Health

Vaccines

Routine and seasonal immunizations.

Why it matters · Appointment delays and local allocation.

6

Inputs

27

Companies

19

Facilities

10

Source countries

How it's made

The process

  1. 01

    Antigen cultivation

    Viruses grown on chicken eggs (flu, >80% of global supply), cell lines (Vero, MRC-5, MDCK), or in bioreactors (bacterial, recombinant protein, mRNA in vitro transcription). Single-use wave and stirred-tank bioreactors now standard for most recombinant and mRNA vaccines.

  2. 02

    Purification and concentration

    Antigen isolated by centrifugation, filtration, and chromatography (affinity, ion exchange, size exclusion). Bioprocess chromatography resins and ultrafiltration membranes (Cytiva, Sartorius) are critical consumables. mRNA purified by DNase treatment plus HPLC or oligo-dT affinity.

  3. 03

    mRNA synthesis and LNP encapsulation

    For mRNA vaccines: T7 RNA polymerase in vitro transcription with co-transcriptional CleanCap capping (TriLink near-monopoly). mRNA then encapsulated in lipid nanoparticles (LNPs) via microfluidic mixing of ionizable lipid, phospholipid, cholesterol, and PEG-lipid in ethanol/aqueous buffer.

  4. 04

    Formulation and adjuvant addition

    Purified antigen combined with adjuvant (alum, AS01B for Shingrix/malaria, MF59 for flu pandemic vaccines) and stabilizers (sucrose, trehalose, polysorbate 80). pH, tonicity, and preservative adjusted. mRNA vaccines formulated in cryoprotectant buffer for ultra-cold storage.

  5. 05

    Fill and finish (aseptic)

    Drug product filled into sterile borosilicate or aluminosilicate (Valor Glass) vials under ISO 5 cleanroom conditions. High-speed lines: 400–750 vials/minute. Rubber stoppers applied; vials crimped with aluminum caps. Only ~20–30 aseptic fill facilities globally; fill-finish is the binding bottleneck for pandemic surge.

  6. 06

    Quality control testing

    Potency assays, sterility testing (7–14 day culture), identity, purity, pH, preservative and adjuvant quantitation, particulate matter, residual DNA. Batch release typically 2–4 weeks. For mRNA: dsRNA content, cap efficiency, poly-A tail length.

  7. 07

    Cold chain distribution

    Most vaccines stored at 2–8°C; mRNA vaccines at –75°C to –15°C. Cold chain infrastructure requires ultra-cold freezers (Thermo Fisher, Eppendorf) from manufacturer through transport to point of care. Last-mile delivery in sub-Saharan Africa fails for 50% of health facilities.

Where it comes from

Country dependencies

Weighted share of upstream inputs sourced from each country.

CountryWeighted shareInputs supplied to vaccines
BEBelgium100%AS01B Adjuvant System (GSK proprietary)
CLChile90%AS01B Adjuvant System (GSK proprietary)
USUnited States36%Borosilicate Glass Tubing (Type I) · Bioprocess Chromatography Resins · Ionizable Lipids for LNP Delivery (ALC-0315 / SM-102 type) +2
DEGermany31%Borosilicate Glass Tubing (Type I) · Bioprocess Chromatography Resins · Ionizable Lipids for LNP Delivery (ALC-0315 / SM-102 type) +2
SESweden28%Bioprocess Chromatography Resins · Single-Use Bioreactor Bags (Cellbag)
JPJapan11%Bioprocess Chromatography Resins · Ionizable Lipids for LNP Delivery (ALC-0315 / SM-102 type) · mRNA Cap Analogs (CleanCap, co-transcriptional)
CNChina10%Borosilicate Glass Tubing (Type I) · mRNA Cap Analogs (CleanCap, co-transcriptional)
CHSwitzerland10%Ionizable Lipids for LNP Delivery (ALC-0315 / SM-102 type)
INIndia8%Borosilicate Glass Tubing (Type I)
FRFrance8%Single-Use Bioreactor Bags (Cellbag)

Who makes it

Supplier companies

27 companies in this supply chain, sorted by market share.

GSK (GSK)
HQ GB100% shareSOLE SUPPLIER

UK pharmaceutical company; sole manufacturer and formulator of AS01B adjuvant system (QS-21 + MPL in liposomes); used in Shingrix (herpes zoster vaccine, $4B+ annual revenue) and RTS,S/Mosquirix (malaria vaccine); retaining AS01E adjuvant supply even as malaria vaccine manufacturing transfers to Bharat Biotech

Supplies these inputs

AS01B Adjuvant System (GSK proprietary)

Replaceability

Substitutability 5% · 60 mo to replace

Business segments

  • Respiratory Inhalers (Ventolin, Advair, Trelegy)35% rev
  • Vaccines (Shingrix, Flu, Mosquirix)40% rev
  • Specialty Medicines (HIV, Oncology, Rare Disease)25% rev
TriLink BioTechnologies
HQ US75% shareSOLE SUPPLIER

San Diego-based mRNA capping reagent company (subsidiary of Maravai LifeSciences, MRVI); inventor of CleanCap co-transcriptional capping technology; near-monopoly during COVID-19 vaccine era with 350+ preclinical/clinical programs using CleanCap; revenue peaked at $883M (2022), fell to $259M (2024) after COVID demand collapse

Supplies these inputs

mRNA Cap Analogs (CleanCap, co-transcriptional)

Replaceability

Substitutability 20% · 12 mo to replace

Business segments

  • CleanCap® mRNA Capping Technology52% rev
  • Modified Nucleotides (m1Ψ, pseudoUTP, 5mC-UTP)20% rev
  • Custom mRNA CDMO Manufacturing15% rev
  • Research Reagents & Diagnostic Reference Standards13% rev

San Diego-based producer of quillaja and yucca saponin extracts; operates Natural Response S.A. forestry and extraction facility in Quilpue, Chile; world's largest producer of QS-21 raw material; critical components in 5 globally approved vaccines including Shingrix (GSK) and Nuvaxovid (Novavax); Desert King is Novavax's sole quillay extract supplier

Supplies these inputs

AS01B Adjuvant System (GSK proprietary)

Replaceability

Substitutability 15% · 24 mo to replace

Business segments

  • Pharmaceutical Quillaja Extracts (QS-21)60% rev
  • Food & Beverage Quillaja25% rev
  • Yucca Saponins10% rev
  • Forestry & Sustainability5% rev

Life sciences tools company (Marlborough, MA; wholly-owned by Danaher Corporation since $21.4B acquisition of GE Healthcare Life Sciences in 2020) that manufactures Whatman membrane filter papers and sterile filtration products alongside its dominant chromatography resin (Capto, Sephadex, Sepharose series) and bioreactor (WAVE, XDR) platforms. Cytiva is the successor to GE Healthcare Life Sciences and Amersham Biosciences. Whatman-branded products include nitrocellulose and mixed cellulose ester membranes used in sterile filtration, diagnostics, and laboratory applications. Cytiva's role in sterile filtration is secondary to Merck KGaA and Pall — Whatman filters are more prevalent in laboratory/QC applications than primary pharmaceutical manufacturing sterilization — but Cytiva's ownership alongside Pall within Danaher creates the world's most concentrated supply position in biopharmaceutical manufacturing consumables. Danaher's combined Pall + Cytiva platform spans filtration, chromatography, bioreactors, and cell culture media — covering essentially every critical consumable step in a biologics manufacturing process.

Supplies these inputs

Bioprocess Chromatography Resins

Replaceability

Substitutability 10% · 36 mo to replace

Business segments

  • Protein A Chromatography Resins (World Dominant)35% rev
  • Single-Use Bioreactors + Cell Culture30% rev
  • Filtration (Whatman + Sterile)20% rev
  • Laboratory Instruments + Services15% rev
Sartorius AG (SRT)
HQ DE38% share

German life sciences company that manufactured the world's first industrial nitrocellulose membrane in 1960 in Göttingen. Its Unisart® CN series is one of the two dominant global LFA membrane brands. Key OEM supplier to virtually every major rapid test manufacturer.

Supplies these inputs

Single-Use Bioreactor Bags (Cellbag)

Business segments

  • Bioprocess Solutions (Single-Use Bioreactors & Filtration)58% rev
  • Nitrocellulose Membranes (Lateral Flow Assay)12% rev
  • Lab Products & Precision Instruments30% rev
Agenus Inc.
HQ US35% share

Lexington MA biopharma; original developer and sole US FDA-approved manufacturer of pharmaceutical-grade QS-21 adjuvant; licensed QS-21 exclusively to GSK for use in AS01-adjuvanted human vaccines including Shingrix and RTS,S malaria vaccine

Supplies these inputs

AS01B Adjuvant System (GSK proprietary)

Replaceability

Substitutability 15% · 18 mo to replace

Business segments

  • QS-21 Adjuvant Manufacturing & Licensing40% rev
  • Checkpoint Inhibitor Antibodies40% rev
  • Heat Shock Protein (HSP) Programs20% rev

Evonik Industries AG (XETRA: EVK; Essen Germany; MDAX listed); world's largest DL-methionine producer under the MetAMINO brand. Total DL-methionine capacity exceeds 700,000 MT/year across three continental hubs: Jurong Island Singapore (~340,000 MT/year — world's largest single methionine complex, expanded +40k MT August 2024), Theodore Mobile County Alabama USA (~245,000 MT/year), and Antwerp Belgium (~120,000 MT/year). The Wesseling Germany DL-Met line closed Q1 2021 as Evonik consolidated production to the three-hub network. Evonik first commercialized DL-methionine synthesis in the 1950s under predecessor Degussa. MetAMINO is Evonik's largest single product. ~30-32% global market share. In February 2022 Evonik announced a $176.5M investment in a new methyl mercaptan (MMP intermediate feedstock) plant at the Alabama site.

Supplies these inputs

Ionizable Lipids for LNP Delivery (ALC-0315 / SM-102 type)

Replaceability

Substitutability 15% · 18 mo to replace

Business segments

  • Nutrition & Care — Animal Nutrition22% rev
  • Nutrition & Care — Health Care15% rev
  • Nutrition & Care — Care Solutions10% rev
  • Smart Materials — Silica18% rev
CordenPharma
HQ CH30% share

Swiss CDMO operating European and US API manufacturing sites; primary lipid partner for Moderna; manufactures SM-102 and full LNP lipid component portfolio including ionizable, PEGylated, phosphocholine, and plant sterols; claims largest complex lipid capacity globally

Supplies these inputs

Ionizable Lipids for LNP Delivery (ALC-0315 / SM-102 type)

Replaceability

Substitutability 15% · 18 mo to replace

Business segments

  • Lipids for LNP mRNA Drug Delivery28% rev
  • Therapeutic Peptide APIs (GLP-1, Oncology)25% rev
  • Small Molecule APIs (Carbohydrate & Fatty Acid Chemistry)22% rev
  • Beta-Lactam Antibiotics & HPAPIs25% rev

Supplies these inputs

Bioprocess Chromatography Resins · Single-Use Bioreactor Bags (Cellbag)

Business segments

  • Laboratory Products and Biopharma Services34% rev
  • Life Sciences Solutions25% rev
  • Analytical Instruments16% rev
  • Specialty Diagnostics10% rev

German pharmaceutical glass specialist (FRA: 1SXP; IPO September 2023 at ~€3.6B market cap); subsidiary of SCHOTT AG, which is wholly owned by the Carl Zeiss Foundation — a non-profit foundation structure that has owned SCHOTT since 1884. SCHOTT Pharma is the world's largest manufacturer of pharmaceutical primary packaging glass, holding an estimated 35-45% of the global pharmaceutical borosilicate glass tubing market from which vials, ampoules, and syringes are drawn. Type I borosilicate glass has been SCHOTT's core product since founder Otto Schott invented borosilicate glass composition in 1884, and SCHOTT has the longest continuous manufacturing history of any pharmaceutical glass maker. Key pharmaceutical glass vial production plants in Müllheim (Germany), Jena (Germany), Schweinfurt (Germany), and multiple international sites. Supplied hundreds of millions of vials for COVID-19 vaccine programs including BioNTech/Pfizer mRNA vaccines.

Supplies these inputs

Borosilicate Glass Tubing (Type I)

Replaceability

Substitutability 25% · 24 mo to replace

Business segments

  • Pharmaceutical Glass Tubing (Type I Borosilicate)40% rev
  • Formed Packaging (Vials + Syringes + Cartridges)55% rev
  • Specialty Containers5% rev

Second-largest single-use bioreactor bag producer; ~25–30% global market share. Revenue ~€3.5B (2024). Produces Biostat STR and Ambr bioreactor systems with proprietary bag technology. Manufacturing in Goettingen (Germany) and Aubagne (France). A publicly traded subsidiary of Sartorius AG. Sartorius Stedim expanded bioreactor bag capacity significantly during COVID-19 and has been the fastest-growing supplier since. Also manufactures filtration membranes and chromatography media for the same biopharma customers.

Supplies these inputs

Single-Use Bioreactor Bags (Cellbag)

Replaceability

Substitutability 35% · 10 mo to replace

Business segments

  • Single-Use Bioprocessing (Biostat/Ambr)40% rev
  • Filtration (Sartorius)30% rev
  • Chromatography & Cell Culture20% rev
  • Lab Instruments (Sartorius AG core)10% rev

World's largest single-use bioreactor bag manufacturer; ~40–45% global market share. Spun out from GE Healthcare and acquired by Danaher Corporation in 2020 ($21.4B). Revenue ~$4B (2024). Produces WAVE Cellbag™ bioreactor bags (10 mL to 1,000 L) used in mAb, vaccine, and cell therapy production. Cytiva's Cellbag was the primary bottleneck limiting COVID-19 vaccine production speed in 2020–21. Manufacturing at Logan, UT (US), Umeå (Sweden), and Whatman, Maidstone (UK).

Supplies these inputs

Single-Use Bioreactor Bags (Cellbag)

Replaceability

Substitutability 30% · 12 mo to replace

Business segments

  • Single-Use Bioprocessing (WAVE/Xcellerex)35% rev
  • Chromatography (Resin & Systems)30% rev
  • Cell Therapy & Gene Therapy15% rev
  • Filtration & Analytical

Washington DC-based conglomerate that owns Cytiva (Whatman brand — nitrocellulose membranes, glass fiber pads), IDT (oligonucleotide probes), and Pall Corporation (filtration). Controls an extraordinary concentration of IVD supply chain chokepoints through acquisitions across multiple independent critical nodes.

Supplies these inputs

Single-Use Bioreactor Bags (Cellbag)

Business segments

  • Cytiva (GE Healthcare Life Sciences) — Bioprocess35% rev
  • Pall Corporation (Industrial & Lab Filtration)25% rev
  • IDT (Integrated DNA Technologies) — Oligonucleotides & CRISPR15% rev
  • Diagnostics (Beckman Coulter, Cepheid)25% rev

Croda International plc (Goole, East Riding of Yorkshire, UK; LSE: CRDA; ~£1.7B revenue) is a specialty chemicals company producing high-performance ingredients for consumer care, life sciences, and industrial applications. Croda's industrial chemicals division produces fatty acid derivatives and specialty esters relevant to fuel additive formulation chemistry — including dimer acid derivatives that overlap with the chemistry platform of jet fuel corrosion inhibitors. Croda's Goole, Yorkshire facility is its historic UK manufacturing base. Croda is primarily an indirect player in aviation CI chemistry — supplying raw material chemistry platforms rather than finished aviation-specification CI products — but its dimer acid and fatty acid derivative expertise is relevant to the corrosion inhibitor supply chain.

Supplies these inputs

Ionizable Lipids for LNP Delivery (ALC-0315 / SM-102 type)

Replaceability

Substitutability 15% · 18 mo to replace

Business segments

  • Consumer Care40% rev
  • Life Sciences30% rev
  • Industrial Specialties20% rev
  • Crop Care10% rev

German science company (Darmstadt; family-owned since 1668) life sciences division (MilliporeSigma in US) produces Fractogel EMD bioprocess chromatography resins alongside its Millipore filtration products and Sigma-Aldrich research chemicals. Fractogel resins (Fractogel EMD SO3-, Fractogel EMD TMAE) are an alternative to Cytiva's Capto resins for cation and anion exchange steps in biologics purification — primarily used by biomanufacturers seeking to reduce single-supplier dependence on Cytiva. Merck KGaA's same Darmstadt facility that makes sterilizing filters for pharmaceutical manufacturers (Durapore, Millipak) also produces the Fractogel resins used in the same manufacturers' upstream purification trains.

Supplies these inputs

Bioprocess Chromatography Resins

Replaceability

Substitutability 15% · 36 mo to replace

Business segments

  • Life Science (MilliporeSigma)40% rev
  • Healthcare (Branded Pharma)30% rev
  • Electronics (EMD Electronics / Versum)30% rev

German pharmaceutical packaging company (XETRA: GXI; MDAX; ~€1.8B revenue 2023); headquartered in Düsseldorf. Gerresheimer is a major pharmaceutical glass and plastic primary packaging manufacturer serving both Type I glass vials (for injectables) and plastic pharmaceutical containers. Glass manufacturing plants include Wackersdorf (Bavaria) and Tettau (Thuringia) in Germany, plus international plants in US (Vineland NJ), India, Mexico, Czech Republic. Gerresheimer is vertically integrated — operates both primary glass tubing drawing capacity and downstream vial conversion at some sites. Listed company focused primarily on high-value pharmaceutical packaging; roughly 17-20% global pharmaceutical glass vial market share.

Supplies these inputs

Borosilicate Glass Tubing (Type I)

Replaceability

Substitutability 25% · 24 mo to replace

Business segments

Major bioreactor bag producer via HyPerforma single-use bioreactor (SUB) product line. ~15% global market share. Revenue ~$43B total (2024); bioprocessing segment ~$6B. Manufactures HyPerforma bags at Logan, UT and multiple international sites. Thermo Fisher also manufactures the LLDPE/EVOH film that goes into its own bags and sells to some competitors. Acquired PAA Laboratories and Gibco brands which supply the same customers.

Supplies these inputs

Single-Use Bioreactor Bags (Cellbag)

Replaceability

Substitutability 40% · 10 mo to replace

Business segments

  • Bioprocessing (HyPerforma SUB)14% rev
  • Life Science Reagents & Chemicals (Gibco/PAA)20% rev
  • Analytical Instruments30% rev
  • Diagnostics & Healthcare20% rev

Where it's made

Facilities

19 facilities producing inputs that feed vaccines.

Agenus – Lexington GMP Facility

US

Agenus Inc. · Massachusetts

Agenus GMP manufacturing site in Lexington, MA; sole US FDA-approved manufacturer of pharmaceutical-grade QS-21; produces under exclusive license to GSK for Shingrix and malaria vaccine programs

Aldevron – Fargo GMP Campus

US

Aldevron · North Dakota

Aldevron's main US GMP campus in Fargo, ND; produces plasmid DNA, mRNA, and nucleic acid materials; as of February 2025 licensed to produce CleanCap cap analogs for mRNA clinical programs up to Phase III

CSL Seqirus Holly Springs

US

CSL Seqirus · Holly Springs, NC · cell-based flu vaccine manufacturing

World's largest cell-based influenza vaccine facility; 150M doses/year capacity; US government designated pandemic-ready; $1B federal investment. Also produces MF59 adjuvant for US market.

CordenPharma Boulder Lipids

US

CordenPharma · Boulder, CO · lipid synthesis

Primary US production site for SM-102 ionizable lipid and LNP components for Moderna. One of 2-3 global facilities capable of commercial-scale ionizable lipid synthesis.

Corning Harrodsburg Glass Fab (Kentucky)

US

Corning · Kentucky · fab

Corning Incorporated's primary display glass substrate manufacturing plant in Harrodsburg, Mercer County, Kentucky. Produces Corning Lotus NXT and Eagle XG glass substrates used as the base for virtually all LCD and OLED display panels. Corning holds approximately 60% of global display glass substrate supply; the Harrodsburg plant is Corning's largest U.S. display glass facility. Display glass must be made near-zero impurities (5 parts per billion iron), thermally stable, and ultra-flat — Corning's fusion draw process is the only method capable of meeting these specifications at scale. Without Corning's glass substrates, all major display panel fabs (BOE, AUO, Innolux, LG Display) would halt production within weeks. Source: https://www.corning.com/worldwide/en/innovation/corning-emerging-innovations/corning-lotus-nxt-glass.html

Croda / Avanti Polar Lipids – Alabaster

US

Croda International plc · Alabama

Avanti Polar Lipids acquired by Croda International in 2021; Alabaster, AL GMP manufacturing facility; produces ALC-0315 and research/commercial-grade ionizable lipids for mRNA vaccine supply chain

Cytiva Logan (Utah) Bioreactor Bag Plant

US

Cytiva (formerly GE Healthcare Life Sciences) · Logan, Utah · manufacturing

Primary Cytiva US bioreactor bag manufacturing facility. Produces WAVE Cellbag and Xcellerex single-use bags. During COVID-19 (2020–21), this facility operated 24/7 with a 12–18 month backlog for bags needed for mRNA vaccine production. The polyethylene film used here must meet USP Class VI / ISO 10993 biocompatibility standards — a small number of film suppliers qualify.

Cytiva Umeå Bioreactor Bag Plant (Sweden)

SE

Cytiva (formerly GE Healthcare Life Sciences) · Umeå, Sweden · manufacturing

Cytiva European bioreactor bag manufacturing in Sweden. Serves European biopharma customers (Novartis, Roche, AstraZeneca). Together with Logan UT, these two plants produce the majority of global Cellbag supply. Swedish facility also produces Sephadex and Sepharose chromatography resin.

Cytiva Uppsala Manufacturing & R&D

SE

Cytiva (Danaher) · Uppsala, Sweden · resin_manufacturing

Primary manufacturing site for Capto and Sephadex chromatography resins. Includes 3D printing (additive manufacturing) center for bioprocess hardware. Resins shipped globally to all major insulin and biologic manufacturers.

Evonik Hanau Pharma Lipids Site

DE

Evonik Industries AG · Hanau, Germany · lipid synthesis and formulation

Primary ionizable lipid synthesis facility for BioNTech partnership. Produces ALC-0315 type lipids and PEG-lipids for mRNA LNP formulations. One of two German production sites for pharmaceutical lipids.

GSK Vaccines – Wavre Campus

BE

GSK · Walloon Brabant

GSK's main global vaccine manufacturing campus in Wavre, Belgium; produces Shingrix (herpes zoster) and other adjuvanted vaccines including AS01B formulation; one of the world's largest vaccine production facilities

Gerresheimer Wackersdorf Glass Plant

DE

Gerresheimer AG · Wackersdorf, Bavaria · glass_vials

Key German vial and ampoule production facility. Part of Gerresheimer's 15+ global manufacturing sites for pharmaceutical glass.

Jena Bioscience – Jena Facility

DE

Jena Bioscience · Thuringia

Jena Bioscience GMP-grade nucleotide manufacturing site; produces ARCA cap analogs, CleanCap alternatives, and modified NTPs for pharmaceutical mRNA programs; supplies European mRNA manufacturers

NOF Corporation – Kawasaki Plant

JP

NOF Corporation · Kanagawa

Primary NOF manufacturing site for specialty lipids including PEGylated lipids and COATSOME SA ionizable lipid series for LNP delivery systems

Natural Response S.A. – Quilpue

CL

Desert King International · Valparaiso

Desert King's Chilean extraction and forestry operation (branded Natural Response S.A.); located in Quilpue, Valparaiso Region; extracts quillaja saponins from Q. saponaria bark; integrated supply chain from forest management to purified QS-21 intermediate; also runs Casablanca plantation as Novavax's sole supplier

Sartorius Goettingen Bioprocessing Plant

DE

Sartorius Stedim Biotech · Goettingen, Lower Saxony · manufacturing

Sartorius Stedim primary manufacturing hub. Produces bioreactor bags, filtration membranes, and fermenters. Goettingen is Sartorius's global R&D and manufacturing center. Expanded significantly during COVID-19 with new production lines. Also manufactures balance weighing equipment at this site (the other Sartorius business unit).

Schott Pharma Mainz Headquarters & Production

DE

SCHOTT Pharma AG & Co. KGaA · Mainz, Rhineland-Palatinate · glass_tubing_and_vials

Primary R&D and production facility. Produces borosilicate glass tubing (Fiolax) and finished primary packaging.

Thermo Fisher Logan Bioprocessing Plant

US

Thermo Fisher Scientific (Bioprocessing) · Logan, Utah · manufacturing

Thermo Fisher HyPerforma bioreactor bag manufacturing. Co-located in Logan UT with Cytiva operations (different facilities). Logan, UT has emerged as a cluster for single-use bioprocessing manufacturing due to its proximity to Cache Valley water supply and established life science workforce.

TriLink BioTechnologies San Diego

US

TriLink BioTechnologies · San Diego, CA · mRNA reagent manufacturing

Primary production site for CleanCap cap analogs and mRNA synthesis reagents. Near-monopoly supply point for mRNA cap analogs used in all major approved mRNA COVID vaccines.