17D yellow fever vaccines: new insights. A report of a workshop held during the World Congress on medicine and health in the tropics, Marseille, France, Monday 12 September 2005

Yellow fever (YF) is a major health problem in endemic regions of Africa and South America. It also poses a serious health risk to travellers to areas with endemic disease. Currently, there is no effective drug treatment for YF; however, 17D YF vaccines have demonstrated high rates of effectiveness and good safety profiles. This workshop was organized to review key data and issues about YF disease and currently available 17D YF vaccines. Starting with an overview of the current disease epidemiology in Africa and South America and a review of the safety data of 17D YF vaccines, data were then presented demonstrating the genetic stability of multiple production lots of a 17D YF vaccine, the immunological responses of healthy subjects post-vaccination and the long-term immunogenicity of 17D YF vaccines. Finally, the findings of the molecular characterization of 17D YF virus sub-strains recovered from rare, fatal cases of post-vaccination serious adverse events were presented. There was unanimous agreement that current 17D YF vaccines have a highly favourable benefit-risk profile when used in persons at risk of exposure to the YF virus, and that appropriate use of 17D YF vaccines will minimize the occurrence of serious adverse events post-vaccination.     

Clostridium difficile vaccine and serum immunoglobulin G antibody response to toxin A

There is a strong association between serum antibody responses to toxin A and protection against Clostridium difficile diarrhea. A parenteral C. difficile toxoid vaccine induced very-high-level responses to anti-toxin A immunoglobulin G (IgG) in the sera of healthy volunteers. After vaccination, the concentrations of anti-toxin A IgG in the sera of all 30 recipients exceeded the concentrations that were associated with protection in previous clinical studies. Furthermore, the median concentration of serum anti-toxin A IgG in the test group was 50-fold higher than the previous threshold. These findings support the feasibility of using a vaccine to protect high-risk individuals against C. difficile-associated diarrhea and colitis.     

Patients’ preference for radiotherapy fractionation schedule in the palliation of symptomatic unresectable lung cancer†

The palliative radiotherapeutic management of unresectable non‐small‐cell lung cancer is controversial, with various fractionation (Fx) schedules available. We aimed to determine patient’s choice of Fx schedule after involvement in a decision‐making process using a decision board. A decision board outlining the various advantages and disadvantages apparent in the Medical Research Council study of Fx schedules (17 Gy in two fractions vs 39 Gy in 13 fractions) was discussed with patients who met Medical Research Council eligibility criteria. Patients were then asked to indicate their preferred Fx schedules, reasons and their level of satisfaction with being involved in the decision‐making process. Radiation oncologists (RO) could prescribe radiotherapy schedules irrespective of patients’ preferences. Of 92 patients enrolled, 55% chose the longer schedule. English‐speaking patients were significantly more likely to choose the longer schedule (P = 0.02, 95% confidence interval: 1.2–7.6). Longer Fx was chosen because of longer survival (90%) and better local control (12%). Shorter Fx was chosen for shorter overall treatment duration (80%), cost (61%) and better symptom control (20%). In all, 56% of patients choosing the shorter schedule had their treatment altered by the treating RO, whereas only 4% of patients choosing longer Fx had their treatment altered (P < 0.001). Despite this, all (100%) patients were satisfied with being involved in the decision‐making process. The decision board was useful in aiding decision‐making, with both Fx schedules being acceptable to patients. Interestingly, despite the longer average survival associated with longer Fx, nearly half of the patients believed that this was not as important as a shorter duration of treatment and lower cost. Despite patients’ preferences, there were significant alterations of preferred schedules because of RO’s own biases.