Exhibit 99.1 Press Release Novavax Reports First Quarter 2024 Financial Results and Operational Highlights · Announces co-exclusive licensing agreement with Sanofi to co-commercialize COVID-19 vaccine, develop novel COVID-19- Influenza combination vaccines and develop multiple new vaccines utilizing Novavax’s Matrix-M adjuvant · This agreement represents a potential multi-billion dollar revenue opportunity for Novavax including: o $500 million upfront payment o Approximately$70 million equity investment in ...