models and various human organ cultures (fallopian tube, cervix) will allow reasonable testing of vaccine components before extensive human trials are considered. It is too early to speculate on the odds of creating an effective vaccine or when it will be available, but the pace and excellence of the research effort offer significant promise of a vaccine, possibly in five to ten years.
Of the existing vaccine candidates the common binding domain of pili and protein I appear promising. Both deserve human volunteer trials, and possibly field trials. Civilian field trials are expensive and only a few will be possible for financial and other reasons. Trials in military populations are generally less expensive. Choices of antigens for field testing (made difficult by the paucity of animal models for the disease) should be made carefully.
Several of the newly described antigens (P.H.8, possibly FeRPs, and others) could be important. An effective vaccine may be composed of multiple antigens. Decisions concerning major field trials could be delayed until new information on antibody responses to several of the less well characterized antigens is available. This postponement could result in a field trial that demonstrates efficacy of a gonococcal vaccine.
Many of the concepts developed in the past decade of intense research on the gonococcus are relevant to other organisms (e.g., meningococci and Hemophilus influenzae); lessons learned in pursuit of a gonococcal vaccine may have significant impact on efforts to develop other bacterial vaccines.
Predictions on the further development of vaccines for N. gonorrhoeae appear in Chapter 5.
The health belief model parameters (perceptions of risk of illness, severity, vaccination benefits, and barriers) used to predict vaccine utilization are described in Chapter 6, where scores assigned to various vaccines are displayed together to ease comparison.
To judge the likely acceptance of a gonococcal vaccine, it was assumed that parental attitudes would predominate for potential recipients in their mid-teens. Perception of risk of the disease was thought to be low. Severity also was ranked low because most individuals believe that the disease is easy to treat and are ignorant about the consequences of PID. Benefits would be recognized as reasonably high, especially with possible physician cueing about PID, but barriers (cost, parental unwillingness to admit that their children might be sexually active, and number of doses) also would be reasonably high.