PREreview of Safety and immunogenicity of PanChol, a single-dose live-attenuated oral cholera vaccine: results from a phase 1a, double-blind, randomized, placebo-controlled trial

Cholera is a global public health threat, requiring oral cholera vaccines to be administered; however, these vaccines have lesser efficacy in smaller children and require several dosages for maximum efficacy. The disease is caused by ingestion of the Vibrio cholerae, which is a bacterium that attacks the small intestine and causes severe diarrhea and vomiting. The only WHO-approved vaccines are whole-cell vaccines consisting of killed Inaba and Ogawa V.cholerae, which require 2 doses for maximum efficacy and have <30% efficacy in children <5 years old (most susceptible population). PanChol is the first live-attenuated cholera vaccine with also co-expresses Inaba and Ogawa antigens, and it also over-expresses the non-toxic cholera toxin B subunit, which prevents toxigenic reversion.

Major/Minor issues

• This study was conducted at a single institution in a non-endemic setting, so the next step of this study is to investigate PanChol’s safety and immunogenicity in a cholera endemic region.

• Some of the ratings were unclear, and it was difficult to understand where the line was drawn between “mild,” “moderate,” and “severe” adverse events; additionally, some adverse events mentioned were said to be normal for ingestion of an oral cholera vaccine, so more clarification is needed.

• There are some uncertainties about the sample size, and it is deduced from the preprint that the sample size was only 28 individuals.

Pre-reviewed by Aglaia Lan and Dilsi Bhagat

Competing interests

The author declares that they have no competing interests.

Use of Artificial Intelligence (AI)

The author declares that they did not use generative AI to come up with new ideas for their review.