FORWARD-LOOKING STATEMENTS This presentation contains "forward-looking statements," which are made pursuant to the safe harbor provisions of the federal securities laws, including the Private Securities Litigation Reform

Vigil Neuroscience Ivana

FORWARD-LOOKING STATEMENTS This

presentation contains "forward-looking statements," which are made pursuant to the safe harbor provisions of the federal securities laws, including the Private Securities Litigation Reform Act of 1995. Any statements that are not

statements of historical fact may be deemed to be forward-looking statements. Such statements may contain words such as "may," "might," "will," "could," "should," "would,"

"expect," "intend," "plan," "prepare," "look," "seek," "anticipate," "believe," "estimate," "predict," "potential,"

"possible," "continue," "ongoing" or the negative of these terms, or other comparable words. These forward-looking statements include, among others, statements relating to: our plans to deliver precision-based

therapies to improve the lives of patients and their families and to target a broad range of neurodegenerative diseases; plans to discover and develop novel therapeutics to leverage microglial biology, such as VGL101 and small molecules active

against TREM2, and to enable success in ALSP in clinical development; beliefs about TREM2 agonism's importance in Alzheimer's disease; beliefs about the profiles and potential, including the commercial potential, of our pipeline and the

strength of our intellectual property position; our analyses and beliefs about data, including pathology and disease biomarkers and the signaling, engagement and potency as an agonism of TREM2 in microglia; plans and upcoming milestones, including

estimated timelines, for our pipeline program development activities and pipeline expansion opportunities; expected timing and next steps regarding data announcement, clinical trial activities and regulatory filings and approvals; expectations

regarding our ability to develop and advance our current and future product candidates and discovery programs; and the belief that we are well-positioned to execute on our mission. These forward looking statements, which are only predictions,

involve risks and uncertainties, many of which are beyond our control and are based on our current beliefs, expectations and assumptions regarding our business. As such, you should not place undue reliance on any forward-looking statements because

such risks and uncertainties could cause actual results, performance or achievement to differ materially and adversely from those anticipated or implied in the forward-looking statements. Factors that could cause actual results to differ from those

predicted in our forward-looking statements include, among others, risks and uncertainties related to product development, including delays or challenges that may arise in the development and regulatory approval of our current and future product

candidates or programs; uncertainties as to the availability and timing of results and data from preclinical and clinical studies; the timing of our ability to submit and obtain regulatory clearance for investigational new drug applications and

initiate additional clinical trials; our ability to initiate and complete our current and expected clinical trials; our ability to establish and maintain collaborations, strategic relationships and supply arrangements, or that we will not realize

the intended benefits from such relationships or arrangements; whether our cash resources will be sufficient to fund our foreseeable and unforeseeable operating expenses and capital expenditure requirements; our ability to raise additional funding

on favorable terms, or at all; the rate and degree of market acceptance and clinical utility of our product candidates; the ability and willingness of our third-party collaborators to continue research and development activities relating to our

product candidates; the accuracy of our data analyses or estimates for the potential and market for our products; our ability, and the ability of our collaborators, to protect our intellectual property and to conduct activities for the development

and commercialization of our candidates in view of third party intellectual property positions; our financial performance; our ability to retain and recruit key personnel, as well as the potential contribution of our employees and board to our

growth and success as a Company; developments and projections relating to our competitors or our industry; the effect of the COVID-19 pandemic, including mitigation efforts and economic impacts, on any of the foregoing or other aspects of our

business operations, including our preclinical studies and clinical trials; changes in general economic conditions and global instability, in particular economic conditions in the markets on which we or our suppliers operate; changes in laws and

regulations; and those risks and uncertainties identified in our filings with the Securities and Exchange Commission (SEC), including under the heading "Risk Factors" in our most-recently filed Annual Report on Form 10-K or Quarterly

Report on Form 10-Q, and such other risks and uncertainties that may be described in subsequent filings we may make with the SEC. You should not rely upon forward-looking statements as predictions of future events or performance, or as a

representation or warranty (express or implied) by us or any other person that we will achieve our objectives and plans in any specified time frame, on such specified terms, or at all. Although our management believes that the expectations reflected

in our statements are reasonable, we cannot guarantee that the future results, performance or events and circumstances described in the forward-looking statements will be achieved or occur. These forward-looking statements speak only as of the date

such statements are made. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking

statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. Certain information contained in this presentation relates to or is based on studies, publications, surveys and other data

obtained from third-party sources and the Company's own internal estimates and research. While we believe these third-party sources to be reliable as of the date of this presentation, we have not independently verified, and we make no representation

Vigil Neuroscience Vigil Neuroscience

is a clinical-stage microglia-focused therapeutics company Our purpose: to treat rare and common neurodegenerative diseases by restoring the vigilance of microglia, the brain's sentinel immune cells We are utilizing the tools of modern

Vigil's Mission: Restoring

Microglial Vigilance to Create Disease-Modifying Treatments for Neurodegenerative Diseases Discovering and developing novel therapeutics designed to leverage microglial biology breakthroughs that activate and restore microglial function

Precision-based development strategy first in rare microgliopathies with plans to advance into larger patient populations First product candidates target microglial receptor protein TREM2 Evaluating new microglial targets and indications IPO in

Vigil's Precision Medicine

Strategy to Target Broad Range of Neurodegenerative Diseases First Indication Rare Microgliopathy (ALSP) Data Driven Expansion in Other Rare Microgliopathies Pipeline Candidates for Genetically Defined Subpopulations in Common Indications Further

Expansion into Broader Populations in Common Indications Apply learnings from genetically defined subpopulations to larger indications ALSP: Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia Vigil Neuroscience, Inc.

Vigil TREM2 Agonists: Differentiated

Strategy & Multiple Modalities TREM2 mAb in Development for ALSP: VGL101 Small Molecule TREM2 Agonist in Development for Larger Indications The ONLY targeted drug candidate in development for ALSP The ONLY TREM2 small molecule agonist in

Our Pipeline Vigil Has Exclusive Rights

to All Programs Discovery Preclinical Phase 1 Alzheimer's Disease VGL101 Healthy Volunteer SAD & MAD Phase 1 Trial (interim data announced)* Healthy Volunteer IND-Enabling Studies Small Molecule TREM2 Agonist Program Phase 2 Preclinical

PoC Evaluation Other Leukodystrophies *SAD: single ascending dose; MAD: multiple ascending dose; Phase 1 completed dosing and interim analysis for certain cohorts ** Additional observational Natural History Study , ILLUMINATE, in ALSP is ongoing

VGL101 - Antibody TREM2 Agonist

regulatory authority

VGL101 - Human mAb Agonist of

TREM2 with a Compelling Profile High TREM2 selectivity; induces microglial genes with sub-nanomolar potency Preclinical proof of concept in human iPSC derived microglia Favorable safety & tolerability profile with linear, dose proportional PK in

HVs Dose dependent, robust & durable CNS target engagement in HVs Established manufacturing competency, strong IP position, and obtained ODD & FTD mAb: monoclonal antibody; iPSC: induced pluripotent stem cells; PK: pharmacokinetics; HVs:

Rationale for ALSP as Initial

Indication for VGL101 Vigil's VGL101 program is the first and only drug candidate in development in this indication with engagement of patient and scientific community Opportunity to be first to achieve human PoC with a TREM2 agonist Orphan,

under-recognized autosomal dominant disorder with prevalence feasible for clinical development and potential commercialization TREM2 agonism rescues CSF1R deficiency in vitro due to the convergence of these 2 microglial receptors on a common

signaling pathway ALSP Genetically-defined Precision Medicine Population Strategic path to PoC and BLA Translatable Therapeutic Hypothesis with in vitro evidence Favorable Competitive Environment Vigil Neuroscience, Inc. 2023. All rights

Compelling Preclinical Data for

VGL101 PoM in ALSP (A) VGL101 Rescued CSF1R Inhibition of Microglia (B) VGL101 Preserved Microglia Morphology Despite CSF1R Ligand Withdrawal Withdrawal Media No Treatment Control Media IgG Control VGL101 VGL101 Rescue via TREM2 Agonism (A)

iPSC-derived microglia grown in media treated with control (Vehicle), CSF1R inhibitor alone (PLX5622), CSF1R inhibitor plus immunoglobulin G control (PLX5622+IgG), or CSF1R inhibitor plus VGL101 (PLX5622+VGL101) were measured for microglia viability

compared to Vehicle (Microglia Viability (% of Vehicle)), ****: p<0.0001; (B) iPSC-derived microglia grown in media containing CSF1 and IL-34 (Control Media) and media depleted of CSF1 and IL-34 (Withdrawal Media) with no treatment, IgG control

and VGL101 were evaluated for microglia morphology - white arrowheads indicate rod-like morphology of pharmacologically rescued microglia. CSF1R Deficiency in ALSP A B C D E Microglia Deficit in White Matter Regions, Cerebellum, & Cortex

IBA-1 Microglia Staining ALPS white matter Control White Matter Control Grey Matter ALSP Grey Matter ALSP White Matter Kempthorne et al. Acta Neuropathologica. 2020; A: superficial white matter (WM); B: deep WM; C: cerebellar WM; D: cortical layers

Proof of target engagement and

pharmacological activity in healthy volunteers 1st antibody to report durability of TREM2 engagement in a clinical setting Summary of Interim Topline VGL101 Phase 1 Data in Healthy Volunteers* *As of October 7, 2022, and includes doses up to 40

mg/kg SAD and 20 mg/kg MAD First-in-human Phase 1 SAD/MAD trial exploring safety, tolerability, PK & PD Favorable safety & tolerability profile demonstrated Human PK linearity/predictability & long half-life supports monthly dosing

First Natural History Study in ALSP

The Illuminate Study Designed to Support Clinical Success in ALSP Ongoing first-ever natural history study of ALSP patients with CSF1R gene mutation Sample size up to 36 subjects globally Objectives: Characterize biomarkers & clinical measures

of disease progression in ALSP Possibility for contemporaneous external comparator arm Observation period: 24 months Key assessments include MRI, CSF biomarkers & clinical assessments at baseline & every 6/12 -month interval 37 yr | Female |

Greater Disease Progression for

Symptomatic vs Prodromal Participants at 6 Months 6-month volumetric MRI findings Disease Progression Greater Disease Progression Based on Greater Reductions in Brain Tissue Volume & Greater Increases in Lesion & Ventricular Volume Disease

Progression 3 -3 -6 -9 Frontal Parietal Corpus Callosum 0 % Change in Brain Tissue Volume from Baseline Brain Regions 20 10 5 0 White matter lesion Ventricle 15 % Change in Brain Tissue Volume from Baseline Brain Regions Vigil Neuroscience,

Fluid Biomarker Baseline Levels

Altered in ALSP Individuals sTREM2 sTREM2 Levels Comparable between Prodromal/Symptomatic & Healthy sCSF1R sCSF1R Levels Reduced in Prodromal/Symptomatic vs Healthy NfL NfL Levels Increased in Symptomatic Reflecting Active Neurodegeneration CSF

Serum Healthy: healthy volunteers from Vigil's VGL101 Phase 1 trial; Prodromal: participants with confirmed CSF1R mutation and MRI findings in Vigil's Natural History Study (NCT05020743); Symptomatic: subjects with CSF1R mutations and

ALSP symptoms in Vigil's Natural History Study; no. of samples for all CSF analyses: 25 (Healthy); 3 (Prodromal); 6 (Symptomatic); No. of samples for serum analysis: 67 (Healthy); 10 (Prodromal); 11 (Symptomatic); all biomarker values are in

mean + standard error of mean (SEM) CSF sTREM2 (pg/ml) Healthy Prodromal Symptomatic 4000 3000 2000 1000 0 CSF sCSF1R (pg/ml) Healthy Prodromal Symptomatic X104 12 0 8 4 16 NfL-CSF (pg/ml) Healthy Prodromal Symptomatic 8000 6000 4000 2000 0 10000

VGL101 ALSP Phase 2 Open-label

Proof-of-Concept Trial Design Screening VGL101 (12 months, IV administration) Follow up Study Population Patients with symptomatic ALSP related to CSF1R gene mutation Study Design Open-label, up to 15 patients Treatment Duration 12 months (with

opportunity for further extension), monthly IV administration Outcome Assessments Safety and tolerability of VGL101 MRI-based assessment of brain volume and white matter lesions CSF biomarkers for neurodegeneration and target engagement Clinical

U.S. adult onset leukodystrophies:

~16,500 (incidence)1 ; ~99,000 (prevalence)2 1. Incidence: ~5/100K; 2. Prevalence: ~300/1M U.S. ALSP*: ~1,000-2,000 (incidence); ~10,000 (prevalence) *~10% of all adult-onset leukodystrophies3 Potentially significant U.S. commercial opportunity

EU27+UK prevalence: ~15,0004; Japan prevalence: ~4,0004 ALSP - Significant Commercial Potential for VGL101 1. Sassi et al Neurobiol Aging 2018; 2. Ahmed et al. J Neurol Neurosurg Psych 2014; 3. Lynch et al. Neurogenetics 2015; 4. Assumes same

Small Molecule TREM2 Agonist Program

MoA & Structural Biology Depth

Understanding Large Safety Margins in Pilot Tox Studies PK Supports Daily Oral Dosing Broad IP Estate World-class R&D platform has produced lead compounds with highly favorable profile & unique MoA Comparable in vivo potency to mAbs with

superior brain penetration & oral dosing SM agonists are molecular glues that potentiate the TREM2 signaling response to natural ligands

Human microglia potency, TREM2 CV

(WT): <5 nM TREM2 KO microglia potency: >3,000 nM First-in-class pharmacology Highly potent & selective agonist profile Precision fit-for-purpose SMs retain agonist profile across key TREM2 genetic variants TREM2 Variant Highly Potent

Common Variant R47H R62H H157Y T96K Precision AD Rationale SM Agonists Demonstrated On-Target TREM2 Activation Across Common & Rare TREM2 Variants Left - Human iPSC derived microglia were cultured and

stimulated by varying nanomolar (nM) concentrations of a Vigil small molecule (SM) TREM2 agonist. To measure the impact of TREM2 activation, the half-maximal induction (EC50) of phosphorylated SYK (pSYK) was quantified by AlphaLISA and expressed as

% increase relative to DMSO negative control (Neg Ctl). Right - To determine TREM2 specificity, pSYK was quantified in wild-type vs TREM2 KO human microglia, validating on-target signaling activation. Human embryonic kidney (HEK) cells

transiently were co-transfected with DAP12 and TREM2 genetic variants (Common Variant, R47H, R62H, T96M and H157Y) and then stimulated with various concentrations of a highly-potent Vigil small molecule TREM2 agonist. To measure TREM2 activation

potency, the half-maximal concentration (EC50) for induction of phosphorylated SYK (pSYK) was quantified for each. Check marks indicate EC50 <5 nM averaged across experimental replicates. TREM2 Signaling Activation (%pSYK induction vs TREM2WT

First-in-class mechanism

Vigil's SMs act as molecular glue Sensitizing TREM2 in microglia Vigil's SMs potentiate TREM2 response to damage-associated ligands SM Agonists: Molecular Glue Potentiating TREM2 Response to Natural TREM2 Ligand Co-Stimulation

Co-Stimulation Co-Stimulation Control TREM2 Ligand Vigil SM TREM2 Activation Maximal TREM2 response profile Co-Stimulation SM TREM2 Agonist (Concentration, nM) 31 2 0.5 0 nM Decreasing concentrations of SM agonist (Right panel) Cultured human iPSC

derived microglia were co-stimulated with varying nanomolar concentrations (nM, x-axis) of a brain-extracted sulfoglycolipid TREM2 ligand, Sulfatide, in the absence (pink) or presence of varying levels of Vigil small molecule (SM) TREM2 agonist

(cyan curves). To quantify SM potentiation of TREM2 signaling, data were normalized to and expressed as the % of maximal pSYK level induced by Sulfatide stimulation in the absence of TREM2 SM agonism (0 nM set as 100%). Vigil Neuroscience,

Vigil Neuroscience, Inc.

fold-change vs control) SM Agonists Recapitulate TREM2 mAb Effects in AD Mouse Model Adult transgenic 5xFAD mice engineered to co-express human TREM2 were dosed either orally with Vigil Small Molecule TREM2 agonist or intravenously with a TREM2

agonist monoclonal antibody in the context of amyloid plaque burden. Additional mice were dosed with negative controls to determine the relative gene expression changes (Log2 fold-change) in brain associated with TREM2 activation. Subsequently,

individual gene expression responses were X-Y plotted and correlated between each modality.5xFAD Alzheimer's mouse model: APP Swedish (K670N, M671L), Florida (I716V), and London (V717I) plus PSEN1 (M146L and L286V) ~ _

Vigil Neuroscience, Inc.

target-engagement profiling post-oral dosing of SM TREM2 Agonist

Select population with microglia