Professor Calman A. MacLennan BA, BM BCh, MA, DPhil, FHEA, FRCP, FRCPath

Professor Calman A. MacLennan

Department of Immunology and Immunotherapy
Professor of Vaccine Immunology

Contact details

Email
c.maclennan@bham.ac.uk
Address
Department of Immunology and Immunotherapy
College of Medicine and Health
University of Birmingham
Edgbaston
Birmingham
B15 2TT

Calman is a clinician, scientist, immunologist, vaccinologist and founder with a career focused on the application of intellectual curiosity to the development of vaccines against diseases of global health significance and the silent pandemics of antimicrobial resistance. This has been achieved through investigating mechanisms of immune protection in the field and laboratory in the UK and overseas, and then taking an interdisciplinary approach to the translation of resulting insights to end-to-end vaccine development in universities, big pharma, biotechs, philanthropy and global networks, notably BactiVac, the Bacterial Vaccines Network, which he founded at the University of Birmingham and directed for its first eight years. It has involved building programmes with inclusive leadership at the interface of academia and industry; strong advocacy and public engagement for vaccines and vaccine policy; mentoring and development of future scientists at doctoral and postdoctoral levels; all combined with successful fundraising and astute management of financial resources.

Qualifications

Professor of Vaccine Immunology:

  • MA, Physiological Sciences, Keble College, University of Oxford, 2026
  • Fellowship of the Royal College of Physicians (FRCP), 2011
  • Fellowship of the Higher Education Academy (FHEA), 2009
  • Fellowship of the Royal College of Pathologists (RCPath), 2008
  • DPhil Medicine, Green College, University of Oxford, 1997
  • BM, BCh Medicine & Surgery, Green College, University of Oxford, 1992
  • BA, Physiological Sciences, Keble College, University of Oxford, 1989

Biography

Calman MacLennan DPhil, FRCP, FRCPath, is Professor of Vaccine Immunology in the Department of Immunology and Immunotherapy, College of Medicine and Health, at the University of Birmingham. His research focus is understanding mechanisms of protective immunity against infection and translating resulting insights into end-to-end vaccine development against diseases of national and global health significance, and antimicrobial resistance. 

Calman has conducted his research at the intersection of academia, industry and philanthropy, involving universities, big pharma, biotechs and global networks. As a Wellcome Fellow, he investigated immunity against invasive Salmonella disease, in Blantyre, Malawi and Kilifi, Kenya. He continued this work at the University of Birmingham as a Senior Clinical Fellow, leading to key findings on the importance of antibodies in protective immunity against invasive Salmonella disease, which paved the way for the development of new vaccines against enteric and diarrhoeal diseases. 

In 2010, he was appointed Head of Exploratory Programme at the Novartis Vaccines Institute for Global Health in Siena, Italy, where he was responsible for vaccine development programmes against Salmonella, Shigella and meningococcus, while retaining close links with the University of Birmingham and a laboratory in the Institute of Biomedical Research. He was an inventor of the licensed and WHO-prequalified typhoid conjugate vaccine, Vi-CRM197, which is marketed as TYPHIBEV by Biological E and was introduced nationally in Nepal in 2022, Malawi in 2023, and Bangladesh and Burkina Faso in 2025. 

In 2015, Calman moved to the Jenner Institute at the University of Oxford as a Jenner Investigator and Group Leader, where he established the Gonococcal Vaccine Group. There he led development of the gonorrhoea candidate vaccine, GonoVac, for ten years though to GMP manufacture. In 2017, he joined the Gates Foundation as a Senior Program Officer, responsible for global portfolios of Shigella and Salmonella vaccines. At the same time, he founded BactiVac, the global bacterial vaccine network at the University of Birmingham which he directed for the following eight years, building it to a network of over 2,000 members across 92 countries. 

More recently, Calman served as Vice President for Vaccine Clinical Research and Development at Pfizer with responsibility for Pfizer’s pneumococcal and meningococcal vaccine clinical franchises. He has established his own consulting company and serves in an advisory capacity to various organisations, including the WHO and Wellcome. He provides clinical care for patients as a Consultant in Clinical Immunology at the Oxford University Hospitals NHS Foundation Trust and is a Visiting Professor at Imperial College London.

Teaching

Teaching on undergraduate and masters courses on vaccinology and immunology.

Postgraduate supervision

Supervision of PhD students in the UK and internationally.

Other activities

  • Visiting Professor, Department of Infectious Diseases, Faculty of Medicine, Imperial College London
  • Consultant Immunologist, Oxford University Hospitals NHS Foundation Trust
  • Field Chief Editor, Frontiers in Vaccines
  • CEO and Founder, Calman MacLennan Consulting Ltd
  • Scientific Advisory Board, Iuvantium, Oxford, UK
  • Chair of Steering Committee – Wellcome-KEMRI/ PATH Shigella Control Human Infection Model

Publications

1. Revie NM, Liu J, Guo MY, Mullin AE, Excler JL, Kim JM, MacLennan CA, Walkinshaw DR. Forecasting demand and return on investment for a trivalent Salmonella vaccine for children in sub-Saharan Africa. NPJ Vaccines In press.

2. Boerth EM, Roffler B, Hancock Z, Gong J, MacLennan CA, Zhang F and Lu YJ. Development of an 8-valent Salmonella and Shigella MAPS vaccine. Front Immunol in press

3. MacLennan CA Shigella’s perfect storm. Lancet Infect Dis 2026 Jul 8:S1473-3099(26)00294-X. doi: 10.1016/S1473-3099(26)00294-X. PMID: 42419334

4. Onofrio I, MacLennan CA. Neisseria gonorrhoeae: Mechanisms of immune evasion, antimicrobial resistance, and vaccine development challenges. Front Microbiol 2026 Jun 16;17:1824540. doi: 10.3389/fmicb.2026.1824540. eCollection 2026. PMID: 42382350

5. Abuga KM, Muriuki JM, Mutua AM, Wambui KM, Mturi N, Mohammed S, Fondo JK, Mwarumba S, Ngetsa CJ, Newton C, Maitland K, Bejon P, MacLennan CA, Nairz M, Scott JAG, Williams TN, Atkinson SH. Severe anaemia and invasive bacterial infections in Kenyan children: A 26-year hospital surveillance observational study. Lancet Global Health 2027 May 12:103976. doi: 10.1016/j.langlo.2026.103976. Online ahead of print. PMID: 42379203

6. Onofrio I, Pagliari S, Francis A, Quinn ME, Belcher T, Dissanayake S, Twumasi C, Vichos I, Grudzien LA, Rollier C, MacLennan CA. Preclinical characterization of immune responses induced by a candidate gonococcal native outer membrane vesicle vaccine. mSphere 2026 Jun 22:e0017426. doi: 10.1128/msphere.00174-26. Online ahead of print. PMID: 42363875

7. Freixeiro P, Lewis LA, Sanchez-Buso L, Unemo M, Gulati S, Linder A, Corander J, Harrison OB, Dold C, Rollier CS, Ram S, MacLennan CA. Pre-clinical efficacy of a candidate Outer Membrane Vesicle gonococcal vaccine in comparison with 4CMenB. NPJ Vaccines 2026 Jun 8. doi: 10.1038/s41541-026-01491-z. Online ahead of print. PMID: 42259835

8. MacLennan CA, Hasso-Agopsowicz M, Abuga KM, Adegbola RA, Anderson AS, Borriello P, Buurman E, Carey ME, Chibuye M, Colquhoun DJ, Cooney R, Descamps F, Dougan G, Kaslow DC, Komo TW, Hatchett R, Hausdorff WP, La Ragione R, Larocque R, Laxminarayan R, McDonnell A, O'Brien K, Oliveira LMA, Qamar FN, Rappuoli R, Tufet M, Westwood E, Yugueros-Marcos J, Davies SC. Vaccines and antimicrobial resistance: from science to policy-summary and outcomes. Philos Trans R Soc Lond B Biol Sci 2026 Feb 19;381(1944):20250012. doi: 10.1098/rstb.2025.0012. PMID: 41710960

9. Al-Hakim A, Trikha R, Phyu Htut EE, Chowdhury O, MacLennan CA, Chee A, Kaul A, Poulter JA, Cargo C, Wason JMS, Ahmed S, Basu TN, Gogoi S, Galloway J, Jolles S, Mistry A, Payne EM, Tattersall RS, Youngstein T, Lachmann HJ, Kulasekararaj A, Savic S. Treatment outcomes in patients with VEXAS syndrome: a retrospective cohort study. Lancet Rheumatol 2025 Jul;7(7):e472-e484. doi: 10.1016/S2665-9913(25)00034-7. Epub 2025 May 21. PMID: 40412417

10. MacLennan CA, Cunningham AF, Dean JE, Pope S, Balandyte-Shergill E, Pillaye J, Greenwood BM, Adegbola RA; BactiVac Network Group of Authors. BactiVac, the Bacterial Vaccines Network. Vaccine 2025 May 31;57:127210. doi: 10.1016/j.vaccine.2025.127210. Epub 2025 May 10. PMID: 40349456

11. Faustini SE, Hodson J, Birtwistle J, Whitelegg A, Masuka S, Singo M, Chigiga J, Shields A, Plant T, Drayson MT, Manavi K*, MacLennan CA*, Richter AG*. Comparison of short- and long-term humoral immune responses to pneumococcal polysaccharide and glycoconjugate vaccines in an HIV-infected population. J Infect 2024 Nov;89(5):106282. doi: 10.1016/j.jinf.2024.106282. Epub 2024 Sep 24

12. Giersing BK, Isbrucker R, Kaslow DC, Cavaleri M, Baylor N, Maiga D, Pavlinac P, Riddle M, Kang G, MacLennan CA. Clinical and regulatory development strategies for Shigella vaccines intended for uptake and impact in infants and young children, living in low- and middle-income countries. Lancet Glob Health 2023 Nov;11(11):e1819-e1826. doi: 10.1016/S2214-109X(23)00421-7. PMID: 37858591

13. Belcher T, Rollier CS, Dold C, Ross JDC, MacLennan CA. Immune responses to Neisseria gonorrhoeae and implications for vaccine development. Front Immunol 2023 Aug 17;14:1248613. doi: 10.3389/fimmu.2023.1248613. eCollection 2023. PMID: 37662926

14. MacLennan CA, Stanaway J, Grow S, Vannice S, Steele AD. Salmonella combination vaccines - moving beyond typhoid. Open Forum Infectious Diseases 2023 Jun 2;10(Suppl 1):S58-S66. doi: 10.1093/ofid/ofad041. eCollection 2023 May.

15. Micoli F, Stefanetti G and MacLennan CA. Exploring the variables influencing the immune response of traditional and innovative glycoconjugate vaccines. Front Mol Biosci 2023 May 16;10:1201693. doi: 10.3389/fmolb.2023.1201693. eCollection 2023. PMID: 37261327

16. Stefanetti G, MacLennan CA, Micoli F. Impact and control of sugar size in glycoconjugate vaccines. Molecules 2022 Sep 29;27(19):6432. doi: 10.3390/molecules27196432. PMID: 36234967

17. Cohen D, Ashkenazi S, Schneerson R, Farzam N, Bialik A, Meron-Sudai S, Asato V, Goren S, Baran TZ, Muhsen K, Gilbert OB, MacLennan CA. Threshold levels of serum IgG to Shigella lipopolysaccharide can predict degrees of vaccine efficacy in field trials and serve as immunological substitute endpoint for protection against shigellosis. Clin Microbiol Infect 2023 Mar;29(3):366-371. doi: 10.1016/j.cmi.2022.10.011. Epub 2022 Oct 13. PMID: 36243351

18. MacLennan CA, Talaat KR, Kaminski RW, Cohen D, Riddle MS, Giersing BK. Critical needs in advancing Shigella vaccines for global health. J Infect Dis 2022 May 4;225(9):1500-1503. doi: 10.1093/infdis/jiab462. PMID: 34558631

19. Micoli F, MacLennan CA. Outer membrane vesicle vaccines. Semin Immunol 2020;50:101433. doi: 10.1016/j.smim.2020.101433. Epub 2020 Dec 9

20. Micoli F, Bjarnarson SP, Arcuri M, Pind AAA, Magnusdottir GJ, Necchi F, Di Benedetto R, Carducci M, Schiavo F, Giannelli C, Pisoni I, Martin LB, Del Giudice G, MacLennan CA, Rappuoli R, Jonsdottir I, Saul A. Short Vi-polysaccharide abrogates T-independent immune response and hyporesponsiveness elicited by long Vi-CRM197 conjugate vaccine. Proc Natl Acad Sci USA 2020 Sep 29;117(39):24443-24449. doi: 10.1073/pnas.2005857117. Epub 2020 Sep 8. PMID: 32900928