Exhibit 99.1 Sanofi Pasteur COVID-19 Vaccine Programs John W. Shiver, Ph.D., Global R&D Head, Sanofi Pasteur ISV Aug 25, 2020 mRNA presentationExhibit 99.1 Sanofi Pasteur COVID-19 Vaccine Programs John W. Shiver, Ph.D., Global R&D Head, Sanofi Pasteur ISV Aug 25, 2020 mRNA presentation

Sanofi’s Two COVID-19 Vaccine Approaches 1 2 Baculovirus mRNA recombinant vaccine Platform + (2) vaccine approach (1) Protein mRNA approach mRNA Adjuvant Antigen Formulation (1) • Licensed recombinant platform • Innovative approach • Existing large scale capacity • Significant existing investment in mRNA capacity Advantage • BARDA collaboration to be applied towards vaccine • License/Collaboration Agreement with • Collaboration with for proven AS03 adjuvant • Phase I/II study start: Sept 2020 • Phase I/II study start: November 2020 Timelines • Earliest potential approval: Jun 2021 • Existing capacity for 100-600 million doses • Capacity for 90-360 million doses by 2021 Capacity • Capacity for >1 billion doses by 2021 BARDA: Biomedical Advanced Research & Development Authority; GSK: GlaxoSmithKline ® (1) Same as that for Flublok , manufactured with this platform and licensed in the U.S. 2 (2) In collaboration with Translate BioSanofi’s Two COVID-19 Vaccine Approaches 1 2 Baculovirus mRNA recombinant vaccine Platform + (2) vaccine approach (1) Protein mRNA approach mRNA Adjuvant Antigen Formulation (1) • Licensed recombinant platform • Innovative approach • Existing large scale capacity • Significant existing investment in mRNA capacity Advantage • BARDA collaboration to be applied towards vaccine • License/Collaboration Agreement with • Collaboration with for proven AS03 adjuvant • Phase I/II study start: Sept 2020 • Phase I/II study start: November 2020 Timelines • Earliest potential approval: Jun 2021 • Existing capacity for 100-600 million doses • Capacity for 90-360 million doses by 2021 Capacity • Capacity for >1 billion doses by 2021 BARDA: Biomedical Advanced Research & Development Authority; GSK: GlaxoSmithKline ® (1) Same as that for Flublok , manufactured with this platform and licensed in the U.S. 2 (2) In collaboration with Translate Bio

mRNA Vaccine Approach to address COVID-19 Pandemic messenger RiboNucleic Acid (mRNA) + Lipid NanoParticle (LNP) mRNA vaccine approach • Deliver mRNA packaged in LNP to the human cell. • The cell’s own machinery is used to translate the mRNA in vitro LNP into protein. Transcription mRNA-LNP mRNA Formulation • Large scale manufacturing capacity (up to 500 g mRNA batch size) • Rapid manufacturing timeline • Cell-free manufacturing process • No infectious elements • No risk of integration 3 3mRNA Vaccine Approach to address COVID-19 Pandemic messenger RiboNucleic Acid (mRNA) + Lipid NanoParticle (LNP) mRNA vaccine approach • Deliver mRNA packaged in LNP to the human cell. • The cell’s own machinery is used to translate the mRNA in vitro LNP into protein. Transcription mRNA-LNP mRNA Formulation • Large scale manufacturing capacity (up to 500 g mRNA batch size) • Rapid manufacturing timeline • Cell-free manufacturing process • No infectious elements • No risk of integration 3 3

SARS-CoV-2 mRNA Sequence Design Full-length pre-fusion stabilized SARS-CoV-2 Spike Protein Structure GSAS PP S1/S2S2’ SS RBD HR1 CD TM NTD SD1 SD2 FP CH HR2 CT QTNSPRRARSVAS SRLDKVEAE 982 SS – Signal Sequence 677 689 990 NTD – N-Terminal Domain RBD – Receptor Binding Domain SD1 – Subdomain 1 SD2 – Subdomain 2 S1/S2 – S1/S2 protease cleavage site S2’ – S2’ protease cleavage site FP – Fusion Peptide HR1 – Heptad Repeat 1 CH – Central Helix Wrapp, et.al. Science. 2020 CD – Connector Domain Mar 13;367(6483):1260-1263. doi: HR2 – Heptad Repeat 2 10.1126/science.abb2507. Epub 2020 Feb 19 TM – Transmembrane Domain CT – Cytoplasmic Tail 4 4SARS-CoV-2 mRNA Sequence Design Full-length pre-fusion stabilized SARS-CoV-2 Spike Protein Structure GSAS PP S1/S2S2’ SS RBD HR1 CD TM NTD SD1 SD2 FP CH HR2 CT QTNSPRRARSVAS SRLDKVEAE 982 SS – Signal Sequence 677 689 990 NTD – N-Terminal Domain RBD – Receptor Binding Domain SD1 – Subdomain 1 SD2 – Subdomain 2 S1/S2 – S1/S2 protease cleavage site S2’ – S2’ protease cleavage site FP – Fusion Peptide HR1 – Heptad Repeat 1 CH – Central Helix Wrapp, et.al. Science. 2020 CD – Connector Domain Mar 13;367(6483):1260-1263. doi: HR2 – Heptad Repeat 2 10.1126/science.abb2507. Epub 2020 Feb 19 TM – Transmembrane Domain CT – Cytoplasmic Tail 4 4

mRNA Vaccine Technology NON-LIVE SAFETY IMMUNOGENICITY MANUFACTURING • Induces potent • In vitro transcription • RNA does not • No live pathogens humoral and cell- • No cell culture integrate into the • Sequence specificity mediated immune host genome and • Scalable to large responses • Flexible product is degraded once capacity design • Self-adjuvanting the protein is • Well characterized made 5 *severe acute respiratory syndrome coronavirus 2, (SARS-CoV-2)mRNA Vaccine Technology NON-LIVE SAFETY IMMUNOGENICITY MANUFACTURING • Induces potent • In vitro transcription • RNA does not • No live pathogens humoral and cell- • No cell culture integrate into the • Sequence specificity mediated immune host genome and • Scalable to large responses • Flexible product is degraded once capacity design • Self-adjuvanting the protein is • Well characterized made 5 *severe acute respiratory syndrome coronavirus 2, (SARS-CoV-2)

Humoral Immunogenicity of CoV2 mRNA/LNP Vaccine in Cynomolgus Monkeys Induction of Robust Binding and Neutralizing Antibody Activities SARS-CoV2 ELISA vs pre-S dTM 4 Microneutralization 10 3 10 2 10 1 10 0 10 Timepoint (d) -4 14 21 28 35 42 -4 14 21 28 35 42 -4 14 21 28 35 42 -4 14 21 28 35 42 Day Day 0 14 21 28 35 42 0 14 21 28 35 42 0 14 21 28 35 42 Conv. 15mg 45mg 135mg Sera 15mg 45mg 135mg 15mg 45mg 135mg I.M. immunizations at Day 0, 21 6 MN Titer (IC50)Humoral Immunogenicity of CoV2 mRNA/LNP Vaccine in Cynomolgus Monkeys Induction of Robust Binding and Neutralizing Antibody Activities SARS-CoV2 ELISA vs pre-S dTM 4 Microneutralization 10 3 10 2 10 1 10 0 10 Timepoint (d) -4 14 21 28 35 42 -4 14 21 28 35 42 -4 14 21 28 35 42 -4 14 21 28 35 42 Day Day 0 14 21 28 35 42 0 14 21 28 35 42 0 14 21 28 35 42 Conv. 15mg 45mg 135mg Sera 15mg 45mg 135mg 15mg 45mg 135mg I.M. immunizations at Day 0, 21 6 MN Titer (IC50)

T Cell Immunogenicity of CoV2 mRNA/LNP Vaccine in Cynomolgus Monkeys Induction of TH1 Biased T cell Response at Day 42 IFNg (TH1) IL-13 (TH2) Peptide Pool: S1 IFNg (TH1) IL-13 (TH2) Peptide Pool: S2 7T Cell Immunogenicity of CoV2 mRNA/LNP Vaccine in Cynomolgus Monkeys Induction of TH1 Biased T cell Response at Day 42 IFNg (TH1) IL-13 (TH2) Peptide Pool: S1 IFNg (TH1) IL-13 (TH2) Peptide Pool: S2 7

Summary • SP is developing 2 COVID-19 vaccine approaches that will advance to clinical testing in Sept-Nov 2020; both candidates are manufacturable at scale needed to address the global pandemic. • Two immunizations of SP’s mRNA or adjuvanted recombinant vaccines into non- human primates induce high neutralizing titers that are comparable to the upper range of those observed in infected humans; pre-clinical efficacy results are forthcoming. • SP’s mRNA and adjuvanted recombinant vaccines induce in non-human primates TH1-biased and mixed TH1/TH2 T cell responses, respectively. • Multi-lateral partnerships (funders, government and academic institutions, private industry) are critical to advance these vaccine solutions at a pandemic pace. 8Summary • SP is developing 2 COVID-19 vaccine approaches that will advance to clinical testing in Sept-Nov 2020; both candidates are manufacturable at scale needed to address the global pandemic. • Two immunizations of SP’s mRNA or adjuvanted recombinant vaccines into non- human primates induce high neutralizing titers that are comparable to the upper range of those observed in infected humans; pre-clinical efficacy results are forthcoming. • SP’s mRNA and adjuvanted recombinant vaccines induce in non-human primates TH1-biased and mixed TH1/TH2 T cell responses, respectively. • Multi-lateral partnerships (funders, government and academic institutions, private industry) are critical to advance these vaccine solutions at a pandemic pace. 8