Mucosal and systemic immune responses to Vibrio cholerae infection and oral cholera vaccines (OCVs) in humans: a systematic review

ABSTRACT

Introduction

Cholera is an enteric disease caused by Vibrio cholerae, a water-borne pathogen, and characterized by severe diarrhea. Vaccines have been recommended for use by the WHO in resource-limited settings. Efficacies of the currently licensed cholera vaccines are not optimal in endemic settings and low in children below the age of five, a section of the population most susceptible to the disease. Development of next generation of cholera vaccines would require a detailed understanding of the required protective immune responses.

Area covered

In this review, we revisit clinical trials which are focused on the early transcriptional mucosal responses elicited during Vibrio cholerae infection and upon vaccination along with summarizing various components of the effector immune response against Vibrio cholerae.

Expert opinion

The inability of currently licensed killed/inactivated vaccines to elicit key inflammatory pathways locally may explain their restricted efficacy in endemic settings. More studies are required to understand the immunogenicity of the live attenuated cholera vaccine in these regions. Various extrinsic and intrinsic factors influence anti-cholera immunity and need to be considered to develop region-specific next generation vaccines.

KEYWORDS:

• Clinical trials
• enteric infections
• immune responses
• Oral Cholera Vaccines (OCVs)
• mucosal immunity
• systems vaccinology
• Vibrio cholerae

Article highlights

• Elucidation of natural infection and immunization-induced inductive and effector immune responses provide more insight into the required protective immune response against V. cholerae

• There is a possible activation of NLRP3/IL-23 axis at the mucosa upon cholera infection but not upon vaccination

• More investigation is needed to study how elicitation of a vibrant innate response might lead to better quality of effector mucosal responses given V. cholerae is a non-invasive pathogen.

• Several intrinsic and extrinsic factors influence immune response against cholera including age, blood group, endemicity, microbiota and co-infections

• A systems vaccinology approach is required for the design and development of next- generation of population specific anti-cholera vaccines

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/1744666X.2022.2136650

Additional information

Funding

This paper was not funded.