2)(B)).

The record matters in the other direction as well. A finding cannot rest on the petitioner's account alone, "unsubstantiated by medical records or by medical opinion" (§ 300aa-13(a)(1)). But the special master may find that onset fell inside the window even where the chart did not record it, or recorded it outside, on a preponderance showing that it did in fact fall inside (§ 300aa-13(b)(2)). In a disease whose first symptoms can be tingling or back pain that precede the weakness, that provision is how a true onset date gets reconstructed against a chart documenting a later one.

Off the Table, Causation Has to Be Proved

The off-Table field is wide. It includes every claim after a covered vaccine other than seasonal influenza, every influenza claim with a first symptom outside days 3 to 42, and every claim whose course fails the definition, whether by a nadir later than four weeks, a relapse after nine, or a variant outside the four subtypes.

The governing test comes from Althen, 418 F.3d 1274 (Fed. Cir. 2005). The petitioner must show by preponderant evidence "(1) a medical theory causally connecting the vaccination and the injury; (2) a logical sequence of cause and effect showing that the vaccination was the reason for the injury; and (3) a showing of a proximate temporal relationship between vaccination and injury." If the petitioner does, the burden passes to the government to show, also by a preponderance, that the injury was caused by factors unrelated to the vaccine.

Two statements in the opinion govern how the medicine is used. Timing counts as evidence but is not enough on its own: "neither a mere showing of a proximate temporal relationship between vaccination and injury, nor a simplistic elimination of other potential causes of the injury suffices, without more." And the medical theory need not be proven by published literature, because the statute allows medical opinion as proof. The first prong may therefore rest on expert opinion, provided it offers what the court, quoting an earlier decision, called a "reputable medical or scientific explanation" of how a vaccine antigen (the component the immune system responds to) could provoke an immune attack on nerve. The opinion sets no fixed number of days for the third prong. Whether a proposed mechanism is reputable, and whether the interval in a given record is one in which it could operate, is where the medical testimony in an off-Table case lives; later decisions on how each prong is applied are counsel's ground rather than the neurologist's. The treating neurologist's opinion on cause is considered but is "not binding" on the special master (§ 300aa-13(b)(1)).

What the Epidemiology Will and Will Not Carry

The clearest measured association is with the 1976 swine influenza vaccine. A re-review of the original cases in two states by an expert neurology panel, which found misdiagnosis equally common in vaccinated and unvaccinated patients, still found 8.6 to 9.7 excess cases (cases beyond those expected without vaccination) per million vaccinated adults in the six weeks after vaccination, and, in that re-review, no increase beyond six weeks.¹ That is a 1976 product, and its risk does not transfer to a modern seasonal vaccine.

For modern seasonal influenza vaccine the signal sits at the edge of detection. Pooled analyses (meta-analyses, which combine the results of many studies) put any increase at roughly 15 to 22 percent in relative terms, small enough that one of them could not distinguish it from no effect.^2,3 The more recent of the two also found the risk after an influenza-like illness itself far larger.³ In absolute terms, an Ontario analysis of seasons from 1993 to 2011 estimated about 1 excess Guillain-Barré admission per million seasonal vaccinations, against about 17 per million health-care visits coded as influenza; the published summary gives neither figure an interval, and the second counts visits rather than infections.⁴

Two further findings bound what any epidemiology can do in an individual case. In a large insured United States population from 2017 to 2023, only a quarter of adults with a new Guillain-Barré diagnosis had any vaccination recorded in the preceding 84 days; the same study flagged influenza and the Janssen COVID-19 vaccine as possible associations in both of its analyses, and several other groups, among them pneumococcal and tetanus-diphtheria-pertussis vaccines, in only one; a flag of this kind marks a question for further study, not a finding of cause.⁵ And among the fatal cases of the 1976 program, the clinical features were similar in vaccinated and unvaccinated patients.⁶ The attribution cannot be read from the patient. The Table supplies it by law; off the Table it has to be built.

Three calibrations follow.

A population association is not an individual attribution. A relative risk (how many times more often the disease occurs among the vaccinated) describes a group; it does not identify which vaccinated patient's illness the vaccine caused. Epidemiology can support a medical theory and inform the question of timing, but a relative risk alone does not show that the vaccine caused the illness in one patient, which is what the logical sequence has to explain. Which study fits the product, population and era in a given file is a question for an expert.

A label warning is not a finding of causation, and an absent warning is not a finding of safety. The label of one licensed respiratory syncytial virus (RSV) vaccine has carried a Guillain-Barré warning since January 2025, based on an estimate of about 9 excess cases per million doses in people 65 and older, from a comparison whose range of uncertainty still included no increase at all. The same label states that the evidence "is insufficient to establish a causal relationship," and that differences in background risk between studies preclude direct comparison of its excess estimate with estimates from other vaccine studies or populations.⁷ A label records a regulatory decision, and the absence of a warning records only that no such decision has been made.

A compensated petition is not necessarily a finding of causation. HRSA states that roughly 60 percent of all compensation comes through negotiated settlements in which the government has not concluded that the vaccine caused the injury.⁸ Of petitions filed from 2006 through 2024 that named influenza vaccine first and had been found compensable by the September 2026 report, 8,369 in all, 366 were won on a court decision and the rest were conceded by the government as meeting the standard for compensation or settled.⁸ Those figures cover every injury alleged after influenza vaccine, not Guillain-Barré alone, and HRSA's monthly data report does not break out Guillain-Barré claims.

Alternative Causes Do Different Work on Each Side of the Line

About two-thirds of patients with Guillain-Barré report symptoms of an infection in the six weeks before onset, according to an international consensus review, and six pathogens have been associated with the disease in case-control studies (studies comparing how often patients and similar people without the disease had the infection): Campylobacter jejuni (a common cause of bacterial food poisoning), cytomegalovirus, hepatitis E virus, Mycoplasma pneumoniae, Epstein-Barr virus and Zika virus.⁹ Roughly 31 percent of cases may be attributable to a preceding Campylobacter infection, yet in the two cohorts that measured it, only between about 3 in 10,000 and about 1 in 1,000 people with that infection went on to develop the disease.¹⁰ Both halves matter. The first arms a defense; the second prevents an alternative cause from being treated as though it were inevitable.

The same documented infection does different legal work depending on the posture. In a Table claim, a respiratory illness two weeks before onset rebuts nothing unless it is documented in the record and the respondent shows that it was principally responsible. In an off-Table claim the same illness can matter before the burden ever shifts: Althen assigns proof of an unrelated cause to the government only after the petitioner has met all three prongs, but an expert account of the logical sequence that ignores a documented infection is open to an obvious challenge.

The absence of an infection cuts both ways too. The consensus review is explicit that the absence of an antecedent illness does not exclude Guillain-Barré, because triggering infections can be subclinical (producing no noticeable symptoms), and that a negative anti-ganglioside antibody test (a blood test for antibodies against components of the nerve membrane) does not rule it out either.⁹ No documented infection does not mean the vaccine did it. No documented infection does not mean the diagnosis is wrong.

What the Record Has to Fix

Before the medicine is argued, the record has to fix six facts. Where one is missing, the gap is itself evidence.

• The vaccine, by product and date. The Table entry belongs to seasonal influenza vaccine alone, and coverage belongs only to listed vaccines. Where several vaccines were given at one visit, the record has to show each of them, because the claim may rest on any.
• The first symptom, dated. Not the diagnosis and not the admission. The first symptom can be tingling in the feet or back pain, days before the weakness, and its date sets both the Table window and the 36-month filing deadline. Fixing that date from a record that never states it, and judging whether tingling or back pain was the first manifestation, calls for a neurologist's opinion.
• The nadir, dated. The worst point of weakness, and how long after the first symptom it came, decides whether the illness satisfies the regulation's 28-day interval.
• Any later worsening, dated. A worsening after treatment can be a permitted fluctuation within nine weeks; a recurrence after that, or a course that ends in a diagnosis of CIDP at any point, takes the illness outside the definition. Dates are what allow the two to be told apart, and reading a worsening as a fluctuation or as the start of a chronic course is a neurological judgment, not a count of weeks.
• The examination, against the regulation's terms. Bilateral weakness, the state of the reflexes in the weak limbs, and enough of the course to assign the illness to one of the four subtypes, or to show it fits none. That assignment is a neurological judgment made from the whole record, not from the discharge diagnosis, and it matters most where, as Part I described, the reflexes were not lost.
• What was looked for besides the vaccine. The infection history for the preceding six weeks, any stool culture or serology (blood tests for antibodies to a recent infection) sent, and the result. A rebuttal needs a documented agent, and a careful petition needs to have addressed one.

Where Causation Arguments Go Wrong

• Onset taken from the diagnosis. The date of the neurology consult is used as the date of onset, which moves the claim across the Table window or past the filing deadline.
• A course outside the definition argued as a Table claim. The petition establishes a first symptom on day 12 and never addresses a nadir at week five, a relapse at week eleven, or a diagnosis later revised to CIDP.
• Timing offered as the whole case. An off-Table petition rests on a short interval, which the Althen court held probative and insufficient.
• A label or a settlement count read as proof. A warning, or a program-wide compensation figure, is cited as though it established causation in this patient.
• A possible infection offered as rebuttal. In a Table case, a cold mentioned in the history is presented as the cause without being documented or shown to be principally responsible.
• No infection offered as proof. The mirror image: the absence of a documented trigger is presented as evidence that the vaccine was the cause.
• An unexplained illness offered as rebuttal. The respondent argues that the cause of the illness is unknown, which the statute excludes from the factors that can defeat a Table claim.
• A normal early test argued as excluding the diagnosis. A first-week spinal fluid or nerve conduction study is offered against a definition that calls both supportive, not required, and frequently normal in that week.
• The wrong program. A claim after an uncovered vaccine is framed under the Table, or a claim inside the Program is framed as an ordinary tort.

These are not separate failure modes. They compound. An onset taken from the diagnosis rather than the first symptom shifts the interval; the shifted interval lands outside the window; the claim moves off the Table without anyone deciding that it should; and an off-Table petition built for a presumption arrives with timing as its only evidence, against an infection nobody documented either way.

Reading a Vaccine Causation Claim in Context

A defensible review of a case in which a vaccine is alleged to have caused Guillain-Barré syndrome, for petitioner or respondent, works through a small set of specific questions.

• Which vaccine was given, on what date, and is it a covered vaccine on the Table, or outside the Program altogether?
• What was the first symptom, on what day after vaccination did it appear, and where is that date recorded rather than inferred?
• How long after the first symptom did weakness reach its worst point, and is the nadir dated in the record?
• Did any worsening follow treatment, and did it fall within nine weeks of onset or after?
• Does the documented examination meet the regulation's definition, including the reflexes in the weak limbs?
• Was an infection in the preceding six weeks asked about, tested for, and documented, and what did the testing show?
• If the claim is off the Table, does the expert opinion address all three Althen prongs, or only the interval?
• Is any epidemiology cited for the specific vaccine at issue, or borrowed from a different product or era?

Some claims that look strong on the petition dissolve against a record dating the first symptom to day 50, or a Campylobacter infection confirmed by culture in the week before onset. Others that look strong for the respondent collapse against a covered influenza vaccine, tingling charted on day 9, a course that fits every term of the definition, and an alternative cause that appears in the argument and nowhere in the chart.

The Table names the window. The record shows where the first symptom fell.

References

Footnotes

1. Safranek TJ, Lawrence DN, Kurland LT, et al. Reassessment of the association between Guillain-Barré syndrome and receipt of swine influenza vaccine in 1976-1977: results of a two-state study. Am J Epidemiol. 1991;133(9):940-951. doi:10.1093/oxfordjournals.aje.a115973 ↩

2. Martín Arias LH, Sanz R, Sáinz M, Treceño C, Carvajal A. Guillain-Barré syndrome and influenza vaccines: a meta-analysis. Vaccine. 2015;33(31):3773-3778. doi:10.1016/j.vaccine.2015.05.013 ↩

3. Petráš M, Králová Lesná I, Dáňová J, Čelko AM. Is an increased risk of developing Guillain-Barré syndrome associated with seasonal influenza vaccination? A systematic review and meta-analysis. Vaccines (Basel). 2020;8(2):150. doi:10.3390/vaccines8020150 ↩ ↩²

4. Kwong JC, Vasa PP, Campitelli MA, et al. Risk of Guillain-Barré syndrome after seasonal influenza vaccination and influenza health-care encounters: a self-controlled study. Lancet Infect Dis. 2013;13(9):769-776. doi:10.1016/S1473-3099(13)70104-X ↩

5. Yih WK, Duffy J, Daley MF, et al. Using tree-based scan statistics to assess vaccines for possible associations with Guillain-Barré syndrome in the Vaccine Safety Datalink. Vaccine. 2026;88:128949. doi:10.1016/j.vaccine.2026.128949 ↩

6. Keenlyside RA, Schonberger LB, Bregman DJ, Bolyai JZ. Fatal Guillain-Barré syndrome after the national influenza immunization program. Neurology. 1980;30(9):929-933. doi:10.1212/wnl.30.9.929 ↩

7. ABRYSVO (respiratory syncytial virus vaccine) [prescribing information]. Pfizer Laboratories Div Pfizer Inc. Revised 12/2025. DailyMed. dailymed.nlm.nih.gov ↩

8. Health Resources and Services Administration. National Vaccine Injury Compensation Program Data Report. Updated September 1, 2026. hrsa.gov/vaccine-compensation/data ↩ ↩²

9. Leonhard SE, Mandarakas MR, Gondim FAA, et al. Diagnosis and management of Guillain-Barré syndrome in ten steps. Nat Rev Neurol. 2019;15(11):671-683. doi:10.1038/s41582-019-0250-9 ↩ ↩²

10. Poropatich KO, Walker CLF, Black RE. Quantifying the association between Campylobacter infection and Guillain-Barré syndrome: a systematic review. J Health Popul Nutr. 2010;28(6):545-552. doi:10.3329/jhpn.v28i6.6602 ↩