PaxVax's cholera vaccine can control outbreaks quickly

A single-dose cholera vaccine marketed by PaxVax, a global biotechnology company based in California, can provide faster protection in epidemics, thereby helping control big outbreaks more quickly, suggest results of a trial.

While the standard regimen for protecting against cholera with existing non-living oral cholera vaccines includes administering two doses over a two-week period, the new research showed that giving a stronger single-dose of a live oral vaccine could be an effective tool in controlling outbreaks fast.

The research, published in the journal Clinical and Vaccine Immunology, was conducted in Mali and included 150 participants.

"Immunisation with a single-dose cholera vaccine that could rapidly protect people in low-income countries who have not previously been exposed to cholera would be a significant asset in helping control outbreaks and lower mortality rates," said Myron Levine, Professor at University of Maryland School of Medicine in the US and senior author of the study.

The vaccine, named Vaxchora, is a single-dose, live-attenuated oral vaccine. It was approved in 2016 by the Food and Drug Administration (FDA) for use in US adults 18-64 years old travelling to regions where cholera is common.

The vaccine was developed by the University of Maryland School of Medicine's Centre for Vaccine Development (CVD) and licensed and manufactured by PaxVax.

In this study, the researchers assessed the effectiveness - ability to stimulate vibriocidal antibody, an immune response that correlates with protection - of the single high-dose of live cholera vaccine versus the standard two-dose killed vaccine approach.

While the two-dose inactivated vaccine approach has been used and made available for protecting against seasonal increases in cholera cases, a stronger single-dose live oral vaccine approach may be a more effective way to rapidly protect individuals in big outbreaks, the research found.

Given the encouraging results, the researchers hope that the vaccine will now be evaluated more completely in low income countries menaced by cholera.

Cholera transmission is endemic in many areas of Africa, Asia and the Caribbean. In severe cases, patients pass large amounts of diarrhoea that causes rapid dehydration and ultimately death if left untreated.

This year, the World Health Organisation estimated that in Yemen alone there have been a million cases of cholera.

The Gram-negative bacterium Vibrio cholerae which causes of cholera is primarily found in warm brackish waters.

Infection can occur following eating or drinking contaminated food or water and disease can spread rapidly in areas with inadequate treatment of sewage and drinking water.

--IANS

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