Disclaimer This presentation has been prepared by AlloVir, Inc. ("we," "us," "our," "AlloVir" or the "Company") and is made for informational purposes only and does not constitute an offer to sell or a solicitation of an

A Leader in Allogeneic, Off-the-Shelf

Virus-Specific T-Cell Immunotherapies Exhibit 99.1

Disclaimer This presentation has been

prepared by AlloVir, Inc. ("we," "us," "our," "AlloVir" or the "Company") and is made for informational purposes only and does not constitute an offer to sell or a solicitation of an offer

to buy securities. This presentation may contain "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, statements regarding the safety, efficacy and

regulatory and clinical progress of our product candidates, including Viralym-M. All such forward-looking statements are based on management's current expectations of future events and are subject to a number of risks and uncertainties that

could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. The use of words such as, but not limited to, "may," "might," "will,"

"should," "expect," "plan," "anticipate," "believe," "estimate," "project," "intend," "future," "potential," or

"continue," and other similar words or expressions are intended to identify forward-looking statements. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on our current

beliefs, expectations and assumptions regarding the future of our business, future plans and strategies, our clinical results and other future conditions. All statements other than statements of historical facts contained in this presentation,

including statements regarding future results of operations and financial position, business strategy, current and prospective product candidates ongoing, and planned clinical trials and preclinical activities, including the initiation, timing,

enrollment, progress and results of our preclinical and clinical studies and our research and development programs, product approvals, research and development costs, current and prospective collaborations, timing and likelihood of success,

including our ability to advance and successfully complete clinical studies, the timing and likelihood of success of our clinical trials, and the timing or likelihood of regulatory filings and approvals, expectations regarding market acceptance and

size, plans for launch and commercialization, plans and objectives of management for future operations, and future results of anticipated product candidates, are forward-looking statements. New risks and uncertainties may emerge from time to time,

and it is not possible to predict all risks and uncertainties. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements. These statements are also subject to a number of material

risks and uncertainties that are discussed in the section entitled "Risk Factors" in our quarterly report on Form 10-Q for the fiscal quarter ended September 30, 2020, as well as discussions of potential risks, uncertainties, and other important

factors in our subsequent filings with the Securities and Exchange Commission. Any forward-looking statement speaks only as of the date on which it was made. Neither we, nor our affiliates, advisors or representatives, undertake any obligation to

publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by law. 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 as to the adequacy, fairness, accuracy or completeness of any information obtained from third-party sources. In addition, all of the market data included in this presentation involves a number of

assumptions and limitations, and there can be no guarantee as to the accuracy or reliability of such assumptions. Finally, while we believe our own internal research is reliable, such research has not been verified by any independent source.

AlloVir: A Leading Innovator in

Allogeneic, Off-the-Shelf Virus-Specific T Cell Immunotherapies Versatile platform with >275 clinical patients dosed and positive data generated Robust development plan with 3 ongoing pivotal/POC trials and 5 additional in 2021 With 93% response

Viralym-M received RMAT & PRIME from FDA and EMA Large Global Market Opportunity for Viralym-M alone Manufacturing expertise leading to efficiencies of scale Robust IP and patent portfolio covering both products and processes Experienced &

proven developmental, clinical, manufacturing and commercial leadership team RMAT: Regenerative medicine advanced therapy; PRIME: PRIority MEdicine; POC: proof-of-concept Catalyst rich story with multiple data readouts expected each year

Leadership Team Led by an Experienced

Management Team with a Strong Operating and Scientific Foundation Ann Leen, Ph.D. Chief Scientific Officer Co-Founder AlloVir Professor, BCM CAGT David Hallal Chief Executive Officer CEO of ElevateBio Former CEO Alexion Amgen Jeroen van Beek, Ph.D.

Chief Commercial Officer Former CCO Tricida Alexion, Pfizer Agustin Melian, M.D. Chief Medical Officer Former SVP Alexion Merck Vikas Sinha, MBA President & Chief Financial Officer CFO of ElevateBio Former CFO Alexion Bayer Edward Miller, J.D.

General Counsel Former SVP Alexion Boehringer Ingelheim Ercem Atillasoy, M.D. Chief Regulatory & Safety Officer Former VP Global Regulatory Affairs & Clinical Safety, Merck Dana Alexander SVP of CMC Operations Former Head of Viral Vectors

Brammer Bio Medha Chadha SVP Strategic Planning and IR Former US Head of Equity Capital Markets Syndicate Cantor Fitzgerald

High Risk Populations with T Cell

Deficiencies are Vulnerable to Life-Threatening Viral Diseases Despite Current Treatment Options PML: Progressive multifocal leukoencephalopathy; HCC: hepatocellular carcinoma 1. Abudayyeh A, et al. Am J Transplant. 2016;16:1492-1502. 2. Camargo JF,

Komarduri KV. Hematol Oncol Stem Cell Ther. 2017;10:233-238. 3. Cesaro S, et al. Bone Marrow Transplant. 2018;doi:10.1038/s4109-018-0421-0. 4. Leen AM, et al. Blood. 2009;114(19):4283-4292. 5. Perruccio K, et al. Biol Blood Marrow Transplant.

2018;24:2649-2557. 6. Saribas AS, et al. Future Virol. 2010;5(3):313-323. doi:10.2217/fvl.10.12. 7. Cho SY, et al. Kor J Intern Med. 2018;33:256-276. 8. Law N, Kumar D. Drugs Aging. 2017;34:743-754. 9. Gentile G, Antonelli G. Viruses.

2019;11:doi:10.3390/v11111049. 10. Luppi M, et al. New Engl J Med. 2000;343:1378-1385. 11. Kedia S, et al. J Stem Cell Res Ther. 2013;doi:10.4172/2157-7633.S3-002. 12. Ison MG, Hirsch HH. Clin Microbiol Rev. 2019;32(4):1-33. 13. Jose RJ, et al.

Medicine. doi:10.1016/j.mpmed.2020.03.006. 14. Simon AK, Hollander GA, McMichael A. Proc Biol Sci. 2015;282(1821):20143085. Viruses with No / Limited Treatments Brain Seizure Severe encephalitis Memory defect PML Eyes Retinitis Blindness

Bladder Severe hemorrhagic cystitis Urinary obstruction Cystectomy Small/Large Intestine Colitis Ulceration / perforation Intestinal bleeding Liver Chronic hepatitis Liver cirrhosis HCC Malignancy Kaposi sarcoma Primary Effusion Lymphoma Kidneys

Nephritis Acute/chronic renal failure End stage renal disease Lungs Pneumonia Bronchitis Respiratory failure High-risk populations BK virus1 Cytomegalovirus2 Adenovirus3 Epstein-Barr virus4 Human Herpesvirus-65 JC Virus6 Respiratory Syncytial Virus7

Parainfluenza Virus7 Human Metapneumovirus8 Influenza Virus7 SARS-CoV-28 Hepatitis B Virus9 Human Herpesvirus-810 Uncontrolled Viral Diseases Cause End-Organ Damage and Mortality1-3,10-13 HSCT Patients11,12 SOT Patients12 Elderly14 Very Young14

Other13 (e.g. Cancer)

AlloVir Has a Deep Pipeline of 5

Allogeneic, Off-the-Shelf VST Investigational Therapies Targeting 12 Viruses POC: Proof-of-concept; Allo-HSCT: Allogeneic HSCT; Auto-HSCT: Autologous HSCT; KT: Kidney Transplant; SOT: Solid Organ Transplant; KS: Kaposi Sarcoma; MCD: Multicentric

Castleman Disease; PEL: Primary Effusion Lymphoma THERAPY CANDIDATE TARGET INDICATION TARGET POPULATION PRECLINICAL POC TRIAL (Phase 1b/2) PIVOTAL TRIAL (Phase 3) Viralym-M (ALVR105) Multi-VST Treatment of Virus-Associated Hemorrhagic Cystitis

Allo-HSCT Treatment of CMV Treatment of AdV Prevention of BKV, CMV, AdV, EBV, HHV-6 and JCV Treatment of BKV Kidney Transplant Treatment of CMV Solid Organ Transplant ALVR106 Multi-VST Treatment of RSV, Influenza, PIV, and hMPV Allo- / Auto-HSCT

High-risk General Population ALVR109 Single-VST Treatment of COVID-19 High-risk General Population ALVR107 Single-VST Treatment of HBV Patients with Chronic HBV ALVR108 Single-VST Treatment of HHV-8 Patients with KS, MCD or PEL IND Cleared Q4 2020

Key Investment Highlights VERSATILE

ENGINE for allogeneic, off-the-shelf, virus-specific T-cell immunotherapies TARGETING 12 devastating and life-threatening viruses WITH NO OR LIMITED TREATMENTS CLINICALLY VALIDATED LEAD PROGRAM, VIRALYM-M, targeting multiple indications 93% overall

response rate demonstrated in Ph 2 trials Large market opportunity in RMAT / PRIME designated indications alone 3 pivotal and 3 POC trials initiated by end of 2021 ROBUST PIPELINE with an additional 4 VSTs in various stages of development ALVR109,

for the treatment of COVID-19, expecting initial data in 2021 ALVR106, multi-respiratory VST, POC trial initiation expected in 2021 ALVR107/108, HBV/HHV8 VSTs, each targeting additional large addressable patient populations CATALYST RICH story with

2-3 data read outs expected every year EXPERIENCED MANAGEMENT TEAM

Transplant Patients and Viral

Nearly Two-Thirds of Allogeneic HSCT

Recipients Have More Than One dsDNA Viral Infection CMV: Cytomegalovirus; AdV: Adenovirus; EBV: Epstein-Barr virus; HHV6: human herpesvirus 6. Hill et al, Blood 2017. Incidence of Viral Infections BKV, CMV, AdV, EBV and HHV-6 100% 90% 80% 70% 60%

50% 40% 30% 20% 10% 0 0 10 20 30 40 50 60 70 80 90 100 Cumulative Incidence Probability Days After HSCT A 37% Increase of Non-Relapse Mortality for Every Log Increase in Viral Load from Day 1-100 in Allogeneic HSCT Patients 1 virus 2

viruses 3 viruses 4 viruses

Virus-Associated Hemorrhagic

Cystitis in HSCT: A Devastating Disease with No Approved or Effective Treatment Options HC, a common manifestation in HSCT, caused by BKV, AdV and/or CMV *Treatment related mortality 1. Cesaro S, et al. J Antimicrob Chemother. 2018;73:12-21.

2. Garguilo et al, ecancer. 2014; 8:420 doi: 10.3332/ecancer.2014.420. 3. Silva LdeP, et al. Haematologica. 2009;95(7):1183-1190. 4. Kloos RQ, et al. Biol Blood Marrow Transplant. 2013;19(8):1263-1266. 5. Type B Briefing Package. 6. Laskin BL, et

al. Clin Infect Dis. 2019. doi: 10.1093/cid/ciz1194; 7. Gilis L, et al. Bone Marrow Transplantation. 2014;49: 664-670. Severe bleeding due to hematuria Severe, prolonged and intractable pain Increased mortality* HC Results in Severe Morbidity

& Mortality1-7 No Approved or Effective Therapies1-7 RBC or platelet transfusions Bladder arteriole embolization and/or cystectomy Narcotics Life-disturbing urinary symptoms Continuous bladder irrigation Kidney dysfunction / failure Dialysis

Cytomegalovirus and Adenovirus in

HSCT: Cause Severe and Life-Threatening Consequences 1. Hill J, et al. Blood 2017; 2. Ljungman P, et al. Clin Infect Dis. 2017; 3. Marty F, et al. NEJM 2017; 4. Sedl ek P, et al. Biol Blood Marrow Transplant 2018; 5. Lion et al. Clin

Microbiol Rev 2014 6. other than for CMV retinitis CMV Affects 65% of allogeneic HSCT patients1 Potentially life-threatening consequences2 Pneumonia Colitis Retinitis Encephalitis Multi-organ failure/Death No FDA- or EMA-approved anti-viral agents6

Off-label antiviral use associated with severe toxicities, including myelosuppression and nephrotoxicity Discontinuation of letermovir increased CMV infection (~18%) >100 days post HSCT3 AdV Occurs in 32% of pediatric and 6% of adult allogeneic

HSCT patients4 Potentially life-threatening consequences5 Pneumonia Hemorrhagic enteritis or cystitis Hepatitis Multi-organ failure/Death No FDA-or EMA approved treatments Off-label antiviral use agent has demonstrated limited efficacy and severe

toxicities including nephrotoxicity

Worse Graft Survival in SOT Patients

with Persistent CMV Infection2 BKV in Kidney Transplant & CMV in SOT Patients: Lead to Decreased Graft Survival Despite Standard of Care1,2 BKVN: BKV Nephropathy 1. Vasudev B, et al. Kidney International 2005; 2. Legendre C and Pascual C. CID

2008 Worse Graft Survival in KT Patients with BKV Nephropathy1 40% 50% 60% 70% 80% 90% 100% 0 0.5 1 2 3 4 5 Patients with BKVN Patients without BKVN P < 0.001 Post-transplant years Graft Survival, % P = .020 5 4 3 2 1 0 Non-persistent or no CMV

Persistent CMV Post-transplant years Graft Survival, % 40% 50% 60% 70% 80% 90% 100%

Our Solution Allogeneic,

Off-the-Shelf Virus-Specific T-Cells

Treated with Current Care Options

Our Approach Utilizes the Adoptive Transfer of Off-the-Shelf VSTs to Restore Virus-specific Immunity1-6 1. Swain, S., et al. Nat Rev Immunol 2012.; 2. Muraro E, et al. Front. Immunol. 2017; 3. Rosendahl HS et al. Front Immunol. 2014. 4. Tzannou, JCO

2017; 5. Vasileiou S et al. Haematol 2019. 6. Type B Meeting Briefing Package. Patients with T-cell Deficiency are at High Risk for Devastating Viral Infections Deficient T-cell Immunity Fails to Control Viral Infections, Resulting in Devastating

Consequences Treated with Off-the-Shelf VSTs Restored T-cell Immunity with Expanded Off-the-Shelf VSTs Controls Viral Infections Virus-infected cells Expanded Off-the-Shelf VSTs CD8+ Off-the-Shelf VSTs CD4+ Off-the-Shelf VSTs CD4+ T cells in

patients CD8+ T cells in patients

Our Patented, Highly Efficient and

Industrialized Platform Provides Key Advantages1-5 *Patent pending | PBMCs: Peripheral Blood Mononuclear Cells 1. Tzannou I, et al. Blood Adv. 2019;3(17):2571-2580. 2. Tzannou I, et al. J Clin Oncol. 2017 Nov 1;35(31):3547-3557. 3.

Vasileiou S, et al. Haematologica. 2019 Apr. 4. Saglio et al. Cytotherapy. 2014 February; 16(2): 149-159. 5. Type B Briefing Package. Mini-Banks of Cryopreserved VSTs Step 1 VST Profiling / Antigen Selection & Donor Selection (CytokinTM*)

Step 3 CytomatchTM* and Immediate Access to Our Allogeneic VST Therapies Step 2 Rapid and Scalable Off-the-Shelf VST Manufacturing (14 2 Days in Viralym-M) Selective Expansion of VSTs Using Proprietary Process Carefully Selected Healthy

Seropositive Donors PBMCs from Donors VST Profiling & Antigen Selection + Selected Antigens CytomatchTM* to rapidly select best-fit VSTs for patients VSTs have long-term stability and are available on demand as off-the-shelf therapy Proprietary

VST profiling and antigen selection* process Immediate availability of off-the-shelf VSTs CytokinTM* ensures broad patient coverage with a targeted number of carefully screened donor pool One manufacturing run from a single donor can generate

hundreds of doses of VSTs Patented expansion process designed to prevent antigen competition and preserve polyclonality of VSTs Mini-banks ensure >95% patient coverage Patient with Viral Infection CytomatchTM* Treatment of Patient CytokinTM*

Viralym-M (ALVR105) The Potential to

Transform the Lives of Transplant Patients by Dramatically Improving or Preventing Morbidity and Mortality

Stimulation and Expansion of

Polyclonal VSTs in One-step, High-yield Process PBMCs from Donors Identified by Proprietary Process Viralym-M: Our VST Therapy Designed to Target Viral Diseases That Result in Significant Morbidity and Mortality Post Allogeneic HSCT PBMCs:

Peripheral Blood Mononuclear Cells 12 Selected Antigens for Viralym-M + PBMCs Stimulation & Expansion Antigens Selected by Proprietary Virus Profiling and Antigen Selection Process Viralym-M (ALVR105) Multi-VST targeting BKV, CMV, AdV, EBV, and

HHV-6 BKV: LT, VP1 CMV: IE1, pp65 AdV: Hexon, Penton EBV: EBNA1, LMP2, BZLF1 HHV-6: U11, U14, U90

<20% 20-40% 40-60% >60% 40-60%

<20% 20-40% Viralym-M is Designed to Treat and Prevent Viral Infections and Diseases Until the Patient's Own Immune System Recovers1-6 aPost 100 day data for proportion of patients with viral detection is from Huang, et al., as Hill et

al. only measured out to 100 days. 1. Kedia et al., J Stem Cell Res Ther 2013. 2. Ison, Hirsch. Clin Microbiol Rev. 2019. 3. Hill et al, Blood 2017. 4. Huang et al, Biol Blood Marrow Trans 2017. 5. Stern L et al. Front Immunol. 2018;9:1-18. 6. Hill

CID 2018. Level of Host T Cells Conditioning for HSCT (Lymphodepletion) Engraftment Post-Engraftment Level of HSCT-Derived T Cells Days Post HSCT HSCT 14 d 100 d 180 d 28 d Viralym-M: Restoration of T-cell Immunity Proportion of Patients with

Detection of Single or Multiple Viruses3,4,a

Phase 2 POC CHARMS Trial Design

(N=59*) Viralym-M Phase 2 Proof-of-Concept Study, CHARMS, Generated Promising Preliminary Disease Outcome and Safety Data Phase 2, proof-of-concept, open label study to assess the safety and clinical effects of Viralym-M in allogeneic HSCT

recipients with 1 treatment-refractory Infections The CHARMS trial treated 58 unique patients. One patient was counted twice: enrolled twice, treated first for AdV and then for JCV. One patient with HHV-6 was not evaluable for response rate

GVHD: graft vs host disease. 1. Tzannou, JCO 2017; 2. Tzannou I, et al. Treatment of severe, drug-refractory viral infections with allogeneic, off-the-shelf multi-virus specific T cells in patients following HSCT: results from a phase 2 study. Paper

presented at: 62nd ASH Annual Meeting and Exposition. December 5-8, 2020. Accessed January 4, 2021. https://ash.confex.com/ash/2020/webprogram/Paper143037.html Population Refractory BKV, CMV, AdV, EBV, HHV-6 and/or JCV Failure of antiviral