Among children younger than 5 years, it is estimated that diarrhoea is responsible for about 446 000 deaths, which are geographically concentrated in sub-Saharan Africa and South Asia.  Shigella was the second-leading cause of diarrhoeal mortality in 2016 among all ages, and the leading bacterial cause of diarrhoea, accounting for approximately 212 000 deaths and about 13% of all diarrhoea- associated deaths (1).  The greatest burden is among children in low- and middle-income countries (LMICs), where it is estimated to be responsible for between 28 000 (Maternal Child Epidemiology Estimation (MCEE) estimates) and 64 000 (Institute for Health Metrics and Evaluation (IHME) estimates) deaths among children under 5 years of age (1,2). It is also an important cause of diarrhoea with or without dysentery in people older than 5 years, with an estimated 270 million episodes occurring annually among all ages.

Treatment options for shigellosis include antimicrobials. The rise of antimicrobial-resistant enteric bacteria, particularly Shigella, means that, in addition to the potential direct effects on morbidity and mortality, a Shigella vaccine might also have indirect effects on reducing the use of antibiotics and consequent emergence of antimicrobial resistance (AMR).  Considering the potential for herd immunity and protection from all-cause diarrhoea, the development of a Shigella vaccine is an important goal for public health.

Although several candidate Shigella vaccines are being evaluated at different stages of preclinical and clinical development, currently no licensed vaccines against Shigella diarrhoea are widely available.  Development of Shigella vaccines has been identified as priority by IVB’s Product Development for Vaccines Advisory Committee , and WHO Preferred Product Characteristics (PPCs) for a safe, effective and affordable vaccine to reduce mortality and morbidity due to dysentery and diarrhoea caused by Shigella in children under 5 years of age , in LMICs are being finalised and will be posted on this website in 2021.

To better inform the Full Vaccine Value Assessment for Enterotoxigenic Escherichia coli (ETEC) and Shigella vaccines, an IVB Burden of Enteric Disease working group has been established to characterize the source and assess the data inputs, modelling methodology, assumptions, and outputs of both IHME and MCEE estimates (3).  Workstreams related to mortality estimates are concluding and will be published in 2021; workstreams related to morbidity assessment and quantification will initiate in 2021.

Drug resistant Shigella has been identified as a pathogen for which there is a priority to develop antimicrobials(4). WHO is evaluating the role of vaccines against Shigella on antibiotic use, health and economic burden due to an infection with a resistant pathogen, and impact on equity and social justice.

Update April 30, 2022

References:

1) Khalil IA, Troeger C, Blacker BF, et al. Morbidity and mortality due to shigella and enterotoxigenic Escherichia coli diarrhoea: the Global Burden of Disease Study 1990–2016. The Lancet Infectious Diseases 2018; 18: 1229–40.

2) Lanata CF, Fischer-Walker CL, Olascoaga AC, Torres CX, Aryee MJ, Black RE. Global Causes of Diarrheal Disease Mortality in Children <5 Years of Age: A Systematic Review. PLoS One 2013; 8. DOI:10.1371/journal.pone.0072788.

3) Butkeviciute E, Prudden HJ, Jit M, Smith PG, Kang G, Riddle MS, Lopman BA, Pitzer VE, Lanata CF, Platts-Mills JA, Breiman RF. Global diarrhoea-associated mortality estimates and models in children: Recommendations for dataset and study selection. Vaccine. 2021 Jun 13.

4) Tacconelli E, Carrara E, Savoldi A, Harbarth S, Mendelson M, Monnet DL, Pulcini C, Kahlmeter G, Kluytmans J, Carmeli Y, Ouellette M, Outterson K, Patel J, Cavaleri M, Cox EM, Houchens CR, Grayson ML, Hansen P, Singh N, Theuretzbacher U, Magrini N; WHO Pathogens Priority List Working Group. Discovery, research, and development of new antibiotics: the WHO priority list of antibiotic-resistant bacteria and tuberculosis. Lancet Infect Dis. 2018 Mar;18(3):318-327. doi: 10.1016/S1473-3099(17)30753-3. Epub 2017 Dec 21. PMID: 29276051.

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