Corporate Presentation

developing The Pill that Moves the Needle Investor Presentation – September 2021 Forward-Looking Statement

This presentation contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, included in this press release regarding Vaxart’s strategy, prospects, plans and objectives, results from preclinical and clinical trials, commercialization agreements and licenses, beliefs and expectations of management are forward-looking statements. These forward-looking statements may be accompanied by such words as “should,” “believe,” “could,” “potential,” “will,” “expected,” “plan” and other words and terms of similar meaning. Examples of such statements include, but are not limited to, statements relating to Vaxart’s ability to develop (including enrolling a sufficient number of subjects and manufacturing sufficient quantities of its product candidates) and commercialize its COVID-19 vaccine candidate and preclinical or clinical results and trial data (including plans with respect to the COVID-19 vaccine product candidates); expectations regarding the timing and nature of future announcements including, those related to clinical trials and results of preclinical studies; Vaxart’s expectations with respect to the important advantages it believes its oral vaccine platform can offer over injectable alternatives, particularly for coronaviruses; the potential applicability of results seen in our preclinical trials to those that may be seen in human studies or clinical trials; the expected role of mucosal immunity in blocking transmission of COVID-19; and Vaxart’s expectations with respect to the effectiveness of its products or product candidates, including Vaxart’s potential role in mitigating the impact of COVID-19 globally. Vaxart may not actually achieve the plans, carry out the intentions or meet the expectations or projections disclosed in the forward-looking statements and you should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions, expectations and projections disclosed in the forward-looking statements. Various important factors could cause actual results or events to differ materially from the forward-looking statements that Vaxart makes, including uncertainties inherent in research and development, including the ability to meet anticipated clinical endpoints, commencement and/or completion dates for clinical trials or preclinical studies, regulatory submission dates, regulatory approval dates and/or launch dates, as well as the possibility of unfavorable new clinical data and further analyses of existing clinical data; the risk that clinical trial and preclinical study data are subject to differing interpretations and assessments by regulatory authorities; whether regulatory authorities will be satisfied with the design of and results from the clinical studies; decisions by regulatory authorities impacting labeling, manufacturing processes, and safety that could affect the availability or commercial potential of any product candidate, including the possibility that Vaxart’s product candidates may not be approved by the FDA or non-U.S. regulatory authorities; that, even if approved by the FDA or non-U.S. regulatory authorities, Vaxart’s product candidates may not achieve broad market acceptance; that a Vaxart collaborator may not attain development and commercial milestones; that Vaxart or its partners may experience manufacturing issues and delays due to events within, or outside of, Vaxart’s or its partners’ control, including the recent outbreak of COVID-19; difficulties in production, particularly in scaling up initial production, including difficulties with production costs and yields, quality control, including stability of the product candidate and quality assurance testing, shortages of qualified personnel or key raw materials, and compliance with strictly enforced federal, state, and foreign regulations; that Vaxart may not be able to obtain, maintain and enforce necessary patent and other intellectual property protection; that Vaxart’s capital resources may be inadequate; Vaxart’s ability to obtain sufficient capital to fund its operations on terms acceptable to Vaxart, if at all; the impact of government healthcare proposals and policies; competitive factors; and other risks described in the “Risk Factors” sections of Vaxart’s Quarterly and Annual Reports filed with the SEC. Vaxart does not assume any obligation to update any forward-looking statements, except as required by law.

2 Key Investment Highlights

Disruptive, Clinically Validated, Oral Vaccine Platform Potential to transform the vaccine ecosystem Completed 13 clinical trials against 7 different viruses Oral, room-temperature stable COVID-19 program May offer the most practical global solution to pandemic Oral convenience, potential superior efficacy due to mucosal immunity, ease of distribution – room temp. stable Potential to mitigate vaccine hesitancy

Pipeline focused on several very large opportunities besides COVID-19 Norovirus, HPV, influenza & RSV

Resources to aggressively continue clinical advancement and commercialization Cash: $199M (as of June 30th 2021)

3 • Overview of Vaxart’s Oral Vaccine Platform

• COVID-19 program

• Norovirus program

• Pipeline and management

4 Developing a Groundbreaking Solution: Oral Tablet COVID-19 Vaccine

Vaccine as a pill +

Convenient mode of administration, rapid and painless: no needles, self administration (no appointments, no lines, social distancing)

Potentially more protective than injectable vaccines: activates mucosal immunity – the first line of defense, plus multiple immune system mechanisms

Ease of distribution and storage, globally: room temperature stable tablet – no cold chain, no needles or devices, no waste

Vaxart’s COVID-19 vaccine is the only oral vaccine with clinical data including T-cell and mucosal responses

5 Our poll demonstrates that a coronavirus vaccine pill could lead to over 18 million more Americans getting vaccinated than currently plan to do so

32% Would be likely to get the vaccine if offered in pill form 23% Of Americans don’t Among those plan on getting who don’t plan to get vaccinated vaccinated for COVID

A pill option could mean: 18.7 million more Americans Vaccinated

6 Americans strongly prefer to get vaccinated without a needle injection, at home, and on their schedule

Of US adults 18+ 7 in 10

Prefer taking a pill Prefer a taking Prefer taking a on their schedule pill at home over pill over an to making an getting a shot injection appointment elsewhere

7 Oral tablet COVID-19 vaccine has several important advantages versus current injectable options

• For society ✓ Can mitigate vaccine hesitance ✓ Can mass vaccinate in days not months ✓ Virtually no environmental footprint: no needles, no syringes, no bandages

• For governments ✓ No need for cold chain ✓ No need for vaccination centers ✓ No need for medical personnel to administer

• For individuals ✓ No needles, no pain ✓ No need to set up appointment, drive to/from vaccination site, wait ✓ Potentially better tolerated

* Based on target product profile Proprietary Oral Vaccine Platform : VAAST TM Intestinal Delivery + Targeted Immune Activation

ANTIGEN COVID-19 (Disease- Norovirus Room-temperature (25⁰C) stable Specific) Influenza enteric-coated tablets Ad5 TLR3 DELIVERY ADJUVANT VEHICLE

(“Vector-Based” (Immune Backbone) Stimulator)

VAASTTM: Vector-Adjuvant-Antigen Standardized Technology

Manufacturing Adjuvant & Antigen are Co-expressed: Patents with Broad Composition of Standardized Potential Safety, Efficacy Benefits Matter and Method Claims

9 Vaxart’s oral vaccine platform designed to activate the mucosal immune system: 1st line of defense against airborne viruses such as COVID-19 and flu

Protection against Airborne Viruses: Oral vaccine activates immunity in the right places

Vaxart’s oral vaccine triggers a broad immune response, activating systemic and mucosal immunity:

✤ Nose

✤ Lungs

✤ Intestine

✤ Mouth Injectable vaccines only activate systemic immunity

10 Efficacy against airborne viruses: Vaxart’s oral flu vaccine protected against illness as well as the leading injectable flu vaccine

Phase II clinical trial comparing Vaxart’s oral tablet flu vaccine and Sanofi’s Fluzone injectable flu vaccine Protection Against Illness

• Trial Funded by the U.S. Reduction in Illness Rate Biomedical Advanced Research and Development Authority -27% (BARDA) -39%

• Results published in January 2020 48% 35% 29% • Compared to those unvaccinated, illness rates were 39% lower in those taking Vaxart’s oral vaccine, and 27% lower in those vaccinated Vaxart Oral Fluzone Placebo with Fluzone Vaccine Liebowitz, et al, Lancet ID, 2020

11 Oral vaccines have the potential for sterilizing immunity against airborne pathogens such as COVID-19 and flu – preventing infection altogether

By triggering a strong Protection Against Infection mucosal immunity, Reduction in Infection Rate Vaxart’s oral vaccine has the potential to prevent infection altogether -48% -38%

71% BARDA-funded phase II clinical 44% 37% trial comparing Vaxart’s oral tablet flu vaccine and Sanofi’s Fluzone injectable flu vaccine. P = 0.001 P = 0.009 Vaxart Oral Fluzone Placebo Vaccine Liebowitz, et al, Lancet ID, 2020 Defined by % of subjects shedding 36 hours post challenge to remove pass-through virus 12 Correlate of protection for oral vaccine very different than for injectable

Vaxart’s oral vaccine generated less than one BARDA’s Random Forest Analysis: IgA ASC most important immunological feature for protection against shedding for the oral vaccine, while HAI most tenth the serum neutralizing antibodies of the important feature for protectionF againsteaFte sheddinguarteu Ir forme the pIm oinjectablerptoarn tvaccinecaence injectable, yet it protected as well ( Ra( nRdaonmdo Fmo rFeosrte )st ) Feature ImFeaptuore rImtpaorntanccee ( Random( RFFanoedaormteu Frsoert eIs mt) )portance VaxaVratxart ( Random ForeFsltu )zoFlnuezone Vaxart VaxarVaxartt FluzoFlnuzoene Fluzone

● IgA IgA ● ● HAI HAI ● IgA ● IgA VaHAIxart ● HAI Flu● zone●

IgG ● IgG ● IgG IgG ● ● IgG IgG ● ● IgG IgG ● ● IgA ● HAI ● ‘IFN gamma‘ ● ‘IFN gamma‘ ● IgA IgA ● ●

● HAI ● ‘IFN gamma‘ ‘IFN gamma‘IgGHAI ● ● ● MN● MN ● IgG ● IgA IgA ● ●

‘Granzyme B‘ ● ‘Granzyme B‘ ‘Dual● Expression‘ ●‘Dual Expression‘ ● ‘IFN gamma‘ ● IgA ● HAI HAI ● ● MN MN ● ●

‘Dual Expression‘ ● ‘Dual Expression‘ ● ‘IFN gamma‘ ● ‘IFN gamma‘ ●

HAI ● MN ●

MN MN ‘Granzyme B‘ ‘Granzyme B‘ ‘Granzyme B‘ ‘Granzyme B‘ ● ● ‘Dual Expression‘‘Dual Expression‘ ● ●

● 0 20 40 60 80 100 ‘Granzyme B‘ 0 20 40 60 80 0 100 20 0 40‘Dual Expression‘20 40 60 60 ● 80 80 100 100 Importance Importance ImportanceImportance

Liebowitz, et al, Lancet ID, 2020 ● ‘Dual Expression‘‘Dual Expression‘ ● ‘IFN gamma‘ ‘IFN gamma‘ ● ● These results indicate‘Dual Expression‘a clear● dThiefsfe eresrueltsn indciceate ian cle tarh dieffe reinmce ipn‘IFN toh gamma‘er imtpaorntacncee● o fo f the measured immune correlathtee msea sbureedt imwmuenee cnorr etlahtese be twweeno th ev tawoc vcacicinnees s

MN MN ‘Granzyme B‘ MN ‘Granzyme‘Granzyme B‘ B‘

0 20 40 60 80 100 0 20 40 60 80 100 0 200 2040 4060 6080 10080 100 0 200 2040 4060 6080 10080 100 Importance Importance Importance Importance Importance Importance These results indicate a clear difference in the importance of ThestehT erh emesesuaelst urser eisndud ilmticsma itunend eai cc acoltrereea lara tdcelsief bfaeertr wedenifecfnee rt ihenen ttcwheeo i nvima tchcpienoe ristmanpcoert oafn ce of the mtehaes umreads iumremdu inmem cournree lcaotrerse blaettews ebeentw theee ntw thoe v tawccoi nveasccines 13 Safety Profile and Tolerability Comparable to Placebo in Influenza

Long-term safety & Flu challenge study tolerability: Any symptoms (solicited) Pain at injection site Tenderness at injection site

Placebo 42% 2.8% 2.8% 497 subjects vaccinated (n=36) Oral tablet vaccine (n=72) 29% 2.9% 4.3%* 13 clinical trials Fluzone 36% 13.9% 26.4% (n=72) 7 different viruses Pain: a key reason for which people don’t like needles

* Placebo injection given to those receiving the oral vaccine Source: Liebowitz et al., Lancet Infectious Diseases, Jan 2020

Leading injectable COVID-19 vaccine candidates have adverse events so severe, they are administered along with Advil

14 • Overview of Vaxart’s Oral Vaccine Platform

• COVID-19 program

• Norovirus program

• Pipeline and management

15 COVID-19 Vaccine Development and Distribution Efforts are Being Outpaced by Rapidly Emergent Strains

South African Rapid Emergence of strain new SARS-CoV-2 strains

- New mutations are starting to accumulate in the S1/RBD domain, where neutralizing antibodies generated by current vaccines bind

Vaccine Distribution & Development Administration ?

Current vaccine strain Future SARS-CoV-2 - We are currently chasing the virus with variants vaccines like a hamster on a wheel

16 Vaxart COVID-19 vaccine candidate contains both the S and N genes from SARS-CoV-2

• S Protein is a surface protein, good target of neutralizing antibodies • N Protein is well conserved, and a good target for T cell responses

17 Oral COVID-19 vaccine protects against a key clinical outcome, weight loss, in a hamster challenge model

105 Post Challenge Body Weights (Mean + SEM) The Syrian hamster is a very sensitive COVID-19 model

100 • Syrian hamsters have an ACE2

)

0 y

a receptor that can bind SARS-CoV-2

o i

t 95 e

n • Hamsters challenged nasally with

c r

e COVID-19 virus have similar disease p ( rAd-S-N oral as humans 90 rAd-S-N i.n. untreated • Clinical symptoms of COVID019 infection include weight loss

0 1 2 3 4 5 Day (post challenge)

18 Orally vaccinated hamsters protected against lung COVID-19 infection

Demonstrated by relative lung weights Demonstrated by qRT-PCR

Unvaccinated animals have 2x the 4-5 logs reduction in lung viral load relative lung weight of orally in hamsters that received two oral vaccinated ones vaccine doses as compared to non- vaccinated animals

Oral administration performed as well as intranasal vaccination 19 VXA-COV2-101 Phase 1 Study Design and Schema

• Single Dose, Oral Tablet Study at Low and Medium Doses

• Small Sentinel Cohort that was boosted

• Primary (Safety) and Secondary (Immunogenicity) Endpoints Met

Treatment Group Vaccine Dose No. of Doses No. of Subjects

Cohort 1 (Sentinels) VXA-CoV2-1 1x1010 I.U. 2 5

SMC Review of Safety Data through Day 8 Visit Cohort 2 VXA-CoV2-1 1x1010 I.U. 1 15 Cohort 3 VXA-CoV2-1 5x1010 I.U. 1 15 Total 35

20 Solicited Symptoms Post Vaccination

Solicited Symptom Low Dose High Dose Days (1 – 8) (n=20) (n=15) No. (%) with Solicited Symptoms 4 (20) 10 (66.7) Gastrointestinal Symptoms Diarrhea 0 (00) 4 (26.7) Nausea 0 (00) 5 (33.3) Vomiting 0 (00) 0 Abdominal Pain 1 (5.0) 2 (13.3) General Symptoms Malaise/Fatigue 2 (10) 2 (13.3) Myalgia (Muscle Pain) 1 (5.0) 1 (6.7) Anorexia 0 (00) 2 (13.3) Headache 3 (15) 2 (13.3) Fever 0 (00) 1 (6.7)

• Most Solicited Adverse Events mild and transient; few moderates @ Days 2 to 6 • 6 Mild unsolicited AEs: sore throat, epistaxis, chills, dry sinus, back pain & testicular pain • No SAEs or MAAEs reported to date

21 Vaxart’s Oral Vaccine generates robust CD8 T cell responses, highest T cell responses ever seen with platform

High numbers of S specific IFN-g, and TNFa producing T cells generated post immunization to SARS-CoV2-S protein

Potent T-cell responses alone may offer multi-variant protection against severe COVID-19 illness

IFN-g 30 10 P=0.0034** 20

8 10

c c

o 5

o h

h 6

y m

l 4

8 +

4 D

8 3

% C 2 % 2

1 0 0 d1 d8 IFNg TNFa CD107a Trial day Cytokine

22 Future Proof: Vaxart’s oral vaccine candidate generates cross reactive T cells to other endemic coronaviruses

23 Vaxart’s Oral Vaccine candidate generates robust CD8 T cell responses – Compares favorably to the mRNA vaccines

Induction of T cells responses measured 7 days after the first dose. Increase over day 1 for IFN-g and TNFa are shown

5 5

s s

4 e 4

p m

m 3 3

a g

2 F 2 N

N Frozen PBMC samples from Vaxart’s Phase I

trial were compared to PBMCs from

% % volunteers that were immunized with the 1 1 Pfizer or Moderna vaccines under EUA. Analysis was done at the same time points post immunization 0 0 r t r t e a r e a r z rn a z rn a fi e x fi e x P d a P d a o V o V M M Preliminary data Vaxart immunized subjects have increased cross-reactive nasal IgA response to other coronaviruses

40 20 Increased IgA antibodies to SARS-Cov-2 also led to 10 increased antibody responses to the S protein of other coronaviruses including SARS-CoV-1, MERS, 8

e and endemic common cold viruses

l o F 6

S N D S S S S S S -2 -2 B -1 V 3 1 3 E V V R V o 6 U 4 9 o 2 o C L K C 2 o - N O 2 C C V C S H S S o S R R R C R E A A S A M S S R S Preliminary Data A S Graph shows increase in nasal IgA at d29 over d1 sample, normalized for amounts of totalAntigen IgA 25 Mucosal Response – First line of defense for airborne viruses

Vaccine-induced plasmablasts preferentially express IgA and upregulate the Mucosal Homing Receptor a4훃7, particularly at higher dose

Before vaccination

a l

* IgA )

b (p=0.0261) e

a 10

a s

l 5

CD2 7

r 7

e 2

+ e

A 1

I n

CD38 b7

f a

o 0.5

c y

After vaccination

o e

f 0.2 (

u ) ) q e e IgA

e s s

r o o d d F w h lo ig ( (h 8 8 CD27 y y a a d d

CD38 b7

26 Increase in CD8 T cell responses on day 8 after vaccination

CD8 T cells measured by intracellular cytokine staining post stimulation of PBMCs with the S – protein Peptide library

4.9% 9.8%

IFNg IFNg

CD8 CD8

Day 1 Day 8

(pre-vaccination) (post-vaccination)

27 Summary of Phase I results

• Well-tolerated, no serious adverse events

• Highly immunogenic on eliciting T cells, to both S and N

• T-cell responses to the S appear much higher than those of injectable mRNA vaccines

• Dose dependent responses observed with B cells

• IgA to SARS-COV-2 induced in serum, nasal, and saliva

• T cell and IgA cross-reactivity to other coronaviruses, including diverse endemic corononaviruses

• May allow for future proofing against diverse variants

28 A room temperature stable oral vaccine would have significant advantages in mass COVID-19 vaccination campaigns

ORAL VACCINE INJECTABLE VACCINE

vs. Ouch!

Order Pill is Take Make Get to Wait in line Get vaccinated Get back home pill shipped pill appointment vaccination site

Higher adoption – more people vaccinated The pill = ✤ Convenient, painless, self-administered more people ✤ Facilitates social distancing during a pandemic vaccinated faster ✤ Appealing to those who dislike injections & needles Fastest way to conduct mass vaccination campaigns

✤ 6+ months with injectables vs. 2-3 days with a pill

Less taxing on healthcare system & local resources

✤ No medical personnel required to administer

✤ No vaccination centers needed

29 • Overview of Vaxart’s Oral Vaccine Platform

• COVID-19 program

• Norovirus program

• Pipeline and management

30 Norovirus: serious disease, most acutely felt by parents of small children

Norovirus in the US causes ~20M illness per year Estimated Lifetime Risk of Norovirus

• Annually 15% children under age 5 catch Norovirus 19-21 Million • 3 M sets of parents need to take time from work (2.2 Total Norovirus Illnesses days) to care for these children 5x 1.7-1.9 Million • Annually ~7.5% of Age 65+ get sick, most Outpatient Visits hospitalizations in this group 1 in 2 400,000 • Economic burden of disease concentrated in these two Emergency Department Visits groups 1 in 9 56,000-70,000 Hospitalizations Source: Incidence of Norovirus and Other Viral Pathogens That Cause Acute Gastroenteritis (AGE) among 1 in 50 - 70 Kaiser Permanente Member Populations in the United States, 2012–2013, Grytdal et al, PLOS 1, 2016 1 in 570-800 5,000 - Deaths 7,000

Source: CDC website (https://www.cdc.gov/norovirus/php/illness- outbreaks.html

31 US Commercial Opportunity $10B+

US Impact Norovirus $10.6 Billion ACIP to recommend 85M+ people vaccinated

Population Size (M) Payer

Pediatrics 20 VFC, Insurance

Elderly 55

First responders 2.7 CMS, Employer, Immunocompromised 7.4 Insurance Military 1.4 Norovirus Vaccine is Cost Saving Rotavirus vaccine sales $750M in US per year with 4M kids recommended • At $500 per year in children < 5 with 70% vaccine coverage • ACIP : Shared Clinical Decision Making (may not be • At $75 per year in adults 65+ with 65% vaccine reimbursed) coverage • HC workers, food industry, travel industry ~ 33M • Travelers: business & leisure ~ 55M

32 Government Policy Expected to Drive $10B+ U.S. Market Ex-US Market Opportunity $5-10B

CDC (Viral Gastroenteritis Branch) Highly Engaged with Norovirus Disease

1.HECON modeling, multiple publications for burden of disease 2.Form working group to inform Advisory Committee of Immunization Practices (ACIP) ▪ Create US Vaccine Policy ▪ Partner with Federal, State, and Professional Organizations to Implement Age 0-4 5 – 64 65+ Population US 20M 260M 55M Price Target $5005 $501 $755 Prospect of ACIP recommendation High Low High Percent vaccinated2 70%3 4% 65%4 Market potential $7.0B+ $0.5B $2.7B+

1) US Disease burden, Bartsch S et al., Vaccine 2012 30(49):7097; 2) Assumes ACIP recommendation; 3) US Rotavirus complete series vaccination rate; 4) US Influenza Vaccine Age 65+ vaccination rate; 5) Potential Clinical and Economic Value of Norovirus Vaccination in the Community Setting, , Bartsch S et al., AJPM 2021- Cost Savings Price

33 Vaxart Norovirus Vaccine Offers Important Potential Advantages

Mucosal Immunity, Oral Delivery

Development / Competitive Status • GI and GII genotypes cause majority of NV-disease • Vaxart bivalent vaccine targets prevalent strain of each genotype • Only Vaxart (oral tablet) & Takeda (injectable) are in the clinic

Mucosal Immunity May Be Important For Protection Against Norovirus • Correlates of protection from human challenge studies shown with rapid induction of mucosal IgA, serum IgA2 • Vaxart vaccine designed to activate mucosal immunity

Oral Tablet Vaccine • Convenient room temperature-stable tablets are easier to distribute and administer than injectable vaccines

1) CDC Norovirus Illness: Key Facts 2) Atmar, et al, CVI, 2015. Ramani, et al, PlosPathogens 2016

34 Clinical Experience with Norovirus Oral Vaccines

Placebo-controlled, dose-ranging, double-blinded, monovalent Norovirus Bivalent Phase 1b Study (103) (Study 101) • GI.1 and/or GII.4, placebo-controlled; 85 subjects • GI.1 vaccine, 66 healthy adult subjects • 90%+ response rate for the GII.4 vaccine at 5e10IU dose • Dose dependent immune response observed • 70%+ response rate for the GI.1 vaccine at 5e10IU dose • Good safety profile; most solicited symptoms transient and mild • Bivalent vaccine as immunogenic as either monovalent vaccine • Good safety profile – transient mild solicited symptoms on Day 1

Open Labeled Dose and Schedule Optimization, monovalent NV GI.1 Challenge Study Preparation (201.1 and 201) (Study 102) • Titration Study completed; paper published in Journal of Infectious • GI.1 vaccine, 60 healthy adult subjects Diseases • Good safety profile; most solicited symptoms transient and mild; • Ph 2 Challenge Protocol submitted to FDA and IRBs and approved • Norovirus challenge strain MTA in place with UNC • WCCT Clinical Site initiated and trained (via titration study)

35 Bivalent Results: No interference, strong antigen specific B cell induction

36 Norovirus Infection – What happens?

Analysis - Mucosal Day 0 Day 28 GMFR Fecal IgA (ng VP1/100 ug total) 45.1 1544 34.2

Analysis - Day 0 Day 7 GMFR Day GMFR Memory 14 Memory IgA 0.2 0.8 7.2 2.5 15.7 (%/5e5 PBMC)

• Ramani, et al, “Mucosal and Cellular Immune Responses to Norwalk Virus” JID 212:397, 2015 • Screened subjects so they are susceptible to infection and then removed uninfected subjects from the analysis. (Data below is from 21 infected out of 36)

37 Memory Responses on the same order of magnitude as infection

IgA Memory

s 1500

C 1000 M

B 500 P

500

6 0

1 400

/ C

S 300

A 200

g I

100

1 P

V 0 D0 D7 D28 D0 D7 D28 D0 D7 D28 Placebo Low Dose High Dose

15 fold GM increase

38 Fecal Samples show durable fecal antibody response

Increased Mucosal IgA to VP1 can be found in Fecal Samples post Immunization Fecal IgA response

10000

g I

D28

1 1000 P

V D180

i 100

s a

e 10

n I

l o F 0.1 o e e b s s e o o c a D D l w h P o ig L H Fecal IgA measured by Marcela Pasetti, Group U Maryland, Baltimore Kim, et al, JCI Insight, 2018

39 Oral Vaccination Generates an Immune Response Similar to Infection

Mucosal Homing IgA & IgG Plasmablasts B Cells Plasmablasts

7 days post- G1.1 vaccine Norovirus study Vaccination

8 days post- G1.1 infection Norovirus study Infection

40 GII.4 Vaccine is cross-reactive against circulating strain

Genotype Distribution of Norovirus Outbreaks September 1, 2018 – June 30, 2019 (n=586)

41 Vaxart Oral Norovirus Vaccine: Well-Tolerated in Clinical Studies to date

No. Subjects with Solicited Adverse Event All Doses Placebo

Subjects per group 171 35

Abdominal pain 19 (5.3%) 4 (11.4%)

Anorexia 1 (0.6%) 0

Diarrhea 35 (20.5%) 4 (11.4%)

Fever (pyrexia)/Feverish 5 (2.9%) 0

Headache 47 (27.5%) 10 (28.6%)

Myalgia (muscle pain) 6 (3.5%) 0

Malaise/Fatigue 23 (13.4%) 3 (8.6%)

Nausea 23 (13.4%) 6 (17.1%)

Vomiting 3 (1.7%) 0

42 Norovirus Clinical Development: Three Trials Expected to Start in 2021

Ph 1b Ph 1b Dose Ph 2 Bivalent Ranging in Challenge Boost Elderly No. subjects ~20 48 120 Age group 18-49 55 -75 18-49 Expected Jan-2021 Mar-2021 3Q2021 start date Time from FPI 2 months 6 months 9 months to topline data

43 • Overview of Vaxart’s Oral Vaccine Platform

• COVID-19 program

• Norovirus program

• Pipeline and management

44 Pipeline focused on large indications includes prophylactic and therapeutic oral vaccine candidates

Trials Conducted to Date or in Progress Preclinical Phase 1 Phase 2 Phase 3 Marketed PROPHYLACTIC VACCINES

COVID-19 Norovirus1 Bivalent Monovalent Seasonal Influenza2 Quadrivalent Influenza Universal3 RSV4

THERAPEUTIC VACCINES

HPV, cervical dysplasia HPV5 and/or cancer

1) Bivalent Phase 1 demonstrated IgA ASC response rates of 90 – 93% for GII.4 and 78 – 86% for GI.1 2) Monovalent H1 flu vaccine completed phase 2 Proof of Concept efficacy study. 3) Janssen collaboration with an option to negotiate an exclusive license. 4) RSV program to be partnered with new antigen partner. 5) HPV therapeutic pre-IND feedback received.

45 Management Team with Deep Experience in Vaccines

ANDREI FLOROIU, MBA Chief Executive Officer

SEAN TUCKER, PHD Founder and Chief Scientific Officer

RICHARD SCHWARTZ, PHD SVP, Technical Operations

SHAILY JAINI GARG SVP, Clinical Development and Project Management

RAJESH KAPOOR SVP, Quality

BRANT BIEHN SVP, Commercial Operations

MARGARET ECHERD, CPA MBA SVP and Principal Accounting Officer

46 Key Investment Highlights

Pipeline focused on several very large opportunities besides COVID-19 Norovirus, HPV, influenza & RSV

Resources to aggressively continue clinical advancement and commercialization Cash: $199M (as of June 30th 2021)

47 vaxart.com