This letter is in response to ‘Boost in availability of oral cholera vaccines is a potential game changer in the global fight against cholera’ in the November 2017 issue of The Pharmaceutical Journal.
The author has weighted the article towards the production of a more transportable vaccine that will assist the World Health Organization in reaching its 2030 target of eliminating cholera. Although we should always applaud the new ideas, there is also a need to consider what could be done right now to help reach this goal.
Currently, there is one UK-licensed cholera vaccine (Dukoral, Valneva) that will provide efficacy up to a maximum of only 70%. In addition, this vaccine is licensed in other countries (Canada and New Zealand) as a pharmacy medicine bought to tackle enterotoxigenic Escherichia coli — an organism that can induce traveller’s diarrhoea (TD). Any new vaccine should be measured against this one, to provide an indication of improved benefit.
The article mentions the current use of the mnemonic WASH (water, sanitation and hygiene). Further reductions in cholera and TD could come from travellers being better informed before travel of the level of risk in the visiting country and having had an emphasis on how to purify water and improve personal hygiene to limit the levels of cross-infection. This can be started with the current technology and could only enhance the new vaccines being produced.
Many studies have highlighted that TD experienced abroad is mainly of bacterial origin (up to 80%). Further studies on returning travellers have shown that 40% will have to change their itinerary; 20% will spend 1–2 days in bed, and 1% will be admitted to hospital. Therefore, raising awareness during a risk assessment is a precursor to limiting risky behaviours.
The measurable clinical outcomes highlighted above do not include the psychological impact on a patient. An illness experienced abroad is not treatable in the same way as on the NHS — there is an increased cost of completion of insurance claim forms; cultural differences; and language barriers, all of which raise the levels of concern and cost in time and financial outlay.
In conclusion, the principle of more transportable vaccines and world eradication by 2030 is ambitious. Until these vaccines can be produced and supplied, the healthcare professional can help realise the target by emphasising the standards of hygiene required; highlighting the levels of risk to the traveller and using the existing vaccine for both licensed and unlicensed use.
Derek Evans
Independent consultant and prescriber in travel medicine
