Novavax's COVID-19-Influenza Combination and Stand-alone Influenza Vaccine Candidates Showed Robust Immune Responses and Were Well Tolerated in Initial Cohort of a Phase 3 Trial Both vaccine candidates indu

COVID-19-Influenza Combination and Stand-alone Influenza Vaccine Candidates Showed Robust Immune Responses and Were Well Tolerated in

Initial Cohort of a Phase 3 Trial

GAITHERSBURG, Md., June 11, 2025 - Novavax, Inc. (Nasdaq:

NVAX) today announced results of the initial cohort of its COVID-19-Influenza Combination (CIC) and stand-alone trivalent hemagglutinin

nanoparticle seasonal influenza (tNIV) Phase 3 trial that showed both the CIC and flu vaccine candidates induced immune responses similar

to licensed comparators Nuvaxovid and Fluzone HD, respectively. This cohort was designed to provide descriptive data on

three flu strains (H1N1, H3N2, B) and SARS-CoV-2 (COVID-19) to inform a future registrational Phase 3 program.

"Both our combination and stand-alone flu

vaccine candidates induced robust immune responses and were well tolerated," said Ruxandra Draghia-Akli, MD, PhD, Executive Vice

President and Head of Research and Development, Novavax. "This data set adds to findings from our Phase 2 trial and will help inform

discussions with potential partners."

Both stand-alone flu and CIC vaccine candidates

induced robust immune responses to the vaccine strains (2.4-5.7-fold over baseline). Both vaccine candidates were well tolerated and

saw reactogenicity comparable to authorized comparators. Nearly all (>98%) solicited adverse events were mild or moderate in severity.

This descriptive trial was designed to evaluate the safety and immunogenicity of the CIC and stand-alone flu vaccine candidates compared to Nuvaxovid and Fluzone HD in approximately 2,000 adults aged 65 and older. This trial was not adequately powered

to demonstrate statistical significance. These results build on previous Phase 2 data.

Novavax, Inc. (Nasdaq: NVAX) tackles some of

the world's most pressing health challenges with its scientific expertise in vaccines and its proven technology platform, including protein-based

nanoparticles and its Matrix-M adjuvant. The Company's growth strategy seeks to optimize its existing partnerships and

expand access to its proven technology platform via research and development innovation, organic portfolio expansion in infectious disease

and beyond, and forging new partnerships and collaborations with other companies. Please visit novavax.com and LinkedIn

for more information.

Forward-Looking Statements

Statements herein relating to the future of Novavax,

its operating plans and prospects, its partnerships, and the potential for its CIC and stand-alone influenza vaccine to be used with

a partner in a registrational Phase 3 program, are forward-looking statements. Novavax cautions that these forward-looking statements

are subject to numerous risks and uncertainties that could cause actual results to differ materially from those expressed or implied

by such statements. These risks and uncertainties include, without limitation, challenges pursuing additional partnership opportunities;

challenges satisfying, alone or together with partners, various safety, efficacy, and product characterization requirements, including

those related to process qualification, assay validation and stability testing, necessary to satisfy applicable regulatory authorities;

challenges or delays in conducting clinical trials or studies for its product candidates; challenges or delays in obtaining regulatory

authorization for its product candidates, including for future COVID-19 variant strain changes, its CIC vaccine candidate, its stand-alone

influenza vaccine candidate or other product candidates; manufacturing, distribution or export delays or challenges; Novavax's substantial

dependence on Serum Institute of India Pvt. Ltd. and Serum Life Sciences Limited for co-formulation and filling Novavax's COVID-19 vaccine

and the impact of any delays or disruptions in their operations; difficulty obtaining scarce raw materials and supplies including for

its proprietary adjuvant; resource constraints, including human capital and manufacturing capacity; constraints on Novavax's ability

to pursue planned regulatory pathways, alone or with partners; challenges in implementing its global restructuring and cost reduction

plan; challenges in obtaining commercial adoption and market acceptance of its updated COVID-19 vaccine or any COVID-19 variant strain

containing formulation, or for its CIC vaccine candidate and stand-alone influenza vaccine candidate or other product candidates; challenges

meeting contractual requirements under agreements with multiple commercial, governmental, and other entities, including requirements

to deliver doses that may require Novavax to refund portions of upfront and other payments previously received or result in reduced future

payments pursuant to such agreements and challenges in amending or terminating such agreements; challenges related to the seasonality

of vaccinations against COVID-19; challenges related to the demand for vaccinations against COVID-19 or influenza; challenges in identifying

and successfully pursuing innovation expansion opportunities; Novavax's expectations as to expenses and cash needs may prove not to be

correct for reasons such as changes in plans or actual events being different than its assumptions; and those other risk factors identified

in the "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations"

sections of Novavax's Annual Report on Form 10-K for the year ended December 31, 2024, and subsequent Quarterly Reports on Form 10-Q,

as filed with the Securities and Exchange Commission (SEC). We caution investors not to place considerable reliance on forward-looking

statements contained in this press release. You are encouraged to read our filings with the SEC, available at www.sec.gov

and www.novavax.com, for a discussion of these and other risks and uncertainties. The forward-looking statements in this press

release speak only as of the date of this document, and we undertake no obligation to update or revise any of the statements. Our business

is subject to substantial risks and uncertainties, including those referenced above. Investors, potential investors, and others should

give careful consideration to these risks and uncertainties.