Cholera, the Current Status of Cholera Vaccines and Recommendations for Travellers

Abstract

Cholera is endemic in approximately 50 countries, primarily in Africa and South and Southeast Asia, and in these areas, it remains a disease associated with poverty. In developed nations, cholera is rare, and cases are typically imported from endemic areas by returning travellers. Cholera is readily preventable with the tools available to modern medicine. In developing nations, cholera transmission can be prevented through improved water, sanitation, and hygiene services and the use of oral cholera vaccines (OCVs). For travellers, risk can be mitigated by practicing regular hand hygiene and consuming food and water from safe sources. OCVs should be considered for high-risk travellers likely to be exposed to cholera patients or contaminated water and food. There are currently three World Health Organization pre-qualified OCVs, which are based on killed whole-cell strains of Vibrio cholerae. These established vaccines offer significant protection in adults and children for up to 2 years. A novel live attenuated vaccine that provides rapid-onset protection in adults and children is licensed in the USA and Europe only. Live attenuated OCVs may mimic the natural infection of V. cholerae more closely, generating rapid immune responses without the need for repeat dosing. These potential benefits have prompted the ongoing development of several additional live attenuated vaccines. The objective of this article is to provide a general review of the current landscape of OCVs, including a discussion of their appropriate use in international travellers.

Travel vaccines throughout history

“…Currently, cholera remains endemic in areas of Africa, the Indian sub-continent (where V. cholerae O139 Bengal emerged), Southeast Asia, where it remains a disease associated with poverty and poor sanitation, and recently cholera cases have been reported in the Caribbean (Haiti and Dominican Republic) [ 24 ]. In developed countries cholera is extremely rare, and cases are traced to travelers returning from endemic areas [ 23 , 25 ]. At present, areas with active cholera transmission include African countries such as Benin, Cameroon, Democratic Republic of the Congo, Ethiopia, Kenya, Mozambique, Niger, Nigeria, Somalia and Uganda, and Asian countries such as Afghanistan, Bangladesh, India, Nepal, and Yemen.…”

“…Early work developing killed culture vaccines was reported by the Ukrainian physician Nikolay Gamaleya in 1888, while Waldemar Haffkine also described efforts with attenuated strains in 1892. The first licensed whole-cell oral cholera vaccine was developed at the University of Gothenburg, Sweden and was pre-qualified by the WHO in 2001 [ 25 ].…”

“…Currently several cholera vaccines developed with different techniques are available ( Table 1 ). These vaccines should be used in cholera-endemic areas, cholera outbreaks, and high-risk humanitarian crises in combination with other sanitation measures [ 24 , 25 , 29 , 30 ]. The oral cholera vaccines include the killed O1 whole-cell with B-subunit and the killed O1 and O139 vaccine [ [29] , [30] , [31] ].…”

Threats and outbreaks of cholera in Africa amidst COVID-19 pandemic: a double burden on Africa’s health systems

“…Cholera has caused havoc for centuries affecting almost every continent, currently with a higher incidence in developing countries, being associated with poverty [ 12 ]. As cholera remains a significant global public health concern, its occurrence is linked to insufficient access to safe water and proper sanitation.…”

CVD 103-HgR live, attenuated cholera vaccine strain viability in drinking waters from the US and Europe

“…Live vaccine strains, such as CVD 103-HgR have the advantage of producing a long-lasting immune response with a single dose by mimicking natural infection 5 , but they can also show greater susceptibility to factors such as temperature and components in the vaccine mixture 6 , including the water used for reconstitution. Here, we describe a study exploring the compatibility of the cholera CVD 103-HgR strain with drinking water from different sources in the United States (US) and Europe in order to better characterize the vaccine and to ensure that the full potency is administered to the patient.…”