Table 8 lists an overview of adverse reactions to vaccines. In the past 5 years, active research has led to the licensing of several new vaccines and to clinical trials of several others. Hepatitis B subunit vaccine and the new human diploid rabies vaccine have been released for commercial use. An improved and unique live, attenuated oral Salmonella typhi vaccine is under active clinical trials in the Mideast and other areas and has shown great promise. Vaccines under development include a gonorrhea vaccine, an oral live H. influenzae type b vaccine, a Pseudomonas aeruginosa vaccine, and a group B streptococcal vaccine. Vaccines for varicella zoster, cytomegalovirus, herpes simplex, respiratory syncytical virus, and hepatitis A viruses are all undergoing clinical evaluations at the present time in an effort to speed these very useful materials to target populations. Adverse reactions to vaccinations will continue to occur and it is important for the allergist-immunologist to be aware of these potentially serious reactions as well as their clinical management.