Patient compliance in the use of Vivotif Berna(R) vaccine, typhoid vaccine, live oral Ty21a.

BACKGROUND

Several live attenuated vaccines against bacterial enteric pathogens have recently been licensed. These include the Salmonella typhi Ty21a typhoid vaccine (Vivotif Berna(R) Vaccine) and Vibrio cholerae CVD103-HgR cholera vaccine (Mutacol Berna(R) Vaccine). They comprise a unique class of biologics in which patient compliance is required for their optimal use. This is of particular importance in the case of the Ty21a vaccine strain of which multiple doses are required. Furthermore, exposure to heat, concomitant use with antibiotics or antimalarial drugs, and timing of vaccination with respect to food intake can affect vaccine potency and/or efficacy. This study was conducted to determine the level of compliance among adult North American travelers and to evaluate compliance errors with respect to potential vaccine efficacy.

METHOD

Questionnaires were provided to 1091 travelers at twelve travel clinics in the United States and Canada. The patients were requested to complete forms which asked questions relating to vaccine storage and usage, and to return them to the travel clinic. A total of 762 completed questionnaires were returned.

RESULTS

Few compliance errors were made regarding proper storage of the vaccine. The most common compliance errors involved not taking all four capsules on alternate days (10%) and not taking all four doses of vaccine prior to departure (6%).

CONCLUSIONS

Pretravel counselling was effective in obtaining a high compliance rate among adult travelers in the use of Vivotif Berna(R) Vaccine. The majority of compliance errors reported would not be expected to negatively impact upon vaccine efficacy.