Last Updated: August 9, 2026

Patent: 9,821,051


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Summary for Patent: 9,821,051
Title:Reducing hospitalization in elderly influenza vaccine recipients
Abstract: Compared to an unadjuvanted vaccine, an adjuvanted influenza vaccine can reduce by almost a quarter the risk of hospitalization for respiratory illness (e.g. influenza and pneumonia) in elderly recipients. Thus the invention provides a method for immunizing an elderly subject by administering an adjuvanted influenza vaccine, whereby the subject\'s risk of hospitalization for respiratory illness (e.g. influenza and pneumonia) is reduced relative to an elderly subject who receives an unadjuvanted influenza vaccine.
Inventor(s): Groth; Nicola (Siena, IT)
Assignee: Seqirus UK Limited (Berkshire, GB)
Application Number:13/279,156
Patent Claims:see list of patent claims
Patent landscape, scope, and claims summary:

Executive summary US 9,821,051 is a method-of-use patent focused on vaccinating elderly humans (≥65) across multiple consecutive influenza seasons with split-virus, inactivated seasonal influenza antigens where the adjuvanted arm uses a specific oil-in-water (O/W) emulsion adjuvant system (notably squalene and surfactant combinations) and yields reduced pneumonia/influenza hospitalization vs an unadjuvanted split-virus comparator. The claim set is layered to progressively narrow adjuvant composition (squalene; polysorbate 80/sorbitan trioleate; or polyoxyethylene sorbitan monooleate/sorbitan trioleate), emulsion droplet size (sub-220 nm; ranges such as 100–250 nm; at least 90% <200 nm), formulation characteristics (purified surface antigen in later dependent claims), administration route (intramuscular), and population selection and vaccination regimen constraints (no crossover to unadjuvanted vaccine in specified seasons; in claim 18 excludes recent hospitalization/nursing home/rehab/home care).

From a competitive and litigation standpoint, the enforceability and practical “design-around” hinge on (i) whether a competitor’s product uses the same split-virus antigen approach and emulsion droplet profile, (ii) whether the adjuvant chemistry matches the recited surfactant matrix (including specific O/W emulsion ingredients), and (iii) whether clinical benefit is framed/used in a way that reads on the claimed hospitalization-reduction method rather than purely on an immunogenicity claim. Infringement exposure is highest for products using MF59-like squalene-based O/W submicron emulsions with the specific surfactant pairing recited and used in elderly multi-season seasonal immunization schemes, especially if promotional or study design aligns with pneumonia/influenza hospitalization endpoints.


US Patent 9,821,051 claims analysis: adjuvanted split-virus influenza vaccination in elderly across consecutive seasons

US 9,821,051 claim 1 establishes the independent method claim; claims 2–13 and 14–22 carve dependent limitations around formulation composition, emulsion droplet size, antigen type, route, and population eligibility.

What does independent claim 1 cover (and what it does not)?

Claim 1 core elements (method of immunization):

  • Target population: each recipient is at least 65 years old.
  • Treatment setting: a predetermined community of elderly human subjects.
  • Regimen timing: consecutive influenza seasons (plural, not limited to 2 or 3 in claim 1).
  • Comparator structure: adjuvanted recipients are compared to a population receiving unadjuvanted influenza vaccine.
  • Efficacy endpoint: vaccine dose sufficient to inhibit at least one condition chosen from pneumonia and influenza, and reduce incidence of hospitalization for the condition during peak of each influenza season.
  • No crossover: none of the adjuvanted-vaccine recipients receives an unadjuvanted influenza vaccine in any of the influenza seasons.
  • Antigen architecture: adjuvanted and unadjuvanted influenza vaccines are split virus antigen vaccines.
  • Vaccine scope: adjuvanted vaccine chosen from:
    • adjuvanted influenza A seasonal vaccine, and
    • adjuvanted influenza B seasonal vaccine.

Claim 1 does not expressly require:

  • A particular named adjuvant chemistry beyond “adjuvanted” (that appears in dependent claims 5–13).
  • A specific number of seasons (that appears in claims 14 and 18).
  • A purified surface antigen description (that appears in claim 14 and 18).
  • An intramuscular route (that appears in claim 4).
  • Specific droplet size distribution (that appears in claims 11–13).
  • The named adjuvant surfactant system unless the dependent limitations are invoked by infringement theory.

Legal consequence for claim scope

Claim 1 is broad on “adjuvanted vaccine” concept but narrow on:

  • split-virus antigen requirement, and
  • multi-season, elderly-only, no crossover with unadjuvanted vaccine, and
  • hospitalization reduction endpoint framing.

A competitor that uses a different antigen processing approach (eg, whole virion or subunit without “split virus antigen” characterization) can avoid at least one core limitation even if it uses an MF59-like adjuvant.


Which dependent claims lock the adjuvant system into a narrow emulsion specification?

Claims 5–13 progressively specify the adjuvant.

Oil-in-water emulsion adjuvant (claims 5–10)

  • Claim 5: influenza is adjuvanted with an oil-in-water emulsion.
  • Claim 6: emulsion comprises squalene.
  • Claim 7: emulsion comprises squalene, polysorbate 80, and sorbitan trioleate.
  • Claim 8: emulsion comprises squalene, an α-tocopherol, and polysorbate 80.
  • Claim 9: emulsion comprises:
    • squalene,
    • an aqueous solvent,
    • a polyoxyethylene alkyl ether hydrophilic nonionic surfactant, and
    • a hydrophobic nonionic surfactant.
  • Claim 10: emulsion comprises:
    • squalene,
    • polyoxyethylene sorbitan monooleate, and
    • sorbitan trioleate.

Key point: these dependent claims define multiple possible adjuvant embodiments. A competitor may try to avoid infringement by selecting an MF59-like adjuvant that does not match the precise surfactant set in a particular asserted dependent claim. But note that infringement analysis can choose which dependent limitation is triggered; a plaintiff typically asserts the tightest-fitting claim family to match the accused product’s composition.

Droplet size constraints (claims 11–13)

  • Claim 11: oil droplets with size <220 nm.
  • Claim 12: average droplet diameter 100–250 nm.
  • Claim 13: at least 90% by volume of oil droplets have size <200 nm.

Design-around leverage: emulsion droplet size distributions are measurable by dynamic light scattering and related methods. If an accused adjuvant uses larger droplets or a different distribution profile, it can avoid droplet-size-dependent limitations. If it still meets “<220 nm” but fails “≥90% <200 nm,” claim coverage narrows to the applicable dependent claim asserted.


What do claims 2–4 do to limit product comparability and administration route?

  • Claim 2: adjuvanted and unadjuvanted vaccines have the same dosage volume, antigen amount, virus strains, antigen type, and non-adjuvant excipients.
  • Claim 3: adjuvanted vaccine comprises the unadjuvanted vaccine plus an adjuvant.
  • Claim 4: vaccines are administered intramuscularly.

Why it matters: claim 2 and 3 establish a “like-for-like” comparator structure, strengthening the causality narrative for hospitalization reduction vs unadjuvanted baseline. If a competitor uses different antigen amounts/strains or substantially reformulates the antigen/excipients beyond adding adjuvant, it can potentially evade the dependent structure even if efficacy appears similar.


What does claim 14 add: purified surface antigen + tetravalent + specific emulsion recipe?

Claim 14 is an independent-like expansion via a dependent path from claim 1 (as written, it is an additional independent claim in the patent):

  • Tetravalent, inactivated influenza A and B seasonal vaccines.
  • Two consecutive seasons.
  • Intramuscular administration.
  • Efficacy endpoint same: reduction in pneumonia/influenza hospitalization during season peak vs unadjuvanted.
  • Adjuvanted vaccine is a purified surface antigen vaccine.
  • Adjuvant is an O/W submicron emulsion comprising:
    • squalene
    • polyoxyethylene sorbitan monooleate
    • sorbitan trioleate
  • Elderly condition and no receipt of unadjuvanted vaccine in the same two-season window.

Claim 14 narrows the adjuvant to the exact surfactant pair in claim 10 and requires “purified surface antigen” framing. Many marketed influenza vaccines for older adults are not described in promotional materials as “purified surface antigen,” so the phrasing matters for claim construction and infringement proof.


What does claim 18 add: three seasons + strict prior-care exclusion?

Claim 18 is a further expansion with additional eligibility constraints:

  • Trivalent or tetravalent inactivated adjuvanted influenza A/B seasonal vaccines.
  • Three consecutive influenza seasons.
  • Adjuvanted vaccine is a purified surface antigen vaccine.
  • Adjuvant: oil-in-water submicron emulsion comprising:
    • squalene,
    • polyoxyethylene sorbitan monooleate,
    • sorbitan trioleate,
    • and droplet size <220 nm.
  • Elderly ≥65, plus:
    • recipients were not resident of hospital/nursing home/rehabilitation center or received home care in 30 days preceding immunization.
  • No unadjuvanted influenza vaccine in any of the three consecutive seasons.

Population selection effect: This exclusion can be a litigation lever. A real-world older-adult target population often includes high fractions with recent care. If an accused program includes such residents or home care patients, a defendant can argue mismatch with claim 18’s pre-immunization status constraints.


How many claims in US 9,821,051 depend on droplet size and the emulsion recipe?

Droplet-size-dependent coverage appears in:

  • Claims 11–13 (direct dependent chain on claim 6),
  • Claim 17 (droplet size <220 nm on the path from claim 14),
  • Claim 18 (explicit <220 nm in the adjuvant definition).

Emulsion recipe dependency appears in:

  • Claims 5–10 (oil-in-water + specific surfactant combinations),
  • Claim 14 (fixed recipe: squalene + polyoxyethylene sorbitan monooleate + sorbitan trioleate),
  • Claim 18 (same as claim 14 plus droplet size).

In practice, claim coverage is strongest for products that match the exact surfactant pair and meet the submicron droplet thresholds called out.


What patents protect adjuvanted influenza vaccination in elderly with oil-in-water squalene emulsions?

US 9,821,051 sits in a crowded adjuvanted-influenza landscape dominated by squalene-based O/W emulsions and by clinical data used to support hospitalization endpoints. Key adjacent patent families (by subject matter) typically include:

  • MF59-like emulsion compositions (squalene + surfactant system) and droplet size targets.
  • Antigen-adjuvant combinations for influenza strains in elderly.
  • Clinical method-of-use patents tied to outcomes such as hospitalization, pneumonia, and influenza incidence in older adults.
  • Split-virus or purified surface antigen processing for inactivated seasonal influenza.

Critical point: the claim language here is unusually specific about:

  • split-virus antigen qualification,
  • multi-season regimen design,
  • comparator requirement with unadjuvanted vaccine,
  • and a particular O/W emulsion recipe and droplet size distribution.

That combination usually narrows the universe of infringing products more than generic “use of an adjuvant for influenza” patents.


How do these claims compare with typical adjuvant influenza method patents?

Common patterns in method-of-use influenza adjuvant patents include:

  • immunogenicity endpoints (hemagglutination inhibition titers, seroprotection/seroconversion),
  • general protection against influenza illness,
  • reduced medically attended influenza,
  • sometimes hospitalization.

US 9,821,051 shifts toward:

  • pneumonia and influenza,
  • hospitalization incidence during peak seasons, and
  • multi-season administration with a “no unadjuvanted crossover” structure.

This can strengthen the argument against broad novelty-destroying prior art that focuses on immunogenicity rather than hospitalization endpoints, but also raises proof burdens tied to trial design, endpoints, and population selection.


What is the Orange Book status of US 9,821,051?

US 9,821,051 is a method-of-use patent and typically would not list in the Orange Book as a “drug product” patent by itself unless it is listed by the NDA holder for a specific NDC. Method claims may or may not be Orange Book listed depending on the NDA labeling and listing strategy.

No Orange Book status can be asserted from the claim text alone.


When does US 9,821,051 lose exclusivity (patent expiration timeline)?

A deterministic expiration timeline requires:

  • the filing date,
  • priority chain,
  • adjustments (PTA),
  • and maintenance status.

No expiration computation can be produced from claim text alone.


Which generic or biosimilar entry risks exist for US 9,821,051?

Influenza vaccines are small-molecule-adjacent in the sense they are chemically distinct biologics category products, and the “generic” model does not apply cleanly. For vaccines, risk usually flows through:

  • substitution of formulations and adjuvant compositions,
  • differences in antigen processing (split vs non-split),
  • different adjuvant emulsion droplet profiles,
  • and labeling or trial program endpoints that do not map to the claimed hospitalization-reduction method.

The most realistic “entry risk” is for next-generation or biosimilar-like competitors using different adjuvants or different antigen processing. The patent is best read as a composition-plus-method lock.


How strong is the patent estate for US 9,821,051 (claim robustness and vulnerabilities)?

Robustness levers for the patentee

  • Multi-element specificity: claim 1 combines age threshold, split-virus antigen requirement, multi-season non-crossover design, and hospitalization reduction endpoint framing.
  • Converging limitations in dependents: claims 5–13 and 14/18 converge on squalene O/W emulsion with specific surfactants and droplet size parameters.
  • Clear infringement mapping potential: a product’s adjuvant composition and droplet size can be matched to claims 11–13; antigen processing and route can be mapped to claims 1–4 and 14/18.

Vulnerabilities for enforcement

  • Comparator and endpoint framing: claim 1 depends on an inhibition/reduction narrative relative to an unadjuvanted comparator. If real-world or clinical evidence used by a defendant does not operationalize those hospitalization endpoints “during the peak” seasons in a comparable manner, infringement proof can be harder.
  • Antigen processing characterization: “split virus antigen” and “purified surface antigen” are technical classification terms. If an accused vaccine is described or prepared differently, the claim scope can narrow sharply.
  • Dependent-claim surfactant specificity: because claims 7, 8, 10, 14, and 18 recite alternative and specific surfactant systems, defendants can attempt to avoid one asserted dependent claim by using a different surfactant combination while still using a squalene O/W emulsion.

What patent litigation strategy typically follows US 9,821,051 claims?

For method patents like this, enforcement typically targets:

  • products using squalene-based O/W emulsion adjuvants with the same surfactant pair(s) and submicron droplet profile, and
  • clinical/trial designs and labeling that align with elderly populations and hospitalization reduction claims.

If a defendant product uses a different adjuvant recipe (different surfactants) or a different antigen processing description, the patentee’s infringement narrative must rely on claim 1 rather than the narrower dependents, or pursue product-specific claim mapping.


Claim-by-claim infringement mapping checklist (accused product alignment)

For infringement under claim 1:

  1. Inactivated split-virus antigen seasonal influenza vaccine.
  2. Elderly ≥65 in a predetermined community.
  3. Multi-season consecutive influenza seasons.
  4. Adjuvanted arm does not receive unadjuvanted vaccine.
  5. Hospitalization incidence for pneumonia/influenza reduced during peak seasons vs unadjuvanted.
  6. Comparator is unadjuvanted influenza vaccine using the same strains/excipients/dosage volume (if claim 2/3 asserted).

For infringement under claims 5–13:

  • O/W emulsion adjuvant with squalene.
  • Specific surfactant set (claims 7/8/10).
  • Droplet size specs (<220 nm; 100–250 nm average; ≥90% <200 nm).

For infringement under claims 14 and 18 (strongest product-specific locks):

  • Intramuscular injection.
  • Tetravalent (claim 14) or trivalent/tetravalent (claim 18).
  • Purified surface antigen description.
  • Submicron O/W emulsion recipe: squalene + polyoxyethylene sorbitan monooleate + sorbitan trioleate.
  • For claim 18: no recent hospital/nursing/rehab/home care in last 30 days.
  • No unadjuvanted vaccine in the stated 2- or 3-season windows.

Key Takeaways

  • US 9,821,051 is a multi-season elderly influenza vaccination method patent with split-virus antigen constraints and hospitalization reduction endpoint framing vs unadjuvanted vaccination.
  • The strongest enforceable scope is tied to dependent claims specifying an O/W squalene emulsion adjuvant, with exact surfactant combinations and submicron droplet size profiles.
  • Practical design-arounds focus on changing antigen processing away from “split virus” or “purified surface antigen,” modifying adjuvant surfactant composition, or altering droplet size distributions.
  • Litigation and infringement proof will likely hinge on product formulation characterization (composition and droplet distribution) and the trial/clinical or labeling evidence demonstrating the claimed hospitalization reduction structure in elderly, multi-season settings.

FAQs

1) Does US 9,821,051 require a specific influenza strain list to infringe?
Yes, claim 2 ties adjuvanted and unadjuvanted vaccines to the same virus strains, and claim 1 requires split-virus antigen vaccines; the independent claim is broader on which influenza A/B seasonal vaccines qualify but still requires split-virus antigen seasonal vaccines and the elderly multi-season regimen.

2) Can a competitor avoid infringement by using a different squalene emulsion surfactant system?
Avoidance is most plausible against surfactant-specific dependent claims (eg, claims 7, 8, and 10) by using a different surfactant pairing than those recited, while still using squalene-based O/W emulsions.

3) Is droplet size a major validity or enforcement battleground for US 9,821,051?
Yes. Claims 11–13, 17, and 18 lock in sub-220 nm droplet specifications and distribution metrics, so droplet characterization is central to infringement mapping and invalidity challenges that rely on prior-art emulsion profiles.

4) Does the patent cover both trivalent and tetravalent influenza vaccines?
Claim 1 covers adjuvanted influenza A seasonal and adjuvanted influenza B seasonal vaccines; later claims include tetravalent (claim 14) and trivalent/tetravalent (claim 18), with additional constraints on purified surface antigen and adjuvant composition.

5) Are the claimed endpoints limited to pneumonia and influenza hospitalization only?
The efficacy language is anchored to “at least one condition chosen from pneumonia and influenza” and specifically targets reduction in hospitalization incidence for those conditions during the peak of influenza seasons.


References

  1. United States Patent US 9,821,051, “Immunization method,” claims 1–22.

More… ↓

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Details for Patent 9,821,051

Applicant Tradename Biologic Ingredient Dosage Form BLA Approval Date Patent No. Expiredate
Glaxosmithkline Biologicals FLUARIX, FLUARIX QUADRIVALENT influenza vaccine Injection 125127 August 31, 2005 ⤷  Start Trial 2031-10-21
Glaxosmithkline Biologicals FLUARIX, FLUARIX QUADRIVALENT influenza vaccine Injection 125127 December 14, 2012 ⤷  Start Trial 2031-10-21
Id Biomedical Corporation Of Quebec FLULAVAL, FLULAVAL QUADRIVALENT influenza vaccine Injection 125163 October 05, 2006 ⤷  Start Trial 2031-10-21
Id Biomedical Corporation Of Quebec FLULAVAL, FLULAVAL QUADRIVALENT influenza vaccine Injection 125163 November 10, 2009 ⤷  Start Trial 2031-10-21
Id Biomedical Corporation Of Quebec FLULAVAL, FLULAVAL QUADRIVALENT influenza vaccine Injection 125163 August 15, 2013 ⤷  Start Trial 2031-10-21
Id Biomedical Corporation Of Quebec FLULAVAL, FLULAVAL QUADRIVALENT influenza vaccine Injection 125163 September 27, 2013 ⤷  Start Trial 2031-10-21
>Applicant >Tradename >Biologic Ingredient >Dosage Form >BLA >Approval Date >Patent No. >Expiredate

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