Statement of Principles concerning Lyme disease/Lyme borreliosis (Reasonable Hypothesis) (No. 17 of 2025)

The instrument defines a small set of foundational legal-medical concepts and links them to adjudicative thresholds used in claims processing. The principal concepts are “Lyme disease/Lyme borreliosis”, “death from Lyme disease/Lyme borreliosis”, “relevant service”, “terminal event”, and the four factors that can, individually, raise a reasonable hypothesis connecting the disease to service (sections 7-11; Schedule 1).

Lyme disease/Lyme borreliosis is defined for this SoP as an infection with spirochete bacteria of the Borrelia burgdorferi sensu lato complex transmitted by the bite of an Ixodes genus tick in a geographic location where the disease is endemic (subsection 7(2)(a)). The definition expressly includes chronic untreated Lyme disease and expressly excludes “Lyme-like illness” (subsections 7(2)(b)-(c)). The instrument also places on the record certain laboratory and clinical points in explanatory notes: it lists Borrelia species considered members of the B. burgdorferi sensu lato complex and Ixodes tick species known to transmit Borrelia spp., enumerates geographic locations described as endemic (for example, the United States, southern Canada, Europe, the United Kingdom, Russia, Japan, and north‑eastern China), and records clinical manifestations and usual laboratory confirmation methods, including IgM/IgG serology and Western blot, while noting that culture is the gold standard but difficult to achieve (notes under section 7).

“Death from Lyme disease/Lyme borreliosis” is included within the meaning of the disease where a terminal event or condition was contributed to by the person’s Lyme disease. “Terminal event” is defined in the Schedule and includes proximate or ultimate causes such as pneumonia, respiratory failure, cardiac arrest, circulatory failure, and cessation of brain function (Schedule 1).

Causation is operationalised through a minimal, permissive test: section 9 requires that at least one enumerated factor must exist before a reasonable hypothesis can be said to be raised connecting Lyme disease or death from it with a person’s relevant service. The factors are temporally bounded to a 33‑day window before clinical onset for exposure, tick bite, or being in an endemic location (section 9, factors 1-3). The fourth factor concerns inability to obtain appropriate clinical management before clinical worsening (section 9(4)). Section 10 subjects any of these factors to a further requirement: the factor must be related to the person’s relevant service. The second paragraph of section 10 clarifies that the factor in section 9(4) applies only to material contribution or aggravation where the disease was suffered or contracted before or during (but did not arise out of) the relevant service.

A cross-reference rule in section 11 provides that where a factor in section 9 refers to an injury or disease covered by another SoP made under subsection 196B(2) of the VEA, the factors in that other SoP apply according to their terms as in force from time to time. The Schedule’s definition of “relevant service” enumerates the statutory categories (operational, peacekeeping, hazardous, British nuclear test defence service under the VEA, and warlike or non‑warlike service under the MRCA).

Collectively, these concepts convert medical facts (lab confirmation, tick bite, presence in endemic area, inability to access care) into statutory evidentiary anchors used in the statutory decision framework to establish a “reasonable hypothesis” of service connection for entitlement purposes (see ss 5, 8-11).

This instrument affects three overlapping categories of persons and several administrative actors. First and primarily, it affects claimants , veterans, members of Peacekeeping Forces, and members of the Forces whose claims fall within the VEA or MRCA frameworks , who assert that Lyme disease or death from Lyme disease is connected to their relevant service. The instrument applies expressly to “a claim to which section 120A of the VEA or section 338 of the MRCA applies” (s 5). Those statutory references identify the types of claims in the two legislative schemes where Statements of Principles are the medical-causation tool; this SoP will therefore be engaged when a claimant relies on Lyme disease as part of such a claim.

Second, it affects the medical and administrative decision‑makers who determine entitlement under those Acts. The Repatriation Medical Authority (RMA) made this SoP under its statutory power (s 3) and records its view that there is sound medical‑scientific evidence supporting the disease-service relationship (s 8). Decision‑makers who adjudicate claims under the VEA and MRCA will use the SoP’s definitions and factors as the medical-causation standard when considering whether a reasonable hypothesis is established. The instrument does not itself name the decision-maker(s) in the statutes but, by operation of ss 5 and 8, it binds the medical causation framework applied in the relevant claims processes.

Third, the instrument affects healthcare providers and diagnosticians whose clinical findings and testing are likely to be used as evidence in claims. The instrument records the commonly used laboratory testing approach (IgM/IgG serology followed by Western blot) and notes that Borrelia culture is gold standard but challenging (note under the disease definition). Claims relying on laboratory confirmation will therefore look to those specified methods as evidentially relevant.

Finally, it affects parties who may be connected with claims for death benefits where Lyme disease is alleged to have contributed to a terminal event. The instrument includes death from Lyme disease within the disease meaning where a terminal event or condition was contributed to by the disease (section 7; Schedule definition of “terminal event”), so estate representatives or dependants making death‑related claims will be affected to the extent the death claim invokes this SoP.

Statutorily, “relevant service” is defined in the Schedule and includes operational service, peacekeeping service, hazardous service, British nuclear test defence service under the VEA, and warlike or non‑warlike service under the MRCA (Schedule 1). The instrument therefore affects claimants with service of those kinds; it does not, on its face, apply outside the classes listed. The RMA’s repeal of the 2016 SoP and replacement by this instrument (s 4) also affects ongoing or future claims previously assessed against the earlier SoP, because the new instrument is in force from its commencement date (s 2).

The instrument itself does not create monetary entitlements or duties in isolation; rather, it prescribes the medical-causation criteria that are applied in claims governed by the VEA and MRCA. Rights and duties therefore arise by reference to the statutory schemes that invoke Statements of Principles. The instrument places specific practical duties on claimants and decision‑makers by defining what evidence and factual circumstances are necessary to raise a reasonable hypothesis of service connection.

Claimant duties (evidentiary): To meet the SoP’s threshold a claimant must show the existence of at least one factor listed in section 9. Those factors are: exposure to Borrelia spirochetes within 33 days before clinical onset; being bitten by an Ixodes tick infected with Borrelia within 33 days before clinical onset; being in a geographic location where human Lyme disease was endemic within 33 days before clinical onset; or inability to obtain appropriate clinical management for Lyme disease before clinical worsening (section 9). For a death claim, the claimant must show that a terminal event or condition was contributed to by the person’s Lyme disease (section 7; Schedule definition of “terminal event”). The instrument requires the factors to be related to the person’s relevant service (section 10(1)). The fourth factor (inability to obtain appropriate clinical management) is limited to claims that allege material contribution to or aggravation of a disease suffered or contracted before or during, but not arising out of, relevant service (section 10(2)).

Decision‑maker duties: Decision‑makers assessing claims under the VEA or MRCA are bound to apply this SoP’s definitions and factors when considering whether a reasonable hypothesis exists. The RMA’s statement that there is “sound medical‑scientific evidence” supporting the relationship (section 8) explains the RMA’s evidentiary basis for publishing the SoP; however, the instrument itself prescribes the criteria that adjudicators must apply in the specified statutory claim contexts (s 5).

Rights: Claimants have the right to have their claim assessed using the SoP where the claim falls within the statutory sections specified in s 5. They also have the right to rely on laboratory and clinical evidence referenced in the instrument. The instrument records usual laboratory confirmation methods (IgM/IgG serology and Western blot) and notes the difficulty of culture despite its gold‑standard status (note under section 7). Where a factor in section 9 refers to another disease or injury that is the subject of a separate SoP, claimants and decision‑makers may rely on the factors in that other SoP as they operate from time to time (section 11).

Limitations and procedural interactions: The SoP must be read alongside the procedural and merits frameworks in the VEA and MRCA. The instrument does not specify adjudicative procedure, appeal rights, or operational timelines; those procedural rights and duties remain governed by the underlying statutes and their regulations. The SoP also does not itself create penalties, criminal liability, or supervisory review mechanisms; it is a medical-causation instrument for statutory claims (see sections 3, 5 and the Schedule).

This Statement of Principles does not itself create criminal sanctions, civil penalties, or an enforcement regime. The instrument is a medical‑causation instrument made under subsection 196B(2) of the VEA (s 3) and applies to claims under specific provisions of the VEA and MRCA (s 5). Its role is to define the medical and factual criteria that must be met to raise a reasonable hypothesis connecting Lyme disease or death from Lyme disease to relevant service in order to access whatever entitlements or processes exist under the VEA and MRCA. The instrument contains no provisions imposing fines, prohibitions, or enforcement measures; it does not amend or add penalty provisions to the underlying statutes.

Enforcement and remedies, insofar as they exist, will arise through the statutory claim processes under the VEA and MRCA. The instrument operates as a determinative medical standard in those claim processes: decision‑makers will apply this SoP when considering whether a claimant has established a reasonable hypothesis of service connection. Any consequences of acceptance or rejection of a claim (such as entitlement to pension, compensation, rehabilitation services or related benefits) flow from the substantive provisions of the VEA or the MRCA and their administrative frameworks, not from the SoP text itself. The instrument does not identify the administrative body or tribunal that will enforce or review decisions; those procedural and review mechanisms remain in the statutory frameworks of the VEA and MRCA.

Because the SoP does not create penalties, the primary enforcement mechanism is administrative: decision‑makers will accept or reject claims based on whether the SoP’s criteria are met. Where a factor in section 9 refers to an injury or disease covered by another SoP, section 11 requires application of that other SoP’s factors “in accordance with the terms of that Statement of Principles as in force from time to time,” which can affect decision outcomes. The instrument does not itself state how disputes about the application of the SoP are resolved; such dispute resolution is governed by the statutory appeal and review pathways in the VEA/MRCA frameworks and any relevant administrative review processes, not by the instrument.

In short, this SoP prescribes the medical-causation standard for entitlement decisions; it does not itself levy penalties or set out enforcement mechanisms beyond its use as an evidentiary and determinative tool within the statutory claims processes referenced in section 5.

This SoP is expressly made under the power in subsection 196B(2) of the Veterans’ Entitlements Act 1986 (s 3) and applies to claims falling within specified sections of the VEA and the Military Rehabilitation and Compensation Act 2004 (s 5). It therefore operates as a medical-causation instrument within those statutory schemes. The SoP supplants the earlier Statement of Principles concerning Lyme disease (No. 25 of 2016), which it repeals (s 4). Any claims or decisions that, under the VEA or MRCA, require application of a SoP for Lyme disease will now be subject to this instrument from its commencement date (s 2).

Operationally, the instrument interacts with other SoPs through section 11, which provides a cross-reference rule. If a factor in section 9 applies in relation to a person and that factor refers to an injury or disease that is the subject of another SoP made under subsection 196B(2) of the VEA, then the factors in that other SoP apply “in accordance with the terms of that Statement of Principles as in force from time to time” (s 11). That provision creates an explicit mechanism for incorporating other SoPs into the evaluation of a factor that overlaps with a different injury or disease. The effect is that adjudicators must apply the relevant other SoP’s criteria when the factual basis of a factor in section 9 implicates another named condition.

The instrument also clarifies its relationship with ICD‑10‑AM coding. It notes that while Lyme disease attracts ICD‑10‑AM code A69.2, “in applying this Statement of Principles the meaning of Lyme disease/Lyme borreliosis is that given in subsection (2)” (section 7, explanatory paragraph). The instrument therefore fixes its own statutory meaning for the condition rather than relying solely on external classification codes; however, it preserves the ICD‑10‑AM reference as a classificatory note. For laboratory and clinical evidence, the notes under the disease definition record typical testing methods and the difficulty of culture, and decision‑makers assessing evidence will consult those notes as part of the SoP’s factual matrix.

The Schedule defines “relevant service” by reference to categories in the VEA and MRCA (Schedule 1). Claims that fall outside the VEA or MRCA frameworks are therefore not governed by this SoP. Similarly, the SoP’s exclusion of “Lyme-like illness” (subsection 7(2)(c)) means that conditions not meeting the definition in subsection 7(2) but presenting similar symptoms will not be caught by this instrument; those conditions would be assessed under other applicable law or other SoPs, if any.

Finally, the instrument’s repeal of the 2016 SoP creates a direct legislative interaction: claims previously assessed against the older instrument must now be assessed under the new instrument from its commencement in accordance with the VEA/MRCA procedures. The SoP does not modify the substantive provisions of the VEA or the MRCA themselves; it operates as a medical standard within the framework those Acts supply.

The instrument records one explicit amendment-type event: the repeal of the prior Statement of Principles concerning Lyme disease (Reasonable Hypothesis) (No. 25 of 2016), Federal Register of Legislation No. F2016L00254 (s 4). The new SoP is dated 17 December 2024 and is stated to commence on 28 January 2025 (ss 1 and 2). No other amendments to this instrument are contained within the text supplied.

Because the instrument is a standalone SoP replacing the 2016 SoP, the immediate amendment history of relevance is the repeal provision and the commencement date. The instrument does not include transitional provisions, savings clauses, or retroactivity language beyond the simple repeal and commencement. It does not specify explicitly how pending claims initiated before commencement are to be treated, nor does it provide direction about whether the new criteria apply to claims lodged before the commencement date but determined after it. Those procedural and transitional questions remain governed by the underlying statutes and administrative practice referenced in section 5 (claims to which section 120A of the VEA or section 338 of the MRCA applies). The instrument itself contains no additional amendment history, savings, or transitional directions.

The Schedule provides definitions that anchor the instrument in the statutory frameworks of the VEA and MRCA. It defines “relevant service” by reference to those Acts’ categories (operational, peacekeeping, hazardous, British nuclear test defence service under the VEA, and warlike or non‑warlike service under the MRCA). Any future amendments to the VEA or MRCA that alter the definitions of those service categories, or to subsection 196B(2) of the VEA, could alter the practical operation of this SoP by changing the class of claims to which it applies; such changes would be made in the primary legislation and not in the SoP itself.

For practical purposes, then, the amendment history recorded in the instrument is limited to the repeal of the 2016 SoP and the issue of the new 2025 instrument with its commencement date. Any further amendment history will be recorded in later instruments or in amendments to the VEA or MRCA.

The text of this Statement of Principles does not record or reference any litigation history. It contains no mention of judicial or tribunal decisions, appeals, or challenges associated with the earlier 2016 SoP or with the matters addressed by this 2025 instrument. The instrument instead records the RMA’s view that there is “sound medical‑scientific evidence” supporting the relationship between Lyme disease or death from Lyme disease and relevant service (section 8), but it does not reference case law, reviews, or litigated interpretations.

Because the instrument is a technical medical‑causation instrument made under subsection 196B(2) of the VEA, the absence of litigation references in the text does not mean that litigation will not arise in the future from application of the SoP to individual claims. Disputes about whether the facts of a particular case meet the SoP’s requirements (for example, whether a listed factor exists, whether it is related to relevant service, or whether a terminal event was contributed to by Lyme disease) may be litigated or reviewed within the appeal routes established by the VEA and MRCA. However, neither the instrument nor its Schedule identify past litigation or give guidance about appellate outcomes.

For present purposes, the instrument’s repeal of the 2016 SoP is recorded (section 4). Any litigation history that pertains to the 2016 instrument is not included in this instrument and therefore cannot be described from the text supplied. Users requiring a litigation history should consult the public record, tribunals, or courts for decisions that may have engaged the earlier or this SoP; such sources are outside this instrument’s text.

This SoP contains several details that materially shape evidentiary outcomes and should attract focused attention from claimants, clinicians, and decision‑makers.

The 33‑day temporal window for three of the four listed factors is a hard threshold in the instrument. Section 9 requires that at least one of the following must exist: exposure to Borrelia spirochetes within the 33 days before clinical onset; being bitten by an infected Ixodes tick within the 33 days before clinical onset; being in an endemic geographic location within the 33 days before clinical onset (section 9, factors 1-3). That 33‑day specification is the sole temporal parameter placed on those factors in the instrument. Exposures or tick bites falling outside that 33‑day window are not captured by those particular factors and, unless the claimant can rely on the fourth factor (inability to obtain appropriate clinical management), will fail to meet the minimum requirements of section 9. Practitioners and claimants must therefore map service records, travel or deployment records, clinical onset dates, and any history of tick bites or exposures onto that 33‑day window to establish that a listed factor exists.

The instrument expressly excludes “Lyme‑like illness” from its meaning of Lyme disease (subsection 7(2)(c)). That exclusion requires claimants to meet the SoP’s defined infection standard , infection with Borrelia burgdorferi sensu lato transmitted by an Ixodes tick in an endemic location , rather than rely on syndromic descriptions of similar symptom clusters. Where a diagnosis is recorded as a “Lyme‑like” condition without laboratory confirmation or without meeting the definitional elements in subsection 7(2), the SoP does not capture that condition for the purposes of raising a reasonable hypothesis under this instrument.

Laboratory evidence is both noted and qualified. The instrument records common laboratory confirmation methods (IgM/IgG serology by ELISA or immunofluorescence followed by Western blot where serology was positive) and states that Borrelia culture is the gold standard of diagnosis but “difficult to achieve” (note under section 7). The practical consequence is potential evidentiary difficulty for claimants: the instrument signals which tests decision‑makers will expect but also acknowledges limitations with the gold standard. This combination may create evidentiary gaps where serology is negative or equivocal and cultures are not available.

Geographic endemicity is treated as an element in the definition and in a factor (section 9(3)); the instrument provides an illustrative list of endemic areas (notes under section 7), introduced with the word “include.” That phrasing indicates the list is illustrative rather than exhaustive. However, claimants whose service occurred in locations not mentioned in the notes may need to establish that the location in question was endemic for human Lyme disease to rely on factor 3. The onus of mapping service locations to the concept of endemicity falls upon the claimant and the decision‑maker applying the SoP.

The fourth factor (inability to obtain appropriate clinical management before clinical worsening) is constrained by section 10(2). That subsection limits the application of factor 9(4) “only to material contribution to, or aggravation of, Lyme disease/Lyme borreliosis where the person's Lyme disease/Lyme borreliosis was suffered or contracted before or during (but did not arise out of) the person's relevant service.” In plain terms, inability to obtain appropriate care can only be relied upon where the disease pre‑existed or was contracted before/during but did not arise out of service; the factor does not otherwise create a freestanding basis for a claim. Practitioners must therefore be careful when invoking factor 9(4): it is not a universal fallback if factors 1-3 are absent.

Cross‑SoP interaction can complicate assessment. Section 11 brings other SoPs into play where a factor in section 9 refers to another condition covered by another SoP. This means that establishing a fact that involves multiple conditions can require navigating multiple SoPs and ensuring consistency with the then-current terms of those other SoPs.

Finally, the instrument’s repeal of the 2016 SoP (section 4) with a commencement date (section 2) raises transitional questions that the instrument does not answer. The SoP does not state whether claims in process at commencement are to be assessed under the old or new instrument; those procedural matters must be determined under the VEA/MRCA regimes or administrative practice. Practitioners should therefore seek clarification about transitional application where that question matters to particular claims.

In short, the primary “gotchas” are the strict 33‑day temporal requirement for factors 1-3, the exclusion of “Lyme‑like illness”, the evidentiary expectations for laboratory confirmation combined with the acknowledged limits of culture, the constrained operation of the inability‑to‑obtain‑care factor, and potential complexity when other SoPs are implicated.

For claimants, clinical advisers, and decision‑makers preparing or assessing claims under the VEA or MRCA where Lyme disease or death from Lyme disease is alleged, the instrument identifies tight evidentiary and relational requirements. Compliance means presenting and testing the factual predicates set out in the SoP.

1. Establish the disease definition elements. The SoP’s statutory definition requires infection with Borrelia burgdorferi sensu lato transmitted by an Ixodes tick in an endemic geographic location, and it excludes “Lyme‑like illness” (subsection 7(2)). To comply with that definitional requirement, gather clinical records that include a diagnosis consistent with Lyme disease as defined in subsection 7(2). Where laboratory testing has been performed, obtain and document results of IgM/IgG serology and Western blot testing in the standard sequence referenced in the instrument (note under section 7). If culture evidence exists, document its result and provenance, noting the instrument’s observation that culture is the gold standard but difficult to achieve.

2. Map temporal exposure to the 33‑day window. For the three primary exposure factors (exposure to spirochetes; bite by infected Ixodes tick; presence in an endemic location), the instrument requires that the exposure or tick bite or presence in an endemic location occur within 33 days before clinical onset (section 9, factors 1-3). Compile contemporaneous service records, deployment logs, travel documents, unit diaries, and clinical onset dates to show that the relevant exposure window falls within 33 days of symptom onset. If a tick bite was reported, secure contemporaneous documentation such as medical entries, incident reports, photographs of bites or rashes, or witness statements.

3. Document endemic location status. If relying on factor 9(3), ensure that service or presence is demonstrably in a geographic location that the instrument treats as endemic. The SoP’s notes list certain areas as examples; the instrument uses “include,” indicating the list is not exhaustive. Where the location is not listed in the notes, obtain authoritative evidence (for example, deployment maps, public health records, local epidemiological statements contemporaneous with the service) that would support a finding of endemicity in the location where the claimant was posted.

4. If relying on inability to obtain appropriate management, document the timing and scope, and check the limitation. Factor 9(4) requires inability to obtain appropriate clinical management before clinical worsening. Section 10(2) limits the application of that factor to cases where the disease was suffered or contracted before or during (but did not arise out of) relevant service and is relied upon as material contribution or aggravation. To comply, assemble contemporaneous medical records showing attempts to obtain care, records of referrals or denials, evidence of local health infrastructure constraints at the time, and clinical notes showing progression in the absence of appropriate management. Also document the disease’s chronology to show it was contracted before or during service if claiming material contribution or aggravation.

5. Link the factor to relevant service. Any factor relied on must be related to the person’s relevant service (section 10(1)). That means aligning the factual evidence of exposure/tick bite/presence in endemic area or inability to obtain care with service records that establish the person was engaged in one of the service types defined in the Schedule (operational, peacekeeping, hazardous, British nuclear test defence service under the VEA, or warlike/non‑warlike service under the MRCA). Provide unit orders, deployment manifests, travel authorisations, and other official records to show the required nexus between the factor and the relevant service.

6. For death claims, document terminal event contribution. The instrument expands the disease meaning to include death “from a terminal event or condition that was contributed to by the person's Lyme disease” (section 7). For a death claim, secure a death certificate, clinical records around the terminal event, post‑mortem findings if any, and medical expert reports that address whether the terminal event listed in the Schedule (for example, pneumonia, respiratory failure, cardiac arrest, circulatory failure, cessation of brain function) was contributed to by Lyme disease.

7. Anticipate cross‑SoP interactions. If any factor in section 9 invokes or overlaps with another disease or injury that is the subject of a separate SoP, be prepared to address that other SoP’s factors, since section 11 requires application of the other SoP’s factors as in force. Identify any potential overlapping conditions early and gather evidence that satisfies the cross‑referenced SoP(s).

8. Prepare expert opinion that addresses the SoP criteria. Medical or expert reports should explicitly address the statutory elements of the SoP: whether the infection meets the subsection 7(2) definition, whether one of the section 9 factors exists within the 33‑day window (as relevant), whether the factor is related to relevant service (section 10(1)), whether inability to obtain management meets the constrained application (section 10(2)), and whether any terminal event was contributed to by Lyme disease for death claims. Reports that tie clinical findings to the specific SoP criteria will align with how the SoP is to be applied in claim adjudication.

9. Preserve contemporaneous evidence. Given the temporal precision required by the SoP, contemporaneous documents and records (clinical notes, service logs, incident reports, travel records, and laboratory test records) will be central to establishing compliance. Where contemporaneous documentation is sparse, secure corroborative statements from colleagues, unit commanders, treating clinicians, and local health providers describing exposure events and medical access at the relevant times.

10. Consider procedural and transitional issues. The instrument does not specify transitional rules for claims in progress at commencement; so check the VEA and MRCA procedures and administrative practice about whether the new SoP applies to claims lodged but not yet determined at commencement. Seek clarification from the relevant claims administration body where that question is material.

Following these steps aligns a claim with the specific, enumerated requirements of the instrument: satisfy the disease definition in subsection 7(2), demonstrate at least one of the section 9 factors within the 33‑day temporal window or satisfy the narrowly circumscribed section 9(4) factor where applicable, and show the factor is related to relevant service (section 10). Documentation and expert opinion should be structured to address those statutory predicates directly.