1
|
Riddle MS, Louis Bourgeois A, Clifford A, Jeon S, Giersing BK, Jit M, Tufet Bayona M, Ovitt J, Hausdorff WP. Challenges and opportunities in developing a Shigella-containing combination vaccine for children in low- and middle-income countries: Report of an expert convening. Vaccine 2023; 41:2634-2644. [PMID: 36932030 DOI: 10.1016/j.vaccine.2023.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 03/17/2023]
Abstract
The gram-negative bacterium Shigella is an enteric pathogen responsible for significant morbidity and mortality due primarily to severe diarrhea and dysentery, mainly among children younger than five years of age living in low- and middle-income countries (LMICs). Long considered a priority target for vaccine development, recent scientific advances have led to a number of promising Shigella vaccine candidates now entering advanced stages of clinical testing. Yet, there is no guarantee that even a highly efficacious Shigella vaccine will be recommended, prioritized, purchased, and widely adopted-especially if it requires additional doses in the immunization schedule and/or visits within the immunization program. This uncertainty is due to a variety of factors, including continuing declines in Shigella-specific and overall diarrheal disease mortality rates, the increasing complexity and cost of infant immunization programs in LMICs, and the recent availability of other high-priority vaccines. Since combining a Shigella vaccine with an existing infant vaccine would conceivably increase its attractiveness, there is a need to systematically consider the challenges determining the public health value, clinical development, manufacturing, licensure, policy recommendations, and financing for a Shigella-containing combination vaccine. The international non-governmental health organization PATH convened an independent panel of 34 subject matter experts across academic, industry, philanthropic, and global health sectors to discuss hypothetical combinations of a notional parenteral Shigella vaccine with three existing vaccines in order to begin exploring the challenges associated with their development. The resulting insights and recommendations from this meeting contribute to PATH's broader effort to evaluate the public health value of potential Shigella vaccines. They may also help guide future combination vaccine development efforts more broadly.
Collapse
Affiliation(s)
- Mark S Riddle
- University of Nevada, Reno School of Medicine, Reno, NV 89557, USA.
| | - A Louis Bourgeois
- PATH, Center for Vaccine Innovation and Access, 455 Massachusetts Ave NW, Washington, DC 20001, USA
| | - Allison Clifford
- PATH, Center for Vaccine Innovation and Access, 455 Massachusetts Ave NW, Washington, DC 20001, USA
| | - Suhi Jeon
- EuBiologics Co., Ltd. 8F, Seongdo Building, 207, Dosan-daero, Sinsa-dong, Gangnam-gu, Seoul, Republic of Korea
| | - Birgitte K Giersing
- World Health Organization, Immunization, Vaccines and Biologicals Department, 1211 Geneva, Switzerland
| | - Mark Jit
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Marta Tufet Bayona
- Gavi, The Vaccine Alliance, Chemin du Pommier 40, 1218 Le Grand-Saconnex, Geneva, Switzerland
| | - Jared Ovitt
- University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - William P Hausdorff
- PATH, Center for Vaccine Innovation and Access, 455 Massachusetts Ave NW, Washington, DC 20001, USA; Université Libre de Bruxelles, Faculty of Medicine, Brussels, Belgium
| |
Collapse
|
2
|
From Concept to Clinical Product: A Brief History of the Novel Shigella Invaplex Vaccine’s Refinement and Evolution. Vaccines (Basel) 2022; 10:vaccines10040548. [PMID: 35455297 PMCID: PMC9025769 DOI: 10.3390/vaccines10040548] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/12/2022] [Accepted: 03/23/2022] [Indexed: 01/13/2023] Open
Abstract
The Shigella invasin complex or Invaplex vaccine is a unique subunit approach to generate a protective immune response. Invaplex is a large, macromolecular complex consisting of the major Shigella antigens: lipopolysaccharide (LPS) and the invasion plasmid antigen (Ipa) proteins B and C. Over the past several decades, the vaccine has progressed from initial observations through pre-clinical studies to cGMP manufacture and clinical evaluations. The Invaplex product maintains unique biological properties associated with the invasiveness of virulent shigellae and also presents both serotype-specific epitopes, as well as highly conserved invasin protein epitopes, to the immunized host. The vaccine product has evolved from a native product isolated from wild-type shigellae (native Invaplex) to a more defined vaccine produced from purified LPS and recombinant IpaB and IpaC (artificial Invaplex). Each successive “generation” of the vaccine is derived from earlier versions, resulting in improved immunogenicity, homogeneity and effectiveness. The current vaccine, detoxified artificial Invaplex (InvaplexAR-Detox), was developed for parenteral administration by incorporating LPS with under-acylated lipid A. InvaplexAR-Detox has demonstrated an excellent safety and immunogenicity profile in initial clinical studies and is advancing toward evaluations in the target populations of children and travelers to endemic countries.
Collapse
|