Why do we not yet have a suitable vaccine against cholera?

The available options, past and present, of cholera vaccines have been summarized above. It is saddening but clear that, more than a century after the introduction of the first cholera vaccine, we still do not have available a suitable vaccine against cholera. The currently raging and expanding new epidemic of cholera in the Western hemisphere dramatically illustrates anew the need, although a new illustration is not necessary if one but considers the innumerable, but unnecessary, victims of cholera of the past which could have been prevented had a suitable vaccine been available earlier. Indeed, it should also be clear from this review that a suitable vaccine against cholera still eludes us and will for an additional period of time. Cholera, a disease of humans only, can be controlled by prevention of human to human transmission, i.e., by universal availability of appropriate sewage disposal and clean water--an expensive solution, but one which will also reduce the toll of the other diseases transmitted by the fecal-oral route. Short of this, we should not be diverted by less than a highly effective, and economical vaccine. The "bottleneck" resides in the difficulty of getting from the laboratory to the field: the essential, and most efficient, intermediate step being the testing of candidate vaccines in volunteers--laboratory animal models do not suffice. Cholera is now, especially under controlled conditions, a perfectly treatable disease. Additional volunteer centers, and studies in volunteers, are essential to the solution of the cholera problem in the near future.(ABSTRACT TRUNCATED AT 250 WORDS)